are brake rotors prone to warp

You need to make sure the rotor "floats" a bit on the jackshaft and both of the pistons move freely in the caliper. I have seen MANY sleds with no "float" on the rotor. My 97 Kawasaki ZX11 needed a lot of TLC on the brake calipers, the some of the pistons were "stuck" causing excessive sideloading on the disc. The seals you refer to in the calipers are sometimes simple o-rings with a round cross section shape but often they are special o-rings with a rectangular cross esction shape. Depending on the riding style, it is possible to overheat and warp a rotor on a sled, especially if the rider keeps a finger or two on the brake all the time. When you take the rotor off, see if it is discolored anywhere on it.
 
oh yeah the rotor does float and on the other sleds also.All I can say is when I replaced the brake pads,1 was almost worn all the way..the other still looked good.There's the rub...On my SRX both pads were worn down equally..lot of high speed running and STOPPING..I will as usual remove it(wrench wrench.. :o| ) and fix it as usual..
 
Last edited:
bluemonster1 said:
oh yeah the rotor does float and on the other sleds also.All I can say is when I replaced the brake pads,1 was almost worn all the way..the other still looked good.There's the rub...On my SRX both pads were worn down equally..lot of high speed running and STOPPING..I will as usual remove it(wrench wrench.. :o| ) and fix it as usual..
Click to expand...


As Jim mentioned, the caliper needs to float (especially on a single piston caliper) but in your case, one of the two pistons within the caliper is sticking and dragging on the rotor causing the warpage.

I'm sure you can guess which one...

I'd guess the piston/bore o-ring is a square cut and I would not substitute it.

It can be tricky getting the piston back into the caliper. I haven't overhauled and SRX caliper but an old trick to getting the piston past the dust boot is to use shop air and blow through the brake line hole while holding the piston in place. The air helps blow the dust boot beyond the piston.

Chuck the caliper in a vise and coat the piston and boot with brake fluid, then hold the piston over and against the boot while applying a little air to the brake line hole. The air will blow the dust boot over the end of the piston - then push the piston into the bore.

The other method is to use a hook tool and work the dust boot around the piston
 
well got everything apart.Yep the brake caliper piston on the inside does not move at all and there is a slight appearance of oil there...damn ..the rotor is shiny on both side..took a straight edge to it..see a little hollow in there..but doesn't look bad.Oh well I will be getting a lite weight rotor and another caliper to replace these and then ready to ride again..
 
seems like the piston that wasn't moving was easy enough to blow out with a little air thru the oil hole.Can't see anything wrong in there//all is clean.So if air can push the piston..why not the oil??? Maybe it needed more bleeding to be done to it..I don't know....
 
I would have expected the "stuck" piston to be stuck and not move with the force applied using compressed air. The hydraulic pressure can be as high as a few hundred PSI. You could reassemble the caliper, connect it back to the brake line and bleed the system then use a C clamp to hold the caliper which was moving OK so the hydraulic pressure will move the previously stuck caliper.
 
I could try that but waiting for another caliper to come in with less mileage on it and this could be a spare if needed.Still a little strange hydraulics can't outdo only like 50 PSI on the air nozzle.Maybe had a air bubble in there somewhere..who knows now.
 
bluemonster1 said:
seems like the piston that wasn't moving was easy enough to blow out with a little air thru the oil hole.Can't see anything wrong in there//all is clean.So if air can push the piston..why not the oil??? Maybe it needed more bleeding to be done to it..I don't know....
Click to expand...


Keep in mind that the piston wasn't releasing (going back into the caliper). Which means you may not have any trouble pushing the piston out.

If there is any portion of the dust boot that allows moisture past it, the piston becomes corroded on the exposed side of the piston. This corrosion doesn't allow the piston to release. It also contaminates the seal surface of the piston the o-ring seals to which will cause fluid leakage past the o-ring.

Look real close at the piston and I expect you'll find a line of corrosion. It doesn't take much of an imperfection of the seal surface to allow the 100's of PSI fluid to leak.
 
actually the pistons look good and I see no contamination anywhere,just a wandering .Sprayed with brake fluid and blew off.Everything seems to work for now,but will install the calipers that I am getting in soon instead...just in case.
 
You must log in or register to reply here.


Back
Top