I guess I need new caliper piston seals?

[bronzeback]

Finally got around to ordering new front pads...dire need. Anyway I got the caliper pistons out by pumping the brakes I've read up on other posts and it seams I should be able to slide that puppy right back in after cleaning. No go. I can get it started but she won't budge past that. I'm guessing the seal is shot/swollen or something. Does that sound like the problem and do you think the local Suzi dealer will have the piston seal? Hate to have to wait a week for it.

[Dink]

I would be stunned if your local dealer stocked the caliper kit, although stranger things have happened.
The caliper kit is the same for many years and models, so it is possible.

Dink

[bronzeback]

A little more reading of old posts on the subject....

Seems most are able to slide the piston in without much effort. Read one post about using a c-clamp to sqeeze it in. A actually did that once but the pads were rubbing way too hard on the rotors, I assumed because the piston was so hard to get back in it couldn't back off when the brakes were let go right? If it is the seal, looking at at it I can't see how the ring that holds it in would possibly come out. Can someone enlighten me??

[BentRod]

I was JUST doing this very same things about 3 days ago. The front caliper on my 81 gs400 was seized, so I used the brakes to get it out, as you did.
I'm assuming you have taken the whole calli assembly appart and cleaned out any grit/rust. from the sounds of your second post it seems like you had a lot of crap inside the caliper. If your bike is older, you may have pitting on the piston, or rust marks. I got the rust off and out of the pit marks with a metal point made from a tin beer bottle cap. Its harder than the rust, but not hard enough to damage the brake.

Look at the seal. are there any cracks? Is it stiff but still flexable? you should be able to twist it about and have it spring back into shape.

As for getting the piston back in. Put a little brake fluid in the caliper, covering all contact surfaces. Set the seals in, and you can use a C-clamp to push it back in, just make sure that you put something accross the piston to brace the clamp on. Do not push on the bottom of the piston. Put pice of plywood, or better yet a metal plate over the open of the the piston and brace the C-clamp on that. Keep pushing till shes in, it should be too much of a problem.

[sharpy]

tight fit?

Also there will be gunk behind the seal that needs cleaning with a toothbrush or fine scraper. That and the seal might be swollen is why u cant get the piston back in. Make sure all is square when starting to put the piston back in.

[bronzeback]

Also there will be gunk behind the seal that needs cleaning with a toothbrush or fine scraper. That and the seal might be swollen is why u cant get the piston back in. Make sure all is square when starting to put the piston back in.

Behind the seal? So I'd need to remove the seal to clean behind it yes? Seems to be a metal ring holding it in with no obvious way to remove the metal ring. I don't see a c-clip or anything to grap onto. The seal doesn't LOOK damaged, or even swollen. It's likely as old as the bike though so I was thinking maybe go ahead and replace it while I'm in there, if I can get it out. Surely there is a way.

[bronzeback]

Or maybe you meant behind like deaper in the piston, not under the seal?

[Nessism]

The caliper seal is basically a square O-ring; not held in with any metal ring on my GS450 or 550.

Note: the seal should be perfectly smooth without any rough edges that contact the piston. Typically, the seal swells up and the rubber starts to look rough after some number of years. It's pretty simple to replace, and cheap, so unless you are in a major hurry to get the bike back on the road, you might want to install a new one.

[bronzeback]

This board rocks!

Well no hurry really, but I did just managed got the pistons back in, brakes bled, wheel spinning freely...all good. The left side piston I had not pulled (well, pushed really) out to clean yet until just now. Cleaned up now. On the first go round I used a too-small c-clamp, right on the back of the piston, thus pushing in it cock-eyed I suppose. Second go round...both pistons cleaned up, bigger c-clamp, and use the old pad across the hole side of the piston for even pressure. I'll keep any eye out for leaks but I think she's right!

[J_C]

Sounds like you got it all sorted out. I only had one of four caliper pistons give me trouble going back in when I did mine this week. In that situation (and I'm sure this wasn;t a good way to do it) but I just used a big piece of wood on top of the piston and tapped on it with a hammer. Had to make sure it went in straight before that tho

[sharpy]

Behind the seal? So I'd need to remove the seal to clean behind it yes? Seems to be a metal ring holding it in with no obvious way to remove the metal ring. I don't see a c-clip or anything to grap onto. The seal doesn't LOOK damaged, or even swollen. It's likely as old as the bike though so I was thinking maybe go ahead and replace it while I'm in there, if I can get it out. Surely there is a way.

Where you talking about the seal that the piston rubs up against ot the dust cover that goes over the piston and connects to the caliper?

[bronzeback]

the seal that the piston rubs up against

[BentRod]

neither the piston boot nor the piston seal are held in by anything other than their own size and the piston. if there is something in the way, it probably shouldn't be there.