Squishy rear brake

[greiffster]

The rear brake seems a bit squishy on my '08 GSA. It seems to have a lot of brake pedal travel before I get substantial brake power. And then, it's not that much stopping power, in my opinion.

 

I just re-bled the rear brake again. I didn't notice any air in the line when I did it, and I don't feel any difference. I have yet to pull out the GS-911 and run the ABS stuff.

 

I am trying to figure out what is normal rear brake pedal travel and power on this bike. I realize this might be hard to quantify/qualify over the internet.

 

I should add that this a new bike to me coming off an '03 1150RT with the whizzy, linked system. So, when stepping on the rear brake pedal on that bike, I got power to both the front and rear. So, maybe it's just my brain that got used to more stopping power when applying the rear brake.

[lkraus]

I have yet to pull out the GS-911 and run the ABS stuff.

 

I'd try that first. It's cheap and easy to check, and seems to be a pretty stringent test. On my RT, passing the GS-911 test took an extreme amount of pressure until it spent a night with the pedal wedged down and the lever strapped tight. It now passes with a normal amount of effort, though I cannot say the brakes feel any different.

[Bernie]

Rear brakes on the none whizzy brake bikes is very weak. But you should have solid pedal.

I don't know how many miles are on the bike or the rear pads, but you may want to check carefully both brake pads, you maybe at or close to the limit. They do not wear evenly, neither do the front pads.

[greiffster]

The bike has 32k miles, but the pads are not original. They look very new with lots of meat and are very even. I'm not sure when they were put on.

[Bernie]

Mine don't wear even. The right side pads wears faster.

The only thing I can think of is that the slide pins are seized.

Try to separate the pads from the disc and work it a few times.

Try that a few times and if it doesn't get better, remove and replace the pins.

Did you perform a complete brake flush? There has to be air in there or the foot pedal is out of adjustment.

How are the front brakes?

 

PS: try something else, take some 3M Scotch pads and clean the rear disc thoroughly on both sides. Maybe there is some sort of coating or residue build up on the discs. You could also sand the pads a little to rough them up, used to work on my Moto Guzzi.

Edited April 2, 2017 by Bernie

[greiffster]

I just did the brake flush last month and inspected the brakes. I'm pretty sure everything is moving on the pins properly. But I'll take a look. I'll clean the disc and give it a try.

 

The front brakes work very well. The way I would expect. I think I might be expecting too much from the rear.

[temesvar]

I just did the brake flush last month and inspected the brakes. I'm pretty sure everything is moving on the pins properly. But I'll take a look. I'll clean the disc and give it a try.

 

The front brakes work very well. The way I would expect. I think I might be expecting too much from the rear.

With all respect,this is just my opinion:

Big bikes don't even need rear brakes, that is what down shifting does.Front brakes are what we need. Rear brakes are for small engines

and bicycles!On the other hand, you may need good rear brake when you panic and have no time to downshift!Altough, it may be of little effect.

I rode my bike for over a month with my right foot in cast. I couldn't drive the car, and had no problems riding the bike.

[Bernie]

I just did the brake flush last month and inspected the brakes. I'm pretty sure everything is moving on the pins properly. But I'll take a look. I'll clean the disc and give it a try.

 

The front brakes work very well. The way I would expect. I think I might be expecting too much from the rear.

With all respect,this is just my opinion:

Big bikes don't even need rear brakes, that is what down shifting does.Front brakes are what we need. Rear brakes are for small engines

and bicycles!On the other hand, you may need good rear brake when you panic and have no time to downshift!Altough, it may be of little effect.

I rode my bike for over a month with my right foot in cast. I couldn't drive the car, and had no problems riding the bike.

You may very well have a good point. My RT never had good rear brakes, but I don't think the pedal is soft or squishy. It's more like wooden, if that is a good description.

As for braking in a emergency, the rear brakes alone ain't going to help you, and neither will done shifting.

[Tri750]

Maybe check what brand/compound pads are in the rear.

