Pinion Angle

Dunno, J. Something is not tallying up.

Were the first and last measurements taken in exactly the same condition? (Vehicle weight on the axles etc)?

Do you think the 2.5 degree shim has been mislabled and is really a 5 degree?
Scratch that I just checked and you have stated the shims are correct.

I'm struggling to think it through with the info given.

If you have driven the car for 9 years why are you adding shims? Do you have a vibration you want to iron out?

Are the shims possibly a bit short? When clamped up do you think the spring is bending around the shim and causing the error in angle? I'm thinking along the lines of why is the resulting change not true to the shim angle.

I'd be tempted to cut the perches off and clamp it up as if building from scratch. Align, clamp, tack, test drive then fully weld when happy. Watch for axle distortion though.

Mart.
 
This is truly strange; the shims should work; no need to cut perches. Do you have or can you get pics of measuring the pinion angle and wedge placement? Were the measurements taken with the weight on both the front and rear axels without any movement in the chassis between measurements? Something really does not make sense here and you must be truly frustrated!
 
Don T said:
This is truly strange; the shims should work; no need to cut perches. Do you have or can you get pics of measuring the pinion angle and wedge placement? Were the measurements taken with the weight on both the front and rear axels without any movement in the chassis between measurements? Something really does not make sense here and you must be truly frustrated!
Click to expand...

Exactly how I feel!! I don't have any pictures, but I can break it down for you.

I lifted the rear tires off the ground so i could spin them to get the pinion straight up and down to put the digital angle finder on and then dropped the rear back down.
I pulled off the driveshaft and measured the pinion angle with two different angle finders and both showed .4(point four). I measured the the pinion off the garage floor just to see how much it would move up.
Then I lifted the car up and put it on 4 jack stands and put the hydraulic jack under the rear so I could lift it independently from the springs. I removed the wheels for easier access. I unbolted the lower shocks
I C-clamped the springs so the didn't come apart when I removed the center bolt. I unbolted the U-bolts and installed the shims and new center bolts. I put everything back together and torqued everything.
I put the wheels back on and drop the car back down. I even jumped up and down on the rear bumper a few times thinking I might need to settle things in. I don't know if this helped or if I should have taken the car for a ride and then retorqued. Anyway, I climbed underneath and measured 5 degrees in the same locations I measured .4 a couple of hours before. I re-measured with the tape measure from the floor to the pinion and now the pinion lifted about an inch and a half if I remember correctly. Then I proceeded to bang my head against the floor and here I am.
I took everything apart and put it back the way it was so I could take my daughter for a ride the next day. The measurement went right back to .4
Hope this helps paint a picture for everyone,
Thanks for your responses
Joe
 
You said you changed the center bolt; is it possible the shim and or the perch got hung up on the new bolt?? Did the shim have a slot cut in it or a hole. I am going to watch this with fascination until solved but am smack out of ideas!
 
Don T said:
You said you changed the center bolt; is it possible the shim and or the perch got hung up on the new bolt?? Did the shim have a slot cut in it or a hole. I am going to watch this with fascination until solved but am smack out of ideas!
Click to expand...

Good idea, but it went back together correctly.
The shim just has a hole. I watched very carefully as I torqued everything down to make sure nothing was hanging up. It actually fell together without and problems.
The search continues
Thanks Joe
 
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