Dancing, Prancing E-350 - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Uncle Rice · 05-08-2007, 08:50

My company bought this brand new E-350 high-top with a wheel chair lift in the back. The first time I drove it on the freeway, I found that it starts to be unstable at 60 MPH and once you reach 75 MPH it's a Prancing Dancing Fool. I took it into a dealer at 190 miles and they did some minor ajustments to the alignment. I didn't get a chance to check for the problem again until it had 900 miles on it. The instability was still there. I took it in to another dealer and they found nothing wrong and like the first dealer, blamed it on it being a high top.

I have a 2001 Dodge van with a taller, more ungainly high top on it, and though it's a bit top heavy, the steering is quite stable. Am I dealing with a design failure, or is there still a problem somewhere? Anybody got a clue?

kaboom10 · 02-17-2008, 08:47

Sounds like a weight distribution problem. The vehicle is designed to have a certain amount (percentage of total weight) on the front wheels and the rest on the rear. The added weight of the lift is causing an imbalance. The rear suspension has to be beefed up to restore the weight distribution back to stock. That's why when you tow a trailer you havea certain amount of tongue weight you can handle. I had to ride in one of your vans during recovery but didn't have to go on the highway. It rode quite well as beefing up the susension gives a harsher ride also.

The top heavy on the other vehicle is fine because the extra weight is distributed more evenly on the vehicle. It stresses the total suspension instead of the rear only.

Uncle Rice · 02-18-2008, 04:33

This makes sense. I'll make a note that an empty van may be unstable. I guess they are made to carry weight and don't do well without it.

kaboom10 · 02-18-2008, 06:10

You would be amazed at what happens when you change spring rates and even tire pressure. Besides improper wear on a tire it is also acting as a spring also. Think of a tire as a ballon and you are squeezing it. It's very enlightening when you learn race car chassis set up and how to adjust it.