Hello all,
I current own a 2000 26 foot class c motorhome that is on an E450 super duty chassis. My issue is when applying the brakes the steering wheel violently shakes but only sometimes. There is no rythm or reason as to when, one minute it stops nice and smooth and the next time you put on the brakes the wheel is shaking like crazy. I have totally redone the brakes and throughly gone over the front end components nothing seems stand out as the cause. Going down the road the vehicle is smooth nothing shaking or pulling. Would air in the lines cause the ABS controller to act up? Could it be something with the hydroboost? Kind of at a dead end here so any help would be greatly appreciated.
Thanks
Charles

Once again this only happens when applying the brakes and only sometimes.

 

I'd check your old rubber brake lines, perhaps replace both with braided steel lines.

 

LOL.....


wheel balance first

 

Thanks for the replies, however the brake hoses are only a year old and there are brand new tires on the front. The issue still remained after the tires.
Thanks again for advice

 

I told you , wheel balance first.
New tires does not mean they are balanced correctly.
Care to place a bet?

 

I understand what you are saying however the problem has been on going. Was coming back from a long trip and had the tires balanced half way through. The shimming was there before and after, had to replace a front tire after returning home and dicovered it was out of round I replaced both front tires and again the shimming was still there. As I stated before this only happens sometimes and only when applying the brakes.
Can you explain to me why out of balance tires would only cause shaking in the wheel sometimes and only when applying the brakes. Not saying your wrong I just don't understand why the shaking would be there on one stop and not the next on the same road conditions.
Thanks

 

I don't know the actual physics but I do know the symptom.
You claim the front end parts are OK. if this IS true, it's balance.

 

Could be the brake rotor having a high spot, BTW new means nothing, buy rotors from a place that can turn them, sadly, they are not true off the shelf they will turn them free if you bought them there.

 

if it was a rotor it would happen every time he hit the brakes

 

I'm leaning toward the tires too, just because they're new doesn't mean there's not a defect. Try this: jack up the van; and spin the wheels/tires with a stationary object (such as piece of wood) as close as you can get to the tire tread and sidewalls to check for runout. I've heard of tires balancing out, but had substantial runout, like egg shaped, if you will.

 

I can't hold this in any longer. A man was waiting for a sale at Firestone for some expensive radials he wanted. Sale hit and he went in and demanded cash & carry which they reluctantly allowed. He took his "prize" tires to a small shop for a cheaper mount & balance. He also asked that they true them up if not perfectly round. He returned just before closing and was happy to see his car in the pickup lot. As he paid for the work the employee informed the owner that 3 of the tires required a bit of grinding but there were now round but would not pass state inspection. Moral of story (beside Firestones are crap) is just because they're new doesn't make them good.

 

Moral of the story is never assume that any new part is a good part!