17 replies to this topic

[Jase_MK]

I've searched but not turned up anything useful... OK, I've noticed within the last couple of hundred miles that the car is pulling ever so slightly to the right. Even if there's a slight left camber on the road, it will still drift right slightly. Sometimes though, it doesn't do it at all. I've not hit anything or done anything to suggest that the geo would have changed at all. Then a few days ago I noticed that the right hand side of the car was totally black whereas the left side only had a mild sprinkling of dirt - so I'm thinking that perhaps the right front caliper is sticking slightly and caking the side of the car in Mintex 1144. Great So then, anyone got any thoughts on how best to proceed with this? I don't really want to soak the caliper in WD40 for obvious reasons. Pads out and push the piston back and forth a few times? I also managed to totally tear off my left turbo chin spoiler yesterday which will do wonders for my high speed stability and pulling-to-the-right problem, no doubt Someone stop me from trading it for a repmobile, please! I can't be arsed anymore.

[djegiant]

I've searched but not turned up anything useful...

OK, I've noticed within the last couple of hundred miles that the car is pulling ever so slightly to the right. Even if there's a slight left camber on the road, it will still drift right slightly. Sometimes though, it doesn't do it at all. I've not hit anything or done anything to suggest that the geo would have changed at all.

Then a few days ago I noticed that the right hand side of the car was totally black whereas the left side only had a mild sprinkling of dirt - so I'm thinking that perhaps the right front caliper is sticking slightly and caking the side of the car in Mintex 1144.

Great

So then, anyone got any thoughts on how best to proceed with this? I don't really want to soak the caliper in WD40 for obvious reasons. Pads out and push the piston back and forth a few times?

I also managed to totally tear off my left turbo chin spoiler yesterday which will do wonders for my high speed stability and pulling-to-the-right problem, no doubt

Someone stop me from trading it for a repmobile, please! I can't be arsed anymore.

Tyre pressures?
Go for a good drive then check wheel temps. Surefire way of checking for a sticking caliper!
Pushing pistons in would only drag more dirt into the seals and increase your problem!
Pistons will probably require cleaning, then lubing with light sillicone grease (be sure to wipe off excess as it attracts dirt!)
HTH

[djegiant]

Group buy on splitters in for sale and wanted if ya need a new set!

[Jase_MK]

Tyre pressures was the first thing I checked. Sorry, forgot to mention that. I did try to feel the temps of the wheels when I got home the other day but they all felt warm as I'd been braking quite a lot (Milton Keynes!) - I guess I need to take the car for a drive for a few miles and try not to use the brakes too much, then feel. Thanks!

[Jase_MK]

Group buy on splitters in for sale and wanted if ya need a new set!

The splitter is fine (I picked it up) - just need new rivets.

[djegiant]

Group buy on splitters in for sale and wanted if ya need a new set! 

The splitter is fine (I picked it up) - just need new rivets.

Bugger!
Trying my best to recruit people! - SOOOO impatient.
Hope ya sort the brake prob!
PS- Rep mobile=
summer is nearly here just live with it till then- gotta be worth it!!!

[Garf]

Before you go panicing about new calipers, reconing one etc etc. It could be dirt on the guides..... Guessing a bit here as I haven't ever taken a caliper of a Vauxhall let alone a VX. However a few times on other makes of cars the rubber seals around these guides have gone allowing dirt in and stopping the brakes releasing. They tend to be a bit more exposed and die first as opposed to the seals on the piston itself. Hope this helps

[djegiant]

Before you go panicing about new calipers, reconing one etc etc. It could be dirt on the guides..... Guessing a bit here as I haven't ever taken a caliper of a Vauxhall let alone a VX. However a few times on other makes of cars the rubber seals around these guides have gone allowing dirt in and stopping the brakes releasing. They tend to be a bit more exposed and die first as opposed to the seals on the piston itself.

Hope this helps

No sliders (guides) on VX fron AP calipers!
They are an opposing piston type caliper!

[dunky]

See how freely the wheel rotates. If it doesn't inspect to see why. Try cleaning up the dirt using dry methods (scrape, brush, w/wool etc). keeping anything off the pad faces Unlikely to be the piston sticking unless the seal or piston are damaged which you can usually see. Any oil or WD 40 can end up on the pad faces or getting a bit smoky with the heat.

[djegiant]

See how freely the wheel rotates. If it doesn't inspect to see why.

Try cleaning up the dirt using dry methods (scrape, brush, w/wool etc). keeping anything off the pad faces

Unlikely to be the piston sticking unless the seal or piston are damaged which you can usually see.

Any oil or WD 40 can end up on the pad faces or getting a bit smoky with the heat.

