I have an 99 FRC 6 speed with 20,000 miles. I just had it in to replace the TPMS and had the brakes check as well. I had an oscillating (before taking it in) when braking at lower speeds. When the shop checked it, the fronts were fine but the rears were shot. I had the rear pads rotors replaced. Granted, this improved the problem, it still exists.

I had a 2001 in 2001 and suffered from the same problem. The only difference with the 01, is that one of the rear brakes would drag and would probably glaze the rotor and cause this. Also, would only happen at high speeds under hard braking.

On my 99, nothing seems to be dragging.

Anyone have any ideas on this?

Thanks.

I did a search and found a couple similar symptoms but nothing on point.

Thanks again..

 

Since the whole system is essentially connected to one point- your brake pedal, even if it's only one rotor, it will seem like they are all bad, and it's hard to figure which one it is.I had a problem with my car, and it felt like the front brakes were bad. After the shop was done with the fronts( it was still under warranty, or else I would have done it myself), it was still there, but better. After all 4 wheels were done, voila, no problem.Also, it seems that power slot rotors tend to prevent the glazing of the rotors which cause some of these issues. I don't need the bling of drilled and slotted rotors, and the drilling seems to weaken them too. My next brake job will be Powerslot Rotors, and new GM pads. From what I've read here on the forum,that's the way to go.I don't track my car, so the Hawk, or the other race type pads are overkill for me.

 

If you have the means, measure the run-out of each rotor with a dial indicator. The shop should have done this. You will probably find at least one rotor out of spec.

 

See the following TSB:

Brakes - Brake Rotor Lateral Runout Correction

File In Section: 05 - Brakes

Bulletin No.: 01~05-23-001A

Date: March, 2003

INFORMATION

Subject:
Brake Align(R) System for Brake Rotor Lateral Runout Correction

Models:
2003 and Prior Passenger Cars

This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 01-05-23-001 (Section 05 - Brakes).

This bulletin is being issued to update General Motors position on correcting brake rotor lateral runout (Refer to Corporate Bulletin Number 00-05-22-002B for additional brake rotor service procedures).

Important: Certain conditions may apply to individual vehicles regarding specific repairs. Refer to those specific repairs in applicable service bulletins. Make sure other possible sources of brake pulsation, such as ABS pedal feedback, have been addressed before checking rotor runout.

Anytime a new or refinished rotor is installed on a vehicle, the rotor must have .050 mm (.002 in) or less of lateral runout. This specification is important to prevent comebacks for brake pulsation. Until now, the only acceptable methods to correct brake rotor runout were to index or replace the rotor or to refinish the rotor using an on-vehicle brake lathe.

GM has approved a new technology for the correction of lateral runout on new or refinished rotors. This new method is called Brake Align(R) It will allow the technician to meet the .050 mm (.002 in) or less requirement for lateral runout by installing a specially selected, tapered correction plate between the rotor and the hub. The Brake Align(R) Correction system does NOT require the use of an on-vehicle brake lathe to correct for lateral runout.

* We believe this source and their products to be reliable There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such items which may be available from other sources.

The Brake Align(R) Starter Kit will include an ample supply of Correction Plates, in various correction sizes, that will cover most current GM passenger car applications It will also include a Brake Align(R) tool kit containing a dial indicator and retaining washers along with other useful tools.

Service Procedure

Follow all the procedures referred to in Corporate Bulletin Number 00-05-22-002B. Dealers who have purchased the Brake Align(R) Starter Kit may use the following simplified runout correction procedure:

1. The existing rotors must first be machined on an approved, well-maintained bench lathe to guarantee smooth, flat and parallel surfaces. Should the rotors require replacement, please note that this is not necessary to machine new rotors.

2. Make sure all the mating surfaces of the rotor and the hub are clean, using the J 42450-A Wheel Hub Cleaning Kit. Mount the new or refinished rotor onto the vehicle hub onto the vehicle hub using the retaining washers provided in the kit. Do not reinstall the caliper or wheel at this time.

3. Tighten all the wheel nuts to the proper specification, using J 39544 Torque Socket or the equivalent.

4. Fasten the dial indicator to the steering knuckle so that the indicator needle contacts the rotor friction surface approximately 12.7 mm (1/2 in) from the rotor's outer edge.

5. Rotate the rotor and observe the total runout.

6. Index the rotor on the hub to achieve the lowest amount of lateral runout. This will require removal and reassembly of the rotor until the lowest total lateral runout reading is obtained. If this reading is .050 mm (.002 in) or less, the assembled rotor is within specification The brake system may be reassembled.

7. If total lateral runout is greater than .050 mm (.002 in), proceed with determining the correct Brake Align(R) Correction as follows:

^ Rotate the rotor to locate the lowest dial indicator reading and set the dial to zero.

