dragging rear brakes

[Rick b]

Hopefully someone can advise me on this issue. I just installed new oem pads on the rear of my 05 RSTD . I noticed some drag when I pushed the bike back and the rotor is hot after a 2 mile test ride. Did I do something wrong? Will the pads wear in?

[V7Goose]

No, the pads will not "wear in".

 

Without knowing what work you did and how, it is unlikely that I can tell you what is wrong. If you had the wheel off, maybe you put the spacer in on the wrong side of the caliper bracket? If you took the caliper off the bracket, maybe you cross threaded one of the bolts and it is not properly tightened, allowing the caliper to be crooked?

 

Maybe there is a lot of old crud built up around the slave pistons, keeping them from easily moving back into the cylinder and taking pressure off the pads? Maybe you didn't get all the pistons properly compressed back into the slave cylinder at all? Maybe you added fluid to your brake system while the old pads were still in there (this should almost NEVER be done!), resulting in an over-full master cylinder now after you compressed the pistons to allow room for the new pads? Maybe your brake pedal is hanging up?

 

Can't think of any other typical problems that could generally cause this after a pad change...

Goose

[Miles]

Just about all the errors have been brought up by V7Goose. If your new brake pads are dragging...something is wrong. If the job is done correctly, then the installation of new pads will have the brakes feel as smooth as the old ones, but with better braking control and power. It may take a little bit to "seat" the new pads to the old rotor, or even to a new rotor if you installed one, but the "seating" process does not take long, maybe 100 miles as an example, however until then, there is no dragging. The brakes will feel normal until that time.

 

As Goose stated, there is a mistake somewhere. Question: Have you ever replaced brake pads on a bike before????????? There are many places on this forum that explain the intimate details of "how to" on just about every job that needs to be done on these bikes, including how to properly replace the brake pads.

 

As far as you stating that the rear rotor gets "hot" after 2 miles...that should never have occured. Meaning...if you rolled the bike ten feet and felt the brakes dragging, you should never have ridden the bike. What if that "dragging" feeling turned into a rear brake lock-up ????

 

Either rear your service manual, look it up on this forum, have someone else help you, but...this needs to be corrected immediately.

[Rick b]

Thanks for the tips and advice on this. I did read thru a lot of the posts on the site and I am fairly confident that I did't do anything completely stupid but I am going to go back and check everything noted here I had some trouble getting all of the pistons pushed back evenly ( one moves out as another is pushed in) so I will check that carefully as maybe one or more is binding in the bore. Can you tell me how the pistons are retracted back into the caliper once you take pressure off of the pedal? are there springs or some device in the caliper to pull the pistons back?

[Pegasus1300]

The easiest way I have found to retract the pistons is to clean around them first then use one of the old brake pads and a C clamp to compress them in.

[frankd]

If one piston moves out when the other moves in (when you are trying to retract the pistons), it's obvious that you didn't open the bleeder and dispose of the old brake fluid in the caliper. Check your master cylinder....it's probably over-full. I'm not sure exactly what 2nd gen master cylinders look like, but on my 1st Gen., you can use a turkey baster to remove any excess brake fluid. You don't want your master cylinder reservoir full to the top....keep it 1/2"-3/4" below the top. Another way to get some of the fluid out would be to open the rear caliper bleeder, push down (and hold) the brake pedal. Then close the bleeder and release the brake pedal. Repeat several times. It would help to have somebody else push the brake pedal for you, and you just tell them to push it down and release it at the proper time. You don't want to release it when the bleeder is open...you will draw air into the caliper.

 

 

After you get the brakes releasing properly, you probably want to flush out ALL of the old brake fluid.

 

 

Frank D.

[Rick b]

O-K This is very helpful , you are correct I did not bleed any fluid. I think I assumed that the the level of fluid would only return to what it was when the bike was new as i have never added any to the master cylinder but maybe it does not work that way.

 

I can't believe the amount of info and help i am getting , Thanks to all.

[V7Goose]

A brake system is a semi-sealed system. There is a pleated rubber cover on top of the fluid in the master cylinder, and as fluid is pushed down into the line towards the slave, air is sucked in on top of that rubber cover. As the pads wear down, the slave pistons must stay further and further out to keep them close to the rotor, so this requires more fluid from the master to move down into the system, lowering the level. A brake system is designed to never run too low on fluid before all the pads in the same system are completely worn out. This is why you should NEVER add fluid unless you have a leak.

 

Nothing really retracts the slave pistons when you take your foot off the brake - just the pressure from the rotor pushes the pads back until they just barely clear the surface.

 

Ordinarily you do not need to open anything or bleed fluid to replace the pads. When you push the pistons back into the slave, the fluid is simply pushed back up to the master. So if you had one piston pushing another out as you tried to push it in, THAT is your problem. That never happens in a properly working system. Either the system is too full (could not be unless someone added fluid when the pads were not new), or there is a problem in the master cylinder that is preventing the fluid from getting pushed back into it.

Goose