First I want to start off that I am ase certified tech that has been in the biz for about 20 years, but I am semi-retired now.(I just work out of my home garage now). My problem is with my own truck that i have owned since its been almost new.
Its a 1994 Chevy Silverado 4×4. It has about 160,000 very reliable miles on it. The problem started about 2 years ago and I have sort of been putting off the problem with it since its not my daily driver anymore I only use it to tow my trailer with atv’s now. It had a horrible vibration when braking that I would normally associate with bad brake rotors. If I got over 50mph or so and hit the brakes it would shake and vibrate just like any other vehicle would with warped rotors.
About a year ago I replaced the front rotors and pads and it made no difference. You dont really feel it in the steering wheel or the pedal(maybe a faint feel in the pedal). Its actually hard to tell where its vibrating from, at first I assumed it was coming from the front but its very hard to tell. So at this point I figured the rear brakes and drums might be the problem and it wouldnt hurt changing them out anyway since the rear drums were original with over 150k miles on them. I changed the drums, shoes, wheel cylinders. The problem was still there.
It was actually getting a little worse. I kept driving it here and there for about another year. Finally about 1 week ago I decided to change the front rotors again and really investigate the whole front end.
I put new calipers, pads, and rotors on the front of the truck. I buffed down the hub to make sure there was no rust behind the new rotors, and I made sure the wheels were perfectly straight and seated when I put them back on. (I also rotated the tires). I took it out and while the problem is I would say 70% better the shake or vibration is still there. Its still very annoying, but i would defintely say its better than before. The truck has nothing loose or broken on the front and everything is tight(pitman arm, tie rod ends, etc..) The truck is smooth as silk on the highway, no vibration at all when driving(I just took it on a 700 mile trip). It still feels like a warped rotor, even though I put brand new ones on it TWICE. Nothing really in the steering wheel and only a faint almost like pulse in the pedal.
I dont know what to do at this point. I am stumped. I love this truck and it really has been rock solid reliable. Its to the point where I dont enjoy driving it though and I am really getting angry that I cant get this problem out of it. The truck sits a lot in the garage because I dont use it as a daily driver so I thought possibly it was a tire or something even though it was a long shot and its really smooth on the highway as long as you dont hit the brakes, so I rotated the tires and it made no difference(the tires have about 70% tread left). I would say its a lot better since putting the second set of new rotors on it and new calipers but its defintely still there and its defintely still annoying.
Can you think of anything else to look for? I am open to any all suggestions at this point. In all my years as a mechanic if I didnt know the history of the truck and it was brought to me I would totally assume that it was the front rotors on how it is acting, but I find it hard to believe I got 2 sets of warped new rotors. It driving me nuts. Any ideas?
Hummm, I think I still have to suspect a brake rotor issue after reading your email. You DID say that is was 70% better after you installed new rotors and calipers. I can only assume that maybe one of the new rotors is warped out of the box.
It would be easy to take them to a local auto parts store and have them trued just to be on the safe side. Since you say there is NO vibration what-so-ever when you are just driving on the road, I would really really really think, this is brake related, and since you have replaced just about everything brake related except the master cylinder and the brake hoses…..which I don’t think is your issue.
You might also want to stop the truck with your emergency brake just to make sure the problem is in the front brakes and not the rear. Hold the emergency brake release handle as you apply the emergency brake so you can make a safe and smooth stop just with the rear brakes.
If there is a pulsation or vibration, the problem is in the rear brakes. If it stops smooth, I would recheck the front end again for wear, check the steering gear lash for play or wear, check front wheel bearings for play, and if you still don’t see anything, have the front rotors cut.
Keep me posted