I bought my chevelle 4 weeks ago from a man who likes the hot rod look. He put cadillac coils under the rear! The factory shocks where extended fully at normal ride. I would drop it back, but there are a new set of 275s on the rear that are nice. My only concern is a driveshaft vibration at 30-40mph. Could it need a ballancing. How much is too much of an angle at the rear yoke??

At that severe of an angle, your driveshaft SHOULD be vibrating, and that isn't healthy for the pinion bearings and the u-joints. Get rid of those monster rear springs and replace with stock ride height springs. You didn't mention what year your Velle is but 275 x 60's should fit just fine under your ride with a stock ride height.

If memory serves me (and that is on rare occasion!), I think the stock pinion angle for most Velles' is something like 3 to 5 degrees - I think. Maybe someone else can confirm this.

Once you replace the springs, you should see a big difference in the amount of vibration and it may well eliminate it totally. And since this car has been running with these high angles (for some time?), you might want to really check those u-joints (especially the rear) for excessive wear...when you put your car into gear from park...do you here a loud 'clunk' noise? Just my opinion, but I would probably just replace them anyway for safety's sake, considering the abuse (high angle) they have been through. Hope this helps some. http://www.chevelles.com/forum/smile.gif

------------------
'70 Malibu - 383 'Fog Fed' Stroker! Houston, Texas Gold Member #39
Chevellz Alwayz!

The rear U-joint was pretty shot, but I put a heavy duty one in there. The tires won't fit inside the wheel wells of my 72... If I drop my body 3 inches (figuratively speaking) then it would be sitting on the tires with about an inch of tire still showing. The pinion bearings "feel" alright. If I do this later on (2-3 months, I am going back to college in a week!) Can I replace these bearings without pulling the rear end's insides out? Does the yoke bolt have to do with the shimming of the Pin gear?

Check out the following link regarding replacing rear pinion bearings/seals:
http://www.chevelles.com/forum/Forum9/HTML/000495.html

What size tires are you using on the rear? Are they a tall 50 series or something? A standard 275-60 tire should fit just fine under a stock 72' wheel well.



------------------
'70 Malibu - 383 'Fog Fed' Stroker! Houston, Texas Gold Member #39
Chevellz Alwayz!

Wes,
what type of rims do you have to have with these sized tires?

------------------

You need 4 1/2 inches of backspacing on the rims to fit 275/60-15s. Any less will probably rub the wheel well.

Tom, 71velle is right...you need 4.5" backspacing with a 15X8 wheel. With a 15X10 wheel, the backspacing will need to be 5.5". I prefer the larger wheel because it will produce more of a 'meaty' look from the rear as opposed to 15X8's. Either look good on Chevelles though.

------------------
'70 Malibu - 383 'Fog Fed' Stroker! Houston, Texas Gold Member #39
Chevellz Alwayz!

I have found a more specific reason for the pinion angle. The cadillac coils (as the previous owner called them) have managed to rotate the entire rear end. Image a fixed axel point, then pivot the front yoke down 1.5 inches. This is in conjunction with a lifter rear end makes for a 12-15 degree shaft to yoke angle. As the pinion yoke rotated, the fixed lower-control-arm caused the entire axle to slide forward. causing a 1 inch gap between the front of the 275s and the fender well, then a 4 inch gap from the rear to the fender well.

MY QUESTION: What holds the rear "pumpkin" level?? I need this ride hight, but I also need a level rear axle....

As you raise the rear of the car the pumpkin will rotate nose down due to the fact that the upper control arms are shorter than the lowers. The combination of upper and lower control arms is what controls the position of the entire third member.

As long as you have the back end jacked way up then the pumpkin will point at the ground.

Get the correct rims for the rear tires. You can put tires on that car that are even bigger than 275 and they will fit into the wheel wells with no rubbing.

PS. you can buy adjustable upper control arms that will allow you to rotate the rear axle and correct your pinion angle. But,I really believe you would be happier with your car if you got the correct rims and lowered the rear end. Check out Wes Colbys 70! It is the april 99 feature car, He has 275-60-15's on the back and they look great!

------------------
Clark
TC #68
Ft. Polk, Louisiana

[This message has been edited by Clark (edited 09-02-99).]

The other problem associated with having the rear of the car up so high is that the front end alignment gets thrown out of whack and is very hard on the ball joints and steering parts. The caster has to be way off! When the caster is so far off the car gets harder to control. I think would recommend to get the correct size rims for the rear and put the correct springs back in.

No sense in re-engineering the whole car just because of two coils springs, and a pair of rims that weren't made for the car.
Just my $.02

------------------
70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103

Could someone elaborate on the whole caster issue? I am in the process of putting front disc brakes on and have the front end in pieces. If I buy new ball joints and (of course) have it all realigned in the end will that help matters? I don't drag race, It will be a year before all that comes around.

How does "caster" relate to camber and toe-in?

When you think of caster, think of a bicycle front wheel. On a bicycle, the caster affects steering in the fact that it lets the bicycle go straight with minimal effort, and helps pull it straight out of turns. This is how cars are set up for caster, just not as drastic as on a bicycle.

When you have the rear of the car up so high, it actually changes caster to be more like a shopping cart front wheel and less like a bicycle front wheel. Some shopping carts have a mind of their own when trying to steer them. Also you'll notice that when going fast with a shopping cart the front wheels like to flop back and forth, kinda wobbly? Check it out next time you go to K-mart, Wall-mart, or the like.

This is similar to what is going on with a car that has the rear end up too high. I seriously doubt that you'll be able to get the alignment corrected for caster with that serious of an angle in the rear. Not to mention the added stress even on new front end and steering parts if you leave it with excessive negative caster like it has. Put it back the way it should be and your nightmare will end.

------------------
70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103