Torque Tube & driveshaft shortening
 

I'm putting a '40 Ford rearend into a completely stock original '32 chassis with a '39 tranny and I need to make a driveshaft and shorten the '40 torque tube. Are there standard dimensions on these 2 pieces since this has been done by many hot rodders over the years that somone could supply me with or should I measure and fabricate anyway?

Re: Torque Tube & driveshaft shortening
 

My experience leads me to say- if you get someone else's measurements, check them by taking your own. I have taken others measurements from books and found them to be wrong... Karl

Re: Torque Tube & driveshaft shortening
 

This is MY measuring...
Axle centerline to banjo flange on a '32 is about 5.96"
Axle centerline to banjo flange on a '40 is about 6.38"
Therefore, torque tube should be about .42" shorter for the '40 rear to fit into the '32.
Torque tube length on a '32 is about 53.31"
Therefore '40 torque tube should be shortened to about 52.89"
When the torque tube has been shortened, if you can turn it on centers at the front end and back end, there should be very little runout on the back flange!

Now, about the drive shaft: Once you have the torque tube shortened, assemble whatever driveshaft you're using into the front of the torque tube with the bearing, speedo gear, retaining clip, etc, etc. and see where the hole for the pinion / coupling pin is from the torque tube flange. See where the same hole is on the pinion from the banjo flange. Shorten the driveshaft so the holes will be in the same location.

As you might guess, I'm in the midst of this myself.

Re: Torque Tube & driveshaft shortening
 

I think I cut about 16" or so out of mine, but I used a quickchange centersection which I believe has a different flange placement than a stock banjo.

You're better off measuring and doing it yourself. Too many variables, even on identical builds... (spring choice, rear crossmember choice, the '32 rear spring is curved and so is the spring, the '40 is straight, wheelwell placement, etc...)

Re: Torque Tube & driveshaft shortening
 

I agree whole heartedly with idea of mocking up the driveshaft in the torque tube and verifying your dimensions. My transmission was destroyed (over time) by having a drive shaft that was too long-it extended thru the u-joint far enough that it was in constant contact with the head of the u-joint retention bolt. It was imposing an unatural thrust on the output shaft that ultimately ruined the gear box. It happened when I had a local shop (with a good rep-up to that time) change a rearend in my '32. I supplied them with a complete '39 rear axle assy to get the 3.78 gear. Still don't know what they did but it was about a half inch too long.

Re: Torque Tube & driveshaft shortening
 

Did you guys cut and weld the drive shaft or have it re-splined?

Re: Torque Tube & driveshaft shortening
 

I was fortunate enough to pick up a '33-'34 driveshaft and a 6 to 10 spline coupling. The female spline end of the driveshaft will be cut off and the coupling will be turned to fit into the driveshaft and then welded. This is one of the items on my "to do" list. Speedway offers a new driveshaft and coupling (I believe it's made by Dick Spadero) to do the same thing, but it's pricey.

PS: The straight '40 spring can have nice smooth reliefs ground in the leaves to fit into the '32 rear crossmember. It will locate the rear just where it should be. I'll see if I can get some pictures to post.

Re: Torque Tube & driveshaft shortening
 

I bored the coupler out to a light press fit on the non-machined area of the shaft. Also opened up the pin holes on the bored side to about 3/4" holes. Cut the shaft accordingly, threw the cut end of the shaft in a snowbank and heated up the bored end of the coupler with the torch. Dropped it on, welded it up, plug welded the enlarged holes. Works great and it doesn't disturb the bearing surface locations so you keep both torque tube bearings!:cool:

Re: Torque Tube & driveshaft shortening
 

I bolted the original '32 spring with long old shackles to the '40 rear just to mock it up. So will the rearend NOT be in the correct location? I don't have a body yet to see if it ends up square with the wheel wells. I have the '40 spring, should I use that instead and grind into the leafs to make it fit?? I'll have to take a lot of leafs out to lower it. I've done the '34 shaft & tube on a Model A build, it works well but those are getting really hard to find now. The Speedway deal is too expensive. I can have a driveshaft shop make me a new shaft for $150 here in Denver and that includes balancing.

