I've spent the last couple days swapping rears in my 52 F-1......got the 9 inch all painted up purty, new seals, new brakes, etc. Went to hook up the driveshaft,........it's too short!!! Seems the 9-inch pinion is 1.5 in shorter than the old rear. I can have a new d-shaft made, but I'm wondering if there is another d-shaft from another truck that will work? Or maybe a longer yoke? Truck has a 3 speed w/column shift. Anybody else have this problem? Thanks T/M

 

I'm pretty sure you can change out the transmission yoke. There are a lot of guys who have done and I'm sure they'll be jumping in. I plan to do the same thing this spring with my panel. I'm keeping an eye on this thread for all the information that comes up.

 

Hey Tinman-

I have the same truck, installed a 9 inch rear end and ended up with the same problem with the drive shaft. I went to my local clutch & driveshaft shop and purchased a longer sliding yoke. You want some free space at the end of the yoke (about 3/4 of an inch was what I used) so that it won't bottom out on the tranny. I ended up getting a sliding yoke that was about 1 inch longer than the original. Works well. Total cost for the longer yoke was about $110.

Good luck!

Fred

 

I put a nine inch in my 52 and had the driveshaft lengthened. I've discovered since that a slip yoke from a 49-50 car is longer than the truck so might be a good one to try as the splines are the same.

 

I think the nine inch comes with different length pinion yokes, maybe some junk yard scouting or get a friendly ford parts guy (like the number dummy) to measure some?

 

I knew you guys would have some ideas.....keep em coming. Swapping the yoke would sure be the simplest, and cheapest. My slip yoke goes on about 1 inch, but thats not enough for me....a new driveshaft would be best, but $$$$$$ spendy. Thanks T/M

 

What was the 9" out of? I'm going to go get one as soon as I get a nice afternoon and can get away from work for a couple hours, I found two in the local pick and pull ($100 or $75 with a core) 68-72 ford F-150's at least they were there, I hope they are still there waiting for me?
I may have to look for a slip yoke as mentioned above, I don't want to spend $$$$ for driveshaft lengthening either..
Thanks
Josh

 

Man, I was hoping to get away without putting much into the swap either.

MTflat said in a tech article that he had posted on the defunct MSN flathead board that he heard you could use a mid '70s station wagon. I have a copy of his procedure on my web site if anyone is interested:

Rear Axle Page

 

I looked at mine. The PO used a '76 f150 9" (too wide, yes) and had the driveshaft hooked up to the 4sp. It appeared that it was original. Most likely it was original to the f150 it came from since it was thicker in diameter than the F1's driveshaft. I measured the center to center at ~65.13" and the thicker barrel part at ~56.69" 2wd had carrier bearings so either his f150 was a shortbed or 4x4.

 

When I bought my 9" I also got the drive shaft. I'll have to compare that one and the one in my panel truck. Maybe I'll get lucky and the one that came with the 9" will be a longer one that will fit. Could I be that lucky?

 

I put a 9" under my 48 with a c6 tranny. Yhe driveshaft was to long so I just went to the yard and mearsured till I found one that would work. It was out of a 1977 1 ton. It was 49" long just what I needed. How long a drive shaft do you need? I might be able to check and find one.
ART

 

I have several driveshafts as well that I ain't doing anything with.

 

Some facts I left out......the F-1 drive shaft is 63.5 in center to center, and the rear is out of a 65/6 F100. Shortening a driveshaft is no big deal, but lengthening one is a little tougher.......so I think I'll try to find a longer one, or a longer pinion yoke. I know they made a bunch of different yokes, not sure if any of them interchange?! Ain't old Fords fun??? T/M

 

If ya go junkyard shopping, the late 70's f150 4x4's with NP205 tcases should have a long enough driveshaft. Bearing size increased sometime in 1979 or so, which might be something to consider...taking the yoke, too.

Maybe someone can verify the length in the 73-79 forum.

 

Havi, 70's 4x4 trucks don't have a slip yoke at the tranny like a 52 f-1 so those shafts are no good (they are more like a 50's 4 speed driveshaft with a fixed yoke and the slip yoke IN the driveshaft itself). Maybe a shortbed 2wd 70's truck would work??

Some cars have a longer slip yoke that has the same splines and outside diameter, like 60's mustangs etc...etc.. they have a slip yoke that is about twice as long at the little 50's yoke. BUT....this may shorten the life of the tranny bearings over time????

60's small cars (mustangs, torinos...etc...etc) had a yoke that was longer ( a little more than an an inch) on the 9" axles. look for a centersection that has a sheetmetal hood with a rubber snubber bolted on top of the pinion support.

I have one of these old centersections on the floor of the garage, it is an old N-case center out of a drag pak torino. I would trade you yokes but unfortunatly the n-case yoke is a tad diferent than the regular 9" yoke (n-cases had the daytona pinion suports which used a diferent yoke). If I remember I will take a pic of it tonight so you know what to look for.


Also lengthing a driveshaft usually doesn't cost much. Around my way it costs about $100 to get one made any length and balanced if you provide the ends.

Also if you do find a driveshaft in a junkyard that is the right length but has the larger U-joint size you can but "combination" joints at the parts store that have both sizes (ie. one cross of the u-joint is larger than the other).