99 & up 7.3L Power Stroke Engine and DrivetrainDiscussion of the 99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
Not something I want a mechanic or doctor to tell me. Here's the problem. If I'm above 35 mph or so and start slowing down, either by just coasting or by braking, I feel a vibration in the wheel, brake pedal, and seat. Slower I go, the worse it gets. And it sounds and feels like I'm driving over rumble strips. When I'm coasting and it's vibrating, applying the brakes makes it a little worse. When it's vibrating and I begin to accelerate, the vibration stops. I had the wheels off and the rotors look fine. I had lots of play in the drag link (connects to the pitman arm) and replaced that and it made no difference. I had the problem when I had on my summer tires and the problem remains since I switched over to my winter tires. The mechanic who took a test drive with me said the symptoms didn't seem like they were tied to rotors, wheel bearings, or u-joints. The place/mechanic specializes in drivetrains and they've done good work for me in the past (ball joints, etc.). The driver's side hub assembly and rotor are 2 years old. The passenger's side is probably the original. Truck has about 270,000 miles on it and I bought it in 2001 with 90,000 on it. The soonest I can get it into the shop is Tuesday next week. Any ideas on what it could be or what I could check myself (limited mechanical ability but haven't screwed anything up yet)?
I'd first thought warped rotors but it also vibrates if I don't apply the brakes. I greased the pins this summer. Shocks seem fine. I have Rancho adjustable and have the same vibration regardless of the setting.
Are the hubs locked? Sounds like a worn stub shaft.....
Turn the front stub u-joints by hand and also jack up a side and spin the wheel.
Also, don't discount the rear driveshaft (which was my original thought). If the u-joints or slip shaft are bad or bound, it can cause all kinds of issues.
__________________ 99.5 F-250 CC LB 4x4 7.3 Red
Trail Boss Replacement Bumpers, Tool Box, Headache Rack, Full Length Running Boards, BFG AT/KO 285/75x16E, 2003 Cup Holder, Marinco Heater Plug, Weather Tech Rain Vents / Hood Guard, B&W GN Hitch, X-Springs, Rear 4" F350 Blocks, Hellwig front and rear sway bars, Airlift / Wireless, Duraflaps
99 F-250 CC SB 4x4 7.3 White
Ranch Truck, Ranch Hand brush Guard, Original Cup Thrower, DP-TUner F6, 4" Turbo Back Magnaflow, AIS Intake, 6.0 Tranny Cooler, Ford 4R100HD, CM Flatbed
My 94 had warped rotors and it would vibrate only when you used the brakes and heated them up a bit. They would warp worse while they were hot and vibrate even if you werent braking. Do you have a way to check them, like a machninists granite surface block? Because everyone and their brother should have one of those.
Are the hubs locked? Sounds like a worn stub shaft.....
Turn the front stub u-joints by hand and also jack up a side and spin the wheel.
Also, don't discount the rear driveshaft (which was my original thought). If the u-joints or slip shaft are bad or bound, it can cause all kinds of issues.
It does the same thing whether or not the front hubs are locked. I have been having some problems with getting them to unlock, but once I was sure they were unlocked I still had the vibration. When you say the front stub u-joints, do you mean the part that's between the upper and lower ball joints? If so, what should I find if I turn them by hand to show that the u-joints are bad? I can turn them by hand when they are unlocked.
You guys that keep referring to rotor issues as "warped" will never understand rotors.
My first check would be if there are any frozen slide pins. If they are hanging up enough to keep the outer pad against the rotor and the rotor has a hard spot or thickness variation you can have an issue without applying the brake pedal.
__________________
Jack
Former Vehicle Test Manager - Friction Products
03 F350SC 4x4 6.0 Auto 5/30/03
Truck Pictorials on Facebook. Google - Facebook TooManyToys
It appears to be brake related, so the rotors/ brakes would be the logical place to really look hard.
Just "looking" at the rotors won't verify their condition. It might be heat related, so I would go for a drive and get some heat into the rotors and try and get one side jacked up and spin the wheel. If it spins freely without hanging up, have someone put a little pressure on the brake pedal and see if the resistance stays even. If you are happy, do the same for the other wheel.
When you pull in, see if both rotors are similar in temp as well. If one is hanging up, it will be noticably warmer.
Ultimately, you may have to pull the rotor/ brake assembly apart and push the calipers back in and re- grease the slides. Also make sure the pads are not binding on the hanger. I have had to pull the metal clips off the caliper bracket and clean the rust off from behind it because it was binding the pads. Ultimately, I replaced it to get new slides and calipers because I was getting the vibration pretty hard when braking.
