[fortythirtyfive]

So last night I was doing some work on my rear right hand disc (it's been rubbing making a metal grinding noise) and accidentally pumped the brake pedal too hard, which unfortunately made one of the pistons pop out.

2 hours later at trying to fix it, brake fluid everywhere and sitting in the pouring rain I called bmw assist for a recovery to flat bed it to a dealer.

What's the likely hood that bmw will just want to replace the entire caliper? I'm really hoping they can replace the seals and refit the piston.. I'm just slightly worried by what they'll end up billing me

[oceanview]

Normally brake caliper can be refurbished. Have done that a few times in the old days.
You should open the bleeding screw when putting the piston back in, otherwise it can be hard to push the piston back in because of the "sealed in" air/fluid.

Just don't put anything else onto the brake caliper o-ring than original brake fluid. Any other oil, grease or whatsoever will ruin the rubber material and end up in a complete brake loss!

[XCRN]

In addition to what oceanview said, sometimes I have needed to use a large C-clamp to get the piston back in and lube the piston and bore very liberaly with brake fluid.

But since it is at the dealer now, my guess is they will do a replacement caliper instead because it would be easier for them to do that and is probably a bit more liability than they are willing for them to rebuild the caliper instead.

[fortythirtyfive]

So for a new caliper they want just over £900.

Or a repair would be:
Remove caliper = £93.33
Refit caliper piston, seals and test pressure = £53.33
Bleeding brake system with DSC = £173.33
Total = £383.99

Am I right in thinking the 4 Series have electronic handbrakes? If not and it's a manual hand break then there's a garage willing to refit it for £120 all in.. otherwise if it's electronic he doesn't want to do it as the handbrake won't accept the piston without it being wound back apparently?

[1QuikWS6]

Out of the above, they really don't have to remove the caliper to replace piston/seals, but whatever...

My 2015 435iX has manual handbrake, no electronic. Parking brake is brake shoes that ride inside bore of rear rotors, caliper does not act as parking brake

You should know which you have - is there a manual handbrake lever on the center console that you pull up on?

[zipphreak]

So you pumped the brakes without pads?? The piston popped out and you expect the dealer to fit the bill ? If your doing maintenance and you break something that's on you. Sounds to me like you should have them just refurb it so you don't have to deal with it. No offense, but it sounds like your over your head.

You have to remove the caliper off the car to refurbish it. No way around that There is no secret passage on the rear of the caliper to remove the piston

[fortythirtyfive]

Originally Posted by 1QuikWS6

Out of the above, they really don't have to remove the caliper to replace piston/seals, but whatever...

My 2015 435iX has manual handbrake, no electronic. Parking brake is brake shoes that ride inside bore of rear rotors, caliper does not act as parking brake

You should know which you have - is there a manual handbrake lever on the center console that you pull up on?

Perfect, sounds like the same for me then. Thing is they've sent me a photo of the caliper already removed from the vehicle, so the fact they're trying to claim that's a cost I find obscene really.

I'll ring up the neighbouring garage in the morning, as long as it's manual then they're willing to do it all in for £120.

Originally Posted by zipphreak

So you pumped the brakes without pads?? The piston popped out and you expect the dealer to fit the bill ? If your doing maintenance and you break something that's on you. Sounds to me like you should have them just refurb it so you don't have to deal with it. No offense, but it sounds like your over your head.

You have to remove the caliper off the car to refurbish it. No way around that There is no secret passage on the rear of the caliper to remove the piston

I wouldn't even say I fully pumped the brakes, I appreciate I sound like a complete noob here, and hey; I am. I have hardly any knowledge on mechanics. I'm a self learner that learns from mistakes unfortunately, but yeah I'm going to go with the rerfurb route.

As for my grovel with the dealer it's more that they dragged the car from the trailer into their garage and then only realised that they were scraping the caliper on the tarmac. That's what has pissed me off, it could have easily been avoidable

Picture attached for those who wish to see their damage (it had zero marks originally, pristine condition as I made sure they were kept that way)

[oceanview]

You can get the caliper for €530.-/£470.- plus shipping cost from German Leebmann24.de shop. (per caliper)

£900.- (per caliper) looks like the classic dealer rip-off.

https://www.leebmann24.de/bmw-ersatz...=34&bt=34_2033

[MacklinUSOB]

Originally Posted by producerlawson

As for my grovel with the dealer it's more that they dragged the car from the trailer into their garage and then only realised that they were scraping the caliper on the tarmac. That's what has pissed me off, it could have easily been avoidable

Picture attached for those who wish to see their damage (it had zero marks originally, pristine condition as I made sure they were kept that way)

Regardless of the existing problem with the caliper, the dealer or whatever shop taking possession is liable to return your property in the same or better condition than provided... They clearly caused this damage and should offer to replace it, however convenient it may be considering the reason you brought it there.

[Billfitz]

FWIW when this happens you can usually just pop the piston back in place, so long as the seal isn't damaged.

[e30]

Originally Posted by Billfitz

FWIW when this happens you can usually just pop the piston back in place, so long as the seal isn't damaged.

Exactly! That sucks you had to tow it. Did you pump the pedal while the piston was off the rotor?