Sticking caliper problems can be totally undetectable when thecar is jacked up and wheel rotation is checked!
The gradual heat build up in slightly binding pads will.......(you know the rest! )
Thi piston sticking (no matter the cause.) is the only reason one caliper would stick on!
Best bet is to get it to a garage for a professional check! Not worth fcukin about with brakes! Rather important!
Dry piston cleaning methods are far more likely to damage the piston (especialy if teflon coated!) and there is no chance of pad contamination due to the fact that the pads need removing to gain proper access to pistons!
Sorry guys but there seems to be lots of bad technical advice given out on this site at times!

[JG]

I posted something about this a few months ago The quality of the cylinders within the front front brake calipers is a bit rubbish, as dunky says, jack the car up and spins the wheels. If they do not rotate freely, then i suggest the following: -Remove pads -replace with very worn ones -reassemble -press as hard as you can on the brake pedal, This lubricates the side walls of the cylinder/caliper. -remove old pads -reassemble with new/the pads you had. It should sort your problem out Another way of detecting sticky calipers is to let the car come to a halt freely at say 10-25mph, if it does so faster than you think is correct then you probably have binding brakes HTH

Edited by JamesGray, 09 January 2006 - 04:50 PM.

[Jase_MK]

Cheers James, something tangible I can try there. I'll give it a go at the weekend - wish the evenings were light.

[djegiant]

I-press as hard as you can on the brake pedal, This lubricates the side walls of the cylinder/caliper.

How?

[JG]

The reason you get binding brakes is that the piston within the caliper does not actually move that much during general use. It relies on a thin film of brake fluid between the two surfaces. If the brakes get very hot, you can burn that film off, causing a lack of lubricant. By allowing the piston to move out with the old pads, the brake fluid coats the inner wall of the caliper. As the piston it pushed back allowing for the extra thickness of prake pad the lubricant is replaced.

[Garf]

LOL shows how much I know about the brakes on a VX As an addition to above abiut slowing down without braking. If the car lurches as it comes to a stop when no brake is applied that shows up a binding brake too. I guess that will not be so pronouced on the VX as other cars though.

[djegiant]

The reason you get binding brakes is that the piston within the caliper does not actually move that much during general use. It relies on a thin film of brake fluid between the two surfaces. If the brakes get very hot, you can burn that film off, causing a lack of lubricant.

By allowing the piston to move out with the old pads, the brake fluid coats the inner wall of the caliper. As the piston it pushed back allowing for the extra thickness of prake pad the lubricant is replaced.

The inner wall of the caliper and the inner surfaces of the piston and seal are in a brake fluid resevoir in itself and is always coated with fluid!
If fluid was able to permeate the flat inner lip of the seal (to lubricate it.) then it would constantly weep. Also with the hydroscopic properties of brake fluid surely air would be able to travel the other way!
The only reason for pumping the piston partialy out of the caliper would be to clean it, apply a suitable lube and replace the piston!
Trust me- I have spent many years rebuilding motorcycle calipers (very similar design to the APs.).
Another cause for sticking worthy of note is aluminium oxidisation behind the caliper seals. This has the effect of tightening the seals and restricting the retraction of the piston, thus causing light binding which in turn generates heat further increasing the unwanted pad-disc contact and so on!
So many variables!

[dunky]

Sticking caliper problems can be totally undetectable when thecar is jacked up and wheel rotation is checked!
CAN be, also CAN be found.

The gradual heat build up in slightly binding pads will.......(you know the rest! )
Nothing to stop you jacking it up whilst it is still hot to check rotation, woudln't start any further inspection until it was cool though

The piston sticking (no matter the cause.) is the only reason one caliper would stick on!
Might be the only reason the caliper would stick, but not the only reason the brakes would bind. If the pins are in poor condition the pad can stick on the pin and stay in contact with the disc when the caliper is released. If his car is covered in brake dust perhaps the caliper is more likely as there is not much brake pressure off a sticking pin.

Best bet is to get it to a garage for a professional check! Not worth fcukin about with brakes! Rather important!
Have to agree if you don't feel confident and competent. I have done hundreds of thousands of miles on brakes I have replaced, fixed, serviced, etc and I haven't killed myself - yet.

Dry piston cleaning methods are far more likely to damage the piston (especialy if teflon coated!) and there is no chance of pad contamination due to the fact that the pads need removing to gain proper access to pistons!

I was thinking of cleaning the pins, pads, caliper area not the piston - but I was not explicit. Spraying W.D. 40 does not risk contaminating pads?

[Pidgeon]

I have only rarely seen sticking pistons and then in old cars that are rarely used, but to free a sticking piston, remove pads, carefully pump the piston out, then push fully home. Repeat a few times and they should be free.