E53 Front Caliper Overhaul

[Skip MacLean]

Greetings - I just replaced the front pads and both front calipers had pistons that weren't frozen but definitely didn't retract the last 3/8" or so very easily (the 6" C-Clamp did the trick). Now the pedal is soft and doesn't seem to be pumping up after bleeding and installing the new pads. I can keep bleeding the other wheels but I'm not sure that will help much. Anyone have experience with soft pedal after new front pads? I don't remember this problem the last time I replaced the pads and rotors all around and I didn't have to bleed the brakes after that to restore typical great BMW brake performance. Thanks.

[Skip MacLean]

So, more clearly, is there a reliable source for parts such as pistons, calipers, piston seals and pad wear sensors apart from the dealers? Tire Rack has a lot of good stuff, but only the most mainstream components such as tires, pads, dampers, etc. Thanks again,
Skip.

[JCL]

I'd use the dealer, but if you don't get along with yours there are lots of companies out there with OE parts. Both Bav Auto and Pelican have parts on line.

[wallyx5]

I have rebuilt both of my front calipers with parts from Bavauto. They are great.

[xriderob]

bimmerspecialst.com has some really good prices as well and good selection of oem

[Skip MacLean]

OK - thanks everyone. I'll try those sources.

[admranger]

What kind of pads did you put on? If you went with ceramic pads, they will have a very different pedal feel than the stock pads.

You might need to pressure bleed your brakes. I use a Motiv bleeder. Bleed in this order: LR, RR, LF, RF (longest distance from reservoir to shortest distrance from reservoir). Go out and activate ABS a couple of times too. Helps get any air out of the ABS pump. Use a whole 500ml bottle of brake fluid for this.

Oh, don't push the pistons back in with the bleeder screw closed. Ever. Any gunk that has settled in the lowest part of the system (your caliper) is now forced back up into the system. Not a good thing.

[nick_083]

I have a dilemma: my right front caliper froze and I barely made it home yesterday. Now, shall I rebuild the calipers or buy remanufactured ones? I am generally concerned about the quality of remanufactured parts, such as Nugeon, Cardone, Centrix - they all seem to be using cheapest components possible... and of course the cheapest labor there is.

On the other hand I can't seem to find replacement pistons (only gaskets) - from either ATE or BMW. What is the probability of opening up the caliper only to find piston that has scoring or rust? What was the condition of the pistons for folks who disassembled theirs? Mine is not leaking... but it is stuck. I and I didn't do a good job replacing braking fluid in the last X years.

[Weasel]

To the OP, usually with new brakes, especially when the rotors aren't replaced, the brake feel is much softer until the pads seat in. Usually after driving around for a little while the brakes feel back to normal again.

To the last post, if you haven't done any brake flushes in the last decade you very well may have some rust in the calipers. You could always pull it off and apart to check the condition, but I'd make sure you have access to replacement parts before you get stuck without a ride waiting on parts. Personally I'd buy a caliper and do a complete brake flush after installed and properly bled. And I'd gently pinch off the brake hose when changing the caliper to avoid any air getting up into the DSC/ABS unit, otherwise it will be a trip to the dealer to bleed that system.