Since I feel like I will be undertaking a potentially dangerous task, I

thought I would first ask the experts on this group. For replacing the

trailing arm on my car, I need to compress the coil spring. I have
already removed the shock absorber from the middle of the spring so
have room work inside the center of the spring.


I purchased a pair of external "hook type" compressors which are
designed to be used on each side of the spring but now I am having
second thoughts about using them. The hooks appear to made from cast
metal and do not appear to be drop forged steel. The width of the
hooks is also thinner than I would like and am concerned that one of
these hooks could crack under tension with disastrous results. For
this reason, I would feel alot safer making my own.


The idea I had would be to use a 10" piece of 5/8" allthread rod (the
kind normally found at Home Depot or Lowe's) and two 1/4" mild steel
plates with a center hole drilled slightly larger than 5/8". To use I
would feed the threaded rod up inside the middle of the coil (where the

shock used to go) through each one of the steel end plates secured with

nuts and washers. The diameter of the spring is approx. 4.5" and the
end plates would measure 2"x8" so there would be 1.75" of overhang on
each side of the coil. Would 5/8" rod be strong enough for this
application or would I be better off using 3/4" rod? Also is 1/4" mild

steel ok or do I need to use something thicker?


Thanks for your help.

"T.C. Mann" wrote: (clip) I purchased a pair of external "hook type"
compressors which are designed to be used on each side of the spring but now
I am having second thoughts about using them. (clip)
^^^^^^^^^^^^^^^^^
Chances are they will not break, but I can understand your well founded
concerns. How about using those hooks, along with some additional support
to prevent disaster? You could make a third hookset, or a drawbar for the
center of the spring like what you are describing. If you use the drawbar
along with the two sets of hooks, the load on the castings will be reduced,
and if worst came to worst, and a hook broke, the spring would still be
controlled.

This one raised the hair on the back of my neck!
The spring compressor you have is designed for Macpherson struts, which
have light springs than a non-strut vehicle. You want the kind that uses
a single large threaded rod, with strong hooks over the springs.

http://www.mytoolstore.com/kd/kdsusp01.html#3450

KD is a common brand available all over the US in most any parts store.
What is your life worth?

The homemade device you describe would not be adequate.

Rex B

T.C. Mann wrote:
Since I feel like I will be undertaking a potentially dangerous task, I

thought I would first ask the experts on this group. For replacing the

trailing arm on my car, I need to compress the coil spring. I have
already removed the shock absorber from the middle of the spring so
have room work inside the center of the spring.


I purchased a pair of external "hook type" compressors which are
designed to be used on each side of the spring but now I am having
second thoughts about using them. The hooks appear to made from cast
metal and do not appear to be drop forged steel. The width of the
hooks is also thinner than I would like and am concerned that one of
these hooks could crack under tension with disastrous results. For
this reason, I would feel alot safer making my own.


The idea I had would be to use a 10" piece of 5/8" allthread rod (the
kind normally found at Home Depot or Lowe's) and two 1/4" mild steel
plates with a center hole drilled slightly larger than 5/8". To use I
would feed the threaded rod up inside the middle of the coil (where the

shock used to go) through each one of the steel end plates secured with

nuts and washers. The diameter of the spring is approx. 4.5" and the
end plates would measure 2"x8" so there would be 1.75" of overhang on
each side of the coil. Would 5/8" rod be strong enough for this
application or would I be better off using 3/4" rod? Also is 1/4" mild

steel ok or do I need to use something thicker?


Thanks for your help.

In article , Rex B
writes
This one raised the hair on the back of my neck!

Pah! Youth of today...

Last time I did this[1], we used a jack in a shed doorway to compress
the spring, tying rope around it to keep it compressed. Several stages
were involved, with paving slabs being used as "shims" to get the
bomb^H^H^H^H spring to where we wanted it.

Then we installed it, and sent an idiot^H^H^H^H^H volunteer in with a
hacksaw to cut the rope.

It made quite an impressive bang when the last strand let go.

And the front end of the car did "fly" a bit. But only a bit.

The volunteer's laundry bill was the most costly bit of the whole
exercise.

(Nobody died, by the way).


[1] Long, long ago; in a Universe far, far away.

--
Nigel

When the only tools you have are a Bridgeport, a CNC Taig Mill, a Colchester
and assorted other stuff, every problem looks like a steam engine.

On 21 Apr 2005 08:57:09 -0700, the inscrutable "T.C. Mann"
spake:

Since I feel like I will be undertaking a potentially dangerous task, I

thought I would first ask the experts on this group. For replacing the

trailing arm on my car, I need to compress the coil spring. I have
already removed the shock absorber from the middle of the spring so
have room work inside the center of the spring.


I purchased a pair of external "hook type" compressors which are
designed to be used on each side of the spring but now I am having
second thoughts about using them. The hooks appear to made from cast
metal and do not appear to be drop forged steel. The width of the
hooks is also thinner than I would like and am concerned that one of
these hooks could crack under tension with disastrous results. For
this reason, I would feel alot safer making my own.

