parting out ?

[Chris Krok]

> From: Zachariah Mully > Subject: Incredibly crappy rear brakes > > Hey all- > Weird brake problem that I have with both my KLRs and that I've not > been able to fix. On both my A5 and A12 the rear brake is nonexistent > unless you stand on the brake lever, then it simply locks up.

Have you checked the pins? Could be that the pads/caliper are hanging up on the pins, and then suddenly letting go once the pressure gets high enough. C -- Dr. J. Christopher Krok John Lucas Adaptive Wind Tunnel Caltech MS 205-45, Pasadena, CA 91125

[tigrebleau]

--- In DSN_klr650@yahoogroups.com, Chris Krok wrote:

> > > From: Zachariah Mully > > Subject: Incredibly crappy rear brakes > > > > Hey all- > > Weird brake problem that I have with both my KLRs and

that I've not been able to fix. On both my A5 and A12 the rear brake is nonexistent unless you stand on the brake lever, then it simply locks up.

> > Have you checked the pins? Could be that the pads/caliper are

hanging up on the pins, and then suddenly letting go once the pressure gets high enough.

>

... Sounds like the solution. I recently put new pads on both ends and changed the brake fluid. Also checked to be sure the pins at both ends were well greased. Even though the old pads had about 1/4 of their life left, there is a huge improvement in the braking. Well worth the $75 for pads and $3.00 for fluid and 1/2 hour or so. Milt Rudy

[ravensval]

I have a quick question to anyone patient enough. I've got 6,900 on my A19 and the rear brake is now squeeking when I use it and it never has before. I put the bike up on a stand and spun the rear wheel to investigate. The brake pads sure seem to be gripping the wheel the entire way round... I know it wasn't doing that before. This is probably something really simple to adjust... I just don't know how or what to look for. Please don't spare any details if you will, I have no mechanical background to fall on. Thanks -Valerie

[klr6501995]

No adjustments to be made on the brakes. In my experience when pads start squeaking after many miles, the pads are worn down past halfway and the resonance of them changes. Also imbedded dirt in the pads and even lose bolts holding the rotor on the wheel. My riding has almost always used up the rear pad before the front, even being almost a front braker only. Squeaks and noises are always worth looking into but as I tell friends a squeaky brake can be perfectly functional. A dab of goop on the back of a pad can quiet it down. maybe just a spraying with a can of brake cleaner on the rotor and pads. My real guess is your pads are nearing the replacement point a 7kmi.

--- In DSN_KLR650@yahoogroups.com, "ravensval" wrote: > I have a quick question to anyone patient enough. I've got 6,900 on > my A19 and the rear brake is now squeeking when I use it and it never > has before. I put the bike up on a stand and spun the rear wheel to > investigate. The brake pads sure seem to be gripping the wheel the > entire way round... I know it wasn't doing that before. This is > probably something really simple to adjust... I just don't know how or > what to look for. Please don't spare any details if you will, I have > no mechanical background to fall on. Thanks -Valerie

[Eric L. Green]

On Wed, 6 Jul 2005, ravensval wrote:

> I have a quick question to anyone patient enough. I've got 6,900 on > my A19 and the rear brake is now squeeking when I use it and it never > has before. I put the bike up on a stand and spun the rear wheel to

Kawasaki uses sintered metal brake pads. They tend to be a bit noisy. That said, check the pads and make sure they are not worn out. Kawasaki has specs on minum pad thickness. You can get a caliper from Sears to measure thickness and use that to see, or if it seems to be getting thin, just replace the pads.

> investigate. The brake pads sure seem to be gripping the wheel the > entire way round... I know it wasn't doing that before. This is

By "gripping", what do you mean? Do you mean they make noise as the disk hits them? Or that they seem to be actually dragging all the way around?

> probably something really simple to adjust... I just don't know how or

Okay, here's the theory. Brake disk pads have no springs to pull them back. Instead, they rely on the fact that all brake disks are slightly warped. The high point on the warp will push the brake pads out a bit. So they should rub at a high point on either side (will not be same point on either side) because that's what shoves them out. Now, there is a complication here. The wheel cylinder is full of brake fluid. If the brake pads are to retract, that brake fluid has to go somewhere. The "somewhere" is back to the reservoir. But there is a master cylinder inbetween the wheel cylinder and the reservoir. This master cylinder has a little hole in it on one end (the end closest to the bottom, where the plunger goes in fron the brake pedal) to let fluid flow to or from the reservoir. When you start pushing down on the brake pedal, the plunger pushes upward, over this hole, and starts shoving the fluid in the master cylinder up into the wheel cylinder, where it then pushes the outside brake pad inwards, which also pulls the inside brake pad inwards since they are on a sliding carrier. As you continue pushing on the brake pad, the plunger continues trying to go upwards, exerting more force upon the brake pads. When you release the brake pedal, the plunger then drops back, and uncovers that hole, and the normal warpedness of the rotor pushes any excess fluid out the hole back into the reservoir.

