rear brake problem

loic · 05-29-2007, 12:10 PM

my rear brake stay stuck after I push on the well.....brake.. i don't mean that the pads are a little touching, i'm talking about, by hand, the wheel won't spin more than half turn. I cleaned the piston, change fluid etc...
the pad shows excessive heat ( they have a blueish color) also they BOTH have uneven wear, one part of the pads is a lot more used up than other part of the pad.
I can push back the piston without difficulty, but when I do , I hear a pffffffftt by the master cylinder ...

idea off what is the problem ?

GoFast · 05-29-2007, 12:43 PM

hmmm dirt in the fluid, caliper itself maybe?? try flushing the rear brake

loic · 05-29-2007, 12:48 PM

I took the caliper appart yesterday, cleaned the piston, seal, replaced fluid.

2upFZ1 · 05-29-2007, 01:09 PM

You are saying that the pedal is returning once you let off, but the pads stay tight on the rear rotor.

If that is it, bleed the brakes. Sounds like you have some air in the line that is staying compressed. Or some trash in the fluid not allowing the return spring to pull the pads off the rotor.

Bleed them enough to replace all the old fluid.

And while you have the tools out and plenty of fresh fluid, do the front too.

2upFZ1 · 05-29-2007, 01:10 PM

Doh, see what happens when I get started posting, then have to do some work.

2upFZ1 · 05-29-2007, 01:13 PM

Oh, and if it still does it after flushing, ziptie a 5lb weight to the pedal overnight, that will allow any trapped air bubbles to work their way up into the reservoir.

ars0n750 · 05-29-2007, 01:14 PM

air bubbles in the system?

Heres what i would do..

1. take off the rear caliper, not totally remove it from the bike, but seperate if from the wheel.
2.remove pads n shim etc
2a-PUMP REAR BRAKE LEVER TILL PISTONS ARE 3/4 out
3. pop off the top of the res.
4. get some brake cleaner and a big container, spray about 1/3 of the container with the brake cleaner, and then fill the rest up with warm water.
5. Soak the caliper in the container for a good hour.
6.get a brush, something that will get in the knooks and cracks clean them calipers goooood.
7.Wash off calipers really good with water.
8.push the pistons back in the caliper with ur fingers (not hard) Must make sure the res cap is off.
9.clean the rotor real well with the brake cleaner.
10. install caliper pads n shims
11.bleed brakes of air bubbles
12. Easiest way to do this.
a. pump lever like 10 times
b open air bleeder (1 at a time) theres 2 on the rear so becarerfull to do both
c. pump lever again but make sure to keep it held down as u tighten the bleeder valve. let go of the pedal after it has been tightened.
d. Pump lever again about ten times
e.cont with other bleeder till all bubbles are out of the system.
13. Fill res. and put cap on
14. good luck!

loic · 05-29-2007, 01:16 PM

yeah, the pedal is coming back, no problems, i used 1 bottle of fresh fluid yesterday..
what return spring you're talking about?

2upFZ1 · 05-29-2007, 01:24 PM

There should be one inside the cylinder. When you push on the pedal, there is a spring connected to the lever to return the pedal, but inside the brake cylinder there is a spring to return the piston and pull the fluid out of the calipers. To release the brake.

First off, what bike do you have?

loic · 05-29-2007, 01:28 PM

Quote:

Originally Posted by 2upFZ1

There should be one inside the cylinder. When you push on the pedal, there is a spring connected to the lever to return the pedal, but inside the brake cylinder there is a spring to return the piston and pull the fluid out of the calipers. To release the brake.

First off, what bike do you have?

a ZZR 1200. so maybe my problems is coming from that cylinder.
also when I pushed the pads away I heard some air ( pfffffttt) coming from the cylinder.
I 'm pretty sure my brake are bleed properly, and I used the mighty vac pump , it's a lot easier...

2upFZ1 · 05-29-2007, 01:48 PM

Go to the Kawi site and go to "Owner Info", then "Parts Diagrams".
http://www.kawasaki.com/DefaultFrame...OSEVEHICLE.ASP

Put in the year and model, and then choose "rear master cylinder" once the list on the left pops up.

There you will see an exploded view of the rear master cylinder. There is a spring that is in with the piston. Either it is corroded, or you got some trash in the valve keeping the fluid from returning into the reservoir.

Also, if at any time you got some moisture in there, it will corrode the brake parts on the inside. Which might account for the sticking.

Brake fluid absorbs water out of the air, so make sure that you close up the bottle of fresh fluid tight. And don't leave the cap (reservoir or bottle) off for any longer than needed.

Everyone should flush their brake system every couple of years just to get that old fluid out, and any moisture that it has absorbed.

loic · 05-29-2007, 01:56 PM

thanks, I guess , i'll take appart that cylinder today... I have 1 more bottle of brake fluid so I'm good !! on the diagram they call it : spring master cylinder, anyway that's the only spring in there...so it got to be that one !!

GoFast · 05-29-2007, 02:06 PM

Quote:

Originally Posted by loic

a ZZR 1200. so maybe my problems is coming from that cylinder.
also when I pushed the pads away I heard some air ( pfffffttt) coming from the cylinder.
I 'm pretty sure my brake are bleed properly, and I used the mighty vac pump , it's a lot easier...

yeah i would definatly use a power bleeder. and do it several times.

