I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.
Thanks,
Eric

fired this volley in
:

The power loss has been gradual over
the years so I'm thinking it's probably the pump.


It could be. It could also be bypass leakage in cylinders, or a weakening
spring in a pressure relief valve.

You can check all that with a pressure gauge and some judicious tapping/re-
routing of a few lines.

Lloyd

wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.
Thanks,
Eric

Is it open or closed center hydraulics? Better machines will be closed
center and they will have variable displacement pumps, not basic gear
pumps. Step one is figure out what type of system you have, step two is
install a pressure gauge in the system and see what pressure you are
operating at. In an open center system you will only have pressure when
you operate an axis to it's limit, on a closed center system you will
have pressure all the time. An open center system will have a relief
valve that limits the max pressure and they can certainly develop weak
springs, debris causing leakage, etc. On a closed center system the
pressure setting is controlled in the pumps displacement control which
causes it to go out of stroke when the pressure limit is reached.
Factory manuals are a good thing to have, particularly on the more
complicated closed center systems.

wrote in message
...
I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power
of
the hydraulics has gotten weaker over the years. I used to be able
to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30
years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the
age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual
over
the years so I'm thinking it's probably the pump.
Thanks,
Eric

I bought a new pump from Bailey after fussing too long with the wrong
size of old Danfoss pump, which I had to regrind like you.
http://www.baileynet.com/#prodcat/Hy...type/Gear-Pump
Second on the pressure gauge, glycerin filled to damp the needle and
located where you can see but not break it. 4000 PSI should cover the
possibilities but not be too hard to read at half scale. I think
common pressures run around 2500 - 3000 or you could check the hose
rating.

"Jim Wilkins" wrote in message
...
...
Second on the pressure gauge, ...

I forgot to mention that the tee and adapters to add it must be rated
for hydraulics. Water pipe fittings aren't strong enough.
-jsw

On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to

Ya, a guage wouldn't hurt to verify what you already know, the pump is
wore out. beware old Case parts must have thick gold plating on them,
judging by what they ask for them. Repairing an old hoe can be a money
pit, BTDT. it might be time to send this one on down the road and shop
for another. that's what I'm doing right now, looking for a ford 555
(triple nickle)

On Thu, 12 Jun 2014 11:00:51 -0500, "Pete C."
wrote:


wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.
Thanks,
Eric

Is it open or closed center hydraulics? Better machines will be closed
center and they will have variable displacement pumps, not basic gear
pumps. Step one is figure out what type of system you have, step two is
install a pressure gauge in the system and see what pressure you are
operating at. In an open center system you will only have pressure when
you operate an axis to it's limit, on a closed center system you will
have pressure all the time. An open center system will have a relief
valve that limits the max pressure and they can certainly develop weak
springs, debris causing leakage, etc. On a closed center system the
pressure setting is controlled in the pumps displacement control which
causes it to go out of stroke when the pressure limit is reached.
Factory manuals are a good thing to have, particularly on the more
complicated closed center systems.
Greetings Pete,
I don't know if the thing is open or closed center. I'll try to find
out soon. I don't have a repair manual but I do have an operator
manual (I think) and some sort of parts manual.
Eric

On Thu, 12 Jun 2014 13:04:55 -0500, Karl Townsend
wrote:

On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to

Ya, a guage wouldn't hurt to verify what you already know, the pump is
wore out. beware old Case parts must have thick gold plating on them,
judging by what they ask for them. Repairing an old hoe can be a money
pit, BTDT. it might be time to send this one on down the road and shop
for another. that's what I'm doing right now, looking for a ford 555
(triple nickle)
I was talking to a friend of mine a few minutes ago and he said
grinding the end plates flat works pretty well to raise the pressure
some. But there will also be some wear around the periphery of the
gears that I can't fix. If I can figure out which pump the thing uses
I'm hoping to find one surplus. As far as the hoe being a money pit I
really haven't had to spend too much on it beyond the 5 grand I paid
for it. So three hundred to fix the hydraulics is probably OK. I
bought it to install my own septic system and saved about 9 grand over
the lowest bid I got for installing one. The County said it was one of
the best installations they had seen, they were actually talking about
me at the health dept. I had never even sat on a backhoe before I
bought it so that's why I don't know if it is closed or open center.
Eric

