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Discussion Starter #1
All right lets keep the jokes to a minimum, but I think my rearend is pointing in the wrong direction. My C6 is higher than the rearend sloping slightly back toward the rear. The driveshaft is pretty much inline with the tranny with the tail of the driveshaft just lower than the rearend pinion yoke. The rearend actually appers to be at a slight angle downwards so that both the driveshaft and rear end come "down" into the u-joint. Ok if anyone followed that please let me know if this is normal. If not normal what are the max allowable angles between the driveshaft and rear pinion?
I did pull the drive shaft last night thinking that maybe it was too long but it has travel in each direction from where it is currently.
Thanks for the help,
Micah
 

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Good Post!

Another way to think of it is,... you want the imaginary centerlines passing thru the transmission and pinion gear in the rearend to be PARALLEL! Therefore the angles should be equal.

You can create a situation where the angles are equal but the centerlines are not parallel. For example, if you lower the rear of the tranny and correspondingly lower the front of the pinion to match. That is wrong....you need to Raise the front of the pinion when you need to lower the tranny.

(I learned this from the hard knocks school and just want you help you not experience what i did!)
 

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roadracer is rite, with the parallel theory
but, also, if you have a high h.p. car , they may have actually pointed the pinion down 2 to 3 degrees max, to compensate for spring wrap up on a hard launch.
if your still worried , you can go get one of those magnetic round levels that has two flat sides on it, it stands up its edges,read degrees on the needle...stand it on the front of the pinnion and read angle, then stand it on a rib on the tranny and read the angle in degrees.
this is only good on a non modified car. like no spring mods or wedges in the spring perches, or maybe a changed out rear housing with different spring perch angle or rear tranny mount wrong? is all stock?
 
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Discussion Starter #5
Great reply's everybody, thanks alot. Wayne, I just got done doing what you suggested - my pinion is pointing down 9° with respect to horizontal. Nothing on this car is original including the rearend. Based on my search for the correct axle bearings, I believe the rear came out of a late '60s bronco. My guess is the spring perches are in the wrong place. Do you think I should try and shim it or do I need to weld new perches in. If that is the case, any idea where I can find info on correct spring perch location? I am currently replacing springs so that may change the number some but the perches definately look like a home made job so they are the primary suspects at this point. Also, any advice on getting the front spring bushing bolt out?
Thanks again,
Micah
 

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Putting an angle finder on the trans tailshaft (or across the rear seal housing) and across the differential pinion yoke will tell you the angles of the two items...they should be at the same angle, relative to the ground. For example, if the trans shaft reads 2 degrees down, the pinion shaft should read 2 degrees up...

Racers often preload the pinion angle downward slightly on leaf spring cars to allow for torque reaction and leaf spring wrap-up, which raises the pinion...in cars with multi-link or ladder bar suspension, like my race car, pinion angle is adjusted with the links...in a plain leaf spring car, it's adjusted with shims under the saddles.

If the centerlines (trans and differential) are parallel but in substantially different planes (either horizontally or vertically), a constant velocity joint or carrier bearing and additional u-joint is used to lessen the shear angles on the u-joints...this is common on trucks and 4WD vehicles..

Have fun!
 
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Discussion Starter #7
Thanks Pat,
I did measure the two angles you described and I came up with the tranny sloping down about 5° and the pinion also pointing down at 9°. If I understand this correctly the pinion should be pointing up 5° or a little less to account for axle wrap. My question now is how do I fix this? Can shims be used to make up this big of an angle (14°)or am I looking at new spring perches. The axle is definately not stock and the perches appear to have been welded on at a later date.
Thanks,
Micah
 

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I'd look for another housing with the correct angle...most any stock housing will work.

Cutting and re-welding the perches is possible, but can change tube alignment. I like to weld perches on before welding ends on when narrowing housings because of this....might not be a problem on a stocker though..

A shim could be used (you could make a couple out of some 1/2" bar) but I'd recommend welding it to the perch to secure it. You'll need to drill a hole for the centering pin on the spring to fit into. Loosen the u-bolts, clamp the rear of the perch edge to the spring and jack the pinion up to the right angle and measure between the spring and the perch front for a proper wedge thickness. You'd have to experiment with stand locations to correctly support the car but I would think directly under the bottom spring plate would work if there's enough room for the stand saddle and still access the u-bolt nuts...

Hope that helps!
 

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i ran into this problem before, i went to a local spring shop, they have wedges to insert into sping perch price is very cheap for them, but,my 9 inch was out of an older ford pickup, the perches where wrong angle for my appilcation, it is possible to reweld new perches, but you need to have someone who knows what they are doin, or you will have major problems with a bent tube from the heat, ill bet you can find a used rear in a local yard that will work.
do a search on here on that front spring bolt, its been covered many times , sawzaw and a hardened blade usually does it.if the axel has already been welded on? is it already ruined ?warped? maybe shims will be a temporary fix, until you can find another good tube housing
 
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