I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres
and wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?
--
Bill

"Bill" wrote in message
...
I may be about to buy, from a scrapyard, a set of 5 replacement wheels for
the recently purchased car to get a spare wheel, proper sized tyres and
wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture was
that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain vehicle
had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel tapping,
that can detect this sort of rot?

I have found them to leak and the seal goes at the rim ......

On 01/10/2017 19:06, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres
and wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?

Paint them well before the tyres are fitted, they will probably be fine.
Testing would cost more than a new wheel.

On 01/10/2017 19:23, Retro Futurist ... wrote:
"Bill" wrote in message
...
I may be about to buy, from a scrapyard, a set of 5 replacement wheels for
the recently purchased car to get a spare wheel, proper sized tyres and
wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture was
that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain vehicle
had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel tapping,
that can detect this sort of rot?

I have found them to leak and the seal goes at the rim ......



That's just happened to me, 57 plate Zafira with 61k miles. NSR very
slow leak, taking a couple of weeks to lose more than a few psi. Fixed
at the local tyre place by cleaning the rim and applying fresh sealer.
Two months ago; so far, so good.

--
Peter

In message , MrCheerful
writes
On 01/10/2017 19:06, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement
wheels for the recently purchased car to get a spare wheel, proper
sized tyres and wheels that fit the wheel nuts.
In the past, I've often been told that the reason for a slow
puncture was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.
I have always wondered whether this is a standard get-rid-of-him
phrase taught as part of the Car Mechanics PhD (Hons) course, or
whether alloy does actually start to leak.
Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?

Paint them well before the tyres are fitted, they will probably be
fine. Testing would cost more than a new wheel.

When you say paint, what with and inside or outside the wheel? Or is
this referring to painting the edges, or more, with sealant.

Sorry if this is a stupid question, but I'm just learning how little I
know about wheels and tyres.
--
Bill

Bill laid this down on his screen :
When you say paint, what with and inside or outside the wheel? Or is this
referring to painting the edges, or more, with sealant.

No point to adding it to the outside, it needs to be inside. The
problem with alloy rims, is that the salt and water corrodes the alloy,
causing a poor seal to develop between tyre and wheel rim. The
corrosion needs to be cleaned off down to bare metal, then the bare
metal painted to protect it.

On 01/10/2017 19:33, Ramsman wrote:


I have found them to leak and the seal goes at the rim ......



That's just happened to me, 57 plate Zafira with 61k miles. NSR very
slow leak, taking a couple of weeks to lose more than a few psi. Fixed
at the local tyre place by cleaning the rim and applying fresh sealer.
Two months ago; so far, so good.


The annoying thing is that you can't fit an inner tube to the things.

On 01/10/2017 20:15, Harry Bloomfield wrote:
Bill laid this down on his screen :
When you say paint, what with and inside or outside the wheel? Or is
this referring to painting the edges, or more, with sealant.

No point to adding it to the outside, it needs to be inside. The problem
with alloy rims, is that the salt and water corrodes the alloy, causing
a poor seal to develop between tyre and wheel rim. The corrosion needs
to be cleaned off down to bare metal, then the bare metal painted to
protect it.

There are plenty of places that will refurbish wheels to better than
new, but it is not cheap and takes a few days or so. One of my
customers had his Lexus wheels refurbed because they leaked extensively
and they were fine afterwards, iirc it was about 200 for all five.

For my wheels I strip the tyre, clean the inner rim up, and use a belt
sander on the important seal area around the edge, then spray them with
etch primer, then some silver wheel paint, works fine, even if you miss
out the etch primer.

On 01/10/2017 20:37, MrCheerful wrote:
There are plenty of places that will refurbish wheels to better than
new, but it is not cheap and takes a few days or so.* One of my
customers had his Lexus wheels refurbed because they leaked extensively
and they were fine afterwards, iirc it was about 200 for all five.

Mine were done by Toyota on a recall when the car was a year or so old.
They lasted over 10 years, and then started to leak on the rims. I had
them redone, and they are bubbling in places only 4 years later.

Andy

On 01/10/2017 20:37, MrCheerful wrote:
On 01/10/2017 20:15, Harry Bloomfield wrote:
Bill laid this down on his screen :
When you say paint, what with and inside or outside the wheel? Or is
this referring to painting the edges, or more, with sealant.

