I was a Ford Service manager many years ago. I can recall a couple of situations similar to that with cars. We balanced the tires of a new Ford car. Had shaking. The traveling Ford warranty manager allow me to put on a completely new set of tires. Solved the problem. You say that you had to park it for an extended periods of time. Did you let it set in one spot for months or did you move your vehicle around from time to time to rotate the tires? If you could get or borrow a known good tire that did not shake from another vehicle or possibly your spare, you could rotate it with your existing wheels and see if one or more of your tires is the problem. New tires can be defective from day one. If you find the culprit, you can get the tire company to give you another one after they see how much tread has been worn off. One last thing: Do any of your tires show any unusual tire wear. Good luck!!!!
Why no replies??
Aug 09, 2005
Last reply: 20 years ago
35 Replies
Tim, Try the alt.rv newsgroup. There may be someone with the same vehicle that could give you some guidance.... Good luck...
Dave D
shake
Okay, I really think I understand what is going on here because I have seen this before and part of the confirmation of the problem is that is less severe on a choppy road. Here is the nuts and bolts of your problem and why they have not fixed it. They do not understand it! You have what I called a "caster death wooble" where the combination of the front axles king pin caster angle and toe and camber create a unstable condition in front axle that can oscillate pretty bad when things are right. Most try to fix this with dampners and tightening up steering but the best way to really fix it it to fix the instabiity. Try adding some negative caster to front axle (about 2 to 3 degrees) and make sure toe is about 1/16 th or so and I bet that will help. (You will do this buy installing shims between axle and springs) Again the answer lays in getting the axle stable to begin with not brute force to control it.
You guys are missing the obvious here. Change the caster angle and alignment of front axle and it will go away. It does not matter if they are at spec or not because if they are spec it is not proper for that application and this is why everyone is scratching their heads because nobody understands or realizes the effect of caster and alignment on front end stabilty. You can change these settings (it may take a tweak or two) and it will fix the problem with the unstable front axle when setup correctly or you can keep beating your head against the wall. I have seen this LOTS of times.
It is going to be curious how long they fuss about this before they try changing the front axle caster and alignment to stabilize the chassis. No wonder it has not been fixed because nobody has really understood the problem, they just keep putting bandaids on it and never curing it.
had a similar problem and mine turned out to me a transmission mount...
Joe
"" wrote: > With all due respect, is this a closed news group? I haven't > received any > replies to a shimmy problem. > I have a motorhome on a Ford F53 chassis. I am trying to get > help with a > shimmy in the Ford built chassis. > Please reply... > Tim fm CT
tierod could cause a bad shaking, like your wheel is falling off.
On Thu 11 Aug 2005 02:35:43p, xmirage2kx assaulted the computer and came up with this:
a good curb check will bend a rim, did you let your wife drive the house again?
Me too, same thing, a truck that shimmied when I hit a bump just so and I had to slow it to a crawl. Turned out to be a bad shock. Impossible to see, but it was bad.
My first thought when I read this was shocks or a bad spring, but RVs are completely alien to my world.
Kate
I had an 86 f250 that developed a shimmy problem, like yours when the PS pump started leaking on the presure side. Not enough presure for the pump to control the steering box. Also check the all the bushings in the front end. Over the years of owning this truck I found out that tires also made a differance in if I would have a front end shimmy. dave
Sounds like a time to replace the king pins and bushing,, and a real good look at the idler arm and tie rod ends for wear!!
Thanks again everybody... Tim fm Ct
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