rear caliper failure.

[Guest SantaFeRider]

Today, I realized my rear brake was not working. I stopped the bike (a 2002 V-11 Le Mans) and saw that brake fluid had leaked from inside the caliper, damaging, of course, the beautiful gold anodizing on the rotor and the paint on the caliper side of the wheel.

 

Have you heard of this kind of failure before? Normally, brake manufacturers are utterly cautious about stuff like this, but it seems to me that the seal had failed.

 

I have not taken off the caliper yet, and injected compressed air to remove the pistons, but my question is:

 

Is this thing rebuildable or do I need to purchase a new caliper?

 

What can be done about the cosmetics? Has the wheel to be totally repainted or just retouched? What about the rotor?

 

I'd like the bike restored to its original appearance.

[guzzijack]

Some info on these threads:

 

Brembo Rear Caliper Thread

 

Hot Brake Caliper Thread

 

and a useful modification while your in the mood

 

Brake mod

 

If you find a seal kit let us know the outcome

 

GJ

[Guest SantaFeRider]

Some info on these threads:

 

Brembo Rear Caliper Thread

 

Hot Brake Caliper Thread

 

and a useful modification while your in the mood

 

Brake mod

 

If you find a seal kit let us know the outcome

 

GJ

 

 

Thanks.

 

First thing I looked for was blueing of the rotor, but such isn't evident.

 

I did ride, however, for the first time since ownership, the bike in the middle of a vile thunderstorm for about 50 miles two weeks ago, and I didn't spray clean the brakes. I was not aware such was needed.

 

If I run my finger over the left side of the wheel, where the fluid dripped, a very grainy deposit is evident along the whole circumference of the wheel. I didn't know what to attribute this, but your links mention accumulation of road grime...

 

It seems that purchasing a new caliper is what I have to do...

 

Who has one and how much?

[Guest ratchethack]

FWIW, I just did some further tracking down of Brembo parts. GuzziJack has had this thing nailed from his first posts on the topic.

 

This appears to be a potentially serious situation just waiting to develop as more and more of these things mature and fail over time, Gents!

 

I can only conclude from the relatively low number of problems with these to date that these brakes are fairly durable and trouble-free long-term, and that the "frontbottom" mounting position and associated impossibility to bleed them in place is only a forerunner of the far more serious problem to come, when more of 'em start to croak due to inevitable neglect -- and just from normal ageing. . .

 

Brembo has OBSOLETED the P32B Gold Line stock-issue V11 rear caliper, P/N 20.4532.70, but shows a seal P/N 120.2799.30 for it, which has NOT been obsoleted.

 

Their parts lists shows a replacement caliper P/N 20.5185.10, but seals for it are not supplied by Brembo, and are not identified!!

 

I had previously INCORRECTLY referred to these calipers as F04 in posts at links above. THIS IS INCORRECT. Mea Culpa! My only excuse for this is dain bramage from getting me bell rung a few too many times immediately after parting company with dirt bikes at speeds far far -- WAY too far -- beyond reasonable in me younger days. I've corrected my posts at the links above. My apologies for any confusion. The correct caliper model designation is P32B, as Jack has posted previously.

 

Ducati, Aprilia, and KTM, among other moto OEMs, as well as Kart OEMs (as Jack pointed out) have also used the P32B caliper, so there may be used spares about.

 

T.A.W. Vehicle Concepts links Brembo parts tables at their site here:

 

http://www.tawvehicle.com/brembo_P32B_P32F_P105.htm

[guzzijack]

As a further update to things rear brakery:

 

David Wye over on the COG list has informed me that he has obtained some upgraded rear brake pads and is very pleased with the results - he does a lot of fully loaded two-up travelling on his Centauro and wanted some extra bite.

 

The guy he dealt with was mentioned in the previous threads and is also doing rock-bottom price deals on Brembo at the moment IanERacing. Price for the Brembo rear caliper from him was less than 50% of the best price elsewhere!

 

Ratch, can you check the replacement P/N for the Brembo caliper - IanE shows it as 20.5185.11 - only one digit out but it might make a difference

 

Cheers

 

GJ

[Guest ratchethack]

Jack, the replacement caliper P/N at the link above -- on Brembo's own parts table -- is 20.5185.10.

[Tom M]

SantaFe,

Before you buy a new or used caliper you should remove, clean & inspect yours. If you're lucky you may just have some crud in the seal causing your leak.

 

I use the brake lever to pump pistons out of calipers because my compressor sucks.