No point to adding it to the outside, it needs to be inside. The
problem with alloy rims, is that the salt and water corrodes the
alloy, causing a poor seal to develop between tyre and wheel rim. The
corrosion needs to be cleaned off down to bare metal, then the bare
metal painted to protect it.

There are plenty of places that will refurbish wheels to better than
new, but it is not cheap and takes a few days or so.* One of my
customers had his Lexus wheels refurbed because they leaked extensively
and they were fine afterwards, iirc it was about 200 for all five.

For my wheels I strip the tyre, clean the inner rim up, and use a belt
sander on the important seal area around the edge, then spray them with
etch primer, then some silver wheel paint, works fine, even if you miss
out the etch primer.

+1

When I was at university, my father used to edit the magazine "Paint
Technology". I used to write all my exam revision notes on his galley
proofs (fan-fold paper, about 5 inches wide, very convenient for
summarising key points). Towards the end of my professional career, I
found myself approving contracts placed with the Paint Research
Association at Teddington, which had been one of his very regular
stamping grounds.

On 01-Oct-17 7:06 PM, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres
and wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?

Porosity is something that will have been there from manufacture. Over
time the pores can open up and then it leaks.

Cylinder head would have to be removed and pressure tested. Though just
running something like steel seal will cure most pinholes.

Wheels you will never find the pore, just paint the inside of the rim.
It seems that epoxy is not longer considered to be best but some sort of
acrylic.

Royal Enfield couldn't cast a non-porous crankcase with integral oil
tank for the 250 Crusader to save their lives. They all had yellow paint
on the inside to stop the oil leaking out.

On 01/10/2017 19:33, Ramsman wrote:
On 01/10/2017 19:23, Retro Futurist ... wrote:
"Bill" wrote in message
...
I may be about to buy, from a scrapyard, a set of 5 replacement
wheels for
the recently purchased car to get a spare wheel, proper sized tyres and
wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was
that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle
had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping,
that can detect this sort of rot?

I have found them to leak and the seal goes at the rim ......



That's just happened to me, 57 plate Zafira with 61k miles. NSR very
slow leak, taking a couple of weeks to lose more than a few psi. Fixed
at the local tyre place by cleaning the rim and applying fresh sealer.
Two months ago; so far, so good.


+1. I have a very good local tyre place and he knew by the wheel (2007
Audi) that the inner rim had likely corroded slightly and leaked.
Cleaned it 6 months ago and it's needed no air in that time.

--
Cheers, Rob

On 01/10/2017 19:06, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres
and wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?

I think the cylinder problem and the wheel problem are different. Alloy
wheels are normally varnished or painted to prevent corrosion. But
flexing of the tyre against the seat area can remove the coating. The
crevice between the tyre and the rim is then more liable to corrosion
from water and, especially, salt during the winter. The alloy becomes
pitted, leaving a leak path. The greasy lubricant used when new tyres
are fitted can help prevent this, but once you have pits the only real
solution is to to remove them by abrasion, and to "paint" the metal
surface to prevent further corrosion before the tyre is re-fitted.
Decent tyre suppliers should be able to sort this out.

On Sunday, 1 October 2017 19:06:37 UTC+1, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres
and wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?
--
Bill

Alloy wheels are laquered inside to get over this problem.

On Sun, 01 Oct 2017 22:54:06 -0700, harry wrote:

On Sunday, 1 October 2017 19:06:37 UTC+1, Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres
and wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?
--
Bill

Alloy wheels are laquered inside to get over this problem.

Until the lacquer flakes off (as it did on my 5 year old car). I ended up
getting all of the wheels skimmed and re-lacquered.



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

Well castings can be p porous, and normally they used to be Xrayed to show
this up, but I've not heard of it happening later without the start of these
issues being there to start with. Seems to be yet another cost cutting
method, but really how old are they?
brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Bill" wrote in message
...
I may be about to buy, from a scrapyard, a set of 5 replacement wheels for
the recently purchased car to get a spare wheel, proper sized tyres and
wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture was
that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain vehicle
had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel tapping,
that can detect this sort of rot?
--
Bill

In article ,
Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres
and wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?

Alloy wheels are generally painted (or coated with something similar to
paint). If the paint is damaged where the tyre meets the rim they are more
likely to leak. As they will often corrode where the paint is damaged.

--
*When cheese gets its picture taken, what does it say? *

Dave Plowman London SW
To e-mail, change noise into sound.

On 01/10/2017 20:22, Ade wrote:
On 01/10/2017 19:33, Ramsman wrote:


I have found them to leak and the seal goes at the rim ......



