Pinion angle shims vs welding perches

[mriplaybass]

I guess there is really no right or wrong to this question since I have seen it done both ways, but I would like some opinions from those with more experience than me. Since the PO totally screwed up the AMC20 axle in our 79 CJ7 , we decided to replace it with a Dana 44 . Since the 79 never came with a Dana 44 rear, we located one from a 72 CJ5 . Problem is, though both the 79 and the 72 use the narrow track axles, the spring seats for the 79 are at roughly 35" centers vs the 72s roughly 27" centers. I am not planing on removing the old spring seats since they do not appear as though they will interfere with anything. The new spring seats should fit nicely with room to spare next to the old ones. Here is my question: I can either achieve my pinion angle using shims, or I can just weld the new spring seats according to the pinion angle that I need. Any insights from those with more experience would be a great help. I have read some rather unkind comments on other forums directed at those who angle the pinion via welding the spring seats. Being a new jeeper trying to correct a multitude of PO's screw ups, and I am trying to do things as correctly as possible!

 

[Torxhead]

On my '86 with the 4" lift and oem Dana 44 , I went the no shim route along with moving the lower shock mounts to the axle housing. This allows more ground clearance to the pumpkin as the distance between the axle housing and leaf spring is minimized. Plus, I don't break shocks like I used to. The pinion angle is slightly below the driveshaft angle with a cv joint at the other end.

 

[caveman]

I've done it both ways and I think your right that it doesn't really matter . However, The last set of springs that I bought had a shim that had a curved bottom, next to the spring pack so when you tighten it down it doesn't flatten the spring out. Skyjacker is the only company that I've seen do this. There may be others, But I haven't seen them. I cut the old perches off and reset them so I could use the shims.

 

[BusaDave9]

Shims are not as good as spring perches welded to the axle shaft. I've seen shims deform, compress and bend causing the axle to rotate.
Also a shim lowers the lift (unless you have SOA). Okay, okay, I know we're only talking about a fraction of an inch but I still say It's best not to have a shim between the axle and spring.

Bottom line: yes we're spitting hairs but no shims are best.

 

[Posi]

My front 60 has 3 steel shims and my rear 60 I cut the old perches off and burnt them in. If your comfortable welding I would recommend welding over shims.

 

[Lumpy Grits]

Get steel shims from a semi-truck driveline shop and your GTG.
LG

 

[tarry99]

I guess there is really no right or wrong to this question since I have seen it done both ways, but I would like some opinions from those with more experience than me. Being a new jeeper trying to correct a multitude of PO's screw ups, and I am trying to do things as correctly as possible!

Simple answer........since there is no hangers there now where you need them.........put the new one's in at the right angle.

Shims should be considered as a crutch and only used when there is already a mistake or no other option!

Do your homework on whatever your ride height is now or will be........that means tire size & springs......if lifted an adjustment may be needed at the Transfer Case mount......get your axle with no oil inside rolled up under the chassis with the hangers loose and wheels and tires on.....make sure you clean the axle up where the welding will be, It should be mocked up with all the weight in the vehicle that would normally be there ( people , gear & fuel...... I use sand bags ) and the suspension compressed both front & rear.......rotate axle pinion to whatever angle you have established by first talking with a competent drive-line person and tack the hangers in place. Check angles again........I like to pull the axle back out.......and weld it up where you can see it......but that's up to you! I also like to mount the shocks on the axle.........

 

[mriplaybass]

Thanks for all the great info. Welding is the way we are going to go. I never gave any thought to the fact that tightening the u bolts actually draws the arc flat at the center of the spring. I'll have to do a bit of research on that since I ordered anti rap spring seats which are 8" instead of the usual 4". As if we don't have enough problems with this project!

 

[tarry99]

Thanks for all the great info. I ordered anti rap spring seats which are 8" instead of the usual 4". As if we don't have enough problems with this project!

The anti wraps are OK if you think you may have that problem via excess Horsepower or large tires........the negative to those is they do help lock the spring up and limit it's movement during articulation........

 

[Old Dog]

I would always weld over using shims. Like some others I also moved my shock mounts so they don't hang below the axle.