GS1000E Brakes

[Texas Don]

Well, this has turned into a real chore. The 79 model that I purchased a couple of months ago only had one brake caliper in the front although it had two discs. The PO had just removed the right one and used a single brake set up for some reason. I scored a set of brakes off a 79 on fleabay. I've been rebuilding the calipers, getting them ready to install while waiting on new hoses.
When I reassembled the right caliper, I noticed that the O-rings that I ordered from partshark were slightly different than the original ones. The originals had a square cross section. The new ones are truly doughnut shaped. These O-rings go on one of the two shafts that the moving arm rides on. The other shaft is installed without O-rings. I'm not even sure why they are needed. The area where they are mounted is not exposed to oils or brake fluid. The problem is that after sitting for a day or so, the moving arm is pretty well locked in place. It takes some effort to make it move. Then it slides just fine. I lubed the shafts with wheel bearing grease when I reassembled the calipers, so perhaps that's causing the O-rings to swell. Should I have installed them with a different lube, or even dry?
Oddly enough, the left side caliper moving arm, has had the holes chamfered by someone using a countersink it appears. There is no way that the hole could have worn itself that way. Is this some sort of fix to allow the slider to move easily? Would appreciate some insight from you pros.
Thanks,
Texas Don

[Nessism]

One thing is you need special caliper grease. It withstands high temperatures better and has moly in it. Not sure what those O-rings are for but if Suzuki installed them there had to be some purpose...I think.

[salty_monk]

Shafts should be lubed with silicon grease... that's what the Suzuki one is. They still sell it at the dealer $7 or so for a tiny pot but you don't need a lot. Yes that could be the cause of the swelling but also could be brake fluid contamination causing the swelling too.

[Steve]

Are you sure the original was a square-section ring?

If you leave a round-section ring in a square channel long enough and apply a bit of pressure and few (thousand) heat cycles, it will look like a square-section ring.

Not sure if it would happen in the brakes, but I have seen it many times in the intake boots. Same principle may apply.

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