Brakes (brake pistons in particular)

[frosty5011]

Rear caliper on my GS850L was really starting to "drag", so I decided to take caliper off, and disassemble. Brake pistons were really kind of stuck/clogged with crud. I cleaned them off, carefully removing rust, and there are places where there was rust that is now pitted.

How pitted can the pistons be before they will start leaking? I've looked but could not find any place either that will sell replacement brake pistons - in fact was told that even Suzuki probably doesn't carry them anymore either.

Any help/suggestions would be appreciated.

[sharpy]

I presume all the pitts are behind the seal. You can get by with a little rust but that not working have you asked a machine shop about the cost of a stainless steel one being made up? :? A Suzuki spare parts counter should have one, 850s are not that old.

[Billy Ricks]

If it is the same caliper as an '85 700 E I have a spare one.

[Billy Ricks]

Just checked Bikebandit, doesn't appear to be the same.

[Anonymous]

Sounds like a job for good ol JB weld.

Ive heard that Jb weld is good for damaged fork tubes. I bet if the part was cleaned properly first it would hold in the pits of your brake piston. The heat might be a factor to wory about though.

[frosty5011]

Thanks for all the help. I found an extra rear caliper on e-Bay that I bought, let's see what shape it is in. If it's in no better shape, then I'll have to probably go with the machine shop deal. My local motorcycle dealer here says Suzuki doesn't supply the brake piston's anymore. Of course, this is a dealer in Alabama....lol....so who knows how accurate this may be.

As far as the JB weld method......I once tried that on a fork set for a small KZ that my wife was learning on. It did not work well at all (for me), and so I really don't feel so enthusiastic about that idea. Brake fluid might be strong enough to turn it into goo.

Let me see what this extra caliper has to offer....maybe its pistons in much better shape.

[Clone]

As long as when you were removing the rust you didn't sand across the entire surface from bottom to top. The piston should still seal pretty well. You should hone your cylinder to remove any rust there. Replace the seal and you should be good. The big concern is whether or not the scoring is going to be across the entire surface the seal will contact.