pinion angle

[VileZambonie]

how did you lower the rear?

[77c15]

Where do we take the measurements at?

[SBC384]

hangers and shackles 4"

[HAULIN IT]

Sbc & Others, The PM was for Chris. The pinion angle can be measured several ways & with several (special) tools. The most common for average guys is to put an angle finder on the backend of the transmission output shaft, you will get a number, say 92*, write that down, now go to the rearend & put the angle finder on the flat across where the U-joint straps go, this is where it gets a little tricky. I'll try to explain so it's understood, you want to read from the other side of center if your finder reads 180*(if you were looking at the tool from the Right at the transmission, when you put it on the rear, look at it from the Left. On angle finders that read every 90*, you have to be careful, the one number is really less than 90* & the other the more than 90* unless the vehicle is perfectly in line (which it won't be or shouldn't be). I hope that makes sense. The ideal condition is to have the two angles added together equal 180*. This is for normal everyday, most manufacture, ect. use. This is what Capt. was getting at & is correct. In vehicles built with other goals, (lifted real high or a low vehicle with big rear tires) some compromises may have to be made to keep the U-joints from binding. In a vehicle being set-up for drag racing, the pinion should be downward slightly from this equation (varying amounts due to how well the suspension controls the axle rotation) so the driveline is straight under power (this is the most efficient), however if used at steady speeds on the highway, most likely will have noticeable droning due to not having the "break" between the tranny & rear.
 Sbc, If your driveshaft is slid all the way in & you can't get it in the rear yoke by a 1/2", the shaft was too long before you lowered it, lowering it (to some point) does make the distance shorter, but not to that much of a degree in 4". Any questions or differences, please speak up. Lorne   

[SBC384]

i already have 2 degree wedges under leafs & rear end yoke is still pointed up to much   what to do now ?

[HAULIN IT]

Sbc, I see 4* shims from Lakewood @ Jeg's pt# 620-20510

[SBC384]

should they go in from front or back to make rear end angle go down

[HAULIN IT]

Sbc, Your axle is still on the bottom of the springs, correct? If so, The wide end would go in the front. Lorne

[SBC384]

thats the way ii have them  they are the wedges from jegs  still pointing up.....confused.............

[HAULIN IT]

Sbc, What numbers are you getting? The pinion could be "straight" & still be correct depending on what your getting at the transmission. My original rear lowering plan was: I moved the bed floor brace & installed the dropped shackles, removed the original rear hangers from the frame & let the jack down until the shackle was 1/4" from the bed floor & drilled new holes in the hanger. Then I removed the front hangers from the frame & let the jack down until I got to where I liked it. The rear angle ended up at -4* so I left it alone. The simple way to fix your problem if your ok with the rear of your truck a little lower is to do the rear hanger. Lorne

[SBC384]

still need to get the rear end yoke down ... has anyone ever heard of cutting the leaf pads then getting the angle you need then rewelding them?  (SORRY)
thanks

[VileZambonie]

How are you measuring your pinion angle? Are going off of true vertical from horizontal with the truck down on it's wheels? Are you then comparing this to your driveline angle from the transmission? What is your actual pinion angle measurement?

[HAULIN IT]

Sbc, Not to be Post Patrolman, But it would be easier to follow & you may get answers to your questions (front brake pads) if you keep the posts separated. I thought it was good to start a new post about the pinion angle, but there is allready 2 pages in your spindle post because you asked there & now your asking about front brake pads in the pinion post. Maybe Chris can move the pinion angle part to this post, it would make it easier to follow what has already been discussed. Just a thought, Lorne

[SBC384]

is it ok to stack the pinion angle wedges to acheive the desired angle?

[VileZambonie]

I certainly wouldn't. Again, how are you measuring your pinion angle? I don't understand why it's so far off.