Replacement brake caliper pistons

[(RIP) Jamie]

I'm just replacing worn pistons and seals.

The new pistons are not just the metal cup shape the old ones are.


They seem to have a cap inserted into the top, which sits just proud of rim of the cup edge. These caps don't pop out very easily, and seem to be made from some kind of brittle material, akin to bakelite - so I'm assuming they stay put.

Any thoughts?

 

[Stewart H]

I have seen both types, why remove them, they are obviously there for something, maybe to stop squeal.
Stewart

 

[dancata]

@Jamie, do you mind taking some pictures while you are doing this? Or maybe detail the steps?

I want to open my front calipers and clean them then replace the o-rings. The weird thing is that my left brake pads are half way worn and my right hand brake pads are worn all the way And I have to change 2 sets because of this, even if one set is still good to go. Also, the left side of my front tyre is worn way more than the right side. Is this related to the brakes?

10x,
Dan

 

[Steptoe]

;2182134The weird thing is that my left brake pads are half way worn and my right hand brake pads are worn all the way And I have to change 2 sets because of this, even if one set is still good to go.

Swop the pads over so they come to the end of their life at the same time.

 

[dancata]

Swop the pads over so they come to the end of their life at the same time.

That's what I will do with the new brake pads that I will install. Is there anything I can do to eliminate this in the future? Like clean everything and that the pads will worn equaly ?

 

[Steptoe]

That's what I will do with the new brake pads that I will install. Is there anything I can do to eliminate this in the future? Like clean everything and that the pads will worn equaly ?

Why not clean them, you won't know if it works until you try.

 

[(RIP) Jamie]

Dan

Sounds like your pistons may be sticking if you've got relatively high mileage on the bike, and the seals or pistons may be buggered.

You may as well get a refurb kit and replace the lot. No need to split the caliper.

Take the caliper off, plug the fluid inlet hole with correct sized bolt, and pump more brake fluid through the caliper via the bleed nipple using a large syringe and some thin pipe, like from a car windscreen washer.

Then refit and bleed as normal.

 

[dancata]

Was thinking of buying a ultrasound cleaning device for cleaning TB's, calipers, etc.

Also, I have new brake lines that I am going to install. The old ones are bad because of friction with the dash frame. Will post a picture as soon as I get to the bike.

Dan.

 

[dancata]

Dan

Sounds like your pistons may be sticking if you've got relatively high mileage on the bike, and the seals or pistons may be buggered.

You may as well get a refurb kit and replace the lot. No need to split the caliper.

Take the caliper off, plug the fluid inlet hole with correct sized bolt, and pump more brake fluid through the caliper via the bleed nipple using a large syringe and some thin pipe, like from a car windscreen washer.

Then refit and bleed as normal.

In order to get the pistons out, I can just get the caliper out and press the front brake, right? Then clean everything and install new SKF o-rings.

Does anyone know the front and/or rear caliper o-rings dimensions? Also, how many are there / piston? I guess there is one for dust and one for pressure, right?

 

[(RIP) Jamie]

Was thinking of buying a ultrasound cleaning device for cleaning TB's, calipers, etc.

Also, I have new brake lines that I am going to install. The old ones are bad because of friction with the dash frame. Will post a picture as soon as I get to the bike.

Dan.

Try brake cleaning fluid and a toothbrush

 

[(RIP) Jamie]

In order to get the pistons out, I can just get the caliper out and press the front brake, right? Then clean everything and install new SKF o-rings.

Does anyone know the front and/or rear caliper o-rings dimensions? Also, how many are there / piston? I guess there is one for dust and one for pressure, right?

Yep. You can do.

Two o-rings per pot as you said. They come as a kit from most reputable BMW parts suppliers.