Caliper Pistons Stuck

[fast_ryan]

Parts

From experience Reactive Parts are normally reasonably quick if they have the parts in stock. The piston/seal kits from them are ?68 for each caliper. The item linked is an OEM Brembo Kit which is the same as what you would get from a dealership. What will slow done the process is that it is actually linking to a product supplied by alpha Racing as Reactive Parts are now a stockist so you will be waiting for it to be sent from Germany. If you want to purchase them from alpha Racing, then buy from Prime Factors as you will receive a discount and they are far quicker at sourcing parts. At ?141 I wouldn?t be at all surprised if your local dealership is charging you for two sets to do both calipers at the same time. This isn?t a bad idea considering you will be taking them off the bike anyway and you will know that both calipers have been serviced together.

As for stripping and reassembling brake calipers yourself it really isn?t all that difficult. Just drain the brake fluid from the reservoir and disconnect the calipers from the brake lines. As already mentioned be careful when seating the new pistons and make sure the surface you are working on is absolutely spotless. Once reassembled just connect the brake lines again and thoroughly bleed the system.

 

[RickS1K]

Re: Parts

The piston/seal kits from them are ?68 for each caliper.

Good point and d'oh...should someone who can't work that out really be trusted to work on their own brakes..... ha ha.

 

[RickS1K]

My caliper removals tool arrived yesterday and I was getting on fine turning and cleaning the pistons. The fun stopped when I actually popped one out, but I got it back in after a bit of faff. I think I'm attaching a picture of it, although I had already cleaned it when the pic was taken. The lower part of the piston (this is one of the really stuck ones that started this thread) seemed pretty clean even before I cleaned it. You can see some light pitting near the top.

Does this look fairly normal for a 15k mile old piston, and do we still think the seals are the likely problem?

I haven't been able to confirm how well it moves after the clean, because I lost brake fluid when it popped out and I need to top up and bleed, haven't had time yet...

Edit: didn't look that blurry on my phone...eww...

 

[alex]

They don't look bad but...

Which tool did you get in the end to move them? I need to order one up.

Also, is there way to bung the hoses so you can take a caliper off without losing all the fluid? I'm thinking a specific plastic red insert cap type of fitting?

 

[fast_ryan]

Calipers

Does this look fairly normal for a 15k mile old piston, and do we still think the seals are the likely problem?

Those don?t look too bad considering the mileage so it?s most likely the seals that just need replacing. Considering they come as a set per caliper I would personally just replace both.

Is there way to bung the hoses so you can take a caliper off without losing all the fluid? I'm thinking a specific plastic red insert cap type of fitting?

Ideally you should drain the brake fluid reservoir first before you remove the calipers as it saves making a complete mess. A simple and cheap vacuum kit will do the job. There will always be some fluid loss as soon as you loosen the brake banjos so wear gloves and keep the fluid away from paintwork and forged wheels. It?s easier to just drain the lot and replace with fresh fluid as if not you will have a mixture of old and new fluid in the system thereby potentially affecting braking performance. Once you have refitted the calipers just refill the reservoir with brake fluid and bleed the system conventionally and you will be good to go.

 

[RickS1K]

Alex, I got the Draper Expert 30838 240mm tool from Amazon, but it looks identical to the Laser one you WhatsApped me the other night. It's a little bigger than the one I remember using before and you have very limited wiggle room, but you get used to it.

As for the hoses, there is almost certainly a step I missed (but don't know what it is..anyone?) that would have lost me less fluid, but as I intended to (learn to) replace it anyway, I wasn't that bovvered...as long as I kept it off sensitive surfaces

 

[Flyingscotsman]

Also, is there way to bung the hoses so you can take a caliper off without losing all the fluid? I'm thinking a specific plastic red insert cap type of fitting?

On car flexible hoses I've used a clamp to prevent fluid loss. Not sure how flexible the S1k hoses are.

An alternative I've used is multiple layers of cling film over the reservoir held in place with an elastic band.