"Karl Townsend" wrote in message
...
On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of
abuse
before I bought it and I have used it pretty hard since. The power
of
the hydraulics has gotten weaker over the years. I used to be able
to

Ya, a guage wouldn't hurt to verify what you already know, the pump
is
wore out. beware old Case parts must have thick gold plating on
them,
judging by what they ask for them. Repairing an old hoe can be a
money
pit, BTDT. it might be time to send this one on down the road and
shop
for another. that's what I'm doing right now, looking for a ford 555
(triple nickle)

No wonder they are priced so low and easier to find. Is this printed
on calfskin vellum?
http://www.yesterdaystractors.com/CAP780CKTLB_2393.htm

On 6/12/2014 2:18 PM, Jim Wilkins wrote:
....

No wonder they are priced so low and easier to find. Is this printed
on calfskin vellum?
http://www.yesterdaystractors.com/CAP780CKTLB_2393.htm

http://partstore.casece.com/us/parts-search.html#epc::mr65628ag43840

--

Lower power output of pumps does happen due to wear. Pay to have it
rebuilt.

i

On 2014-06-12, wrote:
I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.
Thanks,
Eric

On Thu, 12 Jun 2014 14:49:13 -0500, Ignoramus32163
wrote:

Lower power output of pumps does happen due to wear. Pay to have it
rebuilt.
If oil is leaking past the gears then the pressure should drop, right?
Danfoss, who make hydraulic gear pumps agree with me. They say if the
pump pressure plates wear the pressure output will bw lower. And lower
pressure is the problem I am having.
Eric
i

On 2014-06-12, wrote:
I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.
Thanks,
Eric

wrote in message
...
On Thu, 12 Jun 2014 14:49:13 -0500, Ignoramus32163
wrote:

Lower power output of pumps does happen due to wear. Pay to have it
rebuilt.
If oil is leaking past the gears then the pressure should drop,
right?
Danfoss, who make hydraulic gear pumps agree with me. They say if
the
pump pressure plates wear the pressure output will bw lower. And
lower
pressure is the problem I am having.
Eric

This gives 2050 PSI:
http://www.casece.com/en_us/Gallery/...-26-2009_1.pdf

On Thu, 12 Jun 2014 11:00:51 -0500, "Pete C."
wrote:


wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.
Thanks,
Eric

Is it open or closed center hydraulics? Better machines will be closed
center and they will have variable displacement pumps, not basic gear
pumps. Step one is figure out what type of system you have, step two is
install a pressure gauge in the system and see what pressure you are
operating at. In an open center system you will only have pressure when
you operate an axis to it's limit, on a closed center system you will
have pressure all the time. An open center system will have a relief
valve that limits the max pressure and they can certainly develop weak
springs, debris causing leakage, etc. On a closed center system the
pressure setting is controlled in the pumps displacement control which
causes it to go out of stroke when the pressure limit is reached.
Factory manuals are a good thing to have, particularly on the more
complicated closed center systems.

FYI
http://www.coincollectorkings.com/tag/780ck
http://www.ebookily.org/pdf/allis-ch...anual-download
http://us.aolsearch.com/search?s_pt=...vice%20manuals


--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

On 2014-06-12, wrote:
On Thu, 12 Jun 2014 14:49:13 -0500, Ignoramus32163
wrote:

Lower power output of pumps does happen due to wear. Pay to have it
rebuilt.
If oil is leaking past the gears then the pressure should drop, right?
Danfoss, who make hydraulic gear pumps agree with me. They say if the
pump pressure plates wear the pressure output will bw lower. And lower
pressure is the problem I am having.

I recall reading a certain talmudic tome on hydraulics and they say
that neither having a high pressure, or high flow, alone, indicates
that the pump is not worn. Only loss of "power", which is pressure
multiplied by flow, is a good indicator that the pump is worn.

You have a hydraulic pressure gauge on your machine, right? Easy to
add one temporarily and see what the pressure does when the pump is
pumping a lot of fluid.

i

On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.

Don't overlook the pressure regulator, Eric. Maybe try a new spring
there to see if it puts the Oomph! back into it.