That's just happened to me, 57 plate Zafira with 61k miles. NSR very
slow leak, taking a couple of weeks to lose more than a few psi. Fixed
at the local tyre place by cleaning the rim and applying fresh sealer.
Two months ago; so far, so good.


The annoying thing is that you can't fit an inner tube to the things.


Why not?

--
Michael Chare

Dave Plowman (News) wrote:
In article ,
Bill wrote:
I may be about to buy, from a scrapyard, a set of 5 replacement wheels
for the recently purchased car to get a spare wheel, proper sized tyres
and wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture
was that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain
vehicle had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel
tapping, that can detect this sort of rot?

Alloy wheels are generally painted (or coated with something similar to
paint). If the paint is damaged where the tyre meets the rim they are more
likely to leak. As they will often corrode where the paint is damaged.


I have some that got scratched by some weights that were crimped around
the rim, instead of glued, like they seem to be now; and this is where
they have corroded and now leak slowly.

In article ,
Bill wrote:
I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Just the usual meja ********. If alloy really did go porous, your engine
would soon be scrap. Given pistons are made of alloy and have been for
many a year as is much else on a modern engine. And the pressure inside a
cylinder is far higher than in a tyre.

If a steel wheel is rusty where the tyre meets it, that will leak too.

--
*Is it true that cannibals don't eat clowns because they taste funny?

Dave Plowman London SW
To e-mail, change noise into sound.

Michael Chare wrote:

[...]

The annoying thing is that you can't fit an inner tube to the things.


Why not?

You can't use inner tubes with most tyres now, regardless of wheel type.

The inside of the tyre is not smooth enough, plus the tube shape isn't
designed for the low profiles currently in vogue.

Chris

--
Remove prejudice to reply.

Dave Plowman (News) wrote:
In article ,
Bill wrote:
I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Just the usual meja ********. If alloy really did go porous, your engine
would soon be scrap. Given pistons are made of alloy and have been for
many a year as is much else on a modern engine. And the pressure inside a
cylinder is far higher than in a tyre.

If a steel wheel is rusty where the tyre meets it, that will leak too.


ISTR way back when I was a lad, that some Norton crankcases were found
to be porous. They had to paint the inside with something-or-other to
stop them leaking.

On Mon, 2 Oct 2017 11:28:06 +0100, "Dan S. MacAbre"
wrote:



Just the usual meja ********. If alloy really did go porous, your engine
would soon be scrap. Given pistons are made of alloy and have been for
many a year as is much else on a modern engine. And the pressure inside a
cylinder is far higher than in a tyre.

While I may actually agree with the gist of your argument how many
tyres are repressurized a thousand or more times a minute.

G.Harman

On Monday, 2 October 2017 11:37:37 UTC+1, wrote:
On Mon, 2 Oct 2017 11:28:06 +0100, "Dan S. MacAbre"
wrote:



Just the usual meja ********. If alloy really did go porous, your engine
would soon be scrap. Given pistons are made of alloy and have been for
many a year as is much else on a modern engine. And the pressure inside a
cylinder is far higher than in a tyre.

While I may actually agree with the gist of your argument how many
tyres are repressurized a thousand or more times a minute.

G.Harman

With alloy engine parts, the holes/pores soon block with dirt/carbon particles. In any event any leakage is made up in the next fraction of a second. Which doesn't happen with wheels.

In article ,
harry wrote:
On Monday, 2 October 2017 11:37:37 UTC+1, wrote:
On Mon, 2 Oct 2017 11:28:06 +0100, "Dan S. MacAbre"
wrote:



Just the usual meja ********. If alloy really did go porous, your
engine would soon be scrap. Given pistons are made of alloy and
have been for many a year as is much else on a modern engine. And
the pressure inside a cylinder is far higher than in a tyre.

While I may actually agree with the gist of your argument how many
tyres are repressurized a thousand or more times a minute.

G.Harman

With alloy engine parts, the holes/pores soon block with dirt/carbon
particles.

You have carbon/dirt in your cooling system? In which case something is
porous.


In any event any leakage is made up in the next fraction of a second.
Which doesn't happen with wheels.

No it doesn't. But I'd love to hear of a wheel which was genuinely porous,
rather than just a poor seal between tyre and rim.

And somehow I doubt you've ever changed a tyre yourself.

--
*If a pig loses its voice, is it disgruntled?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
says...


And somehow I doubt you've ever changed a tyre yourself.