Re: Torque Tube & driveshaft shortening
 

I did mine by cutting the driveshaft to the length i needed, then cut splines in it with a disc grinder. Bush engineering at its finest! :D I then pushed the coupler on and welded it to the driveshaft. The splines dont have to be accurate, theyr'e only to allow the coupler to slide on. The weld takes the strain that the splines used to take. Turns freely in the shortened torque tube, and there should be no strength issues with a basically stock engine and no drop clutch starts!

Re: Torque Tube & driveshaft shortening
 

They probably used the length of a 32 and did not allow for the fact that (as already posted) the banjo housing flange is about 1/2" longer on a 35-48 and the pinion shaft is also 1/2" longer.

We just went through this on a 36 Columbia rear that had already been shortened to "fit" a 32. The owner had removed the rear from his car and brought it in, so we nor he realized there was a problem. We added a rear seal (from Danny Burroughs at Bruce's Rod Shop in Spring TX) that has a 1/8" plate that goes between the banjo and the torque tube. That 1/8" was just enough to cause the center section to hit the rear crossmember when re-installed. (The rear spring was a little bound-up too...) We took it back apart and re-measured everything and determined that the person who had shortened the torque tube and driveshaft to fit the 32 had used the exact 1932 dimensions without deducting the 1/2" - we deducted that plus the 1/8" more from the torque tube and had our good friend redo the stuff to the correct length. All is well... so far...

If the vehicle will be low in front causing the torque tube to run down-hill, we HIGHLY RECOMMEND Danny's seal setup - which will prevent rear end oil from running into the torque tube (or worse if the front driveshaft seal leaks...)

Re: Torque Tube & driveshaft shortening
 

Yes... The rear end will NOT be in the right position. With the curved springs, the shackle points on the rear are closer to the axle centerline than they are with a "straight spring" rear end. So, for a '32 rear with CURVED spring, the distance from the axle centerline to the TOP CENTER of the spring (where it bolts into the crossmember) is pretty much the same as it is for a '40 rear with STRAIGHT spring.

Re: Torque Tube & driveshaft shortening
 

I just measured the wheelbase and yes it's off by about 2 inches! Thanks for the tip, I'll change to the '40 spring and make it fit. Plus I can get a reversed eye rear main leaf to lower it.

Re: Torque Tube & driveshaft shortening
 

Hopefully, this should be a picture of how I "notched" a straight rear spring to fit into a '32 rear crossmember. I used a 4-1/2" angle grinder to remove the bulk of material. When I had it down far enough so it would fit, I polished all the grinding and rounded the edges with a flap wheel. Do the first leaf, use that piece as a pattern for the rest of the leaves and finally see how it fits when they're all bolted together.

As far as a reversed eye spring goes, you don't need a new leaf- just get your local friendly spring shop to take the old leaf and rearch it so it will be backwards.

Re: Torque Tube & driveshaft shortening
 

Dick Spadaro has a drive shaft kit or at least he did. It comes with the necessary tube and a new splined end to be inserted and welded to the tube. The tube length can be adjusted as required by any number of different applications. A good drive shaft shop could put it together and balance it in short order.

Re: Torque Tube & driveshaft shortening
 

I measured like you did where the "lumps" are inside the '32 crossmember and ground grooves there in the spring pack while it was all together and it fits! I need to smooth it all out still. I'm surprised that the square bolt came up thru the square bolt hole in the crossmember!

Re: Torque Tube & driveshaft shortening
 

It should be fairly easy to disassemble your spring pack once you have it notched and then cleanup all the grinding and radius all of the sharp edges and then paint and lube. I use a 3/4" Pony pipe clamp on the spring- I get it clamped tightly, remove the center bolt and replace it with a length of threaded rod with double nuts on one end and a nut on the other end about 1/2" loose. Then, I loosen up the pipe clamp until the load is on the threaded rod. Then, I "reset" the pipe clamp and loosen up the threaded rod another 1/2" and repeat until the spring is apart. I reassemble the spring the same way. If the spring has reversed eyes, I assemble the main leaf to the shackles and then "build" the spring in place.