--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson

On Thu, 12 Jun 2014 19:30:23 -0500, Ignoramus32163
wrote:

On 2014-06-12, wrote:
On Thu, 12 Jun 2014 14:49:13 -0500, Ignoramus32163
wrote:

Lower power output of pumps does happen due to wear. Pay to have it
rebuilt.
If oil is leaking past the gears then the pressure should drop, right?
Danfoss, who make hydraulic gear pumps agree with me. They say if the
pump pressure plates wear the pressure output will bw lower. And lower
pressure is the problem I am having.

I recall reading a certain talmudic tome on hydraulics and they say
that neither having a high pressure, or high flow, alone, indicates
that the pump is not worn. Only loss of "power", which is pressure
multiplied by flow, is a good indicator that the pump is worn.

You have a hydraulic pressure gauge on your machine, right? Easy to
add one temporarily and see what the pressure does when the pump is
pumping a lot of fluid.

i
Some pumps, when worn, will not even produce rated pressure against a
closed valve, much less into a functioning system.

Larry Jaques wrote:
On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.

Don't overlook the pressure regulator, Eric. Maybe try a new spring
there to see if it puts the Oomph! back into it.

--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson

The Case uses a two stage pump, one stage for the front bucket and one
for the hoe. An easy way to check the pump is to curl the hoe see
what the engine does. If the rpm holds with little extra stress and the
govenor not cutting in too much you most likely have a bad pump. Do this
on both the how and the front bucket to check each section of the pump.
Also get the hydraulic oil tested and that will tell you if the pump
is worn out. It costa about15 bucks.

John

On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.
Thanks,
Eric


Any filters in this system? Like others have said check with a gauge
first, maybe see if the regulator is out of adjustment.

Disassemble pump and look first, then decide how to go. Unless you
depend on this machine for a livng, then get parts on hand first. Your
post hints at this is an ocassional use machine.

On my Ford 4000 tractor/back-hoe the power steering pump was shot, a
grand for a new one, still available though.... I put on a Buick
power steering pump off a FWD car. The inlet pointed the right way on
it. I worked way better than the worn out one. The end plates were
scored over 1/16" deep.

If you do service the pump put in all new fluid and clean the
reservoir out.

Remove 333 to reply.
Randy

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

On Thu, 12 Jun 2014 19:30:23 -0500, Ignoramus32163
wrote:

On 2014-06-12, wrote:
On Thu, 12 Jun 2014 14:49:13 -0500, Ignoramus32163
wrote:

Lower power output of pumps does happen due to wear. Pay to have it
rebuilt.
If oil is leaking past the gears then the pressure should drop, right?
Danfoss, who make hydraulic gear pumps agree with me. They say if the
pump pressure plates wear the pressure output will bw lower. And lower
pressure is the problem I am having.

I recall reading a certain talmudic tome on hydraulics and they say
that neither having a high pressure, or high flow, alone, indicates
that the pump is not worn. Only loss of "power", which is pressure
multiplied by flow, is a good indicator that the pump is worn.

You have a hydraulic pressure gauge on your machine, right? Easy to
add one temporarily and see what the pressure does when the pump is
pumping a lot of fluid.

i
I have lost power. The cylinders don't move as fast or pull as hard as
they used to. The machine does not have a pressure gauge for the
hydraulics that operate the how and loader. I think I know where to
put one now. But of course it's ****ing down rain here and I don't
have a place big enough to drive the backhoe into to work on it. Maybe
tomorrow I can fit a pressure gauge and see.
Eric

On Fri, 13 Jun 2014 00:45:51 -0400, John
wrote:

Larry Jaques wrote:
On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.

Don't overlook the pressure regulator, Eric. Maybe try a new spring
there to see if it puts the Oomph! back into it.

--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson

The Case uses a two stage pump, one stage for the front bucket and one
for the hoe. An easy way to check the pump is to curl the hoe see
what the engine does. If the rpm holds with little extra stress and the
govenor not cutting in too much you most likely have a bad pump. Do this
on both the how and the front bucket to check each section of the pump.
Also get the hydraulic oil tested and that will tell you if the pump
is worn out. It costa about15 bucks.

