Brake caliper intermittent sticking - ?piston leaking fluid

[PistonAFC]

Hi guys,

I noticed my rear nearside brake is sticking intermittently. I am a novice but thought it's probably caliper pins stuck so I take the wheel off and see this...




Looks like piston has a load of dirt / gunk / brake dust on it ... or do you think it looks like brake fluid has leaked and then stuff has stuck to it ?? Sorry I didn't take a better picture.



These Pagid (from Eurocarparts) brake pads have only been on the rear of the car ~30k miles, I replaced the front ones at the same time and they have around 7mm left and are in good condition.

Thanks

Edited by PistonAFC on Sunday 26th July 13:29

[rustednut]

Cant see the piston area of the caliper, where the fluid would leak from.

Clean everything up, reassemble, and then test/look.

Any fluid needed topping up? Any brake unevenness in operation?

Without more detail, can't really say much.

BUT, if in ANY doubt to fluid leakage at all. Replace the caliper.


ETA, if rear have worn out that quickly you definitely have a brake issue. I know pagid are not the best quality, but they should last much longer than the front.

I would suspect sticking caliper, overheating any grease that was on the back of the pad and allowing debris to stick to it.

Edited by rustednut on Sunday 26th July 13:32

[Chris32345]

Everything there is scrap
Discs pads and the probably the caliper if that's rust on the piston does it not have any rubber boot covering the piston?


Also I take it the brake havent been stripped and cleaned recently?
Because that's Far to much rust on the carrier's for things to work well

Edited by Chris32345 on Sunday 26th July 14:54

[GreenV8S]

rustednut said:

ETA, if rear have worn out that quickly you definitely have a brake issue.

I don't think 30k is a bad life for a set of pads - depending on the driving style and use they could wear much sooner than that.

[rustednut]

GreenV8S said:

I don't think 30k is a bad life for a set of pads - depending on the driving style and use they could wear much sooner than that.

Wasn't going on the mileage.

But he replaced fronts at the same time and still 7mm left on them. Are the fronts not working fully, or the rears overworking?

If fronts havent worn out and rears have, there is a brake issue of some sorts that needs to be sorted. 1st check is the operation (binding) of the rears, and looking at the condition in the pic it appears likely.

[PistonAFC]

rustednut said:

Cant see the piston area of the caliper, where the fluid would leak from.

Clean everything up, reassemble, and then test/look.

Any fluid needed topping up? Any brake unevenness in operation?

Without more detail, can't really say much.

BUT, if in ANY doubt to fluid leakage at all. Replace the caliper.


ETA, if rear have worn out that quickly you definitely have a brake issue. I know pagid are not the best quality, but they should last much longer than the front.

I would suspect sticking caliper, overheating any grease that was on the back of the pad and allowing debris to stick to it.

Edited by rustednut on Sunday 26th July 13:32

Actually I couldn't see any brake fluid or wetness, brakes work evenly (as far as I can tell), only reason I decided to open it was that almost every morning it feels like the caliper was stuck for a few seconds, and then I noticed the alloy was hot to touch. Looks like it fried itself before I noticed, I thought it was just calipers stuck in the morning (rust welding action) normal-ish stuff and would just require a bit of greasing up. I think you are right about the grease melting and sticking to the piston with the associated brake dust clumping around it.

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Quote:
Everything there is scrap
Discs pads and the probably the caliper if that's rust on the piston does it not have any rubber boot covering the piston?

---

I can't tell if there is rubber boot underneath the gunk, I opened it and promptly st myself as I thought I'd make it worse and the car would be un-drivable so closed it back up - additionally destroying one of the sliding pin dust covers - oops.

---

quote:
Also I take it the brake havent been stripped and cleaned recently?
Because that's Far to much rust on the carrier's for things to work well

---

Last time they were opened up was around 4 years ago I think the dust is from the pads being pulverized by the extreme heat so as a minimum I need pads which I bought.

---

quote:
I don't think 30k is a bad life for a set of pads - depending on the driving style and use they could wear much sooner than that.

---

old ones lasted 65k miles and I think there was still a few millimeters left on the back one so I definitely think the pads got cooked. I haven't opened up the other side but don't expect a problem.

The caliper slide pins were moving freely, so my thinking is the issue could be stuck piston, brake hose internal collapse preventing brake fluid being pulled back or most likely handbrake mechanism might be stuck on.

Edited by PistonAFC on Sunday 26th July 21:57

Edited by PistonAFC on Sunday 26th July 21:59