Anyone think of any reason I can't use these on a 51?

Wanting to maintain frame to axle clearance when I have a trailer on the car and be able to raise the rear up an inch or so.

Looking at these

MONROE SHOCKS & STRUTS :: e-Catalog

 

I have never been a fan of air shocks for weight carrying. If you think about it, you are relieving the springs of some of the extra weight you have applied. You are transferring that weight to the shocks which are carried by what amounts to a couple of studs.
A better choice would be air bags, which carry the weight on the frame and axle, or helper springs.

 

Ryan, Air shocks were common in the 70's & 80's They worked fine, and were even a factory option. I would look at an air bag set up for your application. It would be and add on between the axle and frame. I would mount an on-board compressor, and adjust as needed. Good luck.

 

Your frame is C-notched as I recall? How heavy a trailer is it?

 

It is not C-notched. I have 3-4" clearance axle to frame (3/4" rubber bump stop on the frame). I have bottomed it out twice in 1000 miles... on really big potholes.

This is acceptable to me, but with a trailer and car being hauled behind... maybe 4000 lbs total and a couple hundred lbs tongue weight, it would be nice to have a little help from bottoming out. really just a couple hundred lbs worth of help.

Not enough room for air bags I don't think (are there 3" tall air bag kits out there)? And this is a finished truck, so not looking to do any fabrication work on it at this point.

 

Do it right, use a load equalizer hitch system. With the one on my enclosed car hauler I could actually raise the rear of the truck with the equalizer if I wanted to. Not a lot more expensive than a pair of air shocks or bags which are a band-aid at best. I like the ones with the round torsion bars over the flat ones. Then add an anti-sway and you'll have a first class towing setup. No truck changes (except hitch tongue swap) needed. You'll almost forget the trailer's back there (at least until you look in the mirror and see that guy tailgating you so close!)

 

We do have some pretty short bags that may be able to work for you. Let me know if you are interested and we can dig into this a little further.

 

I have considered going with air shocks as well, they have worked fine for me in the past, but the shock mounts have to be strong since the shocks will be holding up the weight and not the springs.
I havent found any air shocks that had a compressed height short enough to use with my current setup, I am sure I would have to relocate one end of my shock mounting points to get more travel. Dont want to bottom out on the shock before the bump stop.

 

I found a set of air shocks for a VW beetle MA803 that go from 10.5" compressed to 16.1" extended. My current shock length at ride height is 13", so this gives me about 4" of up and down suspension travel (shocks are mounted on a ~45deg angle).

The only issue with these is the mounting points will require some minor modification. The factory style shocks have a 5/8" bushing and ride on 1/2" hardware. The MA803 have a 12mm insert that will need to be removed or drilled out slightly to fit over the 1/2" hardware. As far as strength goes, I agree it is a question...

However it is not uncommon to have the entire sprung weight of a vehicle mounted on a single or double sheer 1/2" bolt on coilovers in the back. I have seen this a lot and it is common place in mustang coilover setups and in the factory five kit cars. Here we are just supplementing the springs with a little help, not supporting the entire vehicle weight.

The MA803s are $60 a pair... so I think I am going to give this a shot... why not, it is cheap. I will report back if I can get them to fit and if I have any issues.

I would be interested in the low profile air bag setup though!

And AX I agree a load leveler setup is the hot ticket and if I was serious about doing any long distance or high speed hauling with this truck I would go that route. I am always inclined to keep things as simple as possible... so lets see how this works. I will probably look into your suggestion as well.

 

So are you hauling a Mustang to the track? I think your 4000# estimate may be low. Most car hauler trailers are close to 1500# empty, I would think even a stripped Mustang is going to be 3000#. Add tools, tires, etc.

 

No its a 2200 lb factory five. Add 1500 lb 16' car hauler and it is still well under 4000 lbs.

 

The only caution I would give you, Ryan, is to please remember your Mustang coil over rig is designed to be carried on that bolt. Or, more specifically, the bolt was designed to carry the weight. In the case of your shock mount on the 51, it was designed to handle the occasional over extension. And that bolt currently has 64 years of wear, aging and, based upon it's location, probable neglect.