John
Thanks for the advice john. The engine behaves as described. I cannot
lug the engine too much by pulling or pushing too hard with the hoe. I
do not think however that the pump has different sections, one for the
hoe and the other for the front bucket. There is only one outlet from
the pump. It goes into the valve for the front bucket and from the
valve oil goes to the hoe.
Eric

wrote:

On Thu, 12 Jun 2014 19:30:23 -0500, Ignoramus32163
wrote:

On 2014-06-12, wrote:
On Thu, 12 Jun 2014 14:49:13 -0500, Ignoramus32163
wrote:

Lower power output of pumps does happen due to wear. Pay to have it
rebuilt.
If oil is leaking past the gears then the pressure should drop, right?
Danfoss, who make hydraulic gear pumps agree with me. They say if the
pump pressure plates wear the pressure output will bw lower. And lower
pressure is the problem I am having.

I recall reading a certain talmudic tome on hydraulics and they say
that neither having a high pressure, or high flow, alone, indicates
that the pump is not worn. Only loss of "power", which is pressure
multiplied by flow, is a good indicator that the pump is worn.

You have a hydraulic pressure gauge on your machine, right? Easy to
add one temporarily and see what the pressure does when the pump is
pumping a lot of fluid.

i
I have lost power. The cylinders don't move as fast or pull as hard as
they used to. The machine does not have a pressure gauge for the
hydraulics that operate the how and loader. I think I know where to
put one now. But of course it's ****ing down rain here and I don't
have a place big enough to drive the backhoe into to work on it. Maybe
tomorrow I can fit a pressure gauge and see.
Eric

Those EZ-Up tents are handy for working on stuff like tractors and
backhoes if you don't have a shop that can fit them. Put down a tarp,
drive the item onto it and then pop up the tent over the top.

wrote:

On Fri, 13 Jun 2014 00:45:51 -0400, John
wrote:

Larry Jaques wrote:
On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.

Don't overlook the pressure regulator, Eric. Maybe try a new spring
there to see if it puts the Oomph! back into it.

--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson

The Case uses a two stage pump, one stage for the front bucket and one
for the hoe. An easy way to check the pump is to curl the hoe see
what the engine does. If the rpm holds with little extra stress and the
govenor not cutting in too much you most likely have a bad pump. Do this
on both the how and the front bucket to check each section of the pump.
Also get the hydraulic oil tested and that will tell you if the pump
is worn out. It costa about15 bucks.

John
Thanks for the advice john. The engine behaves as described. I cannot
lug the engine too much by pulling or pushing too hard with the hoe. I
do not think however that the pump has different sections, one for the
hoe and the other for the front bucket. There is only one outlet from
the pump. It goes into the valve for the front bucket and from the
valve oil goes to the hoe.
Eric

Single pump, open center hydraulics. Not as high performance as a closed
center system, but much cheaper and simpler. You can probably replace
the pump entirely for a few hundred $. Of course before you replace the
pump be sure to check the relief valve since if that has an issue it's
like $25. I got a small tractor with loader that had poor hydraulic
performance and all I had to do was clean and readjust the relief valve
to fix it.

Single pump, open center hydraulics. Not as high performance as a closed
center system, but much cheaper and simpler. You can probably replace
the pump entirely for a few hundred $. Of course before you replace the
pump be sure to check the relief valve since if that has an issue it's
like $25. I got a small tractor with loader that had poor hydraulic
performance and all I had to do was clean and readjust the relief valve
to fix it.

Maybe I'm a pessimist, but I'd be prepared to drop $3K or don't start.
of course this is to get it back like new - rebuilt pump, new fluids,
new filters, new guage, relief valve, and a few other gotchas that
always come along (like hoses that will pop right away, cylinder seals
etc). I've repaired a LOT of tractors and the costs are always high.

Karl

"Karl Townsend" wrote in message
...

Single pump, open center hydraulics. Not as high performance as a
closed
center system, but much cheaper and simpler. You can probably
replace
the pump entirely for a few hundred $. Of course before you replace
the
pump be sure to check the relief valve since if that has an issue
it's
like $25. I got a small tractor with loader that had poor hydraulic
performance and all I had to do was clean and readjust the relief
valve
to fix it.

