New Brakes are Pulsing

toyota
brakes
selling
corolla

#1

Hello Ray and Tom! I recently downgraded to a 2000 Toyota Corolla. I got it from my in-laws who I know used it rarely and didn’t abuse it. The car only has about 52,000 miles and, barring a couple of dents, is in remarkable condition. One of the things I wanted to do when I got it was to replace the brakes because they made an odd hwa-hwa-hwa sound when I’d brake which I attributed to rust, pitting, and deposits from sitting outside for long periods unused. There wasn’t pulsation, just the odd noise and the braking wasn’t great. So, I thought I’d get a fresh start. I had my brake lines flushed and then enlisted my brother to replace my brakes. He is a full-time mechanic at an area car dealership and has been in the field for about a decade. He’s an earnest guy and has customers who specifically ask for him to do work on their cars. (trustworthy? check. experienced? check.) So, without incident, he replaced my front rotors and pads, greased up the sliders and the works. (The pads didn’t come with new clips so he cleaned them with a wire brush and re-used the existing ones, in case that matters.) He also adjusted the rear drums. Everything got put back together and torqued properly.



When we first test drove the car, he noticed some pulsation at the “top” of the pedal range. You can feel it in the steering wheel. But if you pressed the pedal harder, it went away. Neither of us were worried and we figured it would go away.



Now, a couple of weeks later, the pulsation seems to happen within a wider range of pedal effort and is more pronounced. At lower speeds, if I press hard, past the top end of the pedal range, the pulsing still goes away. At highway speed, it’s much more pronounced and I can’t get it to go away. (I’m probably not pressing as hard at that speed to avoid any dramatic braking.)



So, can you help sort out this mystery? Do you think the new rotors came warped? Something else? (They’re name brand (Raybestos) but were made in China – same with the pads.) I didn’t know if perhaps, in spite of my brother’s quality work and ethic, that maybe something went wrong?



Oh, and another thing that might be worth mentioning in case it’s related: Say that I’m parked and go in Reverse to back out of a spot. Then I put the car in Drive to drive off. The first time I step on the brakes in drive, I hear a single slap sound, kinda like wood blocks struck together or those clogs from the 70s. The same happens in the opposite scenario: Drive, then Reverse, then brake: slap.



What do you guys think? Please help.


#2

Tom and Ray don’t visit here. You’ll only get us lesser beings.

You may have gotten an imperfect rotor, one may have warped due to an imperfection, or he may have missed a side when he cleaned the rotors upon installation. Stuff happens even to the best of us.

Your brother sounds like a super consciencious guy. Bring it back to him and I’m sure he’ll correct it. Problems of this nature are minor and easy to correct. Be aware that it might also turn out to be a tire irregularity also and be willing to fairly compensate him aditionally of that turns out to be the case.

I suspect that the rear brake noises are due to the car’s automatic adjustment feature, but someone wil have to look at it to be sure. Your brother sounds more than capable of diagnosing this one.


#3

Two things to have your brother check for. Make sure there’s no rust on the hub flange. If there is it can cause a new rotor not to seat squarely on the flange causing rotor run-out. Also have him check for a worn wheel bearing. This can also cause rotor run-out.

Tester


#4

Most pedal pulsing problems are due to warped rear brake drums. This is due to worn shoes/drums or overtightening of the lug nuts on the wheels.

In some cases this can be caused by parallelism problems in the front rotors but since the rotors were changed this should not be an issue. This problem can be caused by failure to thoroughly clean new rotors before installing them. Most rotors have a rust preventative film on them (varies in thickness) and this film can clog up or work its way into the pad material.

You need to check with your brother as to whether he inspected the rear brakes or not or had the wheels off, overzealousy used an air wrench on the lugs, etc. Odds are the problem is the rear and that slap sound can often be an indicator of rear brake problems also.


#5

Did your brother remove the rear brake drums? If they were difficult to remove, it is possible to warp the drum attachment plate using the extraction screw holes causing a warped drum. Click made mention of this problem in their shop. He stated even after the drums were turned the warp remained – something about how the lathe chucks up the drums. He said the only solution was to install new rear drums. So by a roundabout way, Ray did answer your question.


#6

Thanks so much. Some very good points. The rotor cleaning question jumps out. I’ll be sure to mention that.


#7

Thanks Tester. I do think he cleaned up the flange but I’ll be sure to ask him about that and the bearing question. I wouldn’t have thought of the bearings given that the symptoms weren’t present or apparent before the brakes were done, but I will mention it.


#8

Interesting. The rotor cleaning question is raised again. Maybe he did and I didn’t notice? I will ask him. My gut says he might not have. W/ two weeks of use, do you think a clean out could do the trick or are the pads now a lost cause, impregnated w/the film?

I know he definitely cleaned out the drums. The drums came off and they were adjusted with the star wheel. No air/impact wrenches were used and everything was torqued.

Now, if there is an issue related to the rear drums, would I feel the pulsation on the steering wheel?

Good to know the slap might be related to the drums.


#9

He did remove them, with a thwack of the hammer. Wonder if that did them in? The point you raise is interesting–with 10 year old drums (I think they’re original)… it might be time for a fresh start.


#10

Poor caliper operation could lead to the problem, or as another possibility rotors became warped due to bad torque of lug nuts.


#11

Take the car out on a deserted road and run it up to about 50 MPH. Now slowly bring the car to a halt with the park brake only. If you feel the pulsation then it’s the rear drums.
Normally you do not notice a brake drum pulsation in the steering wheel; that’s usually felt in the pedal and may even appear to feel like it’s in the seats.


#12

Since your brother’s been doing this for a while, I would assume he has a runout gauge. That can be used to isolate the problem. He probably knows how to check for runout on a rotor, so have him do that and try cleaning the hub flange or indexing the rotor to try to minimize or eliminate runout. Since the pulsation is felt in the steering wheel, it is almost certainly in the front brakes. Sometimes corrosion will accumulate on the hub flange enough to cause a significant pulsation, and no amount of sanding will remove it. It has to be removed with a hammer and chisel.


#13

While checking for a worn wheel bearing also check the tie rod ends for play. Esp. b/c you mention feeling it in the steering wheel - sometimes bad tie rods can show up as brake vibration.