brakes rattle

The front brakes on my KZ1000E1 ST rattle a LOT when going over bumpy roads... I suspect it is the pads since I can apply the brakes slightly and the rattle goes away. The pads are retained by phillips head screws that go into the back of the pads. The screws are tight. I am at a loss. Anyone ever had this problem and fix it? The pads are new and the brakes work great, btw...

Am wondering if the rubber o-rings on the caliper holder shafts are damaged or worn and thereby allowing excessive play in movement between the caliper and caliper holder. Just a guess as to possible source of rattle.

If it's the pads, the copper permatex worked for me to prevent squealing -- maybe it would also stop them from rattling.

Are you certan that there are not spring parts in the brake assembly that you are missing? On my bikes, there is a spring steel piece that sits on top of the brake pads, in the apex of the slot in the caliper. It puts a slight amount of tension on the brake pads so that they do not rattle around. I don't know if yours are similar, but you should look on the schematic parts diagram to be certain you are not missing anything.

Another idea: My brakes were rattling a lot for no apparent reason, except when I applied the brake (when they would stop rattling). The problem turned out to be the start of wheel bearing failure -- just a little side play in the wheel rotation. The rattling disappeared after I replaced the wheel bearings.
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wiredgeorge wrote:

The front brakes on my KZ1000E1 ST rattle a LOT when going over bumpy roads.

I don't know that much about that bike, what year, double piston, or what-have you. I couldn't find it in the model history, but maybe this picture will help.

representative brake schematic?



As Patton alluded to, there are two caliper carrier bolts (#2 in the picture) that are isolated by rubber o-rings (#12 x 4)that keep the caliper itself from moving around excessively inside the bracket that secures them to the fork. There is a possiblilty that one or more of those o-rings have broken and have gone away, especially where dry conditions and ozone have attacked them. Applying the brakes would pull the caliper forward against the bracket, removing the play. It might be time to replace the bolts if this has occurred, becuase if there is any divoting in the bolts, the caliper won't slide on them properly as the pads wear.

Post edited by: KaZooCruiser, at: 2007/03/07 20:19

The front brakes on the ST are pretty much like those on the KZ1000A 1980. There are orings that go UNDER the rubber dust covers that go over the bolts that the pads slide out on. I don't think I used any orings (there were none there to begin with). The other rubber bits were fairly functional so I didn't buy "kits". I will try sticking some orings over the bolts and see if this helps the rattle. I do suspect it will... There are no spring clips like on the square pad rear brakes to keep them from rattling. Thanks to those who replied. I was able to figure out what was missing by comparing the part numbers for the pads as well as a few other part numbers and suspect the same front calipers are used on the shaftie as are on the standard (kz1000A).

wiredgeorge wrote:

. . . There are orings that go UNDER the rubber dust covers that go over the bolts that the pads slide out on. I don't think I used any orings (there were none there to begin with). . .I will try sticking some orings over the bolts and see if this helps the rattle. I do suspect it will... .

The o-rings go inside the mounting bracket. I couldn't see a number for it. It is the part that secures the caliper to the fork. There is an area inside of the bracket that is machined to receive the o-ring, and then the bolt compresses it against the housing when it is installed.

did you try checking the tin disc pieces that the screws go through into backside of pads?maybe they got flattened out a little too much to seat all the way against the caliper body and are rattling a little.i dont think the o rings do anything other than help hold the rubber boots on and keep the dust out if they are like the other kzs and ltds up till 1980 anyway.my guess would be the pad is rattling against piston and maybe try a little brake goo on back of pad to glue it to piston.

do you have a pulse in the handle?, if so it may be the rotor is not true, and is pushing the pads away from the rotor

The pulsing issue is a good point... absolutely no pulsing. It will be a few days before I can stick some orings on and the info on the orings is great! The drawing doesn't really show where the darn things go but I thought it must be fairly obvious once you take the brakes apart. Once I get orings on, I will follow up to note if this fixed the problem. Can't see how the metal cups that hold the pads could cause a rattle but I can put some adhesive on those as well I guess while I have the calipers apart. I hate working on brakes... filthy things hehe

i was thinking if the cups were a little tweaked and werent pulling the inside pad up tight against the caliper they could rattle a little bit.im still having a hardtime thinking what the o rings do decides keep dust out of the sliders;)

There are no sliders... the pads move on the two large bolts. There are orings around the bolts and these sit in recesses in the bodies and I suspect the bolts are what are rattling. The orings are not on the bike. There weren't any when I disassembled and it didn't occur to me to use new ones. There are ALSO dust cups over the bolts to keep crud out and the orings must sit up inside and under those dust covers.

A.S.E. hat on. . .

If the bike uses a full floating caliper, it means it is free to slide back and forth to compensate for wear on both pads. To allow for the back and forth motion, there are two bolts, which run loosely through a securing bracket, anchored to the fork. The bracket remains stationary, while the caliper is free to move back and forth. To isolate the bracket from the bolts, there are o-rings installed inside of the bracket, which isolate the bolts from making metal contact with the bracket itself. The o-rings allow the bolts to move within the bracket without contacting it. They are located about 1/4 inch inside both edges of the bolt cylinders on the bracket. Every time pads are replaced, and especially anytime pads are replaced due to excessive wear to one pad only, the caliper pass-through bolts should be removed and both them and the o-rings checked for binding and deterioration. It is an easily overlooked area. But with road splash, heat, ozone, and time, it is an area that care and caliper grease will protect. Be safe out there. . .