MTFCA Forum

Removed engine last year. Replacing universal joint and cant get the pin hole to line up need drive shaft to move forward another 1/8 inch to line up pin. Help please. Old u joint won't go either.

Sounds like a mis-drilled new driveshaft. There was an issue for a little while with drive shaft pin holes being off 1/8” that was corrected a couple years ago.

Thanks....but have not replaced drive shaft since I took off the old u joint.

Old u joint may have been modified to fit.

Old u joint won't go back either, tried that.

Charles, have you tried pulling in and out on the driveshaft with the joint removed ? , maybe you have some excessive play in the rear axle bearing. Just a thought.

Tried moving shaft with u joint removed. It does not budge either way in or out. Will rotate with wheel jacked up. Should it move in and out. How can I free it up? Thanks for trying to help.

Thrust bearing on the pinion bearing (or the modern version pinion bearing itself) establishes the thrust from rear to forward. The U-joint against the front driveshaft bushing establishes the thrust from front towards rear.
Did you change the front bushing?
Assuming (love to hate that word) everything is as it should be, Ford was rather precise in his manufacturing methods. The holes, both of them, for the pin to hold the driveshaft and U-joint together should be almost perfectly in the center of the hole provided to remove or replace the pin. Therefore, the question becomes, which part is not properly centered? That can help determine where you need to look for the problem.
Even without the U-joint pin in place, if everything is basically right, the drive shaft should be held forward by the ring and pinion gears. So it shouldn't move forward or back much even without the U-joint being pinned. The purpose of the bushing and pin is to prevent the driveshaft from beating the gears together while running and chewing everything to pieces (clearly, a desirable goal).

Again, was the front bushing changed? Some of the new bushings are slightly large in the outer edge, and SOME torque tubes have rivet heads that those bushings catch upon, preventing the bushing, and therefore the U-joint, from going back quite enough. A bit of a nuisance, but a fairly easy fix once the errant bushing is removed.

Thanks. I have not done anything inside the rear axle or drive shaft tube. The front hole in drive shaft is not center of the tube pin removal access holes it is closer to the axel. How can I get it to realign with the pin removal holes. Should I remove the pinion,tube,axel assembly?

Do you still have your old u-joint? If you do compare your old u-joint with the new one and see if there are any overall length or hole differences.
Go back and rethink what was done to to the car after you removed any of the drive line.

With the additional info in the above posts, here is one possibility:

Maybe the pinion gear slipped backwards just far enough for the thrust ball ring to mis-align a bit in its races. This could be possible in an “excessive wear” situation. The pinion bearing could move back a bit if the differential thrust on the left side was a little excessive (like if the thrust washer is worn out or is broken).

Easiest fix is probably to remove the drive shaft tube. Might want to go thru the rear axle while you’re in there too. Get the MTFCA book on the rear axle. It’s not too bad of a job if you have reasonable mechanical skills.

Loosen the U bolts on the rear crossmember and the radius rods to offer some slack, then assemble the unit and retighten the rear assembly.

Got it got it thanks for your post to get my brain moving. Removed drive shaft and tube. Found the problem key that locks the pinion to driveshaft came out of timing with notch in trust washer. Lined them up and shaft moved forward the 1/8 that I needed. Put it back in. Now to reinstall the engine. Thanks thanks thanks

Glad to hear you found it!

Hold on! Hate to say it, but that really should be repaired!

That sleeve needs to be a press fit on the driveshaft. It should never be able to move.

At the very least, you may have to replace the drive shaft and that sleeve.

Failure of the key, or proper mesh of the gears can result in sudden complete loss of brakes with no warning.

Sounds to me like you replaced the front driveshaft bushing. It needs facing off to get the clearance needed to turn the driveshaft. They make a facing tool for doing that, and of course it should be done prior to inserting the u joint into the back of the engine. This is of course assuming you have the correct driveshaft.

You have a major issue in your rear axle. The piece that was not timed with the pinion key is the drive shaft roller bearing sleeve. It must be a press fit on the drive shaft. The fact that it moved on your driveshaft means either the sleeve, driveshaft or both are damaged. If left as it is, the sleeve is going to bust apart and leave you without brakes and likely destroy all internals of the rear axle. Unfortunately, it's time for a full rebuild of the rear end. Please, do not drive the car until you get this sorted out.

Stephen

I had an issue with getting the u-joint and the engine to fully engage. I rebuilt the rear spring and this moved everything back almost 1/2 inch. I wound up loosening everything attaching the springs then used ratchet straps to compress the u-joint and cover in. Then I tightened everything down. I have driven it since then and everything is ok.

Lol,

I did the same than Jim last week. But I have an early one (1911) and I Attached the strap at the front of the car, and it work well. But need to be attached at the middle of the front axel to avoid banding the front axel.

Rebuilding the rear spring won't cause any of the problems you are having!

Yatcwhit wrote: ↑

Thu Aug 08, 2019 1:02 pm

Got it got it thanks for your post to get my brain moving. Removed drive shaft and tube. Found the problem key that locks the pinion to driveshaft came out of timing with notch in trust washer. Lined them up and shaft moved forward the 1/8 that I needed. Put it back in. Now to reinstall the engine. Thanks thanks thanks

Guys, please read this again. The issue was not that he could not get the u-joint back into the output shaft of the transmission. The hole in the drive shaft didn't line up with the hole in the u-joint because the sleeve on the other end of the driveshaft was sitting on the pinion key which was preventing him from pulling the drive shaft forward toward the u-joint to get the pin back in. This is a major and very dangerous problem because it means the sleeve is loose on the end of the drive shaft and getting ready to fail. A rear axle rebuild is in order.

Stephen