Jump to content
Sign in to follow this  

Rear Brakes not working!

Recommended Posts

I took the DRZ E out today for a little spin and the rear brakes barely worked . If I lift the tire off the gound and push the brake pedal, it will stop the wheel from spinning, but not until the very end (ie pushing hard to the end), but when I ride it, I only get a little slow down by pushing all the way down. Last time I took the bike out (Nov), the brakes worked fine. Because of this, I assume the pads are fine, so does this mean I probably need to bleed the brakes? Could it be the master cylinder? I checked the fluid level, and it was fine (and no clog in the line), but it hasn't been changed in a two years! (maybe I should start there!)

I did a search on this branch and found suggestions on how to bleed the brakes, but since I have no clue about brakes, I'm not even sure where the Bleeder screw is. I think it's that bulbed head screw with a dust cap on it that looks like a tube would connect to it on top of the brake caliper? I assume the Master cylinder is the part where the oil resevoir tube connects to (ie where the pedal pulls out from).

Sorry, like I said, I don't have a clue with brakes, but I want to fix it myself and learn. Taking it to a shop would be too easy! Any advice?

Share this post


Link to post
Share on other sites

I've had this happen with my bike when it was basically new. I still have the brake issue, it happened shortly before my bike was put away for the winter. At the end of the month I'm taking it to the dealer to have a look at it cause it's under warranty. I've heard of this happening a few times on this forum, but not many, I'd like to know why as well.

Share this post


Link to post
Share on other sites

You are probably going to need some help with this. I would suggest remove the brake pads and dismount the caliper. Now pump the brake pedal a few times and see if the piston advances. If it does, that's good. Now push the piston all the way back in. It will be stiff but you should be able to do it by hand. If you can't, rebuild the caliper - the piston is frozen. Everything ok so far? - go ahead and reassemble everything and bleed the brakes. New fluid and removal of the air should fix things.

Share this post


Link to post
Share on other sites

Check the rear master remote reservoir. It's the clear plastic part just above the master cylinder itself, attached by a hose. They are prone to bulging and becoming distorted. Could have an effect on pressure, do another search on this forum for the CRF master cylinder upgrade. Soft rear brakes are a common complaint here, and many have swapped to the CRF cylinder.

It is a direct (virtually) bolt on, the smaller piston diameter means higher pressure and firmer braking, and it eliminates the weak plastic remote reservoir. All good things! :cry:

Share this post


Link to post
Share on other sites

Thank guys. I bleed the brakes today and it got a little better, but still not really working. If I push real hard, I can get the tire to skid (kind of), but that all. I think all the air is out too. I purchased some tubing and a resevoir from an auto parts store and pumped pumped pumped, bleed, pumped more, bleed, etc. I didn't see any bubbles in the line. There's pressure on the pedal, but it's still not stopping much. The piston/caliper seem to be working too. Do I need to pump and bleed some more, or as Aspencop129 suggested, is it time to purchase the CRF master cylinder? My local dealer wants $119 for the 450 CRF M/C; $159 for the OEM one. Maybe it's the pads? Thanks again.

Share this post


Link to post
Share on other sites

Dirt or roughness or (?) preventing the pistons from moving properly. I think you need to dismount and dismantle your calipers for a full on inspection. If not that, then it must be your hydraulic circuit - either master or slave. If you got good fluid movement during the bleed, I"d say slave.

Share this post


Link to post
Share on other sites

You can find "used" CRF masters here in the for sale section, or on Ebay fairly frequently for about $40 to $50. Many Quad racers will buy a new CRF450 for the motor, and part the rest out :cry: It was a good and inexpensive upgrade. :cry:

Share this post


Link to post
Share on other sites

Adjust the master cylinder linkage to push on the master cylinder sooner.

The footpeg mount on the frame will stop the lever before you get them working to thier full potential.

A little adjustment so the brakes work 100% and you will probably be fine.

Share this post


Link to post
Share on other sites

I had the same thing happen to me. Bled the barkes. No help. Pads were fine, but I replaced them any way and they worked fine ever after. I don't know why, they just did.

Ken

Share this post


Link to post
Share on other sites
because when you pushed the piston back to install the new pads it forced out the air bubble it had.

Perhaps, but the piston was manipulated several times before I instaled the new pads and the brakes were bled out thoroughly as well. I should think that those measures would have dislodged any air bubles, but may be not.....:cry:

Share this post


Link to post
Share on other sites

Well, thanks again for all the instruction, but I tried everything again with no luck. I took off the break the checked the piston and cleaned everthing. I had good pressure and when I pressed on the break the piston would move. I could push it back in (but only when I openend the bleeder screw, otherise I couldn't push it back in). Does this mean the piston is frozen?

Anyway, I put it back together, added fluid, pumped, bleed, pumped, etc, until no air bubbles and I had good pressure again. I made sure the linkage was adjusted correctly (doesn't hit the foot peg at all). Took it for a test drive, and the breaks were exactly the same!!! My only guess now is that it's the brake pads, or as Slide said, the "Slave" (whatever that is), or frozen piston??? Before I purchase the M/C, how do I know if the pad are bad? Is there a certain mm thinkness they are supposed to be? They measure out about 5.9 mm now. Thanks,

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×