need to pump rear brakes

[Anonymous]

On my '82 GS1100GK when braking with the rear brakes there is very little stopping power. If I brake again or pump the rear brakes then they work well. I've bled the brakes and I have rebuilt calipers, and I have new pads, so the problem isn't with any of that. Any ideas?

 

[Anonymous]

It sounds like you are still getting air in the system. :roll: Its getting compressed and the breake works again after you pump it. The first thing I would check is if the tip of the bleeder bolt to see if it hasn't rusted out. I cleaned the one on my 550 with 600 grit sandpaper and it started to work fine. Next step might be to check if the lines are screwed in tight or if they have a hole, if they sweat anywhere it might be good to replace them.
A final thought might be with the master cylinder, I don't know exacltly what your system is like but I suspect its not integrated, in that case check if its the Master that is not at fault. In my case I could not bleed the cylinder through the brake, so I disconnected the Mastercylinder and pressed the lever GENTLY until fluid came out and solid pressure appeared, then individual part by part I assembled the entire thing "bleeding it as I went along. Its time consuming but it worked. If you try this please remember Not To Release The Lever/Pedal Unless The System Is Cloased/plugged 8O (otherwise air will get back in). I am sure you know most of this already but it might be useful to say anyway.

Good Luck and ride safe

 

[Anonymous]

hose

hose

And if the preceeding posts procedure doesnt cure it, take a look at the hose.
If its a old rubber hose, they can go soft with age and when you pressurise them , they swell along their length instead of just transmitting the pressure making for a spongy lever and the same feeling as air in the system.
If it is the culprit, just get a braided steel replacement made up by the local emporium, it'll look better n work longer...

 

[Anonymous]

re: hose

re: hose

Thank you for the advice...
I did install a new brake line last year though, however it is a Suzuki OEM replacement.. yes rubber. I had read in a forum somewhere that people had advised not to replace rear lines with steel braided.. they claimed that the rear brakes would be *too* good and ultimately dangerous on quick stops, so I opted not to replace with those. Now I am reconsidering. Nevertheless I will rebleed the brake lines again and be ever so careful on how I do that. If that fails to solve the problem, then I'll have to take a look at the brake cylinder for problems there.

 

[Anonymous]

How much braking power are you expecting from the rear brakes? The truth is, you're not going to get much at all from the rear. Make sure you have all of the air out, and everything is properly installed, and of course like someone else mentioned check the hoses for swelling during braking.

TIm

 

[earlfor]

There should be enough rear brake authority to lock up the rear wheel at any time. The limiting factor is tire traction, not the brakes. I dont think its a good idea to "detune" your brakes to be incapable of locking a wheel as a safety measure.

Earl

How much braking power are you expecting from the rear brakes? The truth is, you're not going to get much at all from the rear. Make sure you have all of the air out, and everything is properly installed, and of course like someone else mentioned check the hoses for swelling during braking.

TIm

 

[Gary Lich]

Canroc... your comment about hitting the brakes again or pumping to make the brake work better makes me suspect the seal inside the master cylinder is going bad. If there is no evidence of external brake fluid leakge at any of the fillings that is where I would look. Even with a stock brake line you should have no problem locking up the rear wheel with moderate pressure on your 1100GK.

 

[Anonymous]

re: rear brakes

re: rear brakes

Thanks for all the input.

Recapping: I have newly overhauled rear calipers, new pads, new brake line and I've rebled the line twice now, and there is no evidence of leaking brake fluid. It still takes the second pump on the brakes before it brakes properly. I stopped on a hill yesterday with my front brakes then pushed down on the rear brake once, let go of the front brakes, and started rolling downhill.. on the second pump of the rear brake, the bike held firm.

So, it sounds like the problem may be the cylinder seals. I guess replacing those, or finding a cylinder from a salvage yard is my next little project.

 

[Anonymous]

RE: need to pump rear brakes

Thanks for all the input.

I replaced the rear cylinder with one I got from a member of gsresources (put my ad in parts wanted) and the rear brake works like a charm now.

This website site is great.

--Mike