stange u joint problem

Hello everyone, we bought a rear u joint of our 73 today with a 9" rear and 3 1 /2" yoke on the driveshaft and the caps on the new u joint were flip flopped. The outer clip caps were to big to fit in the driveshaft yoke and the center clip caps were to small for the u bolt/rear flange. What gives? Please help.

I would take it back to the parts house, and make sure they gave you the right one.

As my friend Jim (who was a "parts guy" for many years) has always told me with respect to buying parts from a parts store, "'New' means 'new,' and doesn't always mean 'good,'" and "unless the box is sealed, you have no idea what you're getting until it either fits or doesn't." "Mis-boxing" of parts sometimes happens... especially if the parts guy has a few boxes opened up on the counter trying to find the right one for some other guy - the parts might not always make it back into their correct boxes.

If possible, take the old U-joint with you (with caps) and make them look up from the computer screen and use a micrometer to find the right one.

Thanks for the tip, I dont know if the drive shaft is mounted with the front yoke on the wrong end or not but I noticed the u joint holes on the driveshaft at the front yoke end are 1 1/8" and the rear 1 1/16". Does anyone know if this is correct or bass ackwards?

i had a lot of trouble locating the correct u joints, none of the catalog u joints listed for 72 mustangs was correct. i ended up ordering 1 of each U joint from the parts catalog until i found one with the correct ends that turned out to be listed as a ford bronco part.

now part of this could of been because i had a ford bronco yoke installed by a previous owner or a previous repair with a compatible part.

if you have the original U joint use that for comparison regardless of what the parts numbers are saying.

Do not worry so much about the correct part number so much as the part is correct in function and fits.

Thanks H code, I think I might have figured out whats going on. By doing some internet u joint searching it appears the smaller sized u joint caps go to the transmission side of things on the drivehaft. Hmmmm. Will post back later with follow up.

what will drive you nuts more, is the location of the Zerk fittings on the new made in china replacement u joints.

on the originals you can grease the Zerks with the U joints installed, with the new ones you have to take the drive shaft out to gain access to at least one of each Zerk, its a real pain in the butt.

I found this sites u-joint chart helpful. http://www.driveshaftspecialist.com/HTML%20Measure/UJ%20ID%20Guide.html#OUTSIDE_LOCK_U-JOINTS

Okay here is what we have so far. The front u joint is rectangular shaped with 1.062" caps all around. It has a ford racing yoke on the trans end of the driveshaft. Now on the back the u joint the parts store sold me has 1.062" caps to the u bolts and 1.125" caps for the back of the driveshaft that seem to big and won't even attempt to go in without shearing metal, the 1.062" caps fit alot better and go in with moderate force and seems more correctly sized. I am pretty confused at this point. Does anyone know where to find a rear u joint that is 3 1/2" wide with the small 1.062" caps on it all the way around? Thanks for the input. Oh and I know what you mean about the grease zerks, good luck getting a grease gun on there with everything put together.

Face the grease zerks toward the driveshaft. They also make grease gun adapters for some of those hard to reach fittings.

Thanks everyone, solved it. I had the part store get one with small caps all around and it fit like it supposed to.