__________________ Tom
99.5 PS CC 4x4 SRW ZF-6
Triple Pillar Gauges; Fuel pres, Pyro, Boost
AE, Alldatadiy, and half a clue
- AKA "The Big White Truck"
You guys that keep referring to rotor issues as "warped" will never understand rotors.
My first check would be if there are any frozen slide pins. If they are hanging up enough to keep the outer pad against the rotor and the rotor has a hard spot or thickness variation you can have an issue without applying the brake pedal.
When I jack up my truck and spin my front wheels by hand and I hear the pads dragging on the same exact spot with every revolution, then take the truck into ford and they tell me the rotors need to be resurfaced, then my vibration goes away, that would be generally called a warped rotor.
You may refer to it technically as a 'high spot' or say they're grinding away a hot spot, but that would be arguing semantics.
Now, for some gratuitous brake porn.
__________________
1999.5 F250 creeping up on 400k.
That rotor reminds me of the blades that go into one of those late night infomercial food gadgets. You know, "it slices, dices, cubes, shreds, makes shoestring potatoes with ease, all for $19.99, and if you order right now, ...."
I don't imagine that one costs $19.99, with a second one free- all you have to do is pay S&H.
__________________ Tom
99.5 PS CC 4x4 SRW ZF-6
Triple Pillar Gauges; Fuel pres, Pyro, Boost
AE, Alldatadiy, and half a clue
- AKA "The Big White Truck"
Jack has a very detailed post in one of his threads on hard spots/thickness variations on rotors. Makes very good sense to me. If the rotors were warped, but the same thickness all around, then the calipers would just wiggle back and forth with the rotors (unless they were hanging up on the slide pins.)
Got home tonight. Had driven a bit in 4WD to make sure it wasn't the needle bearings gone bad. Nope, same vibration. Then took it out of 4WD and got out and turned the hubs to Free (or whatever the unlock version is called). Drove the rest of the way home that way. When I got home, I turned the passenger side axle (? whatever is the part between the upper and lower ball joint) and the hub lock or whatever it's called made loud clicking sounds as I turned the axle. Took the hub lock off the truck and it sounded like parts or rocks inside when I shook it. Took off the hub lock from the other wheel and it didn't make any noise when I shook it. So maybe it's the hub lock that's bad and what's making the vibrations. So guess I'll get a new one tomorrow. Question about Warn. Right now on my truck the vacuum is messed up so during the winter I keep the hubs in the lock position. Then when I need 4WD I just turn the ESOF knob in the truck and I'm in 4WE. Would this be the same procedure if I had Warn manual hubs? Or with Warn, once you turn get out to lock in the hubs is it then in 4WD or do you still need to turn the ESOf knob to put it into 4WD? Thanks in advance for the help.
You can keep manual hubs locked and just use the switch to go in and out of 4WD. The switch and manual hubs would be independent of each other. With the manual hubs you can leave them unlocked and have 2WD low, or you can lock the hubs and have 2WD with the t-case switch in 2WD and 4WD with the switch in 4 Hi or 4 Lo. In 2WD, the front axle gears and front DS will turn but not drive.
I have the manual shift t-case and leave the hubs locked all winter long. Then when I need 4WD, I just pull the shift lever.
Sounds like you found the culprit with the lunched locking hub.
You can keep manual hubs locked and just use the switch to go in and out of 4WD. The switch and manual hubs would be independent of each other. With the manual hubs you can leave them unlocked and have 2WD low, or you can lock the hubs and have 2WD with the t-case switch in 2WD and 4WD with the switch in 4 Hi or 4 Lo. In 2WD, the front axle gears and front DS will turn but not drive.
I have the manual shift t-case and leave the hubs locked all winter long. Then when I need 4WD, I just pull the shift lever.
Sounds like you found the culprit with the lunched locking hub.
Follow-up question. When you say that with the manual hubs you can leave them unlocked and have 2WD low, what do you mean low? Wouldn't it be just like what I have now when I have my hubs set on the auto setting (with ESOF switch off)? If it's like what I have now, then it sounds like Warn manual hubs would be the same type of operation as I now have (no ESOF use in the auto setting since I have a vacuum problem, so I leave them in lock position in the winter so they're ready to go into 4WD when I need them). So what's the downside of let's say Warn manual locking hubs? Any? I can either replace the one locking hub with another one just like it for about $300, or I can get a set of Warn premium manual locking hubs for $320. Kevin, what's your opinion? And I assume that the Warns just pop in like the factory ones do?
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