Caliper Failure and Rebuild

[PMB_Performance]

Hello deQuincey,

Here's some answers:

1. No. It is generally not needed. We don't go crazy blasting inside bleeder and fluid inlets because of the machined threads. A quick acid bath makes certain the journals are cleaned as well.

2. Compressed air. No, not extremely critical other than the fact that the caliper core must be free from any media! Here's a shot of a set of Porsche "Big Reds" off a race car. These were "Polymer Coated" by a well known rebuilder (spray painter) in the Pacific Northwest, Seattle to be exact. They left all of the metal shot media in the calipers!!! The aluminum pistons were trashed... the calipers were trashed.

3. Yes. It's the key to a proper rebuild. 99.9% of caliper failures are because of rust... INSIDE the bore. Once the calipers begin to rust and that rust is mixed with old fluid (again, inside the bore) they stick and fail.

4. Don't worry about it. We get this question a lot and, it just doesn't matter. They were meant to be plated. Take the old plating off and put the new plating on.

 

[Nicad]

Thanks guys. Happy to help out.

Bob, with those Brembos, I would glass bead blast the bodies and then re-anodize vs. alodine. Anodizing is a "much" stronger finish and it will last much longer. Alodine is fairly benign and won't offer much protection in the long run.

It's hard to tell from the description but, I think I might leave them as is and reanodize and repaint. If there's enough of the 10x1 thread to hold the fluid line, you may be better than trying to weld etc. It depends on the caliper as well. Some of these Brembos we call "throwaway calipers". Brembo is asking $18.50 for a rubber bore seal (yes, that would be one). Then there's $36 for a wiper seal. Now add it all up and times that by four. Now times that by two and, then by two again if you want to do the rears. Wait! They kind of insist that you buy a bottle of "seal conditioner" if you want to buy their seals. Ummm Okay...

Add to that odd pad plates that have small M4 hex head M6 fasteners that have been loctited into place. These steel fasteners in the aluminum bodies with the smaller hex head are almost always a disaster. Strip a head and you won't be able to get the calipers apart. Then you'll have to grind the head and send them off to Jim for EDM. This is why the other companies simply spray them with paint and put Centrix seals in them. Then the pads don't fit right. And... The aluminum can corrode under those plates making them impossible to get pads out... Heard enough? These can be very difficult and expensive calipers to fix properly. Especially if they're corroded.

Can you post a picture? If so, I can give you a better opinion and try to steer you toward some best options.

Steve, I'd say the anti seize would be fine. You're going to bleed the right afterward anyway so, fluid will push any contaminants out. I understand the reticence but, I think people make a bit too much a big deal out of these small things.

Sorry for the thread drift fellow E9'ers, but I wanted to post a photo of my Brembo issue for
Our generous PMB expert to scrutinize



This is the worst one by far. I don't have access to any type of anodizing and was thinking I would clean it up till I have solid metal and give it a coat of G20 Epoxy caliper paint. Every year or so I could take it apart to clean it out and see how it is holding up. This Gold finish is ultra tough where it is still intact. I thought I would clean this well, scuff the finish and recoat with Silver Epoxy paint. I really don't want to be driving around with Gold calipers or Brembo logos, as Turbo Subarus are about the most stolen car in Toronto and I have been struck twice with daly driver project cars.

 

[Luis A.]

Eric, very helpful post, thanks for doing it.

I had difficulty sourcing the hardware kit for my calipers so ended up replating the old components and they are functioning well.

Where can one source these hardware kits new?

Same for the seals, the aftermarket supplier brand I could find is "FTE". Where can true ATE seals sets be sourced from?

 

[PMB_Performance]

Sorry for the delayed reply...

Hey Bob,

Couple of things:

1. Like the broken bleeder analogy, decide at what point it might be better to get a core caliper.
2. I'd be inclined to leave that, re-anodize and be on the hunt for a good caliper.

Hi Luis,

You can use either ATE or the FTE brands. FTE isn't a bad seal kit.

We can get the ATE kits through our supplier:

34 11 1 158 692 up front and...
34 21 1 103 482 in the rear.

As far as the pad kits, I'd go to a large BMW parts supplier. Same caliper resides on the 528i so, they should be out there.