^ Rotate the rotor to determine and locate the highest amount of lateral runout.


8. Remove the rotor.

9. Select the appropriate Brake Align(R) Runout Correction Plate for this vehicle.

Important: Never attempt to stack two or more Correction Plates together on one hub.

Never attempt to re-use a previously installed Correction Plate.

10. Following the Brake Align(R) procedures and diagram, install the Correction Plate onto the vehicle between the hub and the rotor. The V-notch in the Correction Plate is to be installed and aligned with the noted location of the "high spot" on the vehicle hub and marked wheel stud.

11. Install the rotor onto the vehicle with the Correction Plate placed between the hub and the rotor. Be sure to install the rotor onto the hub in the same location as identified in Step 7.

12. The rotor should then be secured onto the hub and tightened to the proper specificating. The rotor should be dial indicated once more to assure that the rotor is now within specification.

The brake system is now ready for the remaining service and assembly. Once the caliper has been installed, check to ensure that the rotor rotates freely.

 

Thanks guys. Ill probably do the fronts and go from there. Brakes are so cheap for this thing, seems like a good place to start - since they WILL need replaced in the future.

 

If you replace the rotors, take a dremel with a wire-brush, or at least a hand-held wire brush and remove all the rust from the hub. There's alot of rust that builds up in there, and it is not even and can cause runout. This in turn can quickly cause uneven rotor wear which then can't really be fixed.

Hope this helps.
Jon

 

From what I was told by the service manager at my Chev dealership, pulsating brakes are very common. In fact, look at almost all car forums and you'll see the same complaint. The trick is to keep the pads fresh and the rotor a consistent a temperature as possible. I did this with PowerSlot rotors and I have never had a problem since. I've gone on hard-running (and braking) mountain drives a few times and still have plenty of pad left. My advice is that if you want to eliminate getting the pulsations, don't use blank rotors.

 

I'm the guy with the high mileage and been through several sets of brake pads, re-turning of the rotors and such over the years. Each time the rotors were turned and even the front rotors replaced the first time, I kept getting the pulsing brakes within a short time after. Several things are probably the cause...Washing the car with hot brakes, leaving water on the rotors after washing which instantly turns to rust and something I may have found, good old fashion metalic brake pads.
My last change was due to brand new pads squealing like mad even though they were supposedly professional grade metallics. I opted to replace all of the rotors and pads with AC Delco parts and selected ceramic pads. No more pulsing. I did notice that I had to apply a hair more brake pressure when stopping, but only a hair. Now over a year and a half later with these new rotors and pads, still no pulsing and I haven't changed anything else in my driving, washing and etc.. By the way, AC Delco pads come with the noise abatement springs included.

 

Clean the inside of the wheel where it makes contact also.
I have since gone to zinc or cad dipped rotors be they cross drilled,slotted or blank, VERY clean, only way to go on this type of car. Ceramic pads and it is all good. The fronts before looked like some old German car. If you drive/brake real hard expect some warp of the rotor, you can turn them once but really better to replace as the cost is reasonable, especially the fronts.

 

Don't mean to hijack this, but I've seen you mention Powerslots before Dave, and I was wondering which pads you use with them. Also, how long have you had them on the car and how many miles without problems? Thanks. Ralph

 

Ralph,

I've had them for over 2 years (about 12,000 miles) now and bought a fresh set of OEM pads when I bought the cryo-PowerSlots. When I had the OEM rotors, the pulsations occured every 6000 miles. I've gone twice that now with the PowerSlots and have had not even a hint of any pulsations.

My philosophy is this:

If I can buy a component or assembly, install it and then not have to worry about it for 10 years, then the extra cost is well worth it to me. How many people would buy a $50 radiator if they knew it have to be replaced every 2 years? I guess if you were either getting rid of your car before then or if you just didn't have the money, it might happen. However, I can afford to spend the extra money and in almost all cases, it works out well. Research is important and I found that many owners of all types of vehicles have solved their warping/uneven pad deposit problems by installing slotted brakes, especially the cryo-treated ones. They may not be the best rotors for the track, but for all-around use with occasional heavy braking episodes, they are great.

Dave

 

The first step in addressing what appears to be pulsations from the brakes is to retorque the lug nuts 40-70-100 in a three-step sequence, following star pattern. Most common cause of the issue is wheels installed using an air gun on the lugs, giving radically different torque values to the nuts and making the rotor spin out-of-true.

Ranger

 

Dont forget to remove that little washer holding on the rotor.

I use an impact wrench and it is about 65-70 lb ft. Then I take the Tq wrench up to 100 lb ft