Hi,
I have driven 53K miles in the Bay-area, CA on my car. On a recent trip to UT and AZ, my steering wheel started wobbling when I braked downhill. And I started hearing the occasional screeching noise when I braked, when I listen closely. I took to the local auto-care chain back in bay area and they said, I needed my front rotor and brake pads replaced. I however had no such wobbling on plains. Hence I wasn’t sure if I was being over sold on parts. I got the car back without replacing the pads or rotors. I took a picture of the brake inspection readings. Wanted to get an advice if I need to replace my rotors or not. I understand the brake pads need replacement from the screeching noise. But how about the front-rotors?
The “wobbling” to which you are referring sounds like a pulsation in the steering wheel under braking. That could certainly be caused by excessive runout on the rotors. The front pads seem pretty worn based on the workorder but are certainly not at minimum thickness. It may be that your wear indicators are just starting to scrape the rotors to warn you that it is time to change brakes. I would go ahead and do the front pads and change out the rotors at the same time.
Warped brake rotors from overheated brakes in the mountains are common here, they can be resurfaced unless there are “hot spots” showing on the rotors. With your rotors measuring 1.100" + there is enough material for two brake jobs so if you would rather have them resurfaced get an estimate from a different shop.
Your brake pads at 0.135" are thin, you should consider replacement soon.
I would either change out rotors and pads, or replace pads and machine rotors
I just hope whoever is machining the rotors isn’t aggressive. Some guys like to take off huge amounts in one pass, and before you know it, the rotor is under, whereas a more patient guy wouldn’t have ruined the rotor
Got to work smart and multi-task, if you’re able to. While the first rotor is on the slow final cut, you could be removing the second side.
I’m talking about a bench-mount brake lathe, by the way. I have no personal experience with on-the-vehicle brake lathes
If it were a Hennessey Venom I might try turning them.
But, on the other hand, do people who own Hennessey Venoms really need to be concerned about repair costs???
Because I’m such a low-budget guy, I had to look up what that Venom was. I’d never even heard of it. But I also don’t read the kinds of car magazines that would feature the car.
You’re right, of course. A Venom owner would probably be insulted at the idea of machining rotors. Every brake job probably consists of new pads and rotors.
If you were an older auto mechanic who just retired recently after doing the work for 45 years you would have had the work done because you wouldn’t dither with the questions. Since you aren’t that guy, you did well to ask him. Do it and I hope the price isn’t the Bay Area high one.
Rock auto has the front brake rotors for $66, Autozone $47. These are wholesale prices, the shop will charge near $100 each. Toyota OEM rotors are $76 each.
It is less expensive to resurface the rotors. Most places that I have worked charge a flat fee for a brake job and there is no discount on labor for replacing the rotors rather than resurfacing them.
The .004 runout is excessive also. Generally speaking, 002 is the limit. The form states the tires have low tread and weather cracks so tire replacement should be considered as dry rotted tires can be more prone to blowouts.
db4690, I’ve had some experience with on-car lathes and just do not like them at all. I’d take the bench or stand mounted lathe any day of the week.
Unclear to me is the “machine to” part. My assumption is that spec is the minimum thickness and I would hope someone does get overly enthusiastic and machine it down to that number unless it’s absolutely necessary. Take off only what is needed to clean the rotor up.
Thanks everyone for responding to my query with your suggestions. I would also like to ask about the possibility of using lateral runout Correction plates as an alternative to resurfacing. I tried searching the Cartalk communities about it, but couldn’t find any posts about it. Hence asking here. Are correction plates a worthy enough alternative?
My experience has been that some vehicles are more tolerant of “moderate” runout, such as 0.004" . . . whereas with some other vehicles, the brake pedal will be kicking real hard
We have tons of GM and Ford vehicles in our fleet
The old GM trucks with hubbed rotors seem to do okay with 0.004" runout
Whereas the old Ford trucks with hubbed rotors don’t tolerate it. The pedal kicks hard
I’ve only heard stories about the on-car brake lathes.
