70' ElCamino Rear Spring/Suspension Problem

[oobus]

Well, here is my problem:

1970 ElCamino that I just finished re-working that includes replacing the 307 with an LS1 and Auto trans, drop springs (speedway Hyperco in the back 11" single pigtail), Edelbrock upper control arms, LS1 rear brakes and I changed out the original 10 bolt open diff. for a 10 bolt with posi. Also picked up some koni shocks for the car.

I ran the car for a couple of months with the original dif. and had no issues/noises of any sort (except the cronic one-wheel spin anytime I hit the go pedal below 50mph).

So, I go to install the posi differential last night and 1st - springs are way short and will not stay in their perches, 2nd - as the suspension trys drop to the bottom of it's travel, it jams the driveshaft all the way into the transmission. I think that the drive shaft did the same thing with the last rear end, but, the airshocks limited the extended travel so it would not bind - not really sure though.

Questions:

1. Does anybody know if this driveshaft issue is normal?

2. How did everyone with lowering springs keep them from falling out during "Bo Duke" suspension unloading?

I think if I build some travel limiting cables, it may solve all my problems, but, I'm new to this and don't want to screw up my 90% finished ride! Thanks for the help guys.

[Randy67]

1. Sounds like the driveshaft is too short, a driveline shop could tell you how much to shorten it.

2. I used a combination of big washers and bolted the spring to the axle perch. I spaced it so the spring is still free to move some but won't fall out. In a pinch you could just zip tie the spring to the perch. Just check the springs when you jack up the car, as the top can move around. Just last night I had to reseat one spring which was hung up on the upper perch center locator "pin".

Even though I have Pro Shocks which are shorter than stock shocks, the springs are still too short to stay seated on their own when the rear axle is at full droop.

[oobus]

I'm thinking that running a couple lengths of steel cable thru the perches and using cable nuts, tie it together. Put a couple pieces of hose on the points where the cable would rub on the perches and call it done. This would limit the travel and keep the springs in place.
Do I really need 8" of travel for the rear suspension, this car won't be running the Baja 500.

[David Pozzi]

For stock suspension, the shock length controls axle droop. Working with shorter shocks or relocated shock mounts is the only other way.

NASCAR racers use chain to limit droop, it helps get the wheels off the pavement faster on pit stops if there isn't excessive droop.
David

[Marcus SC&C]

One great option for limiting rear axle travel is travel limiting straps (imagine that!) like these http://www.mastercraftseats.com/limitstraps.php
English sports cars and off road racers have used them for the last half a century or so. They don`t make noise like chain and have some shock absorbing qualities so they don`t jerk too hard on the mounts. For the rear axle get them long enough to loop under the axle tubes, bolt the top to the frame or crossmember and voila you`re done. :) Mark SC&C

[wingman]

Mark, you are the man! The idea of straps has appealed to me for years, but I never had a source for ready made ones. I've used seat-belt mounts, but this is much more sanitary ( although there is no provision for adjustment)
:hail:

[The WidowMaker]

1. Sounds like the driveshaft is too short, a driveline shop could tell you how much to shorten it.

by reading the second part i see where you were going, but you meant it was too long, not too short as posted.

Tim

[oobus]

Well, I found out the "deal" rear-end I got had been reworked and will not fit my car. The suspension binds and the driveshaft would need to be shortened. I put the open diff. back in and will sell the other unit and get a posi put in my original 10 bolt. Makes me mad that I took the damn thing apart about 8 times to install the disc brake adapters/calipers.

[derekf]

For stock suspension, the shock length controls axle droop. Working with shorter shocks or relocated shock mounts is the only other way.Is there a shock catalog somewhere that folks can use to find a shorter shock for a given application, or is it a matter of making really good friends with the counter guy at Autozone?