deep fried brake calipers

L

lw395

Well-Known Member
Joined
16 May 2007
Messages
41,941
Visit site
Just had a problem with my car.
Rear brake seems to have seized partly on.
Result very hot wheel and a bit of brake fade.
I.e. needed to pump the pedal slightly to stop.
I guess it got hot enough to either boil water that was in the fluid or boil the fluid itself?
The little plastic cap on the bleed nipple is melted.
Or I assume that lump of snot used to be a plastic cap.....

Is likely that the caliper seals are knackered? Does not seem to be leaking, but should I get a new caliper, new seals or what?
Looks like some grease has escaped from the rear hub, but not much.
I guess the fluid should be changed.

I hate cars sometimes.

Edit
B@@ger, how can I move this to the lounge?
 
Had similar on the front.
Due to sliding caliper not sliding I think.

Overhauling the caliper or simply replacing it may be wise, although I did not.

Bleeding that brake may be wise to get rid of any affected fluid.

I'd re grease the bearing if there is evidence that the grease has overheated. I didn't.

The pads will probably have to be replaced as the friction material is likely to become detached from the back plate.

In my case it may have been the cause of a brake disc cracking right across.
 
whats the car ???? I had similar on a VW on the rear. turned out to be that the handbrake lever on the caliper had seized. knackered my bearings too
 
It's a Citroen C5.
The handbrake must work on the front wheels.
Good job I don't do handbrake turns in this car....
Everything seems normal now, but the smell of burnt friction material lingers.
I thought the clutch was going at first.
I think I will clean it up and stick new pads in, unless the rubber bits look bad.
I will change the fluid as well.
 
I would take the calipers off to find out why they seized in the first place. Solve that, then replace the seals because if the brake fluid boiled the seals have gone beyond their operating temperature (and some!). Having done those jobs you will have automatically replaced the fluid that has been overheated. Brakes are a terribly important bit of a car: not somethng to compromise on.
 
trapezeartist said:
I would take the calipers off to find out why they seized in the first place. Solve that, then replace the seals because if the brake fluid boiled the seals have gone beyond their operating temperature (and some!). Having done those jobs you will have automatically replaced the fluid that has been overheated. Brakes are a terribly important bit of a car: not somethng to compromise on.
Click to expand...

I suspect that the water in the fluid boiled, not the fluid itself, but you are right, I will check the seals out carefully.
Looks like a new caliper is a good option, £60 vs £25 for a seal kit, and less labour to fit.
Thanks.
 
Well done. Excellent riposte to those forumites who persist in posting boaty stuff in the Lounge.

BTW "a bit of brake fade" is not as serious as has been suggested. New calipers? Just make sure they are freed off. They'll be OK. Anyone who drove spiritedly in the '70s and '80s knows brake fade as an old friend.
 
There is nothing particularly special about brake calipers.

It's most likely that the wear/slide mechanism needs to be de-rubbished and then have brake grease (copperslip) applied.

Less likely is a bit of corrosion on a piston.

Either way, buy new seals, strip and inspect. A bit of piston corrosion can be removed with 400 grit, then 800.

Any boiled fluid will be replaced when you bleed, so I wouldn't bother with a total change unless it is due. (And then you must).
 
Just as a FYI: I had similar on a Volvo rear and ( an old experienced mechanic, not I) traced it to a collapsed rubber brake hose that prevented the brake from retracting. A fiver. So if the problem persists on the refitted test drive....?
 
boguing said:
There is nothing particularly special about brake calipers.

It's most likely that the wear/slide mechanism needs to be de-rubbished and then have brake grease (copperslip) applied.

Less likely is a bit of corrosion on a piston.

Either way, buy new seals, strip and inspect. A bit of piston corrosion can be removed with 400 grit, then 800.

Any boiled fluid will be replaced when you bleed, so I wouldn't bother with a total change unless it is due. (And then you must).
Click to expand...

A note of caution.Dont let "copperslip" antwhere near the sliding bits or the pistons as it rots the seals and rubbers.You need red rubber grease for those bits.
 
Biggles Wader said:
A note of caution.Dont let "copperslip" antwhere near the sliding bits or the pistons as it rots the seals and rubbers.You need red rubber grease for those bits.
Click to expand...

What? I said the sliding bits of the wear mechanism should be copperslipped, and you say not?

I'd agree that you shouldn't use it on seals or rubbers, but why on earth would you?
 
Dont think we disagree.I was just pointing out to be careful where copperslip goes.Ive known of several people putting on the pistons where it can contaminate the seals causing the pistons to stick
 
For £60 replace the calliper if the original is sticking, you will need pads as well and check the disc, often it is worn when this happens. If it has stuck once the thing will do it again, they don't self repair! If you have water in the fluid that needs replaced, presumably it hasn't been changed for a few years. Sounds like you have roasted the bearing too, that will likely fail and need replaced at some point soon. Unlikely you will be able to strip clean and re grease unless they are taper bearings.
Copper grease is ok on the pad edges but not on any rubber, the sliding part often has pins that slide in rubber, use proper rubber grease there not copper grease as it will cause problems, the rubber can swell and stick.
 
The rear brakes on small cars do virtually no work at all, particularly if you drive normally only using a fraction of the cars braking potential. For this reason corrosion and seizing up of rear brake components is common place. Rear brake discs will almost always need replacing through corrosion rather than wear.

Now the bit which makes it worthy of a post on here. Cars driven by boaters are even more likely to suffer rear brake issues if they dip the rear wheels in water (especially the sea) when launching and recovering boats.

Have the car looked at properly. It sounds like a new calliper is required if the brake nipple rubber cover has melted. It also sounds like a new hub bearing is required. The discs and pads can be assessed visually. If they need changing then do so as a pair on your rear axel (I know you haven't actually got a rear axel but figuratively speaking).

Finally change the brake fluid. It should be changed anyway every 2-4 years. Brake fluid is hydroscopic ie it attracts and soaks up water which has a lower boiling point than the brake fluid. This encourages air production and brake fade.

There have been a few posts along the lines of, "all it needs is a quick this or that, back in the day we used to get brake fade all the time and it was fine." If you hit my daughter in your car as she crossed the road because your brakes had been knowingly poorly maintained and when you stood on them the pedal went to the floor I would beat your head with my fists until it looked like spaghetti bolognase. I don't give a rat's arse if you choose to drive round in a death trap risking your life. The problem is you need to think of all the other people out there. Not just motorists.

Sorry if the last bit sounds a bit harsh or patronising but the brake components on your car aren't expensive. There is no need to take the risk.

Henry :)
 
Last edited:
You must log in or register to reply here.

Share this page

Top