96 not braking smoothly

Here's an odd problem. For a few months I've been noticing un-smooth braking in my 96. At higher speeds it will be a mild pulsation in the pedal and sometimes the steering wheel. At lower speeds it feels more like a rhythmic grabbing. It is not completely consistent, sometimes seems worse than other times.

I figured I must need my rotors turned, so I did that and surprisingly it didn't seem to make any improvement.

Ideas I've thought of:
-bad brake pads
-rear brake drums need turned
-bad suspension component (have not noticed any other suspension or steering issues, though my front tires are starting to show some even wear on the inner and outer edges over the last several thousand miles)
-rotors are still bad despite turning (had it done at OReilly)

Anybody have any opinions if any of my ideas make sense or is it something else?

Thanks!

There is a possibility it is tire related. Cord separation would cause what you are feeling. You might try rotating the tires so they are on the opposite side of your car and see if the symptom changes.

Had something similar in a different vehicle, the wheel bearings were slightly loose. I loosened and then retightened the castle nuts to reseat the bearings and it's been good since... probably tightened the nuts a half turn, not much but the tiniest amount of play there is very noticeable.

You probably need new rotors. Once they develop a "hard" spot, no amount of turning will permanently correct the issue. The pulsation can vary because when you turn you can "sync" the pulses so they both occur at the same time, and other times they will be out of sync, and the pulses will be more pronounced.

Rev Bob wrote:

There is a possibility it is tire related. Cord separation would cause what you are feeling. You might try rotating the tires so they are on the opposite side of your car and see if the symptom changes.

As part of the maintenance when I turned the rotors, I also rotated and inspectwd all the tires. The tires all looked ok and no difference after doing it.

rcktpwrd wrote:

Had something similar in a different vehicle, the wheel bearings were slightly loose. I loosened and then retightened the castle nuts to reseat the bearings and it's been good since... probably tightened the nuts a half turn, not much but the tiniest amount of play there is very noticeable.

I'll definitely check that out. If that's the case, they would have to have been loose to the same extent both before and after I took the rotors off and repacked the bearings.

Fred Kiehl wrote:

You probably need new rotors. Once they develop a "hard" spot, no amount of turning will permanently correct the issue. The pulsation can vary because when you turn you can "sync" the pulses so they both occur at the same time, and other times they will be out of sync, and the pulses will be more pronounced.

I have a feeling you are right. I've never encountered that before, but there is a good chance the rotors are 25 years old, so anything is possible. The only practical way to confirm that would be to replace them, but that's not super expensive, so I will probably just do that. Of course, that will involve repacking the bearings again, just in case rcktpwrd's idea about loose bearings is a problem.

Thanks everybody for your thoughts!

Fred Kiehl wrote:

You probably need new rotors. Once they develop a "hard" spot, no amount of turning will permanently correct the issue. The pulsation can vary because when you turn you can "sync" the pulses so they both occur at the same time, and other times they will be out of sync, and the pulses will be more pronounced.

Speaking of brake rotors, do you think there's a difference in quality in the cheap ones vs. more expensive? Is it worth springing for the AC Delco?

There are only aftermarket ones. As far as cheap vs. expensive there are some differences. Some are plain, and some are slotted and drilled. I do not know if one is better than the other as far as developing issues. There is one company that cryo treats them, and that may be the best way to minimize the issue of hard spots. The cryo treated ones should have the most resistance to hard spotting, because the atomic structure is so even throughout the rotor. The other side is that they are the most expensive.

https://frozenrotors.com/brake-rotors/frozen-rotors.html

https://www.buybrakes.com/stoptech-127.44175cl-sportstop-cryo-drilled-and-slotted-rotor

After a few months of putting the wagon on light duty, I finally got this problem resolved. A new pair of front rotors did the trick. Car stops smooth as a brand new car now! I've never had rotors just suddenly warp like that. I don't use my brakes particularly hard, so that is kind of strange.

I had a little trouble finding a local auto parts store that had them. Oreilly had a set of ACDelco listed on their website for $79/each, but upon inquiry, they said they didn't actually sell those and the only ones they stocked were like $120. NAPA said they could order a set in for $69, and would call me when they came in. They never called. So I ordered ACDelco for $79 (plus $19 shipping, which wasn't bad for as heavy as they are) from RockAuto and they came in a few days.

Thanks to everyone for the advice!