How often to rebuild front calipers?

CookeD

CookeD

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Hey All,

I rebuilt my front calipers when I un-barnfound my E9 almost exactly 6 yrs ago. At that time, the bores / pistons were in pretty good shape, and all went back together and the braking was great.

I had a seep on one of the fronts that I think is the cause of a soft pedal after the car sits for a bit, so just got done rebuilding that one, and will rebuild the next. I change my fluid pretty regularly (at least 1x / year), and I was surprised that the caliper I just rebuilt was as messy inside as it was. No rust pitting, flakes, or seized pistons were found, but there was dirty, rusty-colored fluid in the bores, and both the bores and pistons needed to be cleaned more than I expected.

So the question-- How often do these calipers need to be overhauled, and is there a preventative maintenance schedule to follow that goes beyond flushing the fluid?
 
Jellobmw said:
Remanufactured calipers are so cheap ($70 at Rockauto) why would you rebuild?
Click to expand...

FYI-
Have you actually tried to order one?
Note those are for solid rotor fronts.
I did not see any for vented rotors.
When I tried a few months ago they didn't have any and weren't going to get anymore. I called.

Getting harder to find rebuilt calipers.
So I rebuilt mine.
As far as the brake fluid looking bad, the fluid picks up moisture and that causes corrosion in steel brake lines. That's why you should change at least once a year. As long as the seals aren't leaking the rebuild time could be 10-15 years depending on use and the weather the car is exposed to.

Gary
 
Why not and to ssbc

And be done with caliper issues once and for all?
Or go to silicon fluid?
 
New calipers would be nice, and maybe I should have asked the question differently.

At $321 per side, if new calipers also need to be rebuilt after 6 years, I'm better off sticking with what I have, and just rebuilding at some interval. These calipers are known to have issues, so per my original post, wondering what the life expectancy between rebuilds is for a typical E9 front caliper. Obviously climate and use come into play, but mine were also rebuilt, so I could have some roughness on my pistons that's causing premature o-ring failure, etc...

Also, AFAIK, silicone fluid is the worst thing to use unless you're changing fluid all the time (i.e.: Racing) because it pushes water to the lowest point in the system, which is the caliper. Is this not true?
 
Slicone fluid is not permitted in race cars as far as I know. Very mushy pedal feel. Race cars need frequent fluid changes. I don't think a well maintained caliper needs rebuilding every 6 years.
 
I still have the original brake calipers on the front of my 2800 CS. I may have rebuilt them once many years ago but I am not sure on that. I have replaced the rear slave cylinders recently and I think they were replaced once before many years ago.

As to silicone brake fluid, I ran that in a 73 FJ55 Landcruiser for many years with great success. It originally went through slave cylinders almost every year with DOT 4 brake fluid. When I switched to silicone brake fluid I did not have to do anything again to the brake system with the exception of shoes. The brakes worked great without any spongy feel to it. I thought if that worked so well I should try it in my race car. It work pretty well for a few laps and then pedal got soft. Eventually I had to pump the brakes to get them to work. Once it cooled down the brakes worked normal again. I tried many things get it to work in my race car but I finally gave up and went back to high temp brake fluid like Motul 600. It has to be flush periodically due to the higher moisture absorption rate but it works great.
 
HB Chris said:
Mesa Performance sends out for rebuilding, about $75 each. No need to buy new ones.
Click to expand...

Hey Chris, thanks on this. Sounds like it may be the thing to do.

Do you know if they sell on exchange, or do they use the cores that are sent for rebuilding?

TIA,

John
 
John,

Not sure but give them a call. If the rebuilder has cores in stock then you only send yours in to avoid the core charge when theirs are rebuilt. Centric is the rebuilder.

Chris
 
I just installed a set of rebuilt calipers from Mesa and yes, they do sell on exchange if they have some cores already rebuilt. In my case they did and I got 2 within a week.

Regarding the rusty fluid - that is probably from corrosion in the steel lines, not the calipers only. I agree re flushing the fluid once a year. Spend $100 on a Powerbleeder and BMW-fit cap and it's a 1/2 hr job.

Cheers
James
 
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