are brake rotors prone to warp

bluemonster1

bluemonster1

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had my sxr600 out today because it snowed almost 3 inches.Only thing that I noticed when I hit the brakes hard I get a vibration big time and my brake lever is vibrating when held tight.Up on a stand I rev the motor and the rotor is wobbling a little.Not so bad the noise when on the stand,but with track on the snow rotating puts force on the rotor and the pads (which are brand new this Fall)are probably fighting the wobble and the sound seems to carry right across the jackshaft.Shaft is straight and 2ndary spinning without ant wobble what so ever.So I guess I should get another rotor.Them suckers are way to expensive to buy new..and if I get a used one..what says it isn't warped either..I can drive the sled no problem,just can't yank on the brake handle to hard..what a noise it makes.Have noticed this even last year a bit.What is your advice here??
 
not impossible, but sleds aren't very hard on brakes. It takes A LOT of heat to warp them, it would be really tough to get the right conditions on a sled to cause that...

I'm thinking there might be some other cause... Driveline bearings all good? Idlers? When you are braking, you are taking tension off the top of the track, and moving it to the bottom. All the forces are different, so if there is a bearing that is bad, it might not be noticeable when driving until you hit the brakes.
 
I changed every bearing in the sled this Fall and went thru the whole skid also..everything is tight.Like I said..I noticed this last year,but brake pads were worn down,,actually 1 pad more then another..don't know why.Now I have new pads on and seems to be more shutter now..but the rotor does waver a tad..not spinning true..so gather it is fluctuating the force on the pads back and forth from one pad to the other,,then getting that pulsating back at the brake lever..
 
found an interesting read on this symptom. It should apply to all brake rotors I imagine.So if it is warped,it is fighting the brake plungers then and pulsating occurs..hmmm!


found this:

A pulsating brake pedal, which may be accompanied by a shuddering or jerky stop during normal braking, usually means a warped rotor or an out-of-round drum -- although it can sometimes be caused by loose wheel bearings, a bent axle shaft or loose brake parts. If the vehicle is equipped with ABS, however, some pedal feedback and noise is normal during panic stops or when braking on wet or slick surfaces. But you should not experience any ABS pedal feedback when braking normally on dry pavement.

The faces of a disc brake rotor must be parallel (within .0005 inch on most cars) and flat (no more than about .002 to .005 inches of runout) otherwise it will kick the brake pads in and out when the brakes are applied, producing a pulsation or vibration that can be felt in the brake pedal as the rotor alternately grabs and slips.

You can often see warpage in a brake rotor by simply looking at it. If the rotor has telltale glazed or discolored patches on its face, chances are it is warped. Measuring it with a dial indicator and checking it for flatness with a straight edge will confirm the diagnosis.

Resurfacing the rotor to restore the faces will usually eliminate the pulsation (unless the rotor is bent or is badly worn and has started to collapse in which case the rotor must be replaced). But it may only do so temporarily because of metallurgical changes that take place in the rotor. Hard spots often extend below the surface of the rotor. Resurfacing will restore the surface, but the hard spot may reappear again in a few thousand miles as the rotor wears. For this reason, GM and others recommend replacing warped rotors rather than resurfacing them.

Pedal pulsation caused by drum warpage isn't as common, but it can happen. A drum can sometimes be warped out-of-round by applying the parking brake when the brakes are hot. As the drum cools, the force of the shoes causes the drum to distort.

What causes a rotor to warp? Overtorquing or unevenly torquing the lug nuts with an impact wrench is a common cause. For this reason, most experts recommend using a torque wrench to tighten lug nuts when changing a wheel. There are also special torque-limiting extension sockets called "Torque Sticks" that can be safely used with an impact wrench to accurately tighten lug nuts. But a plain impact wrench should never be used for the final tightening of the lug nuts because most provide no control whatsoever over the amount of torque applied to the nuts.

Overheating can also cause rotors to warp. Overheating may be the result of severe abuse or dragging brakes. Defects in the rotor casting, such as thick and thin areas can also cause uneven cooling that leads to warpage. Hard spots in the metal due to casting impurities can be yet another cause.
 
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the rotor still has its usual play when you grab it and move it sideways,like that on other 2 sleds..When I changed the brake pads on my SRX..they were both worn down equally.On my SRX one pad was way worn down more then the other...so is this telling me something also..like maybe 1 side is working more then the other.Still after 12,000 km's on the sled ..even with braking taking place and i pad pushing more then the other..wouldn't the rotor still not touch the other brake pad and wear it down anyways..hmm! Again any suggestions what I should do here.I can't be braking with the pulsating it does all the time..sounds bad to.
 
I would say yank the caliper and disc off and take a look. Sounds like one of the pistons is frozen so may be time for a caliper rebuild. Check the disc while it's off. If there is a piston dragging that may have been what warped the rotor to begin with. Good little project. You love to turn wrenches right?
Just my .02.
 
I may take the caliper off and check the pistons.As far as I saw when I installed the new pads..it is all working.There is no oil leaking anywhere..so seals should be good.BUT to take rotor off is a bigger job..May just run this way this season and work on it in the summer..don't feel like wrenching anymore to tell you the truth..I'll just cruise to a stop instead..lol hope the cars will stop for me when crossing roadways..they better!!!
 
what size are the seals..#7.Can I just pick these up in a hardware store.Would take weeks before I could get them here thru a online site..


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I hear ya. Sometimes wrenching is not all that fun. Alot of times though the calipers just need a good cleaning out. May not even need the seals. Probably just a bunch of crystalized crud in there sticking that piston. Atleast you still have the SRX.
 
yeah..just got my hands on a lite weight rotor and low mileage caliper for a real good price from NickyTech.So will just wait for parts to arrive.There is no real snow yet anyways and I do have the SRX to ride.I like to make sure everything works on my sleds before I really go out to ride...thanks for everyones help here.... ;)! :letitsnow :letitsnow
 
I just replaced a badly warped viper rotor. Fortunately I only had the back chain case half on when i caught it. It was warped pretty bad, I am thinking that where I had a minor vibration from last season ? Pads worn even, just warped at least 1/8".
 
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