Rear brake power

[nico]

Hi,

Not having had a GS before I'm wondering about what is "normal" for rear brake power. On my 81 GS850G, when I press the brake pedal it is hardly noticeable. Nothing much happens really, I have to press real hard for anything to happen, but if I press hard enough it will in fact lock the wheel. Its effect is only really noticeable at very low speeds. Right now the tiny drum brake on my moped feels more powerful (obviously it's also about 500 lbs lighter) so I think something has got to be wrong.
I just replaced brake fluid and bled it, the pedal feels real good now from the first push, but not much happens anyway. Pads seem fine too. The rotor doesn't look new but I've seen worse.

So my question is, is the rear brake just this weak or should I look into this further?
If it's not supposed to be like this, what should I be looking into?

Thanks!

 

[ShadowFocus603]

What about the brake line from the master to the caliper? Look for date code. I'd bet you still have a 35 yr old rubber line on there. I ordered stainless steel lines for mine. I will say though that the back brake does the least effective amount of stopping. Something to keep in mind.

 

[nico]

The brake line is indeed a rubber one. I can't find a date on it (there's some text but it's unreadable) but it looks to be in good shape. Not bulging or showing any cracks or anything.
The pedal goes down less than an inch before it goes stiff, I'd expect it to feel soft if the line was bad. It was pretty soft before I changed the fluid but it's nice and stiff now.

I have to take my rear wheel off this week to replace the tire. I'm thinking of putting the rotor up in my lathe and deglaze it to see if that makes any difference.

 

[Guest]

The rear brakes on these bikes are known for being poor. Best you can do is put in stainless lines and new pads, even then they don't really do much. Make sure your front brakes are as good as they can be.

 

[nico]

Thanks for the tips. Good to know that perhaps it's just not going to get much better. A friend took it for a ride today and the first thing he said when he got back was that the rear brake didn't seem to be doing much. That was before the fluid change though. I think the pedal was actually bottoming out against the pipe then so he may not have had full power.
Front brakes are awesome though

About the stainless lines. Does anyone sell ready made that will fit or do I have to get them custom made?

 

[ShadowFocus603]

I just measured mine then added an inch and figured the banjo bolts I needed then took to ebay looking for made to order lines. I can tell you the rear line you want will be 35".
http://www.ebay.com/itm/90cm-35-Mot...ash=item36017aa483:g:x~kAAOSwciVXQgKy&vxp=mtr
Pretty sure that's the one I ordered. One end has a zero degree straight banjo the other end is a 15 degree bend banjo.

 

[nico]

Thanks for the link!
I just measured my brake line and it's about the same length give or take half an inch. I'll see if I can find something that's not made in Hong Kong first though, because of the varying quality of products from there.. Obviously want to be able to fully trust it.

Anyway I just put the bike up on its center stand and put it in 2nd gear and let it idle, and hand sanded the rotor in place with some 240 grit wet sandpaper. There was a lot of black stuff coming off it, and it was not the paper because that was white. Also sanded down the pads until they looked even. Brake performance definitely improved already.
Gonna be fun to see if a new brake line makes a difference. For cars I've read mixed opinions, most say the difference is not really noticeable for regular driving and you're better off with OEM lines for reliability. But this line is a lot longer than the lines on a car are so it might just make enough of a difference to be noticeable.