 

[bananaman]

Have know ppl order parts of reactive site 'in stock' but they havnt been.

 

[RickS1K]

So, I popped down to the dealer on Saturday and ordered the piston servicing kits, since there were none in the country... BvG was there with his new HP4 Race, and was typically off-message in his description of the bike and riding on track

re pistons. I plan to remove and strip down the calipers this week in the hope the piston kit arrives this week. Some Qs:
1. Is it OK to leave everything stripped for a dew days? I know I don't want any dirt in side the pistons, so I'll wrap them up
2. When I put the new seals in, do I need to lubricate them
3. Same for pistons, do they need help to seat them in the bores?
4. Any other time I have cleaned my calipers they have come up like new, but not this time. Either because of heat caused by sticking pistons, or just the Brembo SCs deteriorating quicker by design, there is a still a lot of dust I can't shift. Have/would any of use Autosmart Red 7 or some other "Iron Fallout Remover" type product, or just leave them
5. Any other advice?

Cheers

 

[phil]

https://www.youtube.com/watch?v=C26ww0dsMTI

 

[RickS1K]

Cheers for that Phil. Wasn't anticipating taking the caliper itself apart, thought I'd be able to get the piston out and get the new seals in without that... seem to recall other threads saying I wouldn't have to...must double check that...

 

[phil]

Cheers for that Phil. Wasn't anticipating taking the caliper itself apart, thought I'd be able to get the piston out and get the new seals in without that... seem to recall other threads saying I wouldn't have to...must double check that...

Hi Colin, you probably wont have to take it apart but if you do its a real ball ache as the video shows. Good Luck mate.

Maybe join another ride sometime?

 

[alex]

https://www.youtube.com/watch?v=C26ww0dsMTI

Vacuum cap is neat - and what I was thinking of when asking of a way to bung the banjo.

 

[RickS1K]

Ordered piston kits Saturday, was told they'd come from Germany - collected them from dealer this morning - beat that Reactiveparts

Looks like the football will get in the way for the next couple of evenings, but could have it all sorted Thursday/Friday....

 

[P0u1]

You won't need to split the calipers and I'm not sure if the bolts are stretch bolts so I wouldn't.

You can not find any torque values for the bolts joining the two halfs so I'm certain that you're not ment to take them apart.

I done mine about a year ago it's not too bad but give yourself a couple of hours to do it.

 

[RickS1K]

Hey All. So because of work and the fact that I couldn't get one ***** piston out of the caliper, I have to get them split and new pistons/seals put in by a garage...and tbh I'll probably just give them the job if I have to do this again..

Anyway, I need to put everything back together now. First up, I need to put the calipers back on the hoses. I have new crush washers, but the owners manual doesn't have the torque settings for the banjo bolt, and I seem to have a technical issue with the service manual I downloaded a couple of years ago. Just wondering if anyone knows the right torque?

Cheers

 

[fast_ryan]

Torque Setting

From the Service Manual:

Brake hose with banjo bolt to components - 24 Nm.

 

[RickS1K]

Hopefully the last question on this before it's all done - copper grease. I'm used to putting this on the back of the pads, and the two bolts that attach the caliper. It looks like there was some on the bleeder valve screw, and I just don't remember if there was any on the banjo screws when I took them off - should I be applying it to the banjo and bleeder screw threads or does that risk contaminating the brake fluid?

Cheers

 

[alex]

Don't put it on the back of the pads. Not necessary, old practice for brake pad vibration.

 

[snooker]

Hopefully the last question on this before it's all done - copper grease. I'm used to putting this on the back of the pads, and the two bolts that attach the caliper. It looks like there was some on the bleeder valve screw, and I just don't remember if there was any on the banjo screws when I took them off - should I be applying it to the banjo and bleeder screw threads or does that risk contaminating the brake fluid?

Cheers

Put some PTFE tape on the bleeder screw threads. Stops them seizing and makes suction bleeding more efficient.