When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have A 1979 f150 at around 20-25mph it vibrates so bad it feels like the truck is going to come apart. it does this only in that mph range. does not matter if acclerating, braking or coasting. does not seem to be coming through steering, so i didn't think it would be in the front end. any ideas you all would have are greatly appreciated.
[updated:LAST EDITED ON 10-Sep-02 AT 08:07 AM (EST)]Do you feel it in the seat?...If you do look at the rear of the truck.Try the obvious stuff first its possible you have a balance problem...i.e.tire out of balance,bent rim,bad tire(separating)or a weight missing off the driveshaft look over the rearend real good.
I would check all the tires to see if they were coming apart, had one do the same thing to me and I went through so much time and effort to check hard things that I overlooked the simple. Come to find out that a tire had a bulge in it and was out of round and vibrated horribly at low speeds. Check the U-joints in the drive shaft also, and check for bends in the drive shaft.
10-4 on the tread seperation and "U" joints before they come apart. Some times a tread will seperated internally so you don't see anything untill you watch the tire rotate.
Don't forget to find a big hill you can coast down without being in somebody's way.....turn the engine OFF and coast to the speed you are having troubles with....possibly you have a harmonic balancer problem or something...with the engine OFF, you would have a better chance of possibly hearing where the problem is. Plop somebody back there in the bed and let them listen if you can....that's how I isolated a rear wheel bearing going out on me...
You say it doesnt feel like its coming from steering.Check the drag link and track bar anyways.Have someone rock the steering wheel back and forth while you look for play in the end joints.When the link goes bad the whole truck shakes violently about 20mph and usually wont stop until you do.It wont feel like steering,more like the front end is falling out!Id check that first before you start balancing tires.Its a pretty common problem.Good luck!
thanks for the input. will check some of this tonight and post results.i had not even thought about the tires, but i am thinking that could be it , truck was sitting several years before i bought it.