I always wondered about the safety when using those professionally.
Since I was at a body shop, I grabbed a section of cable and ran it
through the coil, securing it to the control arm/diff so it couldn't
act like a projectile when I had it under full tension. The cheapy
compressors never did break, but I had a couple slip sideways on me.
The 1/4" wire rope with 2 clamps contained it every time, breaking the
tension so the loose coil just dropped limply.

I'd be more leery of a handmade unit unless you have the gear and time
to do it right. Give the commercial unit the proper respect and she'll
treat you right, I'll bet.


================================================== =======
What doesn't kill you + http://diversify.com
....makes you hurt more. + Web application programming
================================================== =======

"Rex B" wrote:
This one raised the hair on the back of my neck!
The spring compressor you have is designed for Macpherson struts, which
have light springs than a non-strut vehicle. You want the kind that uses
a single large threaded rod, with strong hooks over the springs.

http://www.mytoolstore.com/kd/kdsusp01.html#3450

KD is a common brand available all over the US in most any parts store.
What is your life worth?

The homemade device you describe would not be adequate.

FWIW, you can often rent these from your local rental shop - it's pretty
cheap and the right way to do it.. Definitely don't use strut compressors.

Jon

I recall years ago, when I was a youthful delivery guy for a parts
store. I entered one shop with an armful of struts and shocks. Struts
were relatively new at the time. I found the shop owner attending to a
strut assembly w/coil spring, clamped by it's lower end in a vise. The
spring coils were compressed and held that way with several rounds of
baling wire. I asked what he was doing.
"Changing the struts. Bobby over there (indicating large person) sat on
the fender, and I got under and wrapped this wire".
As he spoke, he was using a pair of diagonal cutters to snip the wire,
one at a time. I suggested he sign the ticket so I could get the hell
outa there.

Returning later that day, I asked if he had finished the strut
replacement.

"Sure did. You shoulda seen that spring when it came loose! It shot
all the way across the shop and back, hit the floor, then the roof, and
finally bounced under the bench. Cleared the shop floor in a hurry!"

It's a wonder we're alive.

- -
Rex Burkheimer
WM Automotive
Fort Worth TX

Nigel Eaton wrote:
In article , Rex B
writes

This one raised the hair on the back of my neck!


Pah! Youth of today...

Last time I did this[1], we used a jack in a shed doorway to compress
the spring, tying rope around it to keep it compressed. Several stages
were involved, with paving slabs being used as "shims" to get the
bomb^H^H^H^H spring to where we wanted it.

Then we installed it, and sent an idiot^H^H^H^H^H volunteer in with a
hacksaw to cut the rope.

It made quite an impressive bang when the last strand let go.

And the front end of the car did "fly" a bit. But only a bit.

The volunteer's laundry bill was the most costly bit of the whole exercise.

(Nobody died, by the way).


[1] Long, long ago; in a Universe far, far away.

Jon Danniken wrote:
"Rex B" wrote:

This one raised the hair on the back of my neck!
The spring compressor you have is designed for Macpherson struts, which
have light springs than a non-strut vehicle. You want the kind that uses
a single large threaded rod, with strong hooks over the springs.

http://www.mytoolstore.com/kd/kdsusp01.html#3450

KD is a common brand available all over the US in most any parts store.
What is your life worth?

The homemade device you describe would not be adequate.


FWIW, you can often rent these from your local rental shop - it's pretty
cheap and the right way to do it.. Definitely don't use strut compressors.

Good point. And Zone probably rents them for free.

A few years ago I had to do some work on my old Renault Fuego that required
removing the front springs. I couldn't get a normal spring compressor in
there, so jury rigged something up from all-thread. Got the first spring
compressed, removed the lower support arm, and as I was sitting there,
crosslegged on the floor, I noticed that the hooks I'd used were slowly
straightening out.

I just had time to throw myself backward then the thing let go and the
spring shot downward at a very high rate of speed (it had only been hanging
up in the tower by rust, something I didn't appreciate at the time). It
bounced off the concrete garage floor and headed out of the wheel arch
upward just as fast, past my face just in front of my nose. I don't know
how I did it, but the next thing I knew I had grabbed it as it went by and
was holding it by the last coil while it went "boiiiiiiiiiiiiing" in my
hand. Weighed about six pounds and had really been moving. Talk about
lucky (and stupid, etc.)!

My wife, who had been sitting on a stool nearby watching, had eyes as big as
saucers. Neither of us got hurt and there was no damage, but I sure got an
increased respect for the energy stored in 6" coil springs, both as
potential energy or converted to kinetic energy! Had I not caught it, it
would have bounced around the garage off both cars, us, and who knows what
else. Be very, very careful.

--
Bob (Chief Pilot, White Knuckle Airways)


"Rex B" wrote in message
...
snip


[1] Long, long ago; in a Universe far, far away.

In article , Rex B
writes
(Snip)

It's a wonder we're alive.

G Isn't it?

Mind you, I think the "war stories" are going to be a bunch more boring
in the futu

"I once opened a can of paint - *without a respirator*!"

"Woahhh!"

--
Nigel

When the only tools you have are a Bridgeport, a CNC Taig Mill, a Colchester
and assorted other stuff, every problem looks like a steam engine.