Rear Shackle Install On A '40
 

I just got the L/H axle housing back in and the rear spring loosely bolted up on the U bolts. Got new shackles from Speedway but having major difficulty lining up the shackle eye on the axle housing with the eye in the end of the spring. It appears you need perfect alignment of the two for the metal part of the shackle to pass through the ID of the new bushings without tearing them up. Any tips are appreciated. Fooled with this for an hour on one side with no luck. I didn't want to beat it back together. A 'C' clamp didn't work either.

Phil Swanson

Re: Rear Shackle Install On A '40
 

Are you using a spring spreader?

Re: Rear Shackle Install On A '40
 

Yes, the spring spreader is still on the spring. The problem doesn't appear to be spreading the spring but the axle housing eye has a slight twist whereas the spring eye is relatively square. Not much off but just enough where the shackle frame doesn't want to go on. The other end isn't even connected yet so I doubt the spreader is the problem but I could be wrong.

Re: Rear Shackle Install On A '40
 

I'm not sure I am picturing this correctly. Are you saying the squared end of the pin isn't aligning (orientation) with the shackle bar?
If that's correct, you can twist the pin a bit with an open end wrench.

Re: Rear Shackle Install On A '40
 

Didn't follow your nomenclature. I am saying the two holes aren't exactly parallel. Off just enough to prevent the frame from going through both bushing IDs at the same time.

Re: Rear Shackle Install On A '40
 

I have found that the arm welded to the axle housing that holds the shackle stud can be bent making the two shackle studs you are trying to connect with the shackle bars not parallel to each other. You can check to see if this is the case by measuring the distance between the studs on the axle housings across both sides. I always check to make sure these arms are not bent before attaching the housings to the differential. You can straighten these arms by removing the shackle stud and installing a long 3/4 inch diameter bar in the hole and pulling the arm. Good luck.

Re: Rear Shackle Install On A '40
 

I didn't realize the arms were welded to the axle housing. I thought they were cast as one piece. I was afraid to bend these for fear they would break off. I will check today. If it is bent slightly, I wonder if you can tweak the differential with a floor jack slightly to compensate instead of bending the arm??? Will measure holes across both sides. Thanks!

Re: Rear Shackle Install On A '40
 

Do you have a camera? You know, a picture is worth...

Before you start bending stuff (in my opinion) I think we need to SEE what you have going on there.

40Larry is a sharp guy and offers good advice. Still, with the (literally) dozens of these I've done, I've yet to come upon a bent axle housing / perch.
I am confident Larry would agree that we need a photo...

Re: Rear Shackle Install On A '40
 

Yes, make a careful measurement across the axle housings on both sides and then you will know for sure. I have found about half of the ones I checked to show some bending has taken place. Before installing the shackle studs and assembling the rear axle housings I stand the two housings on a flat floor and slide a 3/4 inch bar into the shackle stud holes and if everything is straight the bar will go through both axle housing holes with the housings still standing flat on the floor. This is the time to straighten them if there is a problem. I am sure many people never check this and just go ahead and pull things together if the error is not very large. The problem with doing this is that the new shackle studs will wear rapidly into the insulated outer shell because of the increased load on one side. This is not rocket science and it is quite easy to measure and see if you have a misalignment due to bending..

Re: Rear Shackle Install On A '40
 

Please follow Kube's suggestion and post some photos. To get the spring eye and the axle housing eyes to align parallel to each other you might try tying a piece of strong rope between the rear cross member at the rear of the car near the splash pan and one end of the spring near the eye. Then twist the rope a little at a time to pull the spring eye into position. You could also use a turn buckle to provide a "controlled" twist.

Many years ago when I removed the rear spring on my 40 I noticed that one of the housing spring eyes was slightly bent. I heated it up red hot, inserted a steel rod through the eye and pulled the eye into correct position. The rear spring shackles then went in really easy.

I had forgotten that the car had been in an accident years earlier that had probably bent the eye. That was 45 years ago. Since then I have removed and installed the rear spring without problems.

That being said, we still need photos. I realize that my home made bushings and shackles are not the same as OEM,but they are the same size between pins as the OEM so idea might work. Are your shocks disconnected?

Re: Rear Shackle Install On A '40
 

I can e mail the pictures but I have no idea how to post them.

Re: Rear Shackle Install On A '40
 

Philip, I sent you a PM with my email address. If you send me the photos i will try and post them for you. jim

Re: Rear Shackle Install On A '40
 

Appreciate it Jim!

Re: Rear Shackle Install On A '40
 

Take the spring off the U bolts. Identify which side has the worse alignment. Attach that side, with the spring not attached anywhere else, so it will go together easy. Pull it as close as you can and try and fit the other side. If it is out in an up and down misalignment, you can pull the spring forward or back to help get it in. If you get the shackle in you just need to get the pins the right distance apart to get the plate on. by adjusting the spring spreader, using a wedge in between the spring and the perch, or a g clamp to pull them together you should get the last plate on.
Once the shackles have been fitted, the spring spreader can be removed and the spring mated up into the crossmember. It might need levering forward at the top to get it to start into the crossmember. Having the shackle nuts loose at this point might help.

Once all is in place, tighten the U bolts and the shackles.

Mart.

Re: Rear Shackle Install On A '40
 

What are you calling pins and plates. Are these the U bolts and lower retainers? Same thing?

Re: Rear Shackle Install On A '40
 

Here are the photos from philipswanson showing his situation.

Re: Rear Shackle Install On A '40
 

It looks close enough to me to install the part you have started and then put a large crescent wrench on the spring main leaf and twist it slightly enough to install the other bar. You may have to twist the main leaf a little to install that part fully.
I have an 18" crescent wrench I use for things like that as it has jaws long enough to span the width of a leaf spring.

Re: Rear Shackle Install On A '40
 

Perfect advice!

Re: Rear Shackle Install On A '40
 

Thanks I will try the crescent wrench tomorrow. I have one about 24" long hanging on the wall. Have only used it for decoration but its time to put it to work.

Thanks to all!
Phil Swanson

Re: Rear Shackle Install On A '40
 

Might want to use a little tap with a piece of wood and a heavy hammer. Looks like you are almost there. Nothing looks like it wont go the rest of the way (might be binding on the rear poly bushing). I was envisioning more like what 19Fordy posted.


Could try a smaller c-clamp to force it through, might have to put a crescent or bar on the clamp for force, it'll need more then you think. Should hold the rear poly bushings in. If not you can take some old stock and drill out the holes to fit over the shafts/pins Or use the back plate.


Once through, you can use a pipe wrench or crescent to put it together.



wiggling it around a bit with the wrench won't hurt or taking a few cranks off/on the spreader.


Good luck!






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