Grinding Front Driveshaft (1 Viewer)

[fieldsken1]

If you measure at the pinion flange, it should be the same as measuring from the top of the knuckle, just add or subtract 90 degrees.



What do you mean my u-bolts look to be angled back to far? If they go though the plate under the springs, how could they be off?



I took apart the springs to grease between the leafs and install the new longer center bolts through the spring pack and shims. This was recomended by the local spring shop in Denver. I used c clamps to tighten down the springs, installed the new bolt with shim on top, top of the bolt sat in the perch just as it there was no shim.



You have shackle reversal so it would be fat side facing back. Fat side should face the shackles to correct for the longer shackles.




Alan, the shafts at the U joint touch due to the steeper angle. I don't know the terminology however where the "U" parts of the shaft connect with the U joint, they rub on the flange part when rotated. I know its the shaft and nothing in the axle or transfer case.

what about rotating the spring perches alittle. to point the pinion upwards?? are the springs on correct. and as far as the shim goes i thought i was right on mine but everyonee says i am not right

 

[BlackDiamond72]

If you have a shackle reversal, you are correct to put your shims with the fat side facing the back of the vehicle, you just might not have known is all. I screw things up all the time and find out later I was correct by accident.

How would I know if my springs were on backwards? If I measure from the center bolt to each end, should one side be longer than the other? And if so, does the shorter side go towards the front or back? Would this even make a difference?

 

[fieldsken1]

yes one side is longer then the other and if i remember right the longer side goes toward the shackle

 

[fieldsken1]

yes i just looked and the long side is toward the shackle

 

[cruiserjunkie]

One side is longer but if you put them oppsite it will increase the wheel base making driveline shorter

 

[fieldsken1]

One side is longer but if you put them oppsite it will increase the wheel base making driveline shorter

it also makes the diff sit higher or lower on the spring on the front

 

[67azcruizr]

One side is longer but if you put them oppsite it will increase the wheel base making driveline shorter

is that a new trick?, increasing your wheel base but shortening your driveline(s)

 

[fieldsken1]

One side is longer but if you put them oppsite it will increase the wheel base making driveline shorter

i wish i would have caught that hahahahahaha

 

[BlackDiamond72]

Sorry, this is long winded.

Well, just to make sure I remeasured everything on the front end. The springs are installed in the right direction with the longer side towards the front (shackles) and the shorter side to the back (rear axle). Measurements from bushing center to center bolt location are 25" front, 22" rear. Measurement of the center of the shackle hanger bushing to the spring bushing are 5.75" (ie, shackle length is 5.75"). The spring on the rear axle are a bit shorter. Taking a much closer look on the truck, I think the PO may have re-welded the spring perches on the axle so now I'm wondering if those are off by a few degrees. Based on the quality of those welds I can say he didn't do a cut and turn on this axle. I measured the pinion angle from the bolts on top of the knuckle and I get the same 3 degrees give or take a bit.

Could it be that these springs are so new and stiff that this U joint grinding condition will go away as the spring sag a bit? I truly do not want to go through a cut and turn right now as I'd like to wheel this the rest of the summer and deal with a SOA this winter. Unfortuntely its hard to wheel without 4x4....

 

[fromme]

If you measure at the pinion flange, it should be the same as measuring from the top of the knuckle, just add or subtract 90 degrees.

This is incorrect. The inner knuckles are not welded on set at 0 degrees to the pinion. They are welded on with some caster added in.

No one has said it but it needs said. You've done everything but determine what your caster is at the knuckle. You need to find that out before you can determine the next course of action. Caster always takes precedence to pinion angle if you care about how it drives down the road.
If the PO did reweld spring perches on incorrectly, you might find you need to rotate the rear of the axle up in order to set the caster correctly, which will fix two problems at once.

If the caster is correct, and your pinion angle is off that much I'm not sure you will be able to find an acceptable compromise with shims, and C&T is your option.

 

[dgangle]

$10 and 10 minutes you can measure your own caster. Post 16 https://forum.ih8mud.com/40-55-series-tech/236966-eating-front-tires.html

I disagree with fromme on the first statement of the last post.

 

[Midwestcruiser]

I have the Hells Creek 2.5 lift with HFS extendes shackles. I am dealing with the same situation, just not quite as bad. I believe I have the 4 degree shims as well..The addition of the shackles as well and the shims are the equivalent of dropping the diff straight down without any rotation-hence the binding..ugh!

 

[BlackDiamond72]

So, for lack of a better solution, I'm going to clearance the companion flanges at the transfer and axle pinion with a dremel so it doesn't rub any longer. Over the summer, I'll probably do a cut and turn with a SOA conversion at least on the front with stock springs. It seems that this a fairly random issue. With stock locations for both the shackle hangers and spring hangers, I don' know how this issue came about.

Fromme: I don't know if you didn't notice my previous statement about me measuring the pinion angle at the knuckle, but I did and it came out very close to the angle measured at the pinion flange (maybe off by .25 of a degree).

To anyone else with this issue, sorry it didn't answer an easy way to fix the problem. If you do have a solution, I'd still like to hear any ideas.

Thanks for all your input everyone!

James