rear end mock up (spring pad replacement)

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skep419

skep419

5.9 Magnum 4 speed afficionado
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I've read up a lot and don't want to have to do this again. I moved the springs in over a year ago but I failed on setting up the pinion angle correctly. I've been chasing a vibration (had another thread started) and this is one of the things that may be causing it. I would just like to make sure everything is perfect before welding everything up.

-where to measure to make sure leaf springs are perfect

-Torsion bar crossmember has been replaced as well so I'm looking for measurements from front to back

-was thinking of putting the pinion at 1-2 deg nose down

-tricks to making sure both tires have equal space in the wheel tubs

-When on the alignment rack the right rear was sitting further back than left rear


Any help would be greatly appreciated
Thanks

1427905499_zps38676d53.jpg


CRASHSHEET.jpg
 
Got it all back in. Measures 111 3/8 from the torsion bar adj bolt to the rear leaf spring bolt (holds spring pack together).
 
Didn't fix the vibration. 904 trans with slant converter and driveshaft going in after all the eggs are found. Happy Easter!

1428031077_zps757e7f80.jpg
 
Tried from 2 deg down to 4 up. Same vibration. Trans is 1 deg down.
 
If the rear is out, get two blocks (make sure they are level), set them under the spring perches. It looks like you have a nice level surface there to work on.

Put your angle finder on the yoke and shoot for 5* up while on blocks on level surface. Once it's in the car, it should be pretty darn close.

I have a housing out here, if I get a minute today I will check it and post back, it's a factory piece, so it should give me that 5* I speak of.

Now, if you have it all welded up, you may need to buy some shims and shim it to get it correct.
 
The rear is back in the car. I have the u bolts snugged up but can still move it up or down to adjust the angle. Tested everywhere its not the angle that's causing the vibration.
 

- Check the fit of the rear u joint in the pinion just using the snap rings. Should be tight , no side movement.
- Look at the surface of the pinion where the snap rings ride. Should be flat and no grooves.
- Remove bearing cups and install straps. The strap should have preload on the cap to hold it firmly in place.
- Working angle of the u joint is important. Measure in ride position. Trans angle - driveshaft angle - pinion angle. Shoot for 1-1.5* working angle on a street car.
 
When does it vibrate? Under load, cruise, change with speed?

If the trans is 1* down, I'd have the pinion pointing from 1-3* down when installed on a street car depending on how hard you beat on it. That will give you a neg 2-4 pinion angle.

How's the tailshaft bushing?
 
Manual valve body?

Does it do it above 3-4k in 1st and 2nd gear?
 
had a manual valve body. Don't think it was as bad in 1st and 2nd.
now I have a transgo shift kit
soon to be stock 904
 
mderoy340 said:
- Check the fit of the rear u joint in the pinion just using the snap rings. Should be tight , no side movement.
- Look at the surface of the pinion where the snap rings ride. Should be flat and no grooves.
- Remove bearing cups and install straps. The strap should have preload on the cap to hold it firmly in place.
- Working angle of the u joint is important. Measure in ride position. Trans angle - driveshaft angle - pinion angle. Shoot for 1-1.5* working angle on a street car.
Click to expand...

no clips on the yoke side (fits very tight)
http://www.doctordiff.com/1350-u-bolt-pinion-yoke-package.html
 
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