But yes, the rear is wimpy like many modern bikes.

I Use the front only unless it's raining .

That's on all my bikes.

Edited April 2, 2017 by Tri750

[dirtrider]

The rear brake seems a bit squishy on my '08 GSA. It seems to have a lot of brake pedal travel before I get substantial brake power. And then, it's not that much stopping power, in my opinion.

 

I just re-bled the rear brake again. I didn't notice any air in the line when I did it, and I don't feel any difference. I have yet to pull out the GS-911 and run the ABS stuff.

 

I am trying to figure out what is normal rear brake pedal travel and power on this bike. I realize this might be hard to quantify/qualify over the internet.

 

I should add that this a new bike to me coming off an '03 1150RT with the whizzy, linked system. So, when stepping on the rear brake pedal on that bike, I got power to both the front and rear. So, maybe it's just my brain that got used to more stopping power when applying the rear brake.

 

Morning Mike

 

Depending on rear brake pad material & amount of brake rotor glazing not having a lot of rear brake power could be normal.

 

But a squishy rear brake pedal isn't.

 

The place to start on the rear brake is to lightly move the rear brake pedal within it's easy movement & see if you have a lot of play in the pedal & push rod BEFORE it makes contact with the master cylinder push rod. (some or all of your perceived pedal movement might be coming from pedal & push rod play)

 

Once you have the linkage part accounted for then you have the hydraulic part to deal with.

 

On the BMW I-ABS gen II brake system it is sometimes very difficult to get all the air out of either end as that system doesn't have any bleeder fittings on the ABS controller.

 

One way to deal with trapped air it is to move massive amounts of fluid through the system as fast as possible.

 

A coupe of ways that I have found that (can) work is to:

 

First bleed as normal to get m-o-s-t of the air out-- then pry the rear brake piston side pad as far into the caliper as you can-- then hit the rear brake pedal as hard & fast as you can (be sure that rear master cyl cover is on for this).

 

If the pedal feel gets a bit better after one of the above then do it again (or a couple more times)

 

This moves a LOT of brake fluid quickly through the ABS controller so can pick up trapped air.

 

Another thing that can help is to take the bike out on a dirt or gravel road then get the rear brake only to lock up & go into ABS mode (do this a number of times). Then return home & re-bleed it (this can free up some trapped air that is trapped high in the rear brake circuit)

 

 

 

[greiffster]

Thanks all for the suggestions.

 

D.R., I think the linkage is good. The free pedal travel is about 1/2", maybe 3/4" before it makes contact and resistance is felt. At that point, the brakes quickly grab the rear disc and stop it from spinning while on the center stand. Maybe there is a bit of trapped air in there, so I'll see if I can work that out.

 

Ultimately, it's probably just me used to linked brakes for a couple of years. I do remember my old v-star having a very weak rear brake. Maybe I'll just have someone at START jump on it and give it spin and compare it to their bike. "Squishy" might be a bit subjective.

[Indy Dave]

FWIW - I've never been real impressed with my (wizzy) rear brake. Even after new pads. Then, later, after new rotor and pads. It does seem better when loaded down, so I finally decided it was related to abs and a light rear end - if that's even possible with me sitting on the bike.

[greiffster]

UPDATE:

So I took the bike on a spirited off road little adventure near the house across some undeveloped lots. I hit the rear brake quick and firm several times and then stopped and re-bled the rear brake. Rinse and repeat once more.

 

The rear brake now has a much firmer feel on a shorter throw of the lever. Plus it's got a bit more stopping power. Clearly, it had some air in the line somewhere. I flushed the brakes last month, but I am very conscious about the fluid level. So, I'm not sure if it was me or the last guy that let the air in.

 

I'm officially ready for START.

 

 

[Bernie]

Great! And of course the air was from the other guy, as we don't know him. LOL

 

[greiffster]

Great! And of course the air was from the other guy, as we don't know him. LOL

 

 

Correct. I rarely screw stuff up.