CUCV Front Axle Pinion Angle

[Barrman]

I am putting a set of CUCV axles under a M715. The M715 belongs to Sermis and the axles belonged to another member. He had them under a M715 but had severe shimmy and drivability issues with them. He also moved the front leaf springs to under the frame instead of outboard like the M715 is stock.

My students have made this truck their project. We have cut off all the previous owners fabbed up spring perches and have the axle centered left to right. I just need to know the kingpin angle or the pinion angle so the camber and caster are correct.

Does anybody have this handy?

Thanks.

 

[Elwenil]

Caster angle is what you are looking for. If you can't get it from the TM, you could probably ask a local alignment shop for the spec on a similar civilian model.

For what it is worth, Dodge axles run between +1/2 degree to +3 1/2 degrees of caster with +2 degrees being the preferred setting. The Factory Service Manuals also note that "If vehicle wanders caster should be increased. If steering effort is very high, especially when cornering, caster should be decreased."

 

[Barrman]

Thanks Lanty. I have an alignment machine here in my class. We are just not building the truck on the machine. That is why I was looking for pinion angle. the plan was to slap an inclinometer on the yoke, rotate to the correct angle with the perches just sitting on the tubes and the u-bolts loose. Tack weld the perches. Tighten everything up and then roll it to the alignment machine. I will just look up a '82 chevy K30 and see what the specs show.

 

[Recovry4x4]

Forget the pinion angle, it will toss you way off base. As Lanty said, you need to set the caster angle for driveability. Pinion angle should be a distant second unless you are cutting the knuckles off and rewelding them back. If you do this then you can accomplish both tasks at once.

 

[K10A]

IIRC for the gm axles it is 6 deg ?maybe ...

 

[Barrman]

You guys have convinced me. We will move production over to the alignment lift. Here is a picture of where we are right now.