Rear brakes locked up... anyone have experience with this symptom??

[Gregory]

I have a 78 gs1000e I am wanting to get rid of but needed to get the rear brakes working first. I bought a kit and I rebuilt the master cylinder. The rear brakes were sticking so I had a friend that cleaned the rear calipers very well.

When we took it for a test ride, the brakes stuck.

We assumed I had put the master cylinder together wrong so I took it off and rechecked everything. It was together properly but the spring was sort of stuck in. When I put it all back together it appeared to work fine.

I drove it a mile to get gas and the rear brake started bogging again. I didn't have tools with me so I rode it back home anyway. By the time I got close to home I was rapping out at 5k rpm and doing less than 25 mph in first gear.

When it finally died completely it was quite a sight.

The rear disk was bright orange and the plastic cap on top of the calipers was melting and smoking. Luckily a guy stopped who had a crescent wrench so I broke the line open to release the pressure to get her home.

Any advise? Could a bad line cause this or what? And.... I suppose I have to now replace the disk and calipers?

[Nessism]

Sounds like the small return port in the master is clogged.

[chuck hahn]

I was thinking the same. The hole is in the master cylinder body behind the brass fitting the fluid hose hooks to. Take the hose off and poke wire in the hole. Hook the hose back up and bleed the system again. I was thinking about this last night after you called me actually...then got into the Goldwing maintenance and forgot to call.

And as hot as it got youre probably gonna need to replace that rotor and the pads.

[Gregory]

Thanks guys, I guess I am getting pretty skilled at taking the thing off. I hope I didnt damage the caliper and rotor by it heating up so much... any advise?

[chuck hahn]

If the rotor was orange hot like you said then its junk. Pads are for sure toast also. Caliper body should be ok. replace what needs be with your spare parts and rebleed the system. Hopefully then piston seal is still ok. once the system is bled pump up the brakes and wedge a hammer handle between the pedal and the frame so the brake stays applied and let it set a few hrs to see if any fluid leaks out under pressure.

Start the bike on the center stand and put it in gear ....work the brake a bunch of times to be sure its releasing every time before riding it again.

[eil]

What Chuck said, but I would add replacing every bit of rubber in the calipers and possibly the rear brake line of it's the original. And rebuild that master cylinder too, like Nessism said, that's probably the root issue.

[chuck hahn]

He did rebuild the master and I cleaned and rebuilt the rear caliper..new seals, no piston pits or rust, cleaned the brake pads pins etc etc etc. It was dragging and we both thought maybe it was due to maybe the rubber cup in the master was goofed up or there was an air leak somewhere after we bled the system.

In any case he called me yesterday and he had rechecked to be sure the guts were in correctly and he couldnt get any pressure built up. He hadnt rebled the system and was trying to get it manually. He then got his power bleeder and bled the system and all was well. Took it out and this happened. Caliper definitely wasnt dirty and the guts in the master were correct. Weak link is most likely something plugged the return port.

[Gregory]

Thanks everyone. I didnt work on it today because I had to cut up a tree in my yard. Anyway, I anticipate that the seals are toast since everything got hot enough to melt the plastic cover on top of the calipers. I think I may have an extra caliper...fingers crossed.

[derwood]

same here.......http://www.thegsresources.com/_forum...MC-and-caliper