The Stovebolt Site Forums The Shop Area Driveline SM 420 install rear axel flip?

On our 1954 3100 the rear axel was flipped or lowered by placing the leaf springs on top of the axel. It was done by the PO he did not use a kit but he did use very heavy plates and heavy duty U-bolts and has been running that way for 25 years. It was an old school way of achieving a couple of inch drop. Now that I'm having a new drive shaft built to facilitate the SM420 tranny. Should I have the shop return the springs to their original location or just leave it alone? If I leave it as it is will it affect the pinion gear angle if we decide later to put the springs back to original location. The new drive shaft is a slip yoke. What is the best thing to do?
Thanks ,Steve

Personally, I'd secure the parts necessary to put it back to original.

Moving the rear end after building your new drive shaft MAY affect
not only pinion angle, but the distance that the slip yoke travels
in and out of the trans tailshaft.

Should just be a matter of new u bolts, spring/shock plates, and possibly perches; if the PO cut them up.

as Squire said, if you are going to put the rear end back, it is best do it before driveline is done. That said, I have done an axle flop and not changed driveline on different vehicles. Drawing it out on paper, you can use geometry to easily figure out the difference in length after you move it, I would assume it would be 1/2" or less. (probably more like 1/4" difference).

Steve, on the '54 and earlier 1/2 tons, as well as the '55 First Series, the axle would be mounted over the springs from the factory. 1/2 tons went to below the springs starting with the '55 Second Series. Your ride hight should be pretty close to stock with the axle above spring, provided that the mounting system doesn't include any sort of lowering blocks.

No lowering blocks also no C to hold the axel. The axel could roll backwards because the PO just used pieces of flat plate. Also the spring perches are still there so I think I'm gong to go with the original setup if it can be done. If not I will buy a kit and give it to the installers. The perches and shock mounts were not cut so it should be an easy thing to put back the correct way....I hope. Sometimes I'm told that the springs were reversed to center the wheel better in the fender so another thing to check. I have always noticed the rear wheels seem to be a bit further back. Lowering and all that hot rod stuff is not for me just leave it alone as my uncle would say!
On another point can anyone recommend a great front(s) set of shocks. I tried Monroe but they do not make coil over fronts for our truck. I'm looking for something very heavy duty...gas...coil over....not air adjustable type. Something you guys used and worked well for you. As always thanks, Steve

I see. Definitely do not want any Mickey Mouse engineered setups holding the axle in.
With the stock setup, the rear wheels should sit roughly 2" forward of the fender centerline. I have heard of some reversing the springs with an open driveline swap to center the axle in the fender opening for appearances.
For the shocks, you might take a look at Gabriel. I've never used their coil overs personally, but I have used their HD truck shocks on my own vehicles and installed more that I can recall on customer vehicles. Good products. If they don't have a listing, you might be able to take the dimensions and match them up to a similar sized shock with the same mounting system. I have done that in the past with vehicles that were raised/lowered for customers.

Here's what I get from this post. Steve says PO lowered truck, PO actually RAISED truck.
Longbox says put it back to "spring under" which WILL lower it. Albeit back to "stock". You would use trigonometry, not geometry, to conclude an angle change, to a 60"(guess) drive shaft, of 2.86 deg +/- a six pack.
For shocks, since you are going to change geometry, watch video no. 2. After getting those three dimensions and observing eye type/mounting type, take all that to anywhere that sells shocks. Napa, Monroe, Gabriel, Rancho, etc.

If the truck appears to be lower than stock, and the springs are now above the axle, I am now suspecting that the springs are not in their original condition.
If you had stock springs and moved them above the axle, you should have at least a six inch lift in the rear of the truck.
Carl

I was estimating moving from one side of a 3" tube to the other. But don't know AD suspension.

As it is right now the rear axel springs are not on their perches the PO did not cut them off. The axel sits below the leaf springs. The PO used U- bolts on to flat 3/8" steel plate under the axel. Thus the axel does not nest in a proper cradle under acceleration the axel can roll because there is little contact with the round axel housing and the smooth steel plates. Steel to steel contact gives very little resistance such as RR wheels on rail. Huge horsepower cars have slapped bars. The axel hangs under the springs so when loading the box the springs open up instead of compressing. Sometimes the spring will break the stack clips because of this geometry. Also the leaf springs have a rivet which holds the stack together and that centers them on the flat perches. I just want it the way it's suppose to be I don't care about the"look" when I have 1/2 ton of horse manure it doesn't care either. If I need new springs so be it.....Gabriel makes a gas shock for the front Sumitt racing sells them...onward!

Virtually every part of the rear suspension, including springs, is available new if needed.

Yep...that's good to know I have both LMC and Brothers catalog and the net. Monday the shop is going to let me know what I will need. I would like to put it back original most people want it to go to original including my 89 year old uncle who has a complete stock 54 in the barn needs restoration but it's all there torque tube and all!...
Best, Steve