Maybe I'm a pessimist, but I'd be prepared to drop $3K or don't
start.
of course this is to get it back like new - rebuilt pump, new
fluids,
new filters, new guage, relief valve, and a few other gotchas that
always come along (like hoses that will pop right away, cylinder
seals
etc). I've repaired a LOT of tractors and the costs are always high.

Karl

Can you divide them into more and less unreasonable?

Does having machine tools generally help? I made or modified steel
parts for the pump, its drive, the relief valve, return manifold +
strainer and cylinders for my homebrew but I had to buy the new piston
seals and hoses and pressure-side fittings.
-jsw

On 2014-06-13, Karl Townsend wrote:

Single pump, open center hydraulics. Not as high performance as a closed
center system, but much cheaper and simpler. You can probably replace
the pump entirely for a few hundred $. Of course before you replace the
pump be sure to check the relief valve since if that has an issue it's
like $25. I got a small tractor with loader that had poor hydraulic
performance and all I had to do was clean and readjust the relief valve
to fix it.

Maybe I'm a pessimist, but I'd be prepared to drop $3K or don't start.
of course this is to get it back like new - rebuilt pump, new fluids,
new filters, new guage, relief valve, and a few other gotchas that
always come along (like hoses that will pop right away, cylinder seals
etc). I've repaired a LOT of tractors and the costs are always high.

Karl

Do it right, it is not that expensive.

i

On Fri, 13 Jun 2014 11:49:57 -0500, Karl Townsend
wrote:


Single pump, open center hydraulics. Not as high performance as a closed
center system, but much cheaper and simpler. You can probably replace
the pump entirely for a few hundred $. Of course before you replace the
pump be sure to check the relief valve since if that has an issue it's
like $25. I got a small tractor with loader that had poor hydraulic
performance and all I had to do was clean and readjust the relief valve
to fix it.

Maybe I'm a pessimist, but I'd be prepared to drop $3K or don't start.
of course this is to get it back like new - rebuilt pump, new fluids,
new filters, new guage, relief valve, and a few other gotchas that
always come along (like hoses that will pop right away, cylinder seals
etc). I've repaired a LOT of tractors and the costs are always high.

Karl
I am willing to replace the pump, filters, and any hoses. That will be
way less than 3000 frog pelts. I am not willing to drop 3 grand on the
thing though. If you saw it, and knew how much I used it, you would
understand.
Eric

On Thursday, June 12, 2014 11:42:50 AM UTC-4, wrote:
Over 30 years

ago I used to repair gear pumps in a lumbermill I worked in by

grinding the end plates of the pumps to remove scoring. But I don't

know how much more pressure the pumps put out after this repair, it

was just what I was told to do and I did it a lot. Considering the age

of the tractor I'm wondering if I might just be better off buying a

new pump and also if there is somwhere else I should look for the

lowered power of the hydraulics. The power loss has been gradual over

the years so I'm thinking it's probably the pump.

Thanks,

Eric

I have no experience, but figure whoever was in charge of the lumbermill did. So I would grind the end plates to remove the scoring and see if that improved it enough for the use you give it.

Dan

On 6/13/2014 1:43 PM, wrote:
....

I am willing to replace the pump, filters, and any hoses. That will be
way less than 3000 frog pelts. I am not willing to drop 3 grand on the
thing though. If you saw it, and knew how much I used it, you would
understand.

....

Why not? If it's otherwise in good shape, what would the replacement
cost be for something you wouldn't (likely) have any idea of whether it
was as good as the one you've got is?

I'd agree you should be able to get in and out for well under $3K, but
(again assuming you do have the need for (or just seriously want )
it, would seem will within the expected of reasonable maintenance costs
to me.

Sorta' like the old JLG 40H manlift I got off eBay for $5k when started
the barn re-roof...it's now been almost 15 yr and I've put about $2-3K
in it since, I'd guess w/o actually going back and looking at the actual
books. The biggest single expense was paying to have the master
cylinder rebuilt--it's a 20-ft long, 3" D(?) single-acting cylinder and
I have no facility on the place to be able to get it out of the boom.
Seems like the labor for it was about ~1200 iirc from the JD dealership
(including them sending the float out to pick it up and deliver it).
Pushed my luck and let a leaking head gasket go thinking we could finish
the south side of the barn and have it closed to weather first and so
ended up w/ a new head and pistons, etc., instead of just a gasket set
that was about $500 could have avoided... But, like you and your
'hoe, it's been so handy to have that wouldn't consider just junking it
over the cost.

