Bump Steer: 1956 Ford F-100
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From: Fortuna, California
Bump Steer: 1956 Ford F-100
I had my last modifacation completed on my 1956 Ford F-100 last fall. I had installed: 3 inch dropped front axle from CPP (Classic Performance Products), power brake booster with front disc brakes from CPP, down & centered front springs from Mid FIfty Ford, KYP shocks, front & rear anti-rool sway bars from Mid FIty Ford, and an extended drag link. I didn't want the front wheels up inside the fender wells so the mechanic added an additional leaf to each of the down & centered springs.
Well, everything went well and 10 days later the job was completed. It looks great but I have one problem. The bump steer is unreal . I have to be really hanging onto the steering wheel when I hit any size bump since it really tosses the truck. Does anyone know how this can be corrected? I appreciate it.
Dave
Well, everything went well and 10 days later the job was completed. It looks great but I have one problem. The bump steer is unreal . I have to be really hanging onto the steering wheel when I hit any size bump since it really tosses the truck. Does anyone know how this can be corrected? I appreciate it.
Dave
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Joined: Jun 2001
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From: Erie, pa
After all that change to the steering geometry did you get the truck realigned?
What condition is the steering box in?
Did you make a major change to the wheel offset?
Were the wheels/tires static or spin balanced?
What condition is the steering box in?
Did you make a major change to the wheel offset?
Were the wheels/tires static or spin balanced?
Last edited by 4tl8ford; Feb 21, 2006 at 05:28 PM.
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From: Fortuna, California
I had the truck realigned immediately after the work was performed, no changes to the wheel offset, the tires were spin balanced, I have power steering (motor & power steering are from a 1956 Thunderbird) and the steering is tight -- no free play.
Hotshot
Joined: Oct 2004
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From: Durham NC
With the forward centerbolt spring you need to add 1 or more alignment wedges between the spring and axle on each side to get enough caster. You should have at least 2-4 degrees positive caster (top of spindle tipped back) to get the truck to track properly. When you add the wedges, be sure the centerbolt head is long enough to fully engage into the axle. If not Mid Fifty sells extended head centerbolts as well as the wedges. Make sure you have about 1/16 -1/8" toe in as well.
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From: Fortuna, California
Originally Posted by AXracer
Just saw the post about the PS. Is the pitman arm vertical and the draglink horizontal when the wheels are straight? If not you will get bumpsteer.
Hotshot
Joined: Oct 2004
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From: Durham NC
Yes, parallel to the ground at rest.
Do you have any pictures of the SB install, I'm not at all familiar with what that box looks or works like. Wasn't the T-bird a cross steer setup? (output shaft points down and pitman arm swings parallel to the ground)
Do you have any pictures of the SB install, I'm not at all familiar with what that box looks or works like. Wasn't the T-bird a cross steer setup? (output shaft points down and pitman arm swings parallel to the ground)
Last edited by AXracer; Feb 21, 2006 at 07:33 PM.
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From: Indianapolis, Indiana
According to CPP web page, if you use lowered springs it will cause bump steer, nothing said about springs with leafs added.
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From: Fortuna, California
Originally Posted by kdmcinnes
According to CPP web page, if you use lowered springs it will cause bump steer, nothing said about springs with leafs added.
Hotshot
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From: Durham NC
I don't know why lowering the springs would cause bump steer, a dropped axle is more likely to cause it. With a drastic drop, you may need to reshape the steering arm the drag link connects to (I think Mid Fifty may sell one already dropped) to get the drag link parallel to the ground.
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From: Fortuna, California
Originally Posted by AXracer
I don't know why lowering the springs would cause bump steer, a dropped axle is more likely to cause it. With a drastic drop, you may need to reshape the steering arm the drag link connects to (I think Mid Fifty may sell one already dropped) to get the drag link parallel to the ground.
I sent CPP an e-mail regarding the problem and I will check back with Mid Fifty about the drag link part. I thought I read some where that if the drag link from the power steering is at too much of an angle it will cause the problem but now I can't relocate the article.
Post Fiend
Joined: Jun 2001
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From: Erie, pa
The drag link has to be parallel to the ground to allow it to swing in the proper arc over bumps, if it isn't your bump steer will not go away.
By the way Z'ing the drag link won't fix the problem, it will still have the incorrect angle between the ends.
By the way Z'ing the drag link won't fix the problem, it will still have the incorrect angle between the ends.
Hotshot
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From: Durham NC
I have a 2" dropped axle, reversed eye lowering springs, and my draglink with my Toyota box is near parallel and no bump steer. I don't have the forward center springs because the panels don't suffer from the wheels too far back in the fender well syndrome for some reason. I do have + caster.
Elder User
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From: Indianapolis, Indiana
Originally Posted by 56fordf-100
What is the web site?
, I havent done my Drop Axel Yet.Kyle
Home
http://www.classicperform.com/
Link to drop Axel Page
http://www.classicperform.com/Store/...cks/4754DA.htm
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