Need Help With Rear-end

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Oct 1, 2006 | 08:56 PM

srjones81

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Need Help With Rear-end

I have a 91 F-150 but i put a rear end from a 89 Bronco in it with a 6 inch lift.
I just recently started having problems with everytime i hit the gas the Rear moves up and down and puts the drive shaft in a bind and breaks U-joints.

Does anyone know what causes this or how i can fix it?

Thank you for your help.

Oct 1, 2006 | 09:45 PM

Conanski

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Joined: Jun 2006

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From: Ottawa, Ontario

I think you are describing axle twist. If so you need to add traction bars. There are a couple different designs around, some mount above the axle, some below. If your lift included large blocks this is the root cause of the problem.
http://www.rockymountainsusp.com/tractionbars.htm

Oct 1, 2006 | 09:46 PM

mikeyswood

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Joined: Jul 2005

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From: Cincinnati

Hi,
First off-welcome.

Now, can you tell us more about the truck: 4x4 or 4x2? Motor? Gears? Wheel base?

My first guess is that the drive shaft is out of travel with the 6" lift.

Mike

Oct 2, 2006 | 05:39 AM

srjones81

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Joined: Oct 2006

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its a 4x4 with 302, the rear has 3.73 possy, and i am not sure about the wheel base.
But its a 1991 f-150 Lariat regular cab with 8 ft bed.

It cant be the drive shaft i had one custom made for it. If you stand behind the truck and watch some one hit the gas. You can actually see the rear rotate down towards the ground. And if you put it in reverse it rotates towrd the sky. I also noticed the if i take the rear lift blocks out and level the driverside that the passenger side with be off level towards the front of the vehicle. I am so confused with this.

Thanks for your help with all this matter.

SCOTT