Again, it depends on what one wants to do, and what on can live with.
Our local electric co-op runs a side business of repair work for
(primarily) truck lifts since they have so many of their own it keeps
their guys occupied when there isn't one of their own needing work.
They, being licensed and all, have to put everything back to
manufacturer's spec's so thinking I'd give them some business I checked
for the seals job on the lift. They cautioned me given the age it
likely would end up at $10k or more because of all the ancillary stuff
they'd see that would be out of spec...I'm comfortable it's safe as is
and do inspect the chains and so on for any signs of wear but the
manufacturer has a set of timed replacements or "replace all this if
touch any of that" to cover their liability.

--

On 2014-06-13, wrote:
I have already called a couple and their advice was to just buy a new
pump. I guess my pump is too small for them to consider. There is one
place I still need to try though. Actually, I did try them but the guy
I need to talk to is gone 'till Monday.
Eric

OK, buy a new pump, they are not super expensive if you need a small
one.

i

Where would I look for the relief valve? I mean on the machine.

Almost always, they're on the pump body or on the main lever valve body.

In either case, look for a large "cover nut"... a hex-housing about 1-1/4"
across the flats and about 2" tall. That cover hides and seals leaks from
the relief valve adjustment screw, which is usually a female hex socket
bolt/stud that you adjust with a large Allen wrench (seen a few slotted
ones, too).

LLoyd

wrote:
On Fri, 13 Jun 2014 00:45:51 -0400, John
wrote:

Larry Jaques wrote:
On Thu, 12 Jun 2014 08:42:50 -0700, wrote:

I have a mid 70s Case CK780 backhoe. The thing had seen lots of abuse
before I bought it and I have used it pretty hard since. The power of
the hydraulics has gotten weaker over the years. I used to be able to
kill the engine by trying to push or pull too hard. Now this doesn't
happen. So I'm thinking that the pump has a lot of wear. Over 30 years
ago I used to repair gear pumps in a lumbermill I worked in by
grinding the end plates of the pumps to remove scoring. But I don't
know how much more pressure the pumps put out after this repair, it
was just what I was told to do and I did it a lot. Considering the age
of the tractor I'm wondering if I might just be better off buying a
new pump and also if there is somwhere else I should look for the
lowered power of the hydraulics. The power loss has been gradual over
the years so I'm thinking it's probably the pump.

Don't overlook the pressure regulator, Eric. Maybe try a new spring
there to see if it puts the Oomph! back into it.

--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson

The Case uses a two stage pump, one stage for the front bucket and one
for the hoe. An easy way to check the pump is to curl the hoe see
what the engine does. If the rpm holds with little extra stress and the
govenor not cutting in too much you most likely have a bad pump. Do this
on both the how and the front bucket to check each section of the pump.
Also get the hydraulic oil tested and that will tell you if the pump
is worn out. It costa about15 bucks.

John
Thanks for the advice john. The engine behaves as described. I cannot
lug the engine too much by pulling or pushing too hard with the hoe. I
do not think however that the pump has different sections, one for the
hoe and the other for the front bucket. There is only one outlet from
the pump. It goes into the valve for the front bucket and from the
valve oil goes to the hoe.
Eric

I should have said it is a tandem hydraulic pump. The pump has two
sections one for the loader and one for the hoe. The pressure for the
one section is 2050 lb/sq in and the other pressure is 2250 . I ran
and owned a 680C for many years and yours is basically the same layout
but bigger.
John

"Carl Ijames" wrote in message
...
Eric, you are probably way ahead of this but Toro has some nice
basic instructional guides at
http://www.toro.com/customercare/com...ing/index.html,
including one on basic hydraulics. Nice explanations and cutaway
pictures of pumps, control valves, cylinders, etc., everything you
would find on a Toro mower. I saved that link from r.c.m several
years ago and have posted it a few times - don't know who the
original poster was but thank you :-).

