Steering issue

[Dewey72]

Hey guys i got a 72 short box with a cummins swap and dana 60 front. My issue is it likes to bump steer with the added weight. Its running 35" and 4" skyjacker front springs. Wound it be worth it do a crossover steering? this truck never really goes off road. I added a Bilstein stabilizer that helped a bit but still would like it better. Not really wanting to put on stiffer springs like the ride now. Thanks for any input

[Richard]

Best you can do with the short drag link stock type steering is to get the drag link fairly level. Can be achieved by using a 2" drop pitman arm or a 4" raised steering arm.
Blocks are available for the arm as well. Not a fan of the blocks as I have sheared the studs off in a knuckle due to stress.
There are also offset or S shaped drag links. All they do is relieve the ball joint angles. Point A to B is still at an angle so geometry is not corrected.

[Dewey72]

Ya it has a raised steering arm and the drag link is level.

[57taskforce]

What’s your toe set at? Is it true bump steer or wander?

[Dewey72]

toe set at 3/16" and it sure seems like bump steer. Hit a good bump and darts one way and back the other but its got to be a pretty good bump.

[mongocanfly]

my old front end guy would do straight axles at 1/8" of toe..so 3/16 isnt a crazy number
havnt driven it yet but i did high steer on my IH/wChevy axles out of necessity...ORD makes a very good setup
what about your spring setup, is it good and tight....easy to check for movement...put someone behind the wheel to work it back and forth and watch your shackles for side movement

[kwmech]

What do you know about the front end?? Did you just bolt it in?

[Dewey72]

Thanks for all the input. The springs have new polyurethane bushings in them and seem tight but have not had someone turns the wheel and inspecting. I'll give it a go. As far as the axle I did install new king pin bushings and replaced the tie rods. Every thing seems tight.

[kwmech]

When you replaced the kin pin stuff, was it a complete kit with new springs?. Was there an alignment done and what are/were the readings? With lift springs, they have a tendency to roll the pinion up (so the driveshaft still fits) and lose any caster that was built into the housing. Degree shims would help with that. This would explain what is happening. Pics would help also

[57taskforce]

Originally Posted by mongocanfly

my old front end guy would do straight axles at 1/8" of toe..so 3/16 isnt a crazy number
havnt driven it yet but i did high steer on my IH/wChevy axles out of necessity...ORD makes a very good setup
what about your spring setup, is it good and tight....easy to check for movement...put someone behind the wheel to work it back and forth and watch your shackles for side movement

1/8th-3/16th is just fine, I’ve run bigger tires as much as 1/4”.

[Dewey72]

The king pins were a spicer kit with new springs. I can't remember the camber specs but was within the specs I looked up. Never looked at the caster wasn't thinking 4" linft springs would change that enough to matter. Was thinking more about the 6BT weighing 1100lbs. That's roughly 425lbs more than a 454 thinking on a good bump might be causing the spring to flex and level out some causing some bump steering.

[mongocanfly]

Dang..that's heavy..

[kwmech]

The caster reading is the magic number here. Another thing is tire rating. Load range E, 8 ply or better. You may find you put more weight than that if you added an inter cooler and all the plumbing. Just the engine weighs 1100, then you've got the larger radiator and inter cooler, dual batteries etc. After market bumper, winch? Was the frame beefed/boxed up? Steering box area re-enforced?

[mongocanfly]

i know one thing i found out on my C30 when i had to put new front tires on it..
i went with a bigger than stock tire...i counldnt hardly keep it in the road...the tire man checked the pressures and they had 75psi in them, which they were rated for..we dropped them to 55psi and the problem went away

[Dewey72]

Forgot to add this is a SWB so the short wheel base and heavy front end gets scary at times.

[57taskforce]

Originally Posted by Dewey72

Forgot to add this is a SWB so the short wheel base and heavy front end gets scary at times.

Please tell me you did some frame work to beef that up. The swb frames are thinner and weaker than even the long bed frames. Torque+frame not intended for said torque=Twisted broke stuff…

[mongocanfly]

yeah a buddy of mine with a lifted K5 had issues..the frame was cracked around his steering box

[Dewey72]

Did a off frame restoration and plated the frame and installed a Autoworld crossmember that is stout. Ya if I didn’t do anything that frame would be a pretzel by now.
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