My 1999 Econoline 150 is having a front end problem. When I brake hard, the front end oscillates. The steering wheel whips left and right. The harder I brake the harder it oscillates. Really violent!! When I take my foot off the brake the oscillation stops.

It was doing the same thing, maybe 25,000 miles ago. Then the steering box started to leak. I replaced the steering box and nearly the same time, the front ball joints. All four of them.

Everything seemed fine until, maybe 1,000 miles ago. Then I started to sense the oscillation, very subtle but there. Now, it feels like it will rip the steering wheel out of my hand.

Yesterday the ABS light came on during some mountain driving (lots of hard braking on hills and turns). I haven't had time to track that down yet but a few years ago I had the same thing and it was just a wheel sensor.

Any idea what the oscillation could be?

Thanks In Advance

Pete

 

I can't say for sure what you're problem is but when ever i had that happen it was usually the front brake rotors. It could be the pads or even the ABS. Have the rotors checked for trueness and the pads for ware.
I have an '88 E250 and just did a brake job on it. The rotors were replaced but I did not have that problem.

 

Jim,

I have been thinking along the same lines. I hesitate to call it the rotors because when I replaced the steering box and ball joints, the problem went away. Even with the same rotors. Now it came back.

Last weekend I jacked her up and did a lot of inspecting, shaking, and wiggling but couldn't find anything. I put a dial indicator on the rotors, both sides and a micrometer measuring the thickness. Nothing stuck out.

I had a rotor laying around that had just two small groves on one side so, in desperation, I put it on the passenger side.

No more shake. But I'm sure it will return. Of course it may have been the wheel bearings that were loose but they sure felt right.

When I fired her up, the ABS light went out.

I am sure this is not the end of the story.

I'll post any new info as it evolves.

Thanks Again,

Pete

 

I have been having a similar problem. Front end vibration while braking, but that vibration became very subdued below 20 MPH. Changed inner and outer tie rods - that helped steering more than vibration. Then changed radius arm bushings - $340 at a local garage - and the vibration while braking is now only related to rotor warp. There's a big difference. If the vibration is nearly gone at low speeds, or if at low speeds you don't feel the rythmic pulse of the rotor turning, then the likely culprit is the radius arm bushings. Good Luck.

 

Thanks bigbus. I will try to sense which it is.
After I did the work described above the vibration seemed to go away except every now and then, braking from high speed, It seemed there, sort of "in the back ground". I convinced myself that it may be coming back.
I was suspicious about how doing a little work under there seemed to lessen or temporarly eliminate the problem. Since taking off and reinstalling the wheel seemed to have some effect, I decided to be real careful how I tighten the wheel bering nut. I read up on the procedure and used my torque wrench to do it like the manual instructed.

I "think" the vibration is gone. I just tried 4 or 5 high speed stops. Most created no vibration. One time I thought I sensed it but it stopped in a split second. When it was bad, nothing would stop it but releasing the brakes.

If it comes back I think I'll do the radius arm bushings. I believe you hit the nail on the head with that one

Thanks.

Pete

 

I think wrong!!! I was able to cause the hard rapid wobble.

That looks like I need to change the bushings.

Anybody know how hard that could be. I see a giant nut with lots'a rust.
Shop Manual says remove coil spring. Then the front end of the raduis arm. Could it be possible to not do that? I doubt it but I thought I would ask.

Then remove the giant nut and take out the pieces. Are any of them pressed in? Like those giant rubber bushings I can see from the side?

Does this effect the wheel alignment? I have a real problem getting this van aligned. They do the toe-in but the camber is off a little and no one, even a dealer, wants to do it. I think it is because there are bushings that have to be calculated and no body wants to try.