1997 Tahoe rotor warping problems....help please!!

[Chris B.]

I can't seem to keep my rotors from warping on my 1997 Tahoe. I had a full brake job done on all 4 brakes 4,000 miles ago and I noticed plusation with in a few hundred miles. I did not have the time to take it back to my mechanic untill now. He still replaced the breaks(front rotors and pads) saying the were warped and did not charge me under warranty. He said they look blue in color like they got real hot. I don't drive hard at all and and try to go easy on the breaks so I don't know how they could get hot enough to warp. I did not have this problem with my other trucks and I brake in the same manner.
Well now the new breaks that my mechanic just put on under warranty are warped I think as I feel the brake peddle plusing when I apply them at higher speeds but not so much at slower speeds. It started this less then 50 miles on them!!!!!!
What the heak might be going on????? Sould I just live with the damm plusing break peddle?

Thanks for any help!

 

[Sparkman]

Calipers problems, hub runout, improper lugnut torque, improper lubrication of sliding parts.

 

[bdcardinal]

what kind of rotors and pads is your mechanic using? are they expensive ones or cheapy ones?

 

[Chris B.]

They said calipers are good and lug nut torque is correct. The pads were AC Delco and not sure on Rotors but I can find out.

 

[Oil stain]

Make sure the rear brakes are adjusted correctly as well. It's possible that there not and are allowing the front brakes to do all the work.

 

[kc8adu]

bad front hoses can cause drag and overheating.
the liner comes apart and acts as a check valve.

 

[cousincletus]

^^^ I agree. This is a common problem and since the Tahoe is 10 years old, that's what I would suspect.

 

[Jim 5]

I'll second what Oil stain said. My 1998 K1500 had the same brake system as your Tahoe. The self adjusters in the rear don't work very well at all. You really need to get going close to 25mph in reverse (in a desolated parking lot) and slam on the brakes...until the ABS kicks in to get them to work as intended. Do this a few times in a row and you'll notice a brake pedal that activates the brakes with less downward stroke. You're brakes will also seem alot more sensitive (because your rear shoes are actually contacting the drum).

I went through a number of sets of front brake pads when I wasn't following this practice regularly. The best ones I found were "Wagner Thermoquiet" pads. Seemed to be good stopping and easy on the rotors.

Replacing front rotors and pads on this truck is bonehead simple (at least on the 4x4's). Don't pay somebody to do it if you can help it!

 

[ocrstar]

Are your rear drums 10" or 11"? That will make a difference in the size of rotors for the front. I incorrectly bought front rotors that correspond to 11" rear drums. The hat on the rotor rubbed on the brake caliper and overheated the rotor. I have a 98 Yukon 4x4 and it has 10" rear drums. Also, the quality of rotor has alot to do with it. At NAPA, they have 2 choices: cheap (Taiwan) and expensive (USA). The USA steel is way better and I haven't had to resurface them once since I bought them 3 years ago.

 

[alreadygone]

Most all info above is good (not too sure about 25mph in reverse!!! and cheap rotors usually give excellent srevice) another thing to consider is having rotors resurfaced

 

[alreadygone]

Most all info above is good (not too sure about 25mph in reverse!!! and cheap rotors usually give excellent srevice) another thing to consider is having rotors resurfaced ON THE VEHICLE. This compensates for any runout in hub/spindle assembly,,yea yea I know shouldn't be necessary in a perfect world, but it aint !

 

[Chris B.]

Thanks guys! I'm going to print this out and show it to my mechanic to see if it might help solve this problem.

 

[Dave H]

All of the above are good suggestions, and should be looked at. The suggestion of the rears not self-adjusting is a very good idea to look at. My '78 Camaro's rears didn't seem to adjust properly when doing stops in reverse slowly. I had to get some speed up and stand on them to get the right pedal feel. I don't know about 25 mph, so since I don't own a Tahoe, I'll defer that to the poster who does. Definitely worth doing, though. I can't see any damage being done if done with due caution.

Your original comment about the mechanic saying they look like they have been overheated raises some questions, though. I've had my Maxima's front brakes literally fail from fade due to hard driving (had to stop with my parking brake). They were smoking (something from each wheel was), and the rotors appeared to have a reddish "glow" for a minute or so. After several minutes of cooling, they worked fine, but ever since had the warped symptom of pulsating brake pedal. They didn't have a blue color to them like your mechanic said yours had. My last brake job (5500 miles ago), I had them resurfaced, and problem is gone. Anyways, my point is if you aren't driving hard, lugnuts are properly torqued, proportioning valve is working, etc..., then I would have to check if this is a common problem with Tahoes, as in being under-braked. Tahoes are pretty heavy and would require bigger braking systems than my 3000 lb Maxima. Like ocrstar said, there are different size brakes for the Tahoe/Yukon trucks. Something to look at. A properly functioning brake system using quality parts shouldn't be warping rotors easily. But you all ready know this.

I assume you're using quality parts. Check a Tahoe board to see what others are using. I've gotten many good suggestions from a Maxima board for various things. But you do have to look out for the "fad" type posters ("Yo, deez are da bomb 'cause they're new and nobody is using them").

Hope this helps. Stick with it till it's figured out. Brakes are too important.

Dave

 

[Jim 5]

Going 25mph is not strictly necessary...but it does work. You just have to be really careful about where you do it to protect your truck and your and others' safety.

Another suggestion I took from the chevrolet truck boards was to apply the parking brake until it is just about making contact. Then put your truck in low range and jam on the brakes, now back up in reverse with the brakes jammed on and this should apply enough force to make the star-wheel on the self adjuster ratchet properly. You don't have to go far...10 feet or so.

I tried this approach and couldn't seem to make it work.

Another simple way is to actually ratchet the star-wheel in your self adjusters using a large flat screwdriver through the aperature in the rear brake drum assembly (in-side of the assembly). My assembly did not have such an aperature, so I couldn't use this.

I typically pulled the rear tires off and pulled off each drum to expose the entire assembly. Then just ratchet the star-wheel until the brake shoes are adjusted to the right distance from the drum. (basically you do this by ratcheting the star-wheel a bit, then test-fitting the drum to ensure that it will still fit over the shoes). It makes a really big difference. I did this every oil change and every time I rotated the tires.

In between times I used the higher speed back-up method...and it worked like a charm. Always choose your location and time of day with safety in mind. I knew I was going fast enough when the front brake ABS system would activate when slamming on the brakes. You do have to apply a ton of backwards braking load to make the self-adjusters actually work.

When I was really into that vehicle, I noticed on the bulletin boards that 3/4 of the complaints people had about the "bad" gm fullsize brake systems were caused by rear drums that weren't doing any braking.

 

[cousincletus]

If your rear brakes are way out of adjustment, you can usually get a different feel in the pedal by pumping twice. That's a pretty good indication (if you get a higher pedal the second push) your rear brakes are out of adjustment. I doubt that's your problem though because they have been replaced recently.

 

[Chris B.]

ARRRRRRGGGGGG!!!!!!

I drove all over today and the brakes felt smooth with no plusing to them at all. They did not feel warped in any way. The truck has been sitting for the last several days, could that have something to do with it? I have not taken' it back to the shop yet as I'm trying to figure out if they are indeed warped. Some times it pluses and other times it is fine????

 

[Chris B.]

TTT