bigredbrick

I've been getting this vibration that starts around 40 mph and is sometimes worse than at other times. The wheel bearings are good as is tire balance. It's also pulling to the right.
Got any ideas on the culprit?

Thanks

Alec

Could be your right front tire is bad -- ply separation or something. U-joint in the front axle, maybe, combined with a stuck hub? Or a bad u-joint causing vibration in the rear drive-shaft unrelated to the pulling.

apache

I had Michelins on my 93 250 that were worn evenly to my view. It did not pull at all. I replaced them with BFG commercial TAs and now it pulls to the left enough to be annoying at least. I have also had a shake since they were installed. I watched them like a buzzard, cause I dont trust anyone working on my stuff so I know they didnt knock the front end out of wack. Try to find a shop with an old style on car balancer and have them just run each front up to speed, if there out it will shake good and you can see if that is the problem. You know the front ends of these are a little weak so maybe its time for some balljoints or? Also have you rotated the tires up front recently?

uncleroty

The first thing to do is look at your fron tires. Is there uneven wear, inner or outer to the tire? If you have a "bad tire", or have recently changed tires, you most likely need an alignment. Getting new tires can offset the alighnment you had on the old ones as they distort over time. Unven wear inside to outside can also be an indicator of poor alignment, or the need for some front end repairs such as tie rods.

Your local alignment guys will have a riot with your truck. Normally a vehicle will have the tow in/out/camber/caster adjustments, and a steering adjustment. As we likely have the very same front end Bigredbrick, you will find that your truck does not have a typical steering adjustment. If your alignment is out of place as I suspect it may be, you have to hope it isn't out too much, as mine was.

If it is, you have to detach the steering colum and move it over to where it works well. ( a spline or two). This can limit your steering range to one side. Mine was out the better part of an inch when I bought it, resulting on a slight loss of motion when steering to the right, but really not openly noticeable.

My advice is to check the tie rods and ball joints, and if they are not too bad, take it for an alignment. Quiet frankly, an alignment once in awhile won't hurt. If you take it into a garage, they will likely tell you if the front end components are bad, but beware the "rip off mechanic", of which there are many. If you, or a friend know enough about the subject, check it out before going to the garage, as we know the mechanic's industry may not be the most honest in the world.

Much good luck to you!

bigredbrick

I'll rotate the tires - it's been awhile. About the only thing you can adjust is the toe. How do you check the ball joints? The last time I had the frontend off the ground nothing "seemed" loose. The front tires are feathering. The front axle u-joints are fairly new. The old ones froze up and caused some real strange steering problems. Could old worn-out shocks cause what kinda feels like wheel hop - with a suspension this stiff?

Thanks, Chris

uncleroty

I would hold off on the tire rotation, given the pull to one side, and especially if the tires are unevenly worn/ feathered. You don't want to damage an otherwise good tire by moving it into a location where damage is happening.

If nothing seems to have any play in it, or visble damage/wear, then you are probably out of the woods for that expensive front end work. Also, your truck does not have a huge amount of miles on it. I hope it's o.k. anyways.

I would take it to an alignment shop and have it aligned. Don't mention anything about the front end to them. If the front end is too worn/damaged, they won't be able to align it, and they will tell you this. You don't want to give them an in for front end work by mentioning anything. (they may need to move a good tire up to get the proper alignment as well.)

My truck had exactly the symptoms you describe, and a $75 (cdn)alignment cured it immediately.

Best of luck!

bigredbrick

I guess I'll check it out the best I can then take it in for an alignment like you suggest.
Thanks

Alec

You are right that the only adjustment is toe (without using caster shims under the spring pack). Different tires like a different amount of toe, because they flex different amounts. If the tires are feathering, it would seem that your toe is out. Unless a spring in the upper king pin is broken, you aren't going to see any play in your knuckles, though they do wear to give a negative camber, and the spring can get weak. (The upper king-pin has a plastic tapered bushing pressed onto a tapered pin by a coil spring. The bushing tends to wallow-out a little to the outside from the leverage of the spindle sticking out.) The spring is supposed to make up for wear, and act as a steering damper.

I would rotate the tires and have the toe set. I have to warn you, though, my advice isn't worth much, 'cause my truck pulls to the right . . .

apache

If your a tightwad like me for a quick check to see, lift each tirs off ground, take a small nail, put it through a board and place it up against the tire in the center, spin the tire to scribe a nice mark around the entire diameter on both sides. let it down and measure the distance in the front and then in the rear at 90 degrees up. This will give you a toe in/out reading. Yeah I know, for $39.95 just take it in, but this is great for the jeep on the trail when you smacked something hard.

bigredbrick

Some front diffs have tapered shims between the spindle and knuckle to adjust camber - the Scout front diffs I've worked on have had them, but I don't remember any on my Dodge.

A real tightwad wouldn't waste the board and nail Just use a tape measure on the same spot on the tread front and back.
Alignments around here are more than that!

Mike S.

Bigredbrick, you might want to check the torsion bars, check both ends of both bars. These are the bars that go from the lower A-arm to the front-center of the frame.

I had the rubber go away on the right one on my '92 and had a bad vibration in the front. It got worse when the brakes were applied. ALSO, one time the A-arm end lost its bolts and the vibration was really bad. I attributed this to poor reassembly after the accident my daughter had with the truck.

Hope some of this helps.