No rear brake !!

[rayban]

I have a 1980 gs750e that was somewhat neglected by po. I rebuilt all the calipers and master cylinders. The fronts work great, but the rear barely works at all. When I press the pedal, it slows the bike a little.... won't lock the rear if I stand on it. I bled them many times... no air at all in system(as far as I can tell!). Pedal 'feels' good, brakes aren't dragging.... just no stopping power !!! Any suggestions???

[jwhelan65]

The rear brakes were not designed to lock up the rear wheel. They are merely there to assist the fronts from diving if used properly. Not sure on your specific year and model but usually there is an adjuster you can tighten to give you a little more bite.

[TopTechRacing]

How did the pad surface look? Try pulling them and sanding the face of the pad and then bed them in. Also check to see that you don't have a stuck piston.

[tkent02]

How did the pad surface look? Try pulling them and sanding the face of the pad and then bed them in. Also check to see that you don't have a stuck piston.

This. How old are your brake pads?

[Guest]

Brake pads and check the caliper, sounds like stuck piston to me. A 1980 750 Will lock the rear wheel very easily if all is working properly

[jwhelan65]

Brake pads and check the caliper, sounds like stuck piston to me. A 1980 750 Will lock the rear wheel very easily if all is working properly

Maybe from highway speed and that is not a good thing

[tkent02]

Locking the wheel is a bad thing, strong brakes are not if you know how to use them. Never seen a GS that couldn't lock the rear wheel easily if the brakes were working normally.

[Guest]

Locking the wheel is a bad thing, strong brakes are not if you know how to use them. Never seen a GS that couldn't lock the rear wheel easily if the brakes were working normally.

I know locking the rear brake is a bad thing , but these old GS's have way more brake than necessary, have you ever noticed the size of the rotor's? I personally bleed air into my rear brake as I seldom use it, only if I want to back a bike into a corner or emergency stopping . Other than that I don't use them . Must have come from my roadracing days.

[tkent02]

I know locking the rear brake is a bad thing , but these old GS's have way more brake than necessary, have you ever noticed the size of the rotor's? I personally bleed air into my rear brake as I seldom use it, only if I want to back a bike into a corner or emergency stopping . Other than that I don't use them . Must have come from my roadracing days.

I use the crappiest brake pads I can find on the back, the old petrified original ones are fine. I don't use it all that much either...

but the OP was asking for help with fixing his brakes, not opinions about how to ride.

[850 Combat]

On a cross country trip in '85, I was heading through the desert around Lake Mead. It was so hot that I took my Leather jacket off and bungeed it to the seat. I stopped at a lake side resort to cool off and get something to drink, down a bumpy dirt road. Getting back on to the paved road and accelerating, by rear brake locked up. It turned out that my Tourmaster jacket had come loose and got wrapped around the rear brake disc. It ripped the caliper off, leaving the bolts and the parts of the caliper where the bolts were. This bike had cast iron discs. The disc was shattered down to the hub. I continued the trip to Huntington Beach. I found out that I used the rear brake a lot more than I thought I did, particularly at gas stations and parking lots. Its nice to have one that works like it is intended to. On my first RD400, when I put rearsets on it, I was able to adjust the orientation of the levers on the rearsets and the linkage to make the brake way less sensitive than it was stock. That bike was way too easy for me to lock up.

I would pull the caliper or rear wheel off and observe how the caliper is operating when you press the brake, and confirm that the caliper is operating properly.