The guys selling them claim they’re the best thing since sliced bread
But all the guys that I know that have used them, or seen them being set up, say it’s a lot of work to set them up, and it’s not the answer for everything.
I don’t know if this is true, but I’ve heard you need lots of expensive adapters, if you want to use them on larger vehicles. For example, rear rotors on a dually truck. That would be a big factor, because we have tons of duallies in our fleet.
We have an old ammco bench mounted lathe. It’s probably older than some of the younger guys in the shop. But it works just fine, and I’ve noticed that the newer ammco lathes aren’t much different.
Actually, I believe “machine to” and minimum thickness are slightly different. I believe it has something to do with leaving some meat for wear
I’d never heard of “lateral runout correction plates” and had to look them up. My feeling on them is that I wouldn’t waste the money. I’d rather spend the money on new rotors. My experience is that generally trying to add one eccentric part to compensate for another eccentric part generally only changes the problem rather than correct it.
@db4690, many years ago a Subaru dealer I worked for made the plunge and spent a fair amount of money on a Bear on-car lathe. Subaru rotors required a few special tools to remove and sometimes removal was difficult so their thinking was to speed the process up.
It just did not go over very well and I went back very quickly to using the old AMMCO lathe. About 6 months later they sold the on-car lathe at a loss rather than have it sitting around in the way collecting dust.
I don’t know about the adapters part of this as the one we had was set up for Subaru.
I know the machine to and min thick are different. I just couldn’t figure out if these guys were going to machine to the min thick even if removing only .010 would take care of it.
I read the rest of the notes the shop made… specifically the tires having age cracks. You should to budget for tires ASAP.
Be sure you have them change the brake fluid when they replace the pads. It is noted as old and likely has water in the fluid making it less than safe.
“I know the machine to and min thick are different. I just couldn’t figure out if these guys were going to machine to the min thick even if removing only .010 would take care of it.”
Sounds like you’re talking about some of my colleagues . . .
The guys that NEVER EVER open the owner’s manual or look at the sticker on the door jamb
The smart guys who automatically look at the sidewall, and whatever the maximum pressure listed on the tire . . . that’s what they get inflated to
The sad thing, is that I’ve seen a lot of tires wear out in the middle rather quickly, because of this
We’ve talked about this countless times during shop meetings. The supervisor says “Inflate the tires to the pressures listed on the door jamb sticker. No ifs ands or butts.” But these guys have selective hearing.
Maybe these same guys think the minimum thickness is what you’re automatically supposed to machine the rotors to
“Darn. This rotor’s too thick. I’ll have to take off 30 thousandths before I can put it back on the truck.”
LOL.
Db, your colleagues have a lot of company.
My personal experience is that every time I’ve had tires installed they’re set at 35psi, sometimes more. My doorjam says 32 front, 29 rear. The first thing I do when I get home (or before) is adjust the pressure to the proper psi. It rides and handles a lot better and I get nice even wear there.
In my experience, it’s slightly unusual to have higher pressures up front. Makes me think of that Corvair you and the other regulars mentioned . . . ?
Anyways . . . occasionally, I’ll work on a truck where the door jamb sticker is missing, faded, or just plain illegible
In that case, I’ll either look in the owner’s manual for the correct spec . . . if there even is one in the glove box . . . or I’ll find a twin to the truck, to determine the correct pressure. Then I’ll write the correct pressures on the doorjamb, with a big fat black sharpie. For example “F 50psi, R 80psi”
Sometimes I’m the next guy working on the truck, when it comes back in 6 months, for the next scheduled service. Saves me time in the long run
The manual is consistent with the doorjam.
Higher pressure up front actually makes sense in FWD cars with 60% of the weight up front. I seem to recall my '91 Camry and my '05 Corolla recommending a bit more pressure up front as well. I suspect it’s common in FWD cars.
