Legion_2

So I pulled off my wheel/rotor/hub/steering knuckle to install some extended wheel studs and replace the wheel bearing. Then I threw everything back together, and now when I'm going 60+ mph and I brake, I get a vibration in the pedal/steering wheel.

Baffled as to how I could have warped the rotor just by removing it, I put the car on jack stands, pulled the wheel off, and let the wheels spin in 1st gear/idle. I checked the runout with a dial indicator and it's only 0.0015"?? So that's not the problem. I checked the runout on the hub too, in case I warped it on the bench press, but it's also < 0.002". The total runout on the outer edge of the wheel is about 0.015", which isn't bad. It's the same on both sides.

So what the hell gives?? What else can cause a vibration during braking? It's not the rotor, hub, wheel, or tire. The problem screams "something is out of round," but everything seems fine. Could it be something with the brake pads or caliper?

Budhound

is it a pulsation? is it pulling? how heavy is the vibration? aside from the rotor and the master cylinder failing i cant think of anything else that could cause that except maybe the rim/tire being out of balance. When was the last time the brakes were serviced? Take the rotors off and have them turned ususally only about 30 bucks at a machine shop and see if that takes care of the problem.If everything does check out then the wheel studs are the vairable.

TunerN00b

Completely trashed bushings produced a bad vibration under braking on my friend's 2002 Civic.

The first 3 mechanics he took it to blamed it on "warped rotors", turned them and sent him on his way, only to have done nothing to cure the issue (which is why he took it to different mechanics each time).

4th mechanic told him it was blown shocks.

So, we took it to the shop I trusted, where the tech actually took the time to figure it out, and showed me the trashed bushings. Big crack in the rubber, lots of slop. Front control arm, front bushing, both sides.

Even the "car guy" who eventually bought the car, took it for a test drive, and came back saying "other than warped rotors, the car drives fine, so can we knock another $100 of the price to account for new rotors? I don't trust turned rotors.". I'd have felt guilty if he wasn't offering $4,200 on a 5 year old Civic...

Scott_Tucker

Did you check rotor parallelism? It is more likely to cause a pulsation that run-out is. There is a great article on the Stoptech web site about brake pulsation, here is the link:

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

I have rarely found that rotors are 'warped' I think it is a much overused term.

Budhound

now that he mentioned it you might as well check that to while your in there. it could jsut be a coincidence that it happened when you took apart the brake system.

Legion_2

Oh man, so many possible issues...

I've considered getting the front rotors turned on the car to completely rule out the possibility of anything being out of round. The problem is that it's $100 for the service, and I'm not sure if I want to take the plunge if it doesn't fix the issue. After all, these Brembo rotors were only $70.

Scott_Tucker

Why is it so expensive to have them machined? I live in one of the most expensive areas of the country and nobody charges that much. Unless you are including labor to remove the rotors from the vehicle.

srmofo

Did you index the rotors when you took them off....so you could put them back in the same position as before....just a thought.....did the problem start immediately after you did the bearings?....there is alot of things that cause this besides rotors......some things to check are ....Did you damage the axles in anyway when removing them? Did you tightening all suspension bolts? (I know its a stupid question but it is a possibility) Are any suspension parts worn, especially tie rods? What about bushings?

And the reason the labor to turn them is so high is because he said "ON THE CAR". If you have ever set up an on the car brake lathe you know why the labor is so high, its a PITA, but it rules out any variance that might be caused in the rotor to hub mating surface

And I have read that Stop Tech article before and the fact that you say you rarely see warped rotors only proves one thing to me....You dont work in the auto repair business.....Most if not all rotors are made overeseas now, I have pulled these damn things out of the box put them directly on the brake lathe and had to turn them because of either inconsistencies in the rotor thickness or because they are warped. This has nothing to do with friction material transfer because they have not been installed yet. If you are going to quote an article verbatim then at least give credit where it is due. Has rotor warpage been oversold? absolutely, Its because of pain in the *** customers who wont tell you they have a problem and as soon as you touch the vehicle they want to blame it on you. so what do you do? Recommend rotors to any that may need them and if they say "no" they cant blame pre exisiting conditions on you.

Scott_Tucker

Yes, actually, I do work in auto repair. I have been in the automotive industry professionally for over 20 years. 16 years of those as a technician and 4 as an engineer. Every shop I have ever worked at I am responsible for most diagnosis and I usually follow up by doing the actual repairs myself. I do not just turn a wrench.