> what to look for. Please don't spare any details if you will, I have > no mechanical background to fall on. Thanks -Valerie

The question is whether the pads are being allowed to retract. Check that one first. Remove the rear brake caliper (it is held to the big aluminum bracket with two hex head screws), and make sure it works properly. I.e., that the carrier can move back and forth with ease on its bracket. Lubricate the bracket with brake lube if that is not true, this will cause the inner brake pad to be a bit 'sticky'. Examine the pads for thickness. Try to push the outer brake pad towards the wheel cylinder to push the wheel cylinder back. Half a wooden clothes pin is good here, it will not break the brake pads and you can pry from both sides with the two halves. If you can make more room between the two brake pads, there's no problem with retraction. Put the brake back on (make sure the pads on on either side of the disc!), bolt it down, spin the wheel. It should spin fine. Press the rear brake pedal a few times. There should be some drag. If this is all okay, then your rear brake pads are just being noisy, it's normal, and don't worry about it. If you couldn't seem to pry more space between the two brake pads (note that it won't be a *lot* of space), first try the "if first don't succeed, use a bigger hammer" approach. That's a big C-clamp. If that's not doing it, there's two main possibilities here. The first is that the master cylinder's plunger isn't retracting all the way, thus not allowing that hole to be uncovered. Check to make sure there's not a mechanical problem keeping the plunger from retracting all the way, such as a loose bushing or junk caught in the brake lever keeping it from returning to its normal starting position. Try pulling the brake pedal up and see if it comes up, if so then try lubing the brake pedal shaft (see the repair manual) and see if the spring is present and pushing on th ebrake pedal. Try pulling the plunger down manually and see what happens. The second is that the hole itself is gunked up somehow. That is a harder one, but if there was gunk in the hole, your big C clamp should have made it come loose. So using your new theoretical knowledge of how the brake system works, and the cut-aways that you can find on Kawasaki's site, plus the contents of your Clymer manual, you should have a good start on figuring out what's the problem. Let us know what you find! -E

[Eric L. Green]

On Wed, 6 Jul 2005, klr6501995 wrote:

> My riding has almost always used up the rear pad before the front, even > being almost a front braker only.

You shouldn't ride the rear brake pedal.

> My real guess is your pads are nearing the replacement point a 7kmi.

My current set of rear pads have around 8k miles on them. They still have plenty of "meat" on them. By contrast, my fronts have only around 4k miles on them. I'm replacing them as soon as the new pads come in from Fred, because the right hand one (the inside one) is just about gone. These were EBC sintered pads (the thick ones). Granted, many of these miles were highway miles, which are easy on brakes. But rear brakes should still last more than 7k miles if you're not constantly using them. If they're not, you should see about cleaning up your rear disk, it's doing something to chew pads up. -E

[April Neave & Norm Keller]

If you don't have a small stone or the like jammed between the calliper and rotor, it is most likely that you have glazing of the pads and rotor. This is a common problem when some sort of material such as dust, mud, etc. becomes cooked to the brake lining and disk rotor. The change in the surface composition of the lining and rotor provides an interaction which makes audible sound rather than sound which is in the in-audible range as the designers intended. Several solutions: 1) Ignore the sound. 2) Hose the rotor and calliper with water then ride gently to attempt to remove/change the coating. Repeat. 3) Remove the calliper and sand the rotor and pad surfaces with 200 grit or so sand paper to remove the glaze. DO NOT USE EMERY PAPER OR CARBORUNDUM TYPE PAPER! It is important not to use harder abrasives which are likely to imbed into the lining and eat the rotor! Wet sanding is even better than dry. In either case use a swirl pattern rather than sanding straight across or axially. 4) Above then, apply an anti-squeal material to the pad and calliper surfaces and/or apply a surface preparation such a BG to the lining surface. DO NOT CONFUSE THE LINING SURFACE PREPARATION WITH THE ANTI-SQUEAL MATERIAL INTENDED TO GO BETWEEN THE CALLIPER AND THE PAD'S STEEL BACKING!!! HIH, if you need more or if this isn't clear please advise. Norm

[ravensval]

> By "gripping", what do you mean? Do you mean they make noise as the

disk

> hits them? Or that they seem to be actually dragging all the way

around? Yes, it's dragging all the way around right now. By contrast, the front wheel just drags in a few places like it's supposed to, and otherwise spins freely. The rear wheel does not spin freely at any point.

> The question is whether the pads are being allowed to retract. Check

that one first. Okay, I'll take the caliper off tomorrow and see what I can learn. Thanks for the description! --Valerie

[klr650_ryder]

Valerie, Well I have had a rear brake squeak since about 500 miles. I looked High and low for anything that would seem out of the norm. So since being a mechanic I tried a trick I use on automobiles. I took the pads off and lightly sanded them with 200 grit sandpaper. Installed them again and they stopped the sgueaking. My only question is are they squeaking when you apply them or all the time. If it is all the time you can try to apply dry graphite to the slides the could be hanging in you a bit. Other than that I can only come up with the pads have a good amount of metalic compound in them . That will make them last longer but they do make noise. It is like metal rubbing metal. Let me know if this helps. Don A19

[ravensval]

Hi everyone thank you for your input about my rear brake squeak. I bought a hex bit socket set and took the calliper off. The brake pads seem fine, over 3mm. It seems the annoying squeak must be from what you described as glazing of the pads and rotor. It's good to find the answer. I didn't realize how simple the braking system was until it was in my hands and I was looking at it. I couldn't get the brake pads out at first, but that turned out to be easy, too. Valerie