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Pitman arm endplay measurement?

4K views 8 replies 4 participants last post by  powerrodsmike 
#1 ·
Is there a way to measure pitman arm endplay to determine steering box lash? I have a 96 Impala SS that is getting progressively sloppier. I have another box to swap in, but wondered if I could test it first before I get disappointed.
 
#2 · (Edited)
Unsafe !

Friend, Do not Kill your self or someone else by having your steering fail. clamp the other box in a vice with the steering shaft,If you know it is sloppy then it needs replaced :nono: if you can move pitman arm over an inch from its position with steering wheel locked in position! it is junk! Your life is worth more than the cost of a box !! Be SAFE
 
#4 · (Edited)
Yeah Ace, I think I'd throw it away if it had an inch of freeplay too.... :rolleyes: You guys must have some wide roads in Ok... :D

Curtis73- Is that an 800 series box? If so, see if you can move the sector shaft up into the box at all with the box centered, any more than a few thousandths and you should adjust the sector shaft screw. If the input shaft moves in and out of the box more than a few thousandths it needs to be adjusted...

Loosen up the sector shaft adjustment screw, then adjust the input bearing preload so you get about 2 - 4 inlbs of drag on the input shaft. if it feels clunky or crunchy it is most likely needing a rebuild, but you can adjust it to get some of the slop out.


Once the input shaft bearing is adjusted , you can see what kind of play is left, and adjust the sector shaft preload..
The gear is tapered, and the sector shaft screw pushes the gears together, to take up the slack between them.
IIRC you tighten the sector shaft screw till it has 3-4 inlbs , then back it off 1/4 turn.. I need to make sure of that value, and will do so in the morning.

Once those 2 adjustments are done, any significant play is a result of the bearings and ball channels, and the box is ready to be rebuilt.

I don't have a book with specs here at home. but I would guess that side to side play shouldn't be more than 30 or 40 thousandths at the end of a pitman arm .015-.020 each direction). I likes em tighter than that, but you live with what you get... :mwink:



It is important that you check for slop when the box is centered, otherwise you'll adjust a hard spot into the box..

Unless someone comes up with specs tonight, I'll try to find some for you tomorrow.

I hope that helps,

Mikey
 
#6 ·
Excellent. I'll get it in a vise tomorrow and see if I can test endplay with a dial gauge. Thanks for the help.

I'm not sure of the series of the box, I just happened to find a free one on craigslist from a 94 caprice (which is the same box of course) and snatched it up. I just wanted to be able to test it before I went through all the trouble of swapping boxes.
 
#7 ·
Good advice Mike, I'd add that all the steering rod ends and tie rod ends should be checked for slack. with someone else moving the wheel back and forth there shouldn't be any slack in any of the rod ends.

I usually grab the rag joint or steering shaft and rock it back and forth to see the movement between it and the pitman arm. It's pretty easy to tell if the box has a lot of slop/slack in it.

I think (and hope) what Ace is say is that you shouldn't have more then an inch of movement at the steering wheel.
 
#8 ·
I have a couple of those boxes on my shelf at the shop, I think one is in really good shape. I'll put an indicator on it as well, to double check the measurements I gave you.

( I keep stuff like that around for mocking things up... :) )

Later, mikey
 
#9 ·
I checked 2 saginaw 800 boxes that were up on my shelf, both were used , but still really tight.. When the box was centered, one pitman arm had about . 0.006" and the other box had 0.002" as measured at the end with the dial indicator at a right angle to the pitman arm. One arm was about 7" long, the other about 8".

When I moved the sector shaft off center about 30* the clearance got up to about .035 total.

My original post was wrong about the sector shaft adjustment, the rotating torque value is measured at the input shaft, not at the screw as I had stated..

(making wrong things wronger... :welcome: that's me)


The thrust bearing preload is measured in rotating drag, 1-4 inlbs greater than the drag created by just the seal, (just like a pinion bearing), and then the sector shaft is adjusted by tightening the screw until an additional 2-4 inlbs resistance is felt at the input shaft.

The proper rebuild and adjustment procedure in the book I have is 9 pages long..I will loan you those pages if you'd like, then you can make the determination of whether or not you want to do an abbreviated adjustment on that box before you put it in.


Later, mikey
 
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