The Stovebolt Site Forums The Shop Area Driveline straight axle position.... shim dimple to front or back?

I am putting everything back on this week and the original pictures I took does not clearly show how the straight axle goes. The leaf spring has a shim under it and I remember reading here but my search comes up with nothing.

Does the dimple in the shim under the leaf spring go towards the back or the front? I know the shim dimple and the straight axle has the indentation and the shim fits dimple fits in the indentation on the straight axle. However Do I place the indentation and dimple towards the back or do I turn the straight axle around and have it facing towards the front of the truck?

Thanks guys

Caster shim? If that is what you have it is a wedge. The thick part goes forward. The dimple would engage the the center bolt on the spring.

Steve has it backwards. The thick part of the wedge and the dimple go to the rear.

My experience agrees with Pre '68 Dave. Thick edge of wedge to rear.
delky dave wy

Thanks Dave. I did have it backwards. My bad.Here it is in the 48-51 manual

http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0310.htm

Just looked in the 55-59 factory assembly manual---Section 3 page 4---shows shim/wedges and its part #. delky dave wy

Just looked in the 55-59 factory assembly manual---Section 3 page 4---shows shim/wedges and its part #. delky dave wy

Straight Axle This is a photo when I was tear everything apart on my 1956 3100. Its been a while and I just forgot.

I guess a picture is worth a thousand words. Steve the dimple I am talking about does not engage the leaf pins.

What I am talking about if you look at the photo you have 4 holes where the u bolts go. You have a hole or dilled area where the spring bolt goes that holds the springs together and towards the back or front of the
I-beam there is a small dimple or round indentation where the shim plate sets on top which has a indentation and allow the shim to fit on way into the straight axle.

The 1955-1959 Truck Factory Assembly Manual Section 3 Sheet 5 calls it a shim that's fits below the leaf spring assembly. Back when I was not knowing what it was called or its function I had shims, straight axle, U-bolts, and some other pieces powder coated. To me the shim did not looked wedged but it could have been. I have installed the straight axle and the shim with the dimple to the back towards the rear end. before I torque the U-bolts down I want to make sure I have installed it correctly.

My question is does the smaller dimple go to rear "the rear end side" or go towards the front "towards the front bumper"? I did not see a pictures of which way it goes in the factory assembly manual and I did not read where it goes in the 1955 truck shop manual or in the 1956 supplement.

I hope that clears up what I meant and what I am trying to do.

Thanks again but still confused.

as it sits now

When it's all together it's got to look like this:
http://www.pbase.com/dennygraham/image/155580527/large
DG

What year truck are we talking? Are these shims necessary? One was missing on my spring packs so I left both out.

The shims aren't 100% necessary, they're installed for caster correction. Mine didn't have any shims in it. You did make a good call leaving it out, since you only had one. Mismatched caster will make for an evil handling vehicle.

This if it works is an image of a caster shim installed in a truck like yours. They need to be the same on both sides and as you can see they are wedge shaped. I don't know about the dimple so not much help with that.

http://www.classiccarsandtools.com/wp-content/uploads/2012/08/4_IMG_2116_comp.jpg
I hope this helps some. Can you post a picture?

as i stated above 1956 3100.

Update today i put the front end back on. When i took my reference pic originally i saw the dimple towards the back but i was not sure if i moved the straight axle. Thats why i was unclear. Then when i put the shim in with the dimple towards the rear, i thought when i looked at the shim it was even not wedge shaped. After looking at your pics posted and after i crawled underneath the truck after everything was put back on i did see the slight wedge in the shim and it was installed correctly. So therefore the dimple does go in the back at least on the 1956 year. Ohh i forgot to add what a pleasure it was pressing out the original tie rod ends and steering knuckle and upgrading to the new style. Other than trying to keep my cool with the tie rod ends and knuckle upgrade it was not that bad.

Thanks guys the pics really help and now i have a rolling chasis again. Next step body work.

I can't find it documented anywhere but with the correct spring
height and no shim the axle should be at neutral caster.
Don't know what truck your asking about Jr. but the 3100 spec is
1 1/2° to 2° pos. caster. Your original shims were probably 2°
as the same shim was used for the 3600 also. And yes, you do
need them under both springs. I would think that if you're
missing the shims that you are having a problem with your truck
wondering and that you're having to chase the wheel to keep it
in a straight line?
Shims of various degrees are available at most shops that do
truck alignments.
DG

Thanks Denny. When i bought this old iron it had been parked in a field for about twenty years. I trailered it home expecting at worse case senerio to rebuild or replace everything mechanical. I am sure that everything was original and untouched except for the front fenders. I dont know how it drove before but you are absolutely right I don't want it all over the road. Now that I have it into a roller and after I get the body work done I'm going to take it to alignment shop and have them do what they need to do. Thanks again to everyone its just one piece at a time suspension finished shim under leaf

Truck is a frame up restoration so it's not driveable at all right now. When I bring it in for alignment hopefully they'll have shims.