2 questions 1972 steering swap and F shims

[saon]

1st does anyone know what the thickness is of the F shims?
I see that each side takes 2 F shims, I'm sure I could use any shim but I'm guessing the fenders are a set gap of 2 shims when the inner is installed? not just a random spacing?

2nd I swapped a '85 square body power steering box into a '72 c20.
works good about 1 3/4 turn lock to lock. but the turning radius is very wide now. I have to Y turn to get into my shop where prior i didnt have to.
what am I missing? or is it normal?

thanks.

[LockDoc]

Originally Posted by saon

1st does anyone know what the thickness is of the F shims?
I see that each side takes 2 F shims, I'm sure I could use any shim but I'm guessing the fenders are a set gap of 2 shims when the inner is installed? not just a random spacing?

2nd I swapped a '85 square body power steering box into a '72 c20.
works good about 1 3/4 turn lock to lock. but the turning radius is very wide now. I have to Y turn to get into my shop where prior i didnt have to.
what am I missing? or is it normal?

thanks.

I think the shims are about 3/16, maybe a little thinner. I would have to look in the morning to be sure. Each truck is different and if you change inner panels it may not take the same number as before. Some trucks don't have any, some trucks have one, some have two, and some trucks are different side to side. It just depends on the sheet metal fit.

For those of you that are not familiar with the "F" shims see picture below. They go between the rear of the front inner panel and the cab, where the 9/16 bolt with the LARGE washer is. They are about 4 1/2 inches long by 1 3/4 inches wide +/-.

Not sure on the steering box. Did you use the original cross link? Which pitman arm did you use? You might want to measure the length of both pitman arms to see if they are the same.

LockDoc

[saon]

thank you. leon,
I cant remember when we took it apart but since I cant find any of the
shims I'm guessing it didnt have any. but now back together with different
fenders and new inner fenders I have a big gap . I didnt crank the bolt down to see if it would tighten I just assumed I needed them. I'll just do what it needs.

steering I used everything 72. except the box its self. I'll check the pitman arm lengths.
didnt think about that being different. other weird thing is when I jack it up both front wheels toe out. i set the toe with a tape measure and everything is centered, not aligned yet
but i never noticed any other vehicle do that before. it is lowered.

[LockDoc]

Originally Posted by saon

thank you. leon,
I cant remember when we took it apart but since I cant find any of the
shims I'm guessing it didnt have any. but now back together with different
fenders and new inner fenders I have a big gap . I didnt crank the bolt down to see if it would tighten I just assumed I needed them. I'll just do what it needs.

steering I used everything 72. except the box its self. I'll check the pitman arm lengths.
didnt think about that being different. other weird thing is when I jack it up both front wheels toe out. i set the toe with a tape measure and everything is centered, not aligned yet
but i never noticed any other vehicle do that before. it is lowered.

How did you lower it, and how much? I wouldn't think that would make the turning radius less but I don't know a lot about lowered trucks. If you used dropped spindles maybe the steering stops on the spindles are different than the originals. I know there are different ratio boxes but I think the overall travel lock to lock would still be the same.

Leon

[saon]

2.5 inch spindle and a 3 inch spring.
there are no stops. I looked tonight and nothing positive on the lower control arm that contacts the spindle. but I do t think the stockers had 1 either.
checking into the pitman arm I think the original is 1/8 shorter then the 1 that
was on the box I swapped in. Unfortunately I tossed it.
so I'm thinking that 1/8 at the box could be a lot out at the tire. maybe?
also I think bump steer is what is pulling the tires out when I lift it. I may have a issue there?

[LockDoc]

Originally Posted by saon

2.5 inch spindle and a 3 inch spring.
there are no stops. I looked tonight and nothing positive on the lower control arm that contacts the spindle. but I do t think the stockers had 1 either.
checking into the pitman arm I think the original is 1/8 shorter then the 1 that
was on the box I swapped in. Unfortunately I tossed it.
so I'm thinking that 1/8 at the box could be a lot out at the tire. maybe?
also I think bump steer is what is pulling the tires out when I lift it. I may have a issue there?

