A while back I posted about my rear brake needing to be pumped to get a full pedal. I have bled the system twice usingthe service manual steps. This did not correct the problem, so here are the problems I have now:
1. Must pump the pedal brake to get a full pedal and brake.
2. Using the front brakeis NOT applying brakes to the rear.

I read about the braking system and how it works. I hate to buy a rear master cylinder kit if thisis not the culprit. What about the secondary master cylinder? Could it actually be the problem? Remember, I have done all bleeding as the servioce manual indicates.

 

Do you have to pump when the bike is cold?

 

If I dont touch the brake for afew seconds, I have to pump it againto get a pedal. Once I get a full pedal, it will hold it until I finish braking and release it. In other words, every time I stop I have to pump the pedal a couple of times to get a brake. It has to build up pressure each time I stop by pumping it. Hope that makes sense.

 

Not the problem I had, brakes where good when bike was cold, after riding a bit, I had to pump brakes, but once they were really hot, I had nothing no matter how many pumps.
My problem was a stuck pistion in the rear.

You are saying that your are not losing fuild and once you have pump the peddle hard, it's holds without slowly losing pressure and it happens cold, warm and hot with out much difference in feel.

You also said in another post that you have change the fuild and bleed the system.

Best to ask other members, but if the above is correct, I would make a call on the master cylinder.

 

MarkR,

You described it correctly. It does it whether hot or cold.

And I did flush all the brake fluid. It was working fine before the flush and shortly after. The guy I bought it from said he had never changed the brake fluid and it sure looked like it. I think changing the fluid has caused seal problems to show up.

I also wonder why the front brake is not applying brake to the rear, although this problem existed before the rear brake problem.

 

My call would be rear brake master cylinder - fit a service repair kit, available on e-Bay. I think the seal has gone, allowing fluid to get past it.

 

I think it's a matter of getting it bled correctly. If it worked prior to changing the fluid, it should work after. The likely hood of new fluid causing a seal to go bad, is nil
First, how do you know the rear brake isn't being applied via the front linked brake system. It doesn't apply any pressure to the rear unless the you are moving and the front caliper rotates enough to actuate the piston in the linked system. In other words just pulling the front brake handle with the bike is stationary won't engage the rear brake.

Did you use a vacuum system like a Mity Vac to pull the fluid through? If not I would suggest using one. Pumping the pedal won't get all the air out of in a linked system.

 

Stray Cat,

I checked the front brake by just squeezing the lever and spinning the back wheel, so maybe it does work then. The only thing is when I bled the front brake lever and opened the rear bleeder screw(both), no fluid would come out using the hand lever.

Concerning the rear pedal, I did not use the mighty Vac, but fluid does squirt out pretty strong by manually bleeding. One other thing to consider. When I first changed the fluid on the rear brake, it worked fine for about a month. Then the problem started.

 

I may just purchase a mighty vac and try it since i can always use it in the future. Which one do i buy and where's a good source? Any suggestions are greatly appreciated!!

 

I purchasedMityVac at my local auto parts store. I think it was about $35. The problem with pumping the brakes on the linked system is you'll just push the air bubble back and forth, and never get it all out.
I forget the correct order, but when I did mine I followed the factory manual procedure and it worked great. IIRC there is also a bolt up front that needs to be lossened to allow fluid to travel from the front caliper freely. Then it needs to be tightened back up after you are done.