I am looking for a set or at least some of the hard anodized aluminium front brake caliper pistons to suit the 4 pot calipers from a K1100.
If I cant get some then I will have to make some stainless steel ones because I surely am not going to buy those crappy straight alloy pistons that are being sold as a kit.
Plan 2 does anybody know if the hard anodized pistons are still available and if so where. Pleeeeeeeeeeeeeeeeeeeeeeeeeeaaaaaaaaaaaaaaaaaaaasssssssssssssssseeeeeeeeeeeeeeeeeeee.

Motorworks BRA31631


https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=5&NU=15&M=40&Ct=IA&SbCt=BA_15_40_IA_30&spPage=3


I have one set (!!) in the garage and they look hard anodised to me.

I think it's only anodized pistons available, as long they coming from BMW
or Brembo......and not Jack Black with a lathe.
Haven't seen anything else.......could be you find them on very early models...

I thought they were all hard anodized but the ones I have just taken from the 97 K1100 I have here are just straight aluminium and very badly corroded and dont look like they have had any coating at all.

Maybe the ones I have are a cheap replacement type. They certainly are rubbish and not even fit for the scrap bin.

Possibly from Jack Black then........

They have been professionally made and have the inserts that look like the pad material with a small hole. This is why I thought the newer ones were cheap alloy.

Sounds strange...

The bike they came from, a 1997 LT has been crashed and fixed very badly so it does not surprise me that other things have not been fixed properly.
The further I go with it the more surprises there are. Think I might just part it out.

RicK G wrote:I am looking for a set or at least some of the hard anodized aluminium front brake caliper pistons to suit the 4 pot calipers from a K1100.
If I cant get some then I will have to make some stainless steel ones because I surely am not going to buy those crappy straight alloy pistons that are being sold as a kit.
Plan 2 does anybody know if the hard anodized pistons are still available and if so where. Pleeeeeeeeeeeeeeeeeeeeeeeeeeaaaaaaaaaaaaaaaaaaaasssssssssssssssseeeeeeeeeeeeeeeeeeee.

Do you mean the black looking ones?
I've got an original set you can have.
I'll bring them with me when I ride down with Charlie.

cheers,

Andrew

They are black and glassy looking. The ones I found in this K1100 have a coating on them that has not reacted well with the watery old fluid. I am not sure what it is but it certainly doesn't last like the hard anodized ones.
Thanks Andrew much appreciated.

Forgive me if this is a thread hijack.

I am getting ready to go into the front calipers on my four valve K100RS because of sticking pistons.  In reading the description of the Motorworks rebuild kit it is mentioned that they strongly advise against splitting the calipers because of the danger of warping and subsequent leakage.  Can the seals and pistons be serviced without splitting the caliper body?

No way.
But that suggests that you should better buy new calipers...
There's no problem about splitting them, it's a basic mecanic operation.
As long as you dont alter the contact surface, grinding it with a blade or hitting with a hammer, there's no risk.
Useful trick: before separating the hydraulic line, remove the pads and pump until the 4 pistons are almost out. Watch out that one is not getting out more than the others, if necessary, use pliers to prevent it.
Then separate and use pliers, or compressed air to remove completely the pistons. If so, be careful, sometimes they pop out strongly, use an old cloth to prevent rebound in your face.

The recommended way is to pump out one side at a time; that implies some method of restraining the opposite side (a length of steel bar and a clamp does the job). What will happen is the pistons won't come the whole way out but they will get past the seals, which means you can pull them the rest of the way with your fingers.

If you do need to split them, the problem you're going to hit is that two of the bolts (the front and rear ones) are exposed inside the caliper and will almost certainly be as rusty as hell. That's going to prevent them from turning in the body. Scrape as much of the rust off as you can and get some penetrating fluid in there. Make sure that the allen keys are a good fit in the bolt heads because you're going to be putting a lot of pressure on them. A hot air gun will a great help - get the caliper good and hot. As each bolt comes loose, tighten it back up again. Not fully tight; you're just want them clamped down. Once all four are loose, wind them out evenly.

I've done three pairs of the four-piston calipers and split each pair in this way. So far I've not had a problem with leakage on reassembly.

Gentlemen, thank you for the useful information.   Having never been inside of a caliper before, I was approaching this job with a bit of trepidation, and the Motorworks comment didn't help.

I would strongly advise against using pliers as you can and often will damage the hard anodized finish DAMHIK. It is a very durable finish but like glass and easily damaged.
I use compressed air and hold a rag in several layers in my hand over the piston.
As for splitting them I have never had a problem with getting them to reseal. I usually check for flat mating surfaces using wet/dry sandpaper on a glass surface, this also makes sure the surface is clean.