Sticking Rear Brake Mystery

[chrissmith4483]

Hey guys/gals it's the orange fizzer guy again...
Anyways, here's the problem. 2005 Fz6
Tires changed a few weeks ago (got the new battle axe 023's)
Went riding and broke them in. Went out with a buddy and locked up my rear brake to avoid hitting him.
The rear started to drag immediately after the lockup (at least I didn't notice it until then)
I have since replaced rear pads and cleaned the rotor and entire caliper assembly. Still rear brake drag, gets very hot after about 10 minutes of riding, and I'm not using the rear during that time!
I pulled the rear caliper again, bled the lines, cleaned and lubed parts that the pads slide on, changed dot4 fluid, and reassembled. Still rear drag.
So, after examining the pads again I've noticed the pad closest to the caliper piston is wearing way fast compared to the other pad. Like noticeable amounts of wear in just 3 weeks?
I've checked the rotor, no noticeable warping it looks perfect to the naked eye anyways. The piston moves in and out of the caliper, but it takes pretty good pressure to make it go back in. I should mention that the rear break still work when used, they just don't seem to let go all the way.i am out of ideas... I even checked the petal adjustment and it releases all the way.
Any ideas before I get *aped by the mechanics?
Could this be as simple as wheel alignment?
Any info would be great...

 

[Humperdinkel]

My 1st thought would be checking the wheel allignment & go from there :thumbup:

 

[TownsendsFJR1300]

The piston should push back in easier than that.

Yamaha recommends brake caliber / brake line replacement every TWO years.

My 07 FZ6, with 5k miles had the front calibers start to stick some. I cleaned them up (no new seals-looked good) and re-assembled with BRAKE SPECIFIC GREASE. Solved the sticky brakes.

The correct way to repair it is to remove the caliber/piston dust seal and fluid seal and clean everything (especially the piston). You should replace the seals and re-assemble with BRAKE SPECIFIC GREASE. Its not like regular grease, most automotive stores carry it (I use Permatex- a fairly large bottle for $8.00). Yamaha included a small packet of grease when I rebuilt my 04 FJR's ft calibers (4 pistons each side).

You can probably get by without new seals (depending on how they look) but use the grease on the seals/piston and sliders. Make sure its CLEAN. It'll assemble MUCH EASIER and won't gunk up as quick.

 

[chrissmith4483]

Okay, thanks to those whom have responded. I went out and bought some of the high temp brake lubricant. My plan is to drain the rear brake of fluid completely and then pop out the piston. Then I will thoroughly clean all the parts and lube up the stuff that moves. Does this sound about right?>

 

[Fred]

Okay, thanks to those whom have responded. I went out and bought some of the high temp brake lubricant. My plan is to drain the rear brake of fluid completely and then pop out the piston. Then I will thoroughly clean all the parts and lube up the stuff that moves. Does this sound about right?>

That's dead on, except that you will also want to replace the seals while you're doing this.

You can sometimes get away with not replacing the seals, but for best results, new seals are the way to go.

EDIT: I'm about to rebuild a caliper here. I'm not going to replace the seals. I figure, if it doesn't work, I can rebuild it again and replace seals. It depends if you're willing to risk a second rebuild versus saving the cost of the seals.

Fred

 

[TownsendsFJR1300]

That's dead on, except that you will also want to replace the seals while you're doing this.

You can sometimes get away with not replacing the seals, but for best results, new seals are the way to go.

EDIT: I'm about to rebuild a caliper here. I'm not going to replace the seals. I figure, if it doesn't work, I can rebuild it again and replace seals. It depends if you're willing to risk a second rebuild versus saving the cost of the seals.

Fred

On my FJR that was older with more miles and was dragging prettty bad. I replaced all the ft seals and used brake grease that came with the seals from Yamaha. Its fine now.. The ft seals were over $100.00 themselves...

The FZ6 was newer, less miles and was just starting to drag. The FZ got cleaned only and greased, new fluid, works fine. If you have the time/knowledge to do it yourself (I know you do Fred) thats what I would do.