[Ballabio Bertie]

SantaFe,

Before you buy a new or used caliper you should remove, clean & inspect yours. If you're lucky you may just have some crud in the seal causing your leak.

 

I use the brake lever to pump pistons out of calipers because my compressor sucks.

Err,thats not a compressor,its a vacuum cleaner......

[Guest SantaFeRider]

ok, here is my take on this:

 

I will not buy a used caliper, or even a new one with the part number that has been discontinued, because no rebuild kits are available for it, so, if this happens again, I'll be back buying another caliper.

 

I will buy the caliper with the new part numbers, because rebuild kits are available for it.

 

I called TAW, and they don't have this particular caliper in stock , but I have to call back in an hour to see if they can get me one.

 

I will do as Tom says, and remove the caliper, clean it, see if the seals are damaged, refill the reservoir with fluid and pump it to see if it holds.

 

The Gold anodized on the rotor is shot. The paint, I still don't know; there is a lot of grime stuck to it and I need to find somethning to clean it with, before I can really take a look.

 

I'll let you guys know.

[Tom M]

Err,thats not a compressor,its a vacuum cleaner......

 

I walked right into that one didn't I?

[Guest SantaFeRider]

I really don't use the rear brake much, but I did use it to take some load out of the front when riding in the thunderstorm; however, you can qualify it as light use because I didn't want to lock the rear wheel.

 

I finally extracted the caliper and it looked like this:

 

 

and the pads like this:

 

 

I could only extract one of the pads, the other is welded to the piston.

 

I need a new caliper.

 

I also noticed when I separated the brake line from the caliper, the nut holding the line was quite loose; maybe - just maybe - the initial fluid loss came from there and then created havoc.

[dlaing]

I also noticed when I separated the brake line from the caliper, the nut holding the line was quite loose; maybe - just maybe - the initial fluid loss came from there and then created havoc.

Yep, I would not trust rebuilding that caliper.

But as to the cause, I would most likely blame dirty or damaged seals and not a loose fluid line.

Glad it did not cause an accident.

[Guest ratchethack]

I finally extracted the caliper and it looked like this:

 

 

and the pads like this:

 

 

I could only extract one of the pads, the other is welded to the piston.

Um, I'm no brake expert, (Where's Dan?) and this is a little hard to analyze from the photo's, but I use the same Ferodo pads, and have changed them out many times, so I'm quite familiar with them. This looks to me like a case where at least one of the pads has worn down clear past the pad material into the steel backing. Er, didn't you notice a change in sound, if not in brake feel?! If the backing has "welded" itself to one of the pistons, at this point the rotor has likely become scored beyond saving. I'd be mighty surprised if any seals in any brake could survive this amount of heat damage, but I'd sure give it a thorough clean and inspection -- who knows, the caliper and seals might actually be salvageable?

[Guest SantaFeRider]

Um, I'm no brake expert, (Where's Dan?) and this is a little hard to analyze from the photo's, but I use the same Ferodo pads, and have changed them out many times, so I'm quite familiar with them. This looks to me like a case where at least one of the pads has worn down clear past the pad material into the steel backing. Er, didn't you notice a change in sound, if not in brake feel?! If the backing has "welded" itself to one of the pistons, at this point the rotor has likely become scored beyond saving. I'd be mighty surprised if any seals in any brake could survive this amount of heat damage, but I'd sure give it a thorough clean and inspection -- who knows, the caliper and seals might actually be salvageable?

 

 

no Ratchet, the rotor isn't badly scored.

 

As I said, I don't use the rear brake much under normal riding. No sound and no drag perceived. The rotor isn't even blued, just appears coated with a very thin foggy appearance that won't disappear after appication of brake cleaner. I'll try soap and water next. I am not interested in salvaging the caliper, since it's a discontinued piece and no rebuilds are available for it. I am trying to purchase the replacement, for which rebuilds are offered

[dlaing]

no Ratchet, the rotor isn't badly scored.

 

As I said, I don't use the rear brake much under normal riding. No sound and no drag perceived. The rotor isn't even blued, just appears coated with a very thin foggy appearance that won't disappear after appication of brake cleaner. I'll try soap and water next. I am not interested in salvaging the caliper, since it's a discontinued piece and no rebuilds are available for it. I am trying to purchase the replacement, for which rebuilds are offered

How many miles did you have on the pads and when were they brakes last bled?

I am curious, because it may give a clue as to what caused the failure.

Certainly one pad is worn down, but that could have happened on just one or just a few rides, if the piston was sticking.

I don't know what a thin foggy appearance on the rotor indicates.