New callipers or new pistons?

D

dhobbs

Senior member
I think my rear brakes are binding a bit so I’m not sure whether to replace the pistons and seals, or simple replace the whole callipers.

I’ve already stripped them and found the pistons were rusty, but moved freely.

Either way I will have to bleed the brakes.

Any advice appreciated.
 
Ask about how much here and might not be as expensive for new calipers as you think. They also do refurb kits
http://biggred.co.uk/
 
My suggestion would be to have a close inspection of the bore and measure it for size and ovality using an internal bore gauge.
If in doubt replace the Calliper.
 

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You really need to dig out the hydraulic piston seal as corrosion can get underneath & force it against the piston, causing binding/drag :?
Rob
 
Replacement calipers (Pagid or Mintex) are about £185 for the pair from ECP if you apply the current mid-month sale discount.
 
I’ve been looking at ECP and car parts for less.
I only recently did one of the front callipers, that was £100 with one of their codes.
I think for hassle it’s worth doing the callipers as it’s simple a bolt off/on job. No fiddling.

Thanks for the advice guys, probably just needed confirmation.
:thumbsup:
 
complete waste of time fitting new seals and pistons, how much is the kit? £30? Why bother when you can buy recond ATE (OE) calipers. The calipers are really common as they are e46, go into any local motor factors and ask for Brake Engineering, owned by TRW, factory in Wrexham. The caliper cylinder is cnc'd, new cnc'd piston, seals and zinc plated, you will not be able to distinguish this from a brand new one and you will keep a proper bmw caliper on your zed not some copy.
Price? I paid £45 each for fronts with £5 back when the old caliper is taken back to the supplier.
If you do go down the pointless rebuild route and you discover the cylinder bore is corroded, the caliper will be fubar anyhow
 
Davz said:
complete waste of time fitting new seals and pistons, how much is the kit? £30? Why bother when you can buy recond ATE (OE) calipers. The calipers are really common as they are e46, go into any local motor factors and ask for Brake Engineering, owned by TRW, factory in Wrexham. The caliper cylinder is cnc'd, new cnc'd piston, seals and zinc plated, you will not be able to distinguish this from a brand new one and you will keep a proper bmw caliper on your zed not some copy.
Price? I paid £45 each for fronts with £5 back when the old caliper is taken back to the supplier.

Yeah that’s my worry. All to save a few pennies. Worth spending a bit extra and get something that works first time.
If you do go down the pointless rebuild route and you discover the cylinder bore is corroded, the caliper will be fubar anyhow
Click to expand...
 
Slightly different with the facelift 3.0si as the callipers aren’t as common and in fact are a sought after mod.

I refurbished mine (front ones) myself using the kit that bigg red supply. Pretty easy to do and plenty of guides and videos. Give it a go if you like that sort of thing or alternatively I’m sure they offer an exchange type service where you can “plug and play”.

Not heard of binding before on the rear but if you’ve stripped them before and all else is good you’re probably looking at the piston and/or rubber boot as the culprit. Good luck :)
 
I find that after washing the wheels the rear brakes bind pretty bad. Plus fuel economy has gone down a bit.
As said, I’ve had them apart and greased the relevant parts. I used silicone grease on the piston and seal and they did seem to go in and out ok.

I’ve replaced both front ones so doing the rear was only a matter of time.
 
One of my calipers seized on a couple of months ago. A new caliper with warranty was £8 more than a seal kit. So £38 (and an hour of my time) later and everything was good again. No-brainer if you ask me :)
 
Update.
Bought two rear callipers off eBay for £68. These were ones compatible with the e46 so were much cheaper than the Z4 specific ones.
Not too long to fit, only issue was fiddling with the flexible pipe at the solid pipe end to stop the pipe twisting.
All bled and works fine.
 
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