BTW, I could not tell the difference between the old seals and the new ones, look/feel.

The single rear brake seal kit should be considerably cheaper and much easier than the 4 pot each fronts.....

 

[Fred]

BTW, I could not tell the difference between the old seals and the new ones, look/feel.

I just finished the four piston Brembos on the black bike. I fixed the dragging brake first, and it went so well that I did the other one as insurance.

The seals were fine, just covered in a grungy substance that wiped off. Saved me $200 by not buying new seal kits from BMW.

On the CX500 Turbo that I did this past summer, it was a different story. The seals were rotted and encrusted with a layer of dried brake fluid crystals. Heck, it took me several hours per caliper just to scrap away all the crystals inside the bores and grooves. Those calipers got all new rubber.

I did a video documentary of that rebuild. Since it's on topic for this thread, I'll repost it here.

[ame=http://www.youtube.com/watch?v=XSQ5MiPq6yQ]YouTube - CX500 Turbo, day 8a.[/ame]

[ame=http://www.youtube.com/watch?v=_vd8heqsQcc]YouTube - CX500 Turbo, day 8b.[/ame]

 

[TownsendsFJR1300]

Fred, have you ever used brake specific grease upon re-assembly? I learned of this brake specific grease when I did my FJR (came from Yamaha with the seals)and have since bought the below listed product which is specifically made for brake seals/pistons/slider pins, etc. It makes re-assembly considerably easier. I lubed up the seals before re-assembly as well as the pistons. Popped right in... I suspect it would also hamper any corrosion..

[ame=http://www.amazon.com/Permatex-24110-Caliper-Brush-Top-Bottle/dp/B000HBNV6W]Amazon.com: Permatex 24110 Ultra Disc Brake Caliper Lube, 8 oz Brush-Top Bottle: Automotive[/ame]

 

[Norbert]

Someone who works at the dealership I go to told me to clean the calipers using car soap or simple green, water and an old toothbrush. (Don't use brake cleaner since it will dry up your caliper piston seals.)
He told me it will prevent brake dust build up and other crud from messing up your seals. It should make the seals work properly and last longer.

What do you all think? Sounds like good preventive maintenance.

 

[Fred]

Fred, have you ever used brake specific grease upon re-assembly?

I use a brake caliper grease like that one for the sliding pins and points where the brake pads touch the calipers. A fine layer on the back of the pads can also cut down on squealing.

I don't use it inside the caliper itself. For the pistons and seals, I just wipe them with a little clean brake fluid before installing them.

There are greases that are meant to be used on the seals of the caliper and master cylinder, but they're assembly and protective grease for OEM parts that may sit on a shelf for years before being used. I don't think they are the same as the caliper grease that you listed. The protective grease I've seen has been clear and smooth like Vaseline, versus caliper grease which is dark and almost gritty.

If you're rebuilding the part and immediately putting it into service, then a little brake fluid is all you need.

Cheers,
Fred

 

[Fred]

What do you all think? Sounds like good preventive maintenance.

I agree.

Fred

 

[chrissmith4483]

Okay guys. Just finished reassembling everything. I'm going for a quick night ride right now to break it in and see if the grease made a diff.
Btw the seals looked completely new, I just cleaned them. I will keep you guys posted.

 

[chrissmith4483]

Okay. After a short ride using only the rear brake it seems that the problem has been resolved. The rear wheel seems to spin better than it ever has. The only thing is is still sounds like it is rubbing. Is this normal? Anyways, i do appreciate all the help guys/gals. :rockon:

 

[TownsendsFJR1300]

There will always be a little bit of rubbing, the seals retract the pistons just slightly, the pads are resting inbetween the piston and disc. If you can get 3/4-1 full spin +, by hand, your good.

As long as the rotors and not getting hot (when not in use), the bikes assembled correctly(spacers, etc), and you have good pads, you should be fine.