Rear disc drags

[dscratch]

On the way home from work today my Speedee felt like it got weak. I pulled over and noticed that my rear disc brake is dragging (pads are rubbing against the disc). When I push the bike I can hear the drag. I checked the brake pedal adjustment screw and it is in it's full up position. Or in this case, the position that would allow the peg in the master cylinder to go to it's full out position. Can someone help me figure out how to adjust the rear disc brake so it doesn't drag?

Here are some pictures of my brakes:

[katoranger]

In the second picture you can attempt to adjust that linkage attached to the pedal.

You need to adjust it so that the bolt portion almost touched the pedal.

I actually removed a portion with a grinder.

Try adjusting it first, but welcome to the club.

Allen

[dscratch]

I adjusted the bolt in picture 2 that is attached to the plunger. I also let a little out fluid from the bleeder screw. It seem to push much easier and doesn't seem to drag. Of course it's cooled down now so we'll see what happens when it warms back up again. It seemed as if the cylinder plunger was stuck because I noticed there is more play in the plunger now. Again, I'll take a cruise tomorrow and see what happens, but for now it seems to push smooth again and doesn't feel like it's hanging up.

Hey katoranger...did you ever figure out your rear brake problem?

[motohillbilly]

I had the same problem. Get some Real DOT4 or 5 break fluid and bleed that Chianese gravy out. The boiling point on that stuff is low, and there is probably air in the caliper. Bleed it well at the very least. Dont trust it until you bleed it.

[PorterzCustomz]

Take the adjuster completely out and you will have not more problems. Same thing happened to me.

[red2003]

Originally Posted by motohillbilly

I had the same problem. Get some Real DOT4 or 5 break fluid and bleed that Chianese gravy out. The boiling point on that stuff is low, and there is probably air in the caliper. Bleed it well at the very least. Dont trust it until you bleed it.

It has nothing to do with the fluid type or bleeding. Do a search here, it's well documented. You need to adjust, or grind off material to let the plunger come completely out of the master cylinder. Pull the linkage apart and you will see what needs to be done.

[katoranger]

I have bled all the fluid out too. It was nasty dark dirty looking.

That wasn't the problem though.

I installed a honda master and the plunger was too long. Cut it done to length.

If it is possible remove the adjuster and mount is direct.

Allen

[dscratch]

Originally Posted by red2003

It has nothing to do with the fluid type or bleeding. Do a search here, it's well documented. You need to adjust, or grind off material to let the plunger come completely out of the master cylinder. Pull the linkage apart and you will see what needs to be done.

Took a ride the other night. Did not use the rear brake at all. After riding for about 20 minutes it starts to grab. I touched the caliper and it's hot. Once the caliper cools down for about an hour it releases.

So, when the caliper gets hot you cannot push the bike. When it's cool, you can.

As suggested,

I took apart the linkage and pulled on the plunger, it's as far out as it can be pulled under cold conditions. There is no doubt the plunger is in it's full out position. The break pedal doesn't hit the adjustment screw, there's about a quarter inch gap between the adjustment screw and the pedal. I can lift the brake pedal up to ensure the plunger is fully out. It is, unless the cylinder is defective.

Since the pads only grab and drag after being heated up with about 20 minutes of riding, I'm going to hit the DOT4 fluid and give that a try. At this stage I would suspect it's not the linkage since the plunger is as far out as I can physically pull it.

I'll let you know what happens with the DOT4 or 5.

[PorterzCustomz]

Originally Posted by dscratch

Took a ride the other night. Did not use the rear brake at all. After riding for about 20 minutes it starts to grab. I touched the caliper and it's hot. Once the caliper cools down for about an hour it releases.

So, when the caliper gets hot you cannot push the bike. When it's cool, you can.

As suggested,

I took apart the linkage and pulled on the plunger, it's as far out as it can be pulled under cold conditions. There is no doubt the plunger is in it's full out position. The break pedal doesn't hit the adjustment screw, there's about a quarter inch gap between the adjustment screw and the pedal. I can lift the brake pedal up to ensure the plunger is fully out. It is, unless the cylinder is defective.

Since the pads only grab and drag after being heated up with about 20 minutes of riding, I'm going to hit the DOT4 fluid and give that a try. At this stage I would suspect it's not the linkage since the plunger is as far out as I can physically pull it.

I'll let you know what happens with the DOT4 or 5.

Duude, like I said before take out the adjustment screw, it don't matter if its hitting or not. Mine did the same thing, took it out haven't had a problem since, end of story.

I don't know why your making it so hard for yourself

[dscratch]

Originally Posted by PorterzCustomz

Duude, like I said before take out the adjustment screw, it don't matter if its hitting or not. Mine did the same thing, took it out haven't had a problem since, end of story.

I don't know why your making it so hard for yourself

As you recommended...I removed the screw last week and it did the same thing. I tried it again today and after 25 minutes of riding the brakes locked up. Been there, done that...didn't work. Thanks for the help.

[motohillbilly]

Change the fluid and bleed the he11 out of it. It will likely fix it.

[PorterzCustomz]

you took out the screw and nut completely? If its still acting up next thing I would do is adjust the petal to master linkage so that there is more play before it activated the brake. If you do both and its still locking up I have no idea. I just really think it is one of those.

Hope this helps!

[dscratch]

I tried literally all link and adjustment screw possibilities. None worked. The brakes still lock up in about 20 minutes or so.

I drained the brake fluid and tried adding DOT4, but the fluid will not pass from the fluid cup to the lines.

I filled the cup to the top and hit the pedal nearly 1000 times. The cup is still full of fluid. I also tried to hold the pedal down. The cup is still full. I cannot get the fluid into the brake line. Nothing comes out of the bleeder screw and the cup remains full of fluid. I tried to close the screw and build some pressure. Nothing happened.

When I drained the fluid, It was almost as if the fluid in the line drained out, but thats all because the cup did not lose any fluid or go down.

Am I doing something wrong or is my master cylinder bad?

How do you get the brake fluid in the line?

[usmc-mustang]

Originally Posted by motohillbilly

I had the same problem. Get some Real DOT4 or 5 break fluid and bleed that Chianese gravy out. The boiling point on that stuff is low, and there is probably air in the caliper. Bleed it well at the very least. Dont trust it until you bleed it.

NONONONO Do not use Dot 5 in a sytem that previously contained Dot 3-4 fluid. Unless, and here it is, the system is completely new. The fluids are not compatable in any way. One is Hygroscopic water based, and the other is a Silicone based fluid. Mixing the two will make a mess that will require full replacement or rebuilding at minimum.

Use dont 3 or 4 fluid only.. Now I return you to your regular forum.

[dscratch]

Originally Posted by usmc-mustang

NONONONO Do not use Dot 5 in a sytem that previously contained Dot 3-4 fluid. Unless, and here it is, the system is completely new. The fluids are not compatable in any way. One is Hygroscopic water based, and the other is a Silicone based fluid. Mixing the two will make a mess that will require full replacement or rebuilding at minimum.

Use dont 3 or 4 fluid only.. Now I return you to your regular forum.

I am using valvoline DOT 3 & 4. Here's a link to the fluid I got....

http://www.valvoline.com/pages/produ...sp?product=138