how many warped rear rotors

[kyle]

i have a 2005 venture with 35,000k on it and i think my rotor maybe getting warped. pulses at slow speeds when slowing down. #1 is it possible to get warped during tire change?? #2 will grease from the rear hub find its way onto the rotor?? i cleaned it real good with brake clean and did good for about 600 miles and then started pulsing again... any thoughts

[Michael_Bishop]

Kyle I have a 2005 RSTD with 43634 miles on it. I have not had any warped rear rotor yet. I have never seen any grease on mine.

[Sylvester]

If you hear a clicking sound, the pins from the hub are too dry. Brake cleaner may be too harsh for this situation.

 

[BuddyRich]

If they took the rotor off and then didn't put it on exactly they way they took it off or didn't torqued correctly it could do that. I did it to myself on the front. Remove the rear wheel. Take the rotor off and spin it 90 degrees. Tighten it back down to the right torque BUT you have to do it in 3 steps. 30% then 60% then 100%. After I did that the pulsating stopped.

[allwx]

Could just be a matter of wear and tear. 35k is a little early for a rear rotor to get bad, but it is possible. Not that it is "bad" but they don't seem to wear exactly evenly. Over time they start to send pulses back to the lever as the pads trace the un-evenness. Most of us wear out the rear rotors much faster than the fronts.

 

It is also possible your rotor has been warped. You'd need some special tools to detect it, though. And there's no fix, AFAIK. A new rear rotor probably costs around $200 oem. Might be cheaper in the long run to just R&R it with a new one than to spend $ trying to find out why it isn't in perfect shape.

[Brake Pad]

had the front one checked today. I'm like .577 of being out of shape, the shop will not change them out under warranty, until they do. I have 6 months left on warranty. This sux 50,400 miles

[dingy]

If they took the rotor off and then didn't put it on exactly they way they took it off or didn't torqued correctly it could do that. I did it to myself on the front. Remove the rear wheel. Take the rotor off and spin it 90 degrees. Tighten it back down to the right torque BUT you have to do it in 3 steps. 30% then 60% then 100%. After I did that the pulsating stopped.

 

I don't think you can rotate the rotors 90 degrees, you have 60, 120 or 180 choices due to 6 bolt pattern

 

Just that you may confuse the heck out of someone trying to do that.

 

Gary

[easternrider]

My rotor is also warped. I just put a marker line all around the face of it, then spun the wheel. There is just one spot about 2 inches long where the marker came off. What would cause something like that? Does anyone think that it is alright, cause it does grab just a bit

[V7Goose]

This is NOT a common problem, but it is absolutely possible to damage a rotor (fairly easily) during a tire change. Also very possible to not get a rotor mounted properly if it was removed. Just for reference, I always remove the front rotors for a tire change, but never the rear rotor - that is simply because my tire machine lets me mount the rear wheel with the rotor in place and down, but not the front wheel. I remove the front rotors simply to remove any possibility of damaging them during the tire change.

 

To properly diagnose this, you should have a runout gauge so you can check for warp or poorly mounted rotors without having to re-mount the wheel. If the gauge shows any warp while spinning the wheel on the axle, remove the rotor and turn it one bolt hole, then try again. If the runout is the same amount, you can pretty much bet the rotor is warped. If the amount of runout changed, then continue trying to move the rotor one bole hole at a time and check for runout - you may find a position where it is within spec and all will be fine.

 

When you get all done with this, remember to locktite the rotor bolts. And ALWAYS use a torque wrench every time you put the rotor on - the spec is only 17 ft lbs, and that is VERY light - once you over-torque any bolt, you ruin it and risk a future broken bolt! I will repeat this for clarity - if you ever even THINK you have over-torqued a bolt, it MUST be replaced - the damage is already done. You cannot simply loosen the bolt and torque it correctly.

 

I use an air ratchet to remove and replace the rotors simply because there are so may bolts, but an air ratchet will instantly over-torque those bolts unless it is held very loosely, so be CAREFUL! Do not overlook the fact that brakes are life support systems - it does not pay to cut corners!!!!

Goose

[darthandy]

A question...possibly stupid, but... he said that the pulsing went away for 600 miles of riding after he cleaned the rotor. Is it possible that the "pulsing" is being caused by something else and is perhaps not actually a "pulse"? I don't see how cleaning a rotor would eliminate a warped area for a while and then it returns...not that I'm an expert on this, but I am curious.

 

Andy

[V7Goose]

No, not possible, IMHO. The only thing that can cause pulsing in brakes is the rotor/pads causing more pressure in part of the revolution, meaning the rotor must be warped or mounted wrong.

 

I do not know what he did to clean things, but extra slippiness between the pads and the rotor can cause them to slide more and mask the pulsing. The normal use of the brakes would eventually wear off whatever was causing the extra slippiness and the pulse would return.

Goose

Edited July 31, 2011 by V7Goose

[darthandy]

Ahhh...got it. Thanks Goose. Extra knowledge never hurts!

 

Whoa...just realized something. If that's what happened, wouldn't that also mean his braking efficiency was lowered (Slippery discs)? Wonder what cleaner was used?

 

Andy

[allwx]

Just for a point of reference: Yesterday I got new brake pads put on my F150 SuperCrew (I love that truck!).

 

When they replace the pads, it is customary to machine or "turn" the rotors to get rid of the little ripply imperfections in the surface that develop over time and wear.

 

These imperfections I can clearly feel in the brake pedal of my truck, and even in the steering wheel, whenever I apply the brakes. it gets worse and worse, until the rotors are either turned, or replaced. It is a gentle pulsing, or vibration, as many would describe it.

 

This also happens on motorcycle rotors. Unfortunately, motorcycle rotors don't generally submit to machining. I've been told that this is because they start out life too thin. Sure enough, compariing a truck or car rotor to a motorcycle rotor shows the motorcycle rotor to be much thinner.

 

On pretty much every motorcycle I've ever owned, including my old RSTD, I started noticing pulsing in the front brakes around 40k miles or so. Replacing the rotors fixed the problem.

 

It is possible those rotors got tweaked a bit during one of my ham-fisted tire change sessions, but I doubt it, since I religiously remove the rotors whenever I start to change a tire.

 

With 35k miles on the rotors, I would suggest that the pulsing "may" be nothing more than normal wear and tear, and will disappear when the rotors are replaced. If the rotors are warped (for whatever reason) then, likewise, the pulsing will disappear when the rotors are replaced. Either way, the fix is the same, because these rotors can't be repaired or machined. If they pulse, they're still good. They still stop the vehicle and will work fine for a long time.