No pressure in rear brakes


Information and questions on GL1100 Goldwings (1980-1983)
  • Sponsored Links
Post Reply
User avatar
goldwingingit
Posts: 21
Joined: Wed Oct 18, 2017 9:46 pm
Location: Seattle, WA
Motorcycle: 1981 Honda GL1100 Interstate

No pressure in rear brakes

Post by goldwingingit » Thu Nov 02, 2017 8:49 pm



Hello again folks,

So I'm in the process of restoring the brakes on this GL1100.

Edit: After some further reading online, I found out that these came standard with linked brakes? Damn! Well, I didn't realize, because at some point a previous owner must have delinked them. There is no way for the front to connect to the rear on this bike. One hose goes straight from the rear reservoir to a pump, the other hose goes to the brake caliper.

The rear brake was in a bad state. The pedal was totally frozen. I got the brakes off, unstuck and greased the rear pedal.

Cleaned the reservoir, flushed out the master cylinder but didn't rebuild it, rebuilt the rear brake caliper.

Rear brake caliper: The piston was seized, got it unstuck with a grease gun, cleaned it up and it went back in with no problem. I ordered a set of seals, a rebuilt kit online, but they might be incomplete.

It looks like there is a seal that is supposed to go around the actual piston, the moving part. Well, in the kit, that part wasn't there. And there was nothing on the piston. There were two seals in the kit, one boot type thing, and one for the inside of the cylinder. I thought I'd trust the kit because I'm still a novice. It's also possible I put the boot on backwards.

I put the master cylinder back on the bike and had the caliper next to it on the ground. The brakes bled just fine, the master cylinder was pumping with no problem. I'm pretty sure there is no air left in the line. But with brake fluid in the system, pressure isn't buliding up in the brake caliper. I thought it might be those seals, but I don't see any leaks.

What's going on here? Sure wish the rear was a drum right about now :D



User avatar
WingAdmin
Site Admin
Posts: 18277
Joined: Fri Oct 03, 2008 4:16 pm
Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: No pressure in rear brakes

Post by WingAdmin » Sat Nov 04, 2017 7:37 pm

First off, linked brakes didn't begin until 1983, so your bike is as it came from the factory.

There are no seals that go on the piston, the seals are always in the cylinder itself.

Lastly, if you have rebuilt the master and slave and aren't getting pressure, you've probably got air to bleed still. These brakes can be a little difficult to bleed, using a vacuum bleeder like a Mity-Vac is the easiest and best way to bleed them and get them nice and firm.

User avatar
goldwingingit
Posts: 21
Joined: Wed Oct 18, 2017 9:46 pm
Location: Seattle, WA
Motorcycle: 1981 Honda GL1100 Interstate

Re: No pressure in rear brakes

Post by goldwingingit » Sat Nov 04, 2017 10:07 pm

Oh, sweet, thanks for the good news!

Air in the lines is something I can handle. Thanks for the reply :)

User avatar
goldwingingit
Posts: 21
Joined: Wed Oct 18, 2017 9:46 pm
Location: Seattle, WA
Motorcycle: 1981 Honda GL1100 Interstate

Re: No pressure in rear brakes

Post by goldwingingit » Thu Nov 09, 2017 12:59 pm

I bought a MityVac and thought that was the end of my problems, but everything is exactly the same.

I attach the Mityvac to the bleeder valve, pressure it and then loosen the valve. Brake fluid comes out with a lot of air. Like a lot of air. When the Mityvac runs out of pressure and I use the brake pedal, I can see less air come through. Well I kept on with this running through the reservoir twice. When I pumped the brake lever, it was moving fluid, and no air, for almost the entire length of hose. Figured it was good, but nope same problem.

I've replaced the hose from the reservoir to the pump as well as the fasteners there.

I can hear fluid swishing around in the pump. I think it might be that pump that's broken because I didn't open it up or do anything to it. Just a surface clean and put it back on. Maybe I'll just buy a refurbished one on ebay, but that would be so frustrating. The mityvac was $40 and didn't fix anything!

User avatar
goldwingingit
Posts: 21
Joined: Wed Oct 18, 2017 9:46 pm
Location: Seattle, WA
Motorcycle: 1981 Honda GL1100 Interstate

Re: No pressure in rear brakes

Post by goldwingingit » Thu Nov 09, 2017 1:10 pm

Lol, nevermind. I ended up lifting the caliper above everything to get the last bit of air through. Probably had something to do with physics and gravity



Post Reply