2004 LS Brakes Thumpy- how do I stop that?

[dmorlow]

Ok, I don't know why all my cars have this problem. After a few thousand miles, all of my brakes get thumpy. On my previous cars, I always changed my brakes myself and just figured there has to be something I'm doing wrong. This car, I bought new and the brakes are still OEM original never changed brakes, and they are thumpy. So, the only thing I can think of is that brake wrong. But, when my girlfriend rides with me, she says I drive like a grandpa, so I don't think I brake hard. So, when I replace my brakes soon, some tricks I do to stop it from happening is I scuff up the rotors so they aren't so smooth when I get done. I was taught if I don't do that, the brakes will get glazed. I also make sure the hub is completely clean before putting the rotor on and I adjust the back brakes with the parking brake to make sure it's adjusted properly. Then I make sure to tighten my wheels with a torque rachet to make sure the wheels are the right tightness, which would also make sure the rotors are the right tightness. Yet, all of my brakes are thumpy after driving for a few months. I can't imagine what I'm doing wrong. Like I said, I always just figured I was doing something wrong installing them, but these brakes on my car now, I've never touched them and they do it. My car has about 50,000 miles on it with the original brakes, so it's about time to change them...

[57chevyragtop]

I think you'll find these brakes are easier to work on than what you are used to doing. And you are probably right that it is time for a change of pads at least. There have been discussions here on the quality of the chevy discs though I have not enountered the problems mentioned, it could be that you are. Your braking habits may play a role in your problem since you mention it has happened time and again on other cars you've had. I don't know if you pump the brakes to stop as was at one time a way some were taught to do years ago which may cause this but I have my doubts. I changed out all 4 of my rotors ( mine were shot at 61k and elected not to have turned because of rust in the vanes) using NAPA Parts and got the best pads for the front and standard for the rear..$180 total cost. Just be sure your flexible lines are in good condition (NO SOFT spots). Clean and Lubricate the slide pins well with brake grease. Sorry couldn't be of more help with the (thumpy) deal. Maybe someone here has a better answer for you.

[la1]

I also make sure the hub is completely clean before putting the rotor on

good idea

 adjust the back brakes with the parking brake to make sure it's adjusted properly]

Doesn't really matter you have rotors all the way around. The parking brakes have there own surface on the inside of the rotor hub.

 Clean and Lubricate the slide pins

If it were me I would replace the pins. They may get hot and cooled by the brakes + stress. Get hi-temp grease made for brakes.

[dmorlow]

I called a local shop and he has a theory that makes total sense. I've never spent a lot for rotors. I'd imagine GM probably puts the cheapest rotors on their car from the factory. Cheap rotors warp when they get hot which would cause the brakes to get thumpy. He told me to get better rotors. I'm shopping around and I can't figure out what is a good rotor. They have many different prices for rotors... but how do I know that spending $25 more per rotor is enough? Why not the one that's $10 more? I can't figure out what to look for in a rotor to tell me it's a well made rotor made out of good strong metal that won't warp. Does people have good recommendations of good rotors? The guy I talked to recommended raybestos rotors... but I can't find raybestos rotors. I see raybestos brake pads everywhere... but I don't see rotors by them.

Autozone sells Duralast rotors, which is their high end rotor. They have another rotor called something like valuelast or something that sounds cheaper and is cheaper. But other than it having a better sounding namebrand and a higher price, I don't know if it's going to be better.

[la1]

I put Brembo rotors on my 2003 Impala. Just about any aftermarket rotor is better then the factory. Most of the big online auto parts houses have good quality rotors. If you see a brand you like make a post here ( new) with the name of the rotor and price. As far as the warping. I think it is because they use a different metal inside the rotor. They both heat up and cool down different so you get warping.

[dmorlow]

Well, I took my dad's advice and went to a local shop that's been in business forever that all they do is brakes. They sold us the parts. All they sold was "Wagner" namebrand pads. So I bought the best pads by them for the front and back and bought the best rotors they had. My brakes work like a dream now. I've never had brakes work this good. We'll see how long this lasts.

[57chevyragtop]

Glad you finally got your work done, Wagner is a good brand, I've used them many times over the years. Been around for a long time.

[dorlow]

So, I posted this thread a long time ago. The brakes I put on my car at that time worked great for about 2 years.... which is pretty good for my book. They were starting to get thumpy again and it's been 2 years/ 50,000 miles. My car has about 100,000 miles on it now. So I went back to the same store and bought the same brake pads and rotors and replaced them yesterday. I don't know if I'm being too picky, but my brakes still feel a little thumpy. I think my wheels are out of balance too, because when driving constant speeds, I feel a vibration in the car. So, I'm going to have my wheels balanced and rotated tonight. But, I just spent $200+ for new rotors and brake pads, and them not working 100% perfect is kind of bothering me. I mean I just got done putting them on last night at about midnight. I just drove it for the first time this morning (other than my test drive last night), and the brakes still have a very slight thump to it. Maybe if I wasn't thinking about it, I wouldn't notice... but seeing I just changed them, I'm concentrating on it a lot.

The other wierd thing too is after taking my car for a test drive and then parking my car in the garage, the first thing I noticed when I got out was a wierd smell. It smelled like the smell after you put out a torch. I couldn't pin-point it on a certain wheel. None of them were hot. When I got down and smelled them all individually, they all had a slight smell of it. I don't know if it was just the brake cleaner I used on the rotors and it was just burning off.

I'll see how my car does after I get my wheels balanced tonight. I did go out and buy a torque wrench to tighten my lugs to 100 pounds. I know that's important to getting the rotors to spin right and everything to stop without thumping.

[maxwedge]

Maybe the rear brakes are out of round, no?

[dorlow]

I changed the pads and rotors for both the front and back. I'll have to see if the wheel balancing helps later.

[denco]

Originally Posted by maxwedge

Maybe the rear brakes are out of round, no?

This would have been my reply as I was puzzled after putting new brakes and rotors on the front of my 04. A few days later the pulsating was back.
My wife (her car) took it to the dealer, they did brakes, rotors on rear.
End of problem.
What could I say...
It could just be cheapo parts from China.

[CRDuncan]

the brakes warp the rotors and that gives you the surg you feel in the pedal. They put no dust ceramic high end pads on these cars and the rotors cannot take the heat. Put the orginal high quality pads on a shelf somewhere and by some cheap pads that make a lot of dust and get some rotors that are not warped and you will have no more problems.