Bump steer with power steering
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Post Fiend
Joined: Apr 2002
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From: Central Kali
Bump steer with power steering
Installed a F-150 power steering box on a 72. The manual box had no signs of bump steer The power steering does. Lift is maybe 2". The steering linkage has a very slight angle up to the pitman arm. Anyone got any ideas as to what is causing this? 
Postmaster
Joined: Dec 2002
Posts: 3,594
Likes: 2
From: Southern Oregon USA
Bump steer with power steering
Installing the F150 box caused it...
It's very common for this to happen with the 2wd box conversion. The main problem is the long pitman shaft used in that box changes the angle of the draglink in relation to the angle of the track bar.
You want the draglink and the track bar to run as parallel to each other as possible.
Do you have any steering correction for the lift kit? Pitman arm, drop track bar bracket, adjust. track bar?
This is the main reason why most of the Bronco specialty companies have gone away from the F150 conversion.
Jason
It's very common for this to happen with the 2wd box conversion. The main problem is the long pitman shaft used in that box changes the angle of the draglink in relation to the angle of the track bar.
You want the draglink and the track bar to run as parallel to each other as possible.
Do you have any steering correction for the lift kit? Pitman arm, drop track bar bracket, adjust. track bar?
This is the main reason why most of the Bronco specialty companies have gone away from the F150 conversion.
Jason
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Post Fiend
Joined: Apr 2002
Posts: 7,157
Likes: 1
From: Central Kali
Bump steer with power steering
Hi Jason, I just checked the angles. The draglink to the pitman arm is 2 1/2 degrees. The track bar is 10. Another Bronco that does not have the bump steer measures 10 and 12 degrees, has a Toyota box. If I put a drop bracket for the track bar on so I can match the angle, do you think it will correct it? Thanks 
Postmaster
Joined: Dec 2002
Posts: 3,594
Likes: 2
From: Southern Oregon USA
Bump steer with power steering
So the draglink is almost flat compared to the tie rod?
The drop track bar bracket should help some of it. It will drop the track bar down about 3.5" from stock.
What pitman arm are you using on the F150 box?
I have a stock 77 box on mine with a drop pitman arm. With roughly a 2.5" lift, the bottom of the pitman arm measures about 5.25" from the bottom of the frame. I have a track bar bracket and this makes the draglink and track bar just about where they need to be. I can't remember how far the F150 box hangs down, but that should give you a ballpark to shoot for.
There is a steering box that shares the bolt mounting pattern with the F series box but has a short pitman shaft. Mid 60's Lincoln Continentals used a 3 turn box that matches the F150 box. The pickup steering box puts a lot of stress on the frame because of the extra leverage from the long pitman shaft. It isn't a very popular swap because they are getting hard to find.
Jason
The drop track bar bracket should help some of it. It will drop the track bar down about 3.5" from stock.
What pitman arm are you using on the F150 box?
I have a stock 77 box on mine with a drop pitman arm. With roughly a 2.5" lift, the bottom of the pitman arm measures about 5.25" from the bottom of the frame. I have a track bar bracket and this makes the draglink and track bar just about where they need to be. I can't remember how far the F150 box hangs down, but that should give you a ballpark to shoot for.
There is a steering box that shares the bolt mounting pattern with the F series box but has a short pitman shaft. Mid 60's Lincoln Continentals used a 3 turn box that matches the F150 box. The pickup steering box puts a lot of stress on the frame because of the extra leverage from the long pitman shaft. It isn't a very popular swap because they are getting hard to find.
Jason
Last edited by RCrawler; Feb 16, 2003 at 09:44 PM.
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