An immigrant does it for him

On 02/10/2017 11:15, Dave Plowman (News) wrote:
In article ,
Bill wrote:
I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Just the usual meja ********. If alloy really did go porous, your engine
would soon be scrap. Given pistons are made of alloy and have been for
many a year as is much else on a modern engine. And the pressure inside a
cylinder is far higher than in a tyre.

If my pistons lose 0.1% of the gas on every stroke I won't notice. They
are typically running about 25 power strokes a second. If my tyre lost
0.1% of its contents every 25th of a second I think I'd notice...

If a steel wheel is rusty where the tyre meets it, that will leak too.


Agree there.

Andy

In article ,
Vir Campestris wrote:
On 02/10/2017 11:15, Dave Plowman (News) wrote:
In article ,
Bill wrote:
I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Just the usual meja ********. If alloy really did go porous, your engine
would soon be scrap. Given pistons are made of alloy and have been for
many a year as is much else on a modern engine. And the pressure inside a
cylinder is far higher than in a tyre.

If my pistons lose 0.1% of the gas on every stroke I won't notice. They
are typically running about 25 power strokes a second. If my tyre lost
0.1% of its contents every 25th of a second I think I'd notice...

How about the cooling system often made of alloy these days. If that were
porous, it wouldn't hold pressure.

If a steel wheel is rusty where the tyre meets it, that will leak too.


Agree there.

Andy

--
*Shin: a device for finding furniture in the dark *

Dave Plowman London SW
To e-mail, change noise into sound.

On 03-Oct-17 11:36 PM, Dave Plowman (News) wrote:
In article ,
Vir Campestris wrote:
On 02/10/2017 11:15, Dave Plowman (News) wrote:
In article ,
Bill wrote:
I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Just the usual meja ********. If alloy really did go porous, your engine
would soon be scrap. Given pistons are made of alloy and have been for
many a year as is much else on a modern engine. And the pressure inside a
cylinder is far higher than in a tyre.

If my pistons lose 0.1% of the gas on every stroke I won't notice. They
are typically running about 25 power strokes a second. If my tyre lost
0.1% of its contents every 25th of a second I think I'd notice...

How about the cooling system often made of alloy these days. If that were
porous, it wouldn't hold pressure.


The tubes of an alloy radiator are wrought and not cast. The process
that makes the tubes compacts the alloy, distorts the crystal grain
structure and removes (most) porosity.

Casting process can entrain gas and that results porosity. So cast
blocks and heads can be porous but drawn tubes and rolled sheet won't be
porous. In part the thicker walls of castings prevent porosity as all
the holes have to line up and join up for it to leak.

Aero grade alloys for large cast structures (jet engine intercase) are
vacuum melted to remove gas and vacuum cast. They can still suffer from
strain induced porosity, where voids open up between the crystal grain.
Unlike a crack that will go though a grain.

In article ,
Peter Hill wrote:
How about the cooling system often made of alloy these days. If that
were porous, it wouldn't hold pressure.


The tubes of an alloy radiator are wrought and not cast. The process
that makes the tubes compacts the alloy, distorts the crystal grain
structure and removes (most) porosity.

But loads of the rest of the engine, cast. Many engines these days have an
alloy block and heads.

--
*Filthy stinking rich -- well, two out of three ain't bad

Dave Plowman London SW
To e-mail, change noise into sound.

On Tuesday, 3 October 2017 11:02:25 UTC+1, Dave Plowman (News) wrote:
In article ,
harry wrote:
On Monday, 2 October 2017 11:37:37 UTC+1, wrote:
On Mon, 2 Oct 2017 11:28:06 +0100, "Dan S. MacAbre"
wrote:



Just the usual meja ********. If alloy really did go porous, your
engine would soon be scrap. Given pistons are made of alloy and
have been for many a year as is much else on a modern engine. And
the pressure inside a cylinder is far higher than in a tyre.

While I may actually agree with the gist of your argument how many
tyres are repressurized a thousand or more times a minute.

G.Harman

With alloy engine parts, the holes/pores soon block with dirt/carbon
particles.

You have carbon/dirt in your cooling system? In which case something is
porous.


In any event any leakage is made up in the next fraction of a second.
Which doesn't happen with wheels.

No it doesn't. But I'd love to hear of a wheel which was genuinely porous,
rather than just a poor seal between tyre and rim.

And somehow I doubt you've ever changed a tyre yourself.

I have built cars from the ground up.
How a bout you?

