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:

http://aycu37.webshots.com/image/49756/2003409597379033587_rs.jpg (http://allyoucanupload.webshots.com/v/2003409597379033587)

http://aycu23.webshots.com/image/48782/2003412221399517319_rs.jpg (http://allyoucanupload.webshots.com/v/2003412221399517319)

http://aycu14.webshots.com/image/51973/2003404112631351517_rs.jpg (http://allyoucanupload.webshots.com/v/2003404112631351517)

http://aycu24.webshots.com/image/48823/2003407596884763757_rs.jpg (http://allyoucanupload.webshots.com/v/2003407596884763757) :cry:

[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]

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]

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.

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]

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.

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]

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.

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

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]

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]

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.

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

http://www.valvoline.com/pages/products/product_detail.asp?product=138

[motohillbilly]

Im using dot 5 with out issues. I did flush quite a bit thruogh though. I removed the line at the caliper and let it run through. then quickly put the line on and removed the bleeder. Gravity did the rest. After I did bleed the regular way. You may try a suction on the bleeder. I too tried everything else with no luck. This has been trouble free for 400 miles now.

[dscratch]

Went back out after posting. Decided to keep hitting the pedal as if I were pulling a handle on a slot machine that had a million $$ in it. Nothing happened until I started lightly taping on the Master Cylinder with a small rubber hammer. Yes...I started to see air bubbles. Took it through the rest of the process without a hitch. Blead the hell out of the thing as suggested. Time to go for a cruise with the new valvoline DOT fluid to see what happens.

Thanks for all your help. I'll let ya know how it turns out.

[dscratch]

Took Speedee Blue for a test drive and all is good. Drove for about 45 min without a problem. Replacing the brake fluid with the valvoline DOT 3 & 4 seems to have worked. Thanks for everyones help.

[motohillbilly]

Everything still working well?

[dscratch]

Everything still working well?

Yup, everything works well. The rears have not hung up since the DOT4 change. So, draining the fluid and putting in DOT4 has kept it working.

Did my first oil change at 50 miles this weekend. There were no medal flakes or pieces in the oil I drained, but it was a little dirty. Put in some new 15w-40 and will drain again around 100 miles.

I just ordered a 46t sprocket for the rear, the front is currently a 17t. This should work better than the 56t that came stock.

[motohillbilly]

Glad to hear it worked for you too. I am going to do it on the new bike one day this week. Only the front though.Rear is a drum.

[katoranger]

I got my cbr rear master mounted better and my rear brake has been fine.

Allen

[PorterzCustomz]

You said you changed the oil and you don't have any flakes are you sure? Mine still has flakes on the 5th oil change. They are very small they just make the oil metalic so you need a trained eye to see. What brand oil ru using?

[katoranger]

I had fine particles for a long time too.

[nathead]

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


How do you do this? I have been having this problem with my back brake for some time and it is really frustrating. I don't know much about bikes and wanted to try and take the adjuster out, but I don't really know what this is.. Please forgive my ignorance. I also don't know how to drain the fluid...i'm really really new..

[DesertDog]

:!: well i be ,
thats good info i'll have to try that on a quad i'm having fits with , the rubber mallet trick that is , i've bled and bled and i'm blue in the face from bleeding it, even made a pressure bleeder nothing works, so i will go do that
I've got to read more of these threads
DD

[dscratch]

You said you changed the oil and you don't have any flakes are you sure? Mine still has flakes on the 5th oil change. They are very small they just make the oil metalic so you need a trained eye to see. What brand oil ru using?

Maybe there were some flakes, my eyes are not trained. I'm using Mobil oil. Ordered a 46t from RabbitScooters. No response from them yet, but it's only been 2 days. Hopefully, the 46t will work much better than the 56t.

[Skip_200gy]

Ok, now I'm having this problem. Same symptoms , bike losing power and then realizing that it is the back brake dragging.
I've bleat the whole system and I'm 99.9% sure there is no air in the system. It does not seem to drag anymore, but then again, I suspect I might not have back brakes either. I'm hoping that maybe a bit of brake fluid spilled on the pads and that is why they aren't gripping, but I suspect there might be another problem. I'll only be able to go out tomorrow to see what it is really doing.
I've adjusted the nut under the master cylinder allow the piston to move out as far as possible. I'm sure there is enough travel to allow it to work properly.

[katoranger]

If you got some brake fluid on the pads it will need time to burn off before they will start working again.

My master cylinder failed so I bought one from honda cbr600 and modified the mount on the bike slightly. Seems to be working good now that I have it securely mounted.

Allen