Warped Rotor?

[chevelles240]

I've been noticing that as my vehicle is braking to a slower speed (between 0 - 15mph) it feels like there is more pressure being applied to one of the rotors as its rotating when a certain area of the rotor(s) makes contact with the brake pad. It's kind of like a smooth to jolt smooth to jolt feeling. Like the car is almost being jerked a bit when the brakepad hits a certain area of whatever rotor. Yeah, I am not very good at describing this..

I think a rotor may have a minor warp in it so at lower speeds the braking feels kind of uneven.

Is this something indicative to early signs of rotor warp? I've never noticed this before and its only when the car is braking to almost a stopping point. It's a very subtle jerk but when the car reaches almost 0 mph then I really notice it.

Can a caliper or something else on a vehicle cause a rotor to warp over time? because I've never noticed this until now, and I've had these rotors installed for a little over a year now.

 

[915_P5]

Caliper is sticking

 

[P-Funk!]

Sticking caliper can warp rotor... Could be both.

 

[pcb]

You may have some oil (or brake fluid, or grease, or undercoating...) on part of your rotor,... that can also make the brakes pulse.

 

[Maroon]

It is disc thickness variation that you are experiencing. Rotors don't warp. If the rotors are old, thickness variation is not uncommon. There isn't necessarily anything wrong with the calipers.

Replace the pads and rotors. If the pistons pushes back in the calipers, and the boots are good, there is no reason to replace the calipers.

 

[chevelles240]

Yeah, it turns out the front rotors needed resurfacing. The dealership wanted to charge me $160 for labor, plus the mandatory $99 diagnostics fee. I opted out of the $160 resurfacing fee and I will just go ahead and replace the rotors on my own time. Much cheaper to replace them. In other news, they also said my front catalytic converter would need to be replaced to the tune of $1232, not including labor costs. (boom08)

 

[Maroon]

Yeah, dealerships have no value. They only exist to rip people off.

You can do pads and rotors on the front for <$75 for the cheap stuff from your local store. Spend more if you want something better. But from personal experience, the cheap stuff works just fine, and the car isn't worth more than that. It's a very easy job.

The catalytic converter is expensive, but $200-$300 (not really sure where the hell $1200 comes from). Of course, it's unlikely that it's bad, they just want your money. Leave it alone.

 

[BlueBomber]

Is there anything special that needs to be done when installing new rotors? I've done pads before but not rotors. Is it just as simple as taking the old ones off and putting new ones on? New rotors don't need to be machined do they?

 

[Maroon]

Is there anything special that needs to be done when installing new rotors? I've done pads before but not rotors. Is it just as simple as taking the old ones off and putting new ones on? New rotors don't need to be machined do they?

Nothing special at all. Just put them on.

 

[MrGiggles]

Is there anything special that needs to be done when installing new rotors? I've done pads before but not rotors. Is it just as simple as taking the old ones off and putting new ones on? New rotors don't need to be machined do they?

You only need to cut a new rotor if you're just replacing one and the other is thinner. They need to be within .010" or so of each other in thickness.

Clean the hub surface really well, and make sure you get all of the shipping oil off of the rotor with hot soapy water.

 

[chevelles240]

Sorry to bring this thread alive again but I have another theory that could be causing the rotor to warp. I've replaced the rear calipers, all brake pads, all calipers, replaced a brake line in the back, and had the brake fluid flushed. After all of this exhaustive troubleshooting and parts replacement, it turns out the driver side front rotor keeps warping. Every so often I have to have the calipers filed down so the pulsating stops, but this is only a temporary fix. The mechanic is at a loss for what could be causing this rotor to always warp.

So here is what I theorize might be the problem. The brake proportioning valve. I am thinking there is too much pressure being applied to driver side front brake as compared to all of the other brakes. Have any of you all had problems with this in the past and is there any easy fix?

 

[MrGiggles]

The proportioning valve splits power to the front and rear, not side to side. I doubt this is your issue.

Check and make sure that the caliper is releasing like it should and not dragging.

The flex hose can collapse and make a caliper stay applied. That heats the rotor and causes them to warp.

 

[chevelles240]

The proportioning valve splits power to the front and rear, not side to side. I doubt this is your issue.

Check and make sure that the caliper is releasing like it should and not dragging.

The flex hose can collapse and make a caliper stay applied. That heats the rotor and causes them to warp.

We ruled out the front calipers not releasing properly because based on what the mechanic said the front calipers were fine. The driver side caliper in the back was actually sticking but replacing that did not resolve the issue with the rotor by the front driver side warping every X amount of miles.

I can look into the flex hose issue but when you say flex hose do you mean the brake hose, by any chance? Sorry for the newbie question lol.

 

[MrGiggles]

We ruled out the front calipers not releasing properly because based on what the mechanic said the front calipers were fine. The driver side caliper in the back was actually sticking but replacing that did not resolve the issue with the rotor by the front driver side warping every X amount of miles.

I can look into the flex hose issue but when you say flex hose do you mean the brake hose, by any chance? Sorry for the newbie question lol.

The flexible rubber hose that connects the caliper to the brake line.

Jack up each wheel and give the brakes a hard push, then try to spin the wheel. They should release pretty much immediately.

 

[Maroon]

Again, your rotors are not warping. You are experiencing disk thickness variation. The cause of this is usually caliper related, but on some vehicles, pad and rotor quality can exacerbate the issue (but I've had no issue with the cheap stuff on this car).

DTV can be caused by the pads brushing the rotor inconsistently during one revolution (with the brakes off) creating low/thin spots. It can be caused from the pads transferring a layer of material to random spots on the rotor causing high/thick spots. (This is on the micron level. You'd need a micrometer to pick up the variation.) Or it can be caused only when the rotor is excessively hot caused by a sticking caliper which will expand the rotor non uniformly. But you said the caliper is not sticking so that shouldn't be your issue. Do the 2 front calipers have a temperature difference after driving?

These are the things to check if you are experiencing DTV:

Check that the caliper slides well on the guide pins. Check the guide pin boots.

Check that the pad abutment clips are in good condition and that the pads slide freely.

Check that the pad return springs are in good condition and are able to push back the pads.

Check that the piston boot is not torn and that the piston can be pressed into the caliper easily.

Check runout and play in the hub bearing. You should not be able to see or feel any play.

If you keep thinking it's warping caused by excess heat, you're going to go down the wrong path of diagnostics.

Also, most rotors develop some DTV and cause some vibration, but usually that vibration is dampened by the suspension and steering so you never perceive it. However, bad suspension or steering components can resonate in the presence of these usually insignificant vibrations. Have you checked tie rods, ball joints, control arm bushings, and struts? Maybe your rotor has developed what would be an acceptable amount of DTV for a Protg 5 with good suspension and steering.

Every time I've had a bad ball joint or tie rod, I have experienced the pulsation symptoms of a rotor with DTV. Upon correcting the ball joint or tie rod, the brakes were just fine.