In article ,
harry wrote:
And somehow I doubt you've ever changed a tyre yourself.

I have built cars from the ground up.

That I very much doubt.

How a bout you?

Very well, thanks.

--
*You're never too old to learn something stupid.
Dave Plowman London SW
To e-mail, change noise into sound.

On 01/10/2017 20:37, MrCheerful wrote:
On 01/10/2017 20:15, Harry Bloomfield wrote:
Bill laid this down on his screen :
When you say paint, what with and inside or outside the wheel? Or is
this referring to painting the edges, or more, with sealant.

No point to adding it to the outside, it needs to be inside. The
problem with alloy rims, is that the salt and water corrodes the
alloy, causing a poor seal to develop between tyre and wheel rim. The
corrosion needs to be cleaned off down to bare metal, then the bare
metal painted to protect it.

There are plenty of places that will refurbish wheels to better than
new, but it is not cheap and takes a few days or so.* One of my
customers had his Lexus wheels refurbed because they leaked extensively
and they were fine afterwards, iirc it was about 200 for all five.

For my wheels I strip the tyre, clean the inner rim up, and use a belt
sander on the important seal area around the edge, then spray them with
etch primer, then some silver wheel paint, works fine, even if you miss
out the etch primer.

Can you see the corrosion if you take the tyre off. i.e. is it obvious
to repair.


--
Michael Chare

On 08/10/2017 20:33, Michael Chare wrote:
On 01/10/2017 20:37, MrCheerful wrote:
On 01/10/2017 20:15, Harry Bloomfield wrote:
Bill laid this down on his screen :
When you say paint, what with and inside or outside the wheel? Or is
this referring to painting the edges, or more, with sealant.

No point to adding it to the outside, it needs to be inside. The
problem with alloy rims, is that the salt and water corrodes the
alloy, causing a poor seal to develop between tyre and wheel rim. The
corrosion needs to be cleaned off down to bare metal, then the bare
metal painted to protect it.

There are plenty of places that will refurbish wheels to better than
new, but it is not cheap and takes a few days or so.* One of my
customers had his Lexus wheels refurbed because they leaked
extensively and they were fine afterwards, iirc it was about 200 for
all five.

For my wheels I strip the tyre, clean the inner rim up, and use a belt
sander on the important seal area around the edge, then spray them
with etch primer, then some silver wheel paint, works fine, even if
you miss out the etch primer.

Can you see the corrosion if you take the tyre off. i.e. is it obvious
to repair.




yes, but I would usually put detergent around the tyre first to confirm
the leaking side/area.

On Sunday, 1 October 2017 19:23:23 UTC+1, Retro Futurist ... wrote:
"Bill" wrote in message
...
I may be about to buy, from a scrapyard, a set of 5 replacement wheels for
the recently purchased car to get a spare wheel, proper sized tyres and
wheels that fit the wheel nuts.

In the past, I've often been told that the reason for a slow puncture was
that the alloy wheels had gone porous.
More recently, I've been told that the cylinder head on a certain vehicle
had gone porous and that was why it chuffed when cold.

I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Does anyone know? Is there any sort of standard test, like wheel tapping,
that can detect this sort of rot?

I have found them to leak and the seal goes at the rim ......

I had mine resealed they just spun them on a jig then applied some magic to the milled surface and they were excellent afterwards. 20 quid.

On Sunday, 1 October 2017 20:15:20 UTC+1, Harry Bloomfield wrote:
Bill laid this down on his screen :
When you say paint, what with and inside or outside the wheel? Or is this
referring to painting the edges, or more, with sealant.

No point to adding it to the outside, it needs to be inside. The
problem with alloy rims, is that the salt and water corrodes the alloy,
causing a poor seal to develop between tyre and wheel rim. The
corrosion needs to be cleaned off down to bare metal, then the bare
metal painted to protect it.

I doubt that is the problem as the tryes need to be leaking to allow ingress.

In article ,
Weatherlawyer wrote:
I have found them to leak and the seal goes at the rim ......

I had mine resealed they just spun them on a jig then applied some magic to the milled surface and they were excellent afterwards. 20 quid.

They seem to use some form of sealer these days. I was having two new
tyres fitted to the old car when the fitter took a phone call after
applying it to one wheel. And was on the phone for ages. He didn't apply
more, and that tyre leaked. The other OK. Had it re-done and it was fine.

--
*If Barbie is so popular, why do you have to buy her friends? *

Dave Plowman London SW
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