2upFZ1 · 05-29-2007, 02:12 PM

Make sure that the passageways inside the cylinder are clean, and the piston is clean as a whistle. Not even lint from the rag on either one.

As Arson mentioned, it might be a buildup of brake dust around the caliper piston not allowing it to return back into the caliper.

Oh, are the rear pad springs still there?

loic · 05-29-2007, 03:00 PM

Quote:

Originally Posted by 2upFZ1

Make sure that the passageways inside the cylinder are clean, and the piston is clean as a whistle. Not even lint from the rag on either one.

As Arson mentioned, it might be a buildup of brake dust around the caliper piston not allowing it to return back into the caliper.

Oh, are the rear pad springs still there?

there is no spring at the pads. there is 2 "clips"that hold the pads and 1 "clip"that hold the pin that goes into the pads

2upFZ1 · 05-29-2007, 03:17 PM

The ones at the pads are the ones I was referring to. They don't do much as far as retracting the pads, but they do help keep them centered when retracting.

loic · 05-29-2007, 03:19 PM

Quote:

Originally Posted by 2upFZ1

The ones at the pads are the ones I was referring to. They don't do much as far as retracting the pads, but they do help keep them centered when retracting.

ok, well they're both there..... I'm gonna try and check the spring in the cylinder and rebleed everything. i'm gonna start in about 30 minutes....so we'll see..

loic · 05-30-2007, 09:13 AM

well i took apart the master cylinder, the calipers ( again) cleaned everything, put it back and bleed it. but it does the same thing, it seems that when the brake is applied a little, then the piston retract, but if I put a lots of pressure on the pedal then the pads get stucks....
also both pads are wear down a lot more on the bottom than the top of the pads....which doesn't really make sens....

2upFZ1 · 05-30-2007, 09:15 AM

What year and how many miles on your ZZR?

2upFZ1 · 05-30-2007, 09:21 AM

If the pads are tapered, they might be jamming in the caliper, and not retracting straight.

loic · 05-30-2007, 09:32 AM

2002, 25000 miles,

loic · 05-30-2007, 09:33 AM

i'm gonna order new pads anyway those are shot..

2upFZ1 · 05-30-2007, 10:30 AM

I'd like to know why they didn't wear evenly. maybe the caliper piston was coming out at an angle (worn piston or cylinder) or hanging up on one side, causing it to push the pads at a weird angle.

Make sure that before you put the new pads on the glazed rotor, you take a 3M Scotchbrite pad to the rotor and get it all nice and cleaned up. So the new pads can seat properly.

loic · 05-30-2007, 11:47 AM

Quote:

Originally Posted by 2upFZ1

I'd like to know why they didn't wear evenly. maybe the caliper piston was coming out at an angle (worn piston or cylinder) or hanging up on one side, causing it to push the pads at a weird angle.

Make sure that before you put the new pads on the glazed rotor, you take a 3M Scotchbrite pad to the rotor and get it all nice and cleaned up. So the new pads can seat properly.

I will clean up the rotor properly. I had done that with the front wheel a couple months ago, I took the wheel off and then the rotors off and clean them off nice with a soft metal brush.

the way the pads are wear, it would be like the rotor as a V shape ?!!!!... that doesn't make sens. also the pistons can't really come out on a side. and if even one side was coming that way that would not make the other side to be exactly the same... at least I don't think so...
now , let's talk about something that's is easier, what type of engine oil is better, synthetic or not ?...hahahahah

2upFZ1 · 05-30-2007, 12:26 PM

If you have a micrometer or calipers, I'd check the inside/outside thickness of that rotor. Pads wear on the rotor just like a car (only not as bad)

Another thing you can do is remove the caliper from the mount, and push on the pedal until the pads just come together and see if the pads are flush on the pistons. If so, then you know that the pistons are coming out crooked. For some reason the two pistons aren't coming out straight like they should. Or the pads aren't tracking straight when squeezed.

Screw it, buy a new caliper/pads/rotor and be done with it. :-)

Synthetic/Non-Synthetic isn't as bad as the WD-40 as a chain lube controversy.

loic · 05-30-2007, 12:33 PM

Quote:

Originally Posted by 2upFZ1

If you have a micrometer or calipers, I'd check the inside/outside thickness of that rotor. Pads wear on the rotor just like a car (only not as bad)

Another thing you can do is remove the caliper from the mount, and push on the pedal until the pads just come together and see if the pads are flush on the pistons. If so, then you know that the pistons are coming out crooked. For some reason the two pistons aren't coming out straight like they should. Or the pads aren't tracking straight when squeezed.

Screw it, buy a new caliper/pads/rotor and be done with it. :-)

Synthetic/Non-Synthetic isn't as bad as the WD-40 as a chain lube controversy.

i whish I could afford new calipers.... but that won't happen anytime soon... now , wouldn't the wd40 dry to fast ?

2upFZ1 · 05-30-2007, 12:47 PM

I was kidding about replacing parts. If you need some help checking it out you can bring it by my house and I can help trace down the problem. Unless it can't be moved.

As for the WD-40 conundrum, forget I even mentioned it.

Find out why the pads are wearing funky, and you'll find your problem with the dragging brakes.