Rear brakes

[D-50Dave]

On the ride home from replacing the clutch cable, I found I had no rear brakes. Checked the system and everything looed dry and attached. I did have to manhandle the brake peddle to get the aftermarket chrome panel out of the way. Any ideas? Thanx, Dave

 

[AApple]

No brake....is the pedal hard to push, or mooshy? If it is hard to push, I would suspect the master cylinder, a kinked rubber hose, or the brake caliper seized. If you loosen the bleeder on the caliper, will the pedal move, and fluid come out?

 

[D-50Dave]

No brake....is the pedal hard to push, or mooshy? If it is hard to push, I would suspect the master cylinder, a kinked rubber hose, or the brake caliper seized. If you loosen the bleeder on the caliper, will the pedal move, and fluid come out?

No resistance at all. I'll look into this weekend. Thanx

 

[zman]

Sounds like the piston stuck up inside the master cylinder maybe try a few taps with a hammer and a wooden dowel or lightly with a punch.

 

[D-50Dave]

Up on the center stand, Brake applied will stop the wheel, just not enough to notice when on the road. The reservoir is at the "Low" line. I will top up and bleed the brakes. Any other ideas? Thanx, Dave

 

[AApple]

If the reservoir is low, but you see no leaks, the pads must be worn. If no leakage anywhere, I would take a look at the pads. The reason for a low reservoir can only be from a leak, or worn pads...(or it wasn't full to begin with)

 

[D-50Dave]

The pads are reasonably with not a lot of miles on them. Less than 10,000 mostly highway. Bled the brakes some and got a little air out and some pedal back. Gonna ride it this week to work and bleed more next weekend. The journey continues.

 

[D-50Dave]

Rode to work yesterday and that'll be it till the weekend. Initially no rear brake. Half dozen pumps and they worked they're way up to poor. Stayed that way thru town. 20 minutes highway and no brakes at the exit ramp. Half dozen pumps and back to poor but working. More bleeding this weekend. Anything else? Thanx, Dave

 

[mcgovern61]

Losing brake pressure and regaining some brake after pumping the pedal points to air in the system. Air can get in via leaking master cylinder or there is air trapped in the caliper (very common on the 1100 once air gets in). The issue is that once air is purged and the pedal gets normal pressure, you should not be getting air in the system again. It is possible that the return hole in the master cylinder is clogged and brake fluid is not returning.

 

[D-50Dave]

... It is possible that the return hole in the master cylinder is clogged and brake fluid is not returning.

I had that problem a couple of years ago that resulted in the brakes dragging. Rebuilt the MC and resolved that problem. Thanks for the input, Dave

 

[DaveO430]

Rode to work yesterday and that'll be it till the weekend. Initially no rear brake. Half dozen pumps and they worked they're way up to poor. Stayed that way thru town. 20 minutes highway and no brakes at the exit ramp. Half dozen pumps and back to poor but working. More bleeding this weekend. Anything else? Thanx, Dave

Same thing happened to me yesterday on my 81. Bled the rear after I got home and it's good again. With the reservoir well above the rest of the system I don't get how air can get in it. I think I'll hang a weight on the pedal when it's parked.

 

[D-50Dave]

Update: Bled the brakes again this past weekend not much improvement. Clamped the brake down for 36 hours and when I removed it to ride to work it was normal, like it's been all the years I've owned it! Why does clamping down like that work? It seems like voodoo magic. Maintained full brake the entire ride in, but 10 hours later the pedal was soft but better braking power. Borrowed a hand-pump brake bleeder system from my friend. We'll bleed and clamp some more this weekend.

 

[gallagherj36]

I had gone through this and turn out after replacing master cylinder and pads it was rotor had warned down so as nothing would fix it .had to replace rotor.all was good

 

[DaveO430]

I have a theory. Does your reservoir cap look like the one on the right or left? It woke me up thinking about it. Mine was like the one on the right. The bellows is already extended so when the fluid cools off it doesn't allow expansion so it sucks air in around the master cylinder outer cup. I found this other cap with the bellows like it should be and put it on, we'll see.

 

[dan filipi]

The one on the right should fold down and look like the one on the left.

 

[DaveO430]

The one on the right should fold down and look like the one on the left.

Yes, it doesn't, that's my point.

 

[dan filipi]

Ah, okay. Hope that fixes it for you!

 

[D-50Dave]

Mine looks like the one on the left.