-----
Regards,
Carl Ijames

That might have been me, the pump I was fussing with supposedly came
from Toro. I have it bookmarked to download if I visit someone with
broadband. The Vickers manual is also bookmarked but the link is now
broken.
http://forums.hydraulicspneumatics.c...1/m/8997006595

-jsw

The Vickers manual is also bookmarked but the link is now
broken.

Look in the Wayback Machine...

Example:

http://web.archive.org/web/*/http://cnn.com/
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

"David Lesher" wrote in message
...
The Vickers manual is also bookmarked but the link is now
broken.

Look in the Wayback Machine...


The goofy moose tells me they don't give it away on line any more.
http://www.amazon.com/Industrial-Hyd.../dp/0978802209

On 2014-06-14, Jim Wilkins wrote:
"David Lesher" wrote in message
...
The Vickers manual is also bookmarked but the link is now
broken.

Look in the Wayback Machine...


The goofy moose tells me they don't give it away on line any more.
http://www.amazon.com/Industrial-Hyd.../dp/0978802209

The "good guys" do give it away

http://igor.chudov.com/manuals/Vicke...ics-Manual.pdf

i

"Ignoramus30183" wrote in
message ...
On 2014-06-14, Jim Wilkins wrote:
"David Lesher" wrote in message
...
The Vickers manual is also bookmarked but the link is now
broken.

Look in the Wayback Machine...


The goofy moose tells me they don't give it away on line any more.
http://www.amazon.com/Industrial-Hyd.../dp/0978802209

The "good guys" do give it away


http://igor.chudov.com/manuals/Vicke...ics-Manual.pdf

i

Thanks, good guy.

Could you leave the server on overnight, since it will take 5 hours to
download 87MB on dialup?
-jsw

On Sat, 14 Jun 2014 18:24:25 -0400, "Jim Wilkins"
wrote:

"Ignoramus30183" wrote in
message ...
On 2014-06-14, Jim Wilkins wrote:
"David Lesher" wrote in message
...
The Vickers manual is also bookmarked but the link is now
broken.

Look in the Wayback Machine...


The goofy moose tells me they don't give it away on line any more.
http://www.amazon.com/Industrial-Hyd.../dp/0978802209

The "good guys" do give it away


http://igor.chudov.com/manuals/Vicke...ics-Manual.pdf

i

Thanks, good guy.

Could you leave the server on overnight, since it will take 5 hours to
download 87MB on dialup?
-jsw

It'll likely take 5 hours to get it off of Igor's "server"
regardless!!!

On 2014-06-14, Jim Wilkins wrote:
"Ignoramus30183" wrote in
message ...
On 2014-06-14, Jim Wilkins wrote:
"David Lesher" wrote in message
...
The Vickers manual is also bookmarked but the link is now
broken.

Look in the Wayback Machine...


The goofy moose tells me they don't give it away on line any more.
http://www.amazon.com/Industrial-Hyd.../dp/0978802209

The "good guys" do give it away


http://igor.chudov.com/manuals/Vicke...ics-Manual.pdf

i

Thanks, good guy.

Could you leave the server on overnight, since it will take 5 hours to
download 87MB on dialup?

I never shut it down.

i

On 2014-06-15, wrote:
On Sat, 14 Jun 2014 18:24:25 -0400, "Jim Wilkins"
wrote:

"Ignoramus30183" wrote in
message ...
On 2014-06-14, Jim Wilkins wrote:
"David Lesher" wrote in message
...
The Vickers manual is also bookmarked but the link is now
broken.

Look in the Wayback Machine...


The goofy moose tells me they don't give it away on line any more.
http://www.amazon.com/Industrial-Hyd.../dp/0978802209

The "good guys" do give it away


http://igor.chudov.com/manuals/Vicke...ics-Manual.pdf

i

Thanks, good guy.

Could you leave the server on overnight, since it will take 5 hours to
download 87MB on dialup?
-jsw

It'll likely take 5 hours to get it off of Igor's "server"
regardless!!!

What do you mean. It takes 1.5 minutes from another computer with
goodinternet connection.

i