Yeah, like I said I don't know much about drops. That sounds like a lot for the front though. 1/8" doesn't sound like much but it could make quite a bit of difference.

Maybe others with drop experience will chime in on this.....

LockDoc

[Ironangel]

Originally Posted by saon

2.5 inch spindle and a 3 inch spring.
there are no stops. I looked tonight and nothing positive on the lower control arm that contacts the spindle. but I do t think the stockers had 1 either.
checking into the pitman arm I think the original is 1/8 shorter then the 1 that
was on the box I swapped in. Unfortunately I tossed it.
so I'm thinking that 1/8 at the box could be a lot out at the tire. maybe?
also I think bump steer is what is pulling the tires out when I lift it. I may have a issue there?

When I installed 2" drop coils with the 2-1/2" drop spindles I had to tighten up the toe in one full turn on each tie rod sleeve, one on each side. The steering wheel needs to be centered and clamped and both front tires need to be on the ground loaded with the driving weight. Park the truck on a level concrete surface with a 12" X 12" piece of floor tile or sheet metal with silica sand, table salt, or even wheel grease under those tiles to allow the wheels to rotate without binding the tires. Then measure the lower front of each tire from tire to tire using predetermined measuring points such as a tread edge that is a constant point of measure front and rear of the tires. The front should be 1/16th less than the rear, anything less than that the truck will wander and to much will wear the tires prematurely. The drop coils will not only change your toe in but will also change the camber angle as well, lowering springs always lower camber and camber directly affects toe in. Camber must be shimmed out to zero degrees or just past zero for a 1 degree positive camber. Equal thickness shims front and rear on the respective upper control arm. I set my camber at 1/8" positive, (top out) each side and my toe in 1/16th and leave the caster where the factory put it and have yet to need a professional alignment or address premature tire wear issues. GM got it right in the 60's and 70's and is why I will drive my 72 C/10 right through them pearly gates...

[Boog]

1 3/4 turn lock to lock does not sound right. That's under even a quick ratio sector. Definition of lock to lock is turn the wheel all the way to one side then starting from there count the turns all the way to the other side. You should have about 3 turns with an '85 sector. You might want to disconnect the pitman arm to cross link and turn the steering wheel and count the turns that way. That will tell the sector ratio which should be approximately 3 or 4 turns lock to lock. If that checks out then move onto the steering center link and tie rods then spindles to see if they are binding anywhere. Have you had the center link off the truck? Installing it backwards causes driving issues. It's well documented on this forum.

[saon]

Originally Posted by Boog

1 3/4 turn lock to lock does not sound right. That's under even a quick ratio sector. Definition of lock to lock is turn the wheel all the way to one side then starting from there count the turns all the way to the other side. You should have about 3 turns with an '85 sector. You might want to disconnect the pitman arm to cross link and turn the steering wheel and count the turns that way. That will tell the sector ratio which should be approximately 3 or 4 turns lock to lock. If that checks out then move onto the steering center link and tie rods then spindles to see if they are binding anywhere. Have you had the center link off the truck? Installing it backwards causes driving issues. It's well documented on this forum.

yes, i worded that wrong. its 1 3/4 turn from center to lock each way. so 3 1/4 turns approximately lock to lock. verified the center link is correct base off pictures on here. looked everything over for binding or hitting. i am pretty sure i need to correct the bump steer by lowering the outer tie rod mount to under the spindle. probably have to go to rod ends to do it correctly. tonight i will map out some of the steering and suspension intersection points and play with spacing and moving the tie rod location to see what that does.
thank you

[saon]

so, after careful measuring, plotting out the intersect points I figured out something,
my dumbass had the center link on backwards!! I had looked at the pics and thot it was correct until I saw the inner tie rods pointing back. swapped it around and all is well!
so now to get it aligned and work on the tune.
thanks all for helping. I'll post some pics when I can get it out Saturday

[Boog]

Hmmm. No one’s ever done thaaat before.
I’m teasing. 👍

[saon]

just to add in case anyone comes across this in a search.
use the 72 pitman arm with the square body box