U-Joint Replacement
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Joined: Dec 2009
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From: Central Connecticut
U-Joint Replacement
I bought a new universal joint from Mac's for my '50 F-1 but it doesn't fit. The original part, pictured below, is dished out so that there's enough clearance between the universal and the plug (grease cup) on the inside of the knuckle on the left in the photo. The replacement is too thick to clear the plug. I also checked with the local NAPA store and a drive shaft rebuilding business in town and they didn't have anything that fits any better. I've thought about removing the plug and replacing it with a flat disc to gain more room. Has anyone else had this problem? If so, what did you do about it?
Lead Driver
Joined: Jun 2011
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From: Winnipeg, Manitoba
I bought a new universal joint from Mac's for my '50 F-1 but it doesn't fit. The original part, pictured below, is dished out so that there's enough clearance between the universal and the plug (grease cup) on the inside of the knuckle on the left in the photo. The replacement is too thick to clear the plug. I also checked with the local NAPA store and a drive shaft rebuilding business in town and they didn't have anything that fits any better. I've thought about removing the plug and replacing it with a flat disc to gain more room. Has anyone else had this problem? If so, what did you do about it?
Fleet Owner
Joined: Jul 2004
Posts: 27,299
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From: NM
You need to find someone who carries a different brand. I'm suspecting the places you tried all have the same brand/model? What brand was that? Spicer would seem likely to fit.
I need to check mine, I don't remember it having that cup at all. Maybe that's why there is a stripe of oil on the bottom of the cab!?
I need to check mine, I don't remember it having that cup at all. Maybe that's why there is a stripe of oil on the bottom of the cab!?
Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
C3AZ-4635-E (replaced C3AZ-4635-C, B7AZ-4635-A, B7A-7039-A, 21C-7039) .. U-Joint / Front/Rear applications: 1948/52 F1, 1953/56 F100, and...
This is the same 'Spicer type' as the front u-joint used on: 1965/73 289/302 Mustang / 1970/77 Maverick/Comet and a gazillion other 1942/80's FoMoCo vehicles.
So, there's no need to buy u-joints in Lockport NY (Mac's) and pay shipping charges, when you can buy them at local autoparts stores. Just take the original along to match it up.
Note: Ford changed the u-joints basic part number from 7039 to 4635 sometime after 1956.
This is the same 'Spicer type' as the front u-joint used on: 1965/73 289/302 Mustang / 1970/77 Maverick/Comet and a gazillion other 1942/80's FoMoCo vehicles.
So, there's no need to buy u-joints in Lockport NY (Mac's) and pay shipping charges, when you can buy them at local autoparts stores. Just take the original along to match it up.
Note: Ford changed the u-joints basic part number from 7039 to 4635 sometime after 1956.
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Joined: Dec 2009
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From: Central Connecticut
I agree. Taking it out and grinding it down is probably the way to go. Another suggestion has been to see if there's a freeze plug the right size that could be used as a replacement. I'm still curious if I'm the only one who's run into this problem.
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From: Central Connecticut
The drive shaft company you took it to should be able to solve your problem, If not try another shop. They are supposed to be expert's. We have at least a dozen shop's here, and every one of them would be able to help you. I really can't understand in this day and age people will just sluff you off. When job's are tight and everyone complain's, these shop's should sometime's just suck it up and deal with it! Help the average Joe and the average Joe will help you. My 2c worth, and it feel's good. We have the same problem up here.
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Joined: Dec 2009
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From: Central Connecticut
C3AZ-4635-E (replaced C3AZ-4635-C, B7AZ-4635-A, B7A-7039-A, 21C-7039) .. U-Joint / Front/Rear applications: 1948/52 F1, 1953/56 F