I have have seen defective rotors out of the box like you and it sucks. He stated his brakes were fine and then after replacing studs the brakes vibrate. That means they were not 'warped' or defective at the time he said they were fine. I have had many cars come through that had brake pulsations, we replaced pads and turned the rotors, the brakes worked fine when it left, and then came backs months later again with pulsation. This drove me crazy for years so I spent time researching and spent time during diagnosis to determine what most often caused it. A difference in rotor thickness of less than .001" can cause a perceptable pedal pulsation. It seems unlikely that a metal rotor would wear on some spots a lot more than on others. The quality of the metal would have to be terrible. I also have noticed the faint outlines of a brake pad burned into the rotor on many vehicles with pulsation. Changes in parallelism will cause a pulsation in the pedal much faster than a rotor that is warped and that burned on pad material is enough to be perceptable in the pedal. I have measured it with a mic.

I live in the mountains and the road down to the main highway is long, winding, and completely downhill. If I get the brakes (of any of my cars) nice and hot down the hill and come to a complete stop and keep my foot hard on the pedal at the stop sign for a few seconds it will burn a pad imprint onto the rotors and cause the pedal to pulsate for a while. Several panic stops later without letting the car to ever come to a complete stop the pulsation will go away. I have not ever driven the OP's car so I don't know what his situation is but it's possible without even thinking about it he got the brakes hot enough to bake the pads to the rotors on his after-repair test drive.

I agree with you that we get blamed for pulsation a lot of times when it is absolutely not our fault. It's also not uncommon to get poorly machined rotors out of the box. As long as you document everything you shouldn't feel guilty if you have a pulsation related come back. It sounds like you've been blamed before for a customers brake pulsation and I guarantee if I had to take sides I would take yours, I know what the business is like.

Where did I quote something verbatim and then not give credit? I said read this article, it is good, and I agree with them!

Legion_2

The rotors don't get removed. You drive onto a lift, pop off the wheels, start the car in 1st gear and the rotors turn against a stone cutter/grinder until they are adequately resurfaced. Having them resurfaced when they're off the car wouldn't do much good.

Legion_2

I didn't mark them at the time, but I've already tried indexing the rotor and the wheel too. Didn't help. But this shouldn't be the problem anyway, because my dial indicator shows that the rotor is not out of balance or wobbling at all.


Yes


Could it really be the axle? Because I just noticed that the axle boot is slipping off and it's starting to spray axle grease everywhere. And sometimes I hear a loud "clunk" under hard braking. I've been meaning to check the axle to cure the clunking problem, but I didn't think it could cause the braking vibration problem too.


Everything torqued to spec. All bushings look okay, except for my torn lower trans mount and torn rear LTA bushings. But again, this problem just surfaced after the bearing install, so I don't think it's bushing related.


Yup, and that's the important thing, because I fear I might have warped the hub somewhere during the pressing process. Turning the rotors on the car would rule out any possible out-of-balance condition that affects the rotors.

Scott_Tucker

Sorry, I didn't know you meant they would be turned on the car. I have used the on the car brake lathe, it works well once set up properly.

Legion_2

Problem seems to come and go...? Sometimes vibration is severe when braking at 60+, other times I can barely feel it when braking at 80+. Perhaps the pads just needed to re-seat after being disturbed. Or maybe it's related to the rotor temp.

At any rate, I'm just going to ride this out. ****, my clutch is going out, the axle is going bad, my trans bearings are failing, and the rotor might have uneven wear... so **** it. I'll just ignore the problem and if it leads to something else failing down the line... well pretty much everything is failing anyway.

Budhound

Year, Make, Model and how much you want for it lol ive got some cash lol

SovXietday

Weird...

I have the EXACT SAME PROBLEM in my car. I put new wheel bearings and ARP extended studs on and now the car vibrates above 70 and it's even worse when I hit the brakes. Kinda sucks when the car should be trapping 130 by summers end.

Legion_2

^^I tested by braking from 120 to 70 and the vibration is actually worst around 80mph. At 120 it's not that bad. For the record, I've just noticed that there is a slight pulsing vibration even when I'm NOT braking, so I'm starting to lean towards a bad axle.

Scott_Tucker

Did you happen to rotate your tires when you had the wheels off? If one of your rear wheels was slightly out of balance it will be more noticeable when rotated up front.

srmofo

Im telling ya...axles can cause alot of different issues if something is starting to bind up. and since they were disturbed while you had the knuckle of, its possible that could be your culprite