2000 F350 SC 4x4 PSD with 33x12.50x16.5. 95k on the truck. New shocks 5k mi ago. Alignment 5k miles ago.
This may be a long post. I've had brake problems on the above vehicle for a while. Very bad vehicle shake/bouncing around 50mph. Put the brakes on at 70 and there is some bounce but really magnified around 50 which decreases once you get under 40. I could feel it in the steering wheel, but not the brake pedal. The hood would really bounce (1-2 inches). It was somewhat intermittent also. Always there, but much worse at times. My thought was a sticking piston in one of the front calipers as a warped rotor would always cause the problem.
I had the front brakes replaced. New calipers/rotors/pads. One caliper was leaking and the rotors were warped (what a shock). Got the truck back from the shop and it felt good around town, but still had some bounce/shake at freeway speeds. I didn't notice the shake in the steering wheel like before but the front still bounces. This got progressively worse over the next couple days so I took it back to the shop. As you couldn't feel the problem in the steering wheel, they decided the rear rotors were warped and replaced them along with new pads. Rear calipers checked out ok.
The problem remains and is getting worse. The shop put a dial indicator on all four rotors and all four check out good. At this point, the truck is non-driveable - you cannot control it when the brakes are applied at freeway speeds. The shop pulled the ABS fuse and that made no difference.
One thing I have noticed is that the problem is not as severe when towing - perhaps the extra weight helps hold the back end down.
Does anyone have any ideas as to where to look next? We're leaving on Sat. (I hope) for a 4k mi trip so I need this resolved quickly.
It might take a tech that's familiar with the Super Dutys to do the brakes, Mike, they're finicky to say the least. Donít give up on the brakes yet and lose money looking elsewhere.
I know youíve already spent this money, and if the mechanic keeps using his brain and learning as he goes he could figure it out eventually.
The rotors can warp very easily from being just junk to having bad pads installed, then thereís the problem turning the rotors and all that. Itís a hit and miss sometimes Ė just stick with the brakes until they get right. You may even need to get new rotors and pads.
OK, here's the final answer. According to the shop, one of the new rotors was warped by .020! I test drove the truck and the brakes felt good, yet I still noticed a slight shimmy/vibration, more noticeable under braking, but still always there so I knew something else was not quite right. I could not believe the damage to the rear tires from the truck bouncing with that bad rotor.
I had an appt to get the front end aligned just after getting the truck out of the shop. They found the passenger side wheel bearing was bad. The brand new front rotor was rubbing against the shield on the inner side - that's take a LOT of play to bridge that 1/4 inch gap! Don't know why the other shop didnt notice that. So, $489.09 later, I had a new wheel bearing, front end alignment and tires all balanced. The truck now rides great, but still has a slight pull to the left. It's done that for a while and is not causing visible uneven tire wear. I'll address that when I get back from the trip ( Montana to NM via UT and AZ, return thru CO and WY). The alignment has a 30day warranty.
Good tip on the lugnuts being evenly torqued or rotor warpage may occur. Les Schwab always hand torques the lugnuts.
Another cause of warpage is to sit in one spot with your brakes applied - like coming off a freeway offramp. It's best to creep forward slightly so the pads are not on the same spot on the rotor.
One thing that is often overlooked when replacing the pads and/or caliper is the caliper pins. If they are not cleaned and well lubricated (I use brake caliper grease) the pins hang and cause the caliper on one side to not "float" and close as well as the one on the opposite wheel. This will cause the truck to pull toward the "good" side. Sometimes the pins get stuck so bad that they cannot be removed and the whole caliper bracket has to be replaced. Always be sure to clean and lubricate those caliper pins.