Fun with my 1983 GS750ES - Brakes

[Anonymous]

OK. Had bike on the road for a grand total 4 rides... and now my front brake pads are rubbing BAD!!!!

Just had the work done on the front forks (seals and oil) and had BOTH front brake calipers rebuilt with new pads put on.

Background, the mechanic I took the bike to was close, but did not seem cheap (but was at the same quote as the Yamaha dealer - no Suzuki dealer for 1 hour away). And maybe it is a fluke that I am still having front brake problems after he did the work on the calipers.... but I need some background info on costs, etc. Please bear with me, I have not had to have a bike worked on by a mechanic for several years and am "out of touch" with this end of things. I would take it on and do some learning, but my time is limited and I NEED the bike for transportation.

Now, I am guessing I am looking at replacing or rebuilding the master cylinder. It is possible to rebuild a master cylinder? It is worth finding a used one somewhere? How much should I expect to pay a mechanic on replacement / rebuild of the master cylinder?


Thanks!
Jay

 

[Anonymous]

Jay, pulling the calipers is pretty easy and straight-forward. About an hour a piece and you can have them working pretty again. Sounds like maybe he didn't get all the crud out of them or clean the pistons up well. Bob

 

[Anonymous]

Jay,
Did you check the vent holes at the master cylinder cap and diaphram. If these are clogged the brake pistons won't return.
Axel

 

[Anonymous]

Well, I opened up the master cylinder and did not see anything wrong, and the holes did not LOOK clogged, but after I replaced the top, the brakes were released and have been working fine since then.

I guess I will see if another 3-4 days causes them to not release fully again and then take another look at everything.

 

[Anonymous]

Jay:

I have a 1983 GS750ES and have found that fork alignment on reassembly can be a problem. This may not be your problem but you may wish to see what clearance you have between the brake caliper housing and the disc. On my bike, the steel fork brace (under the plastic mudguard) is slightly out of tolerance and, if torqued down prior to tightening the axle and axle pinch bolts, will pull the lower fork ends too close together. This in turn causes the caliper housing to rub on the disc. The permanent solution is probably to slightly "open" the brace but I have got away with just tightening it last (a royal pain because of access problems with the wheel in already place).

Simon

 

[Anonymous]

Brakes are not releasing again. Anyone else have ideas? Calipers were removed again and inspected... master cylinder appears to be working. Plunger moves then returns to where it was on pressing the lever. Clogged return lines?

Thanks,
Jay

 

[Anonymous]

Jay,
I was incorrect in saying there is a vent in the diaphram but there should be one or two notches in the sealing surface of the cap, that's so air can vent above the diaphram. I've seen these clog up and the results were the same as yours. When the brakes heat, up the fluid expands and eventually locks the wheel solid. If you're sure that isn't the problem, yes you can rebuild the master cylinder. Everything is held in place by one snap ring and parts should be available at a Suzuki dealer. I don't think I would go for the used part unless you know it works and hasn't been sitting around unused very long.
Axel

 

[Anonymous]

I hate to say this....
your post said the pads were rubbing!! this is by design, its how they work.
ok on the funny stuff.
What is the ACTUAL problem your experiencing with the brakes.
Then as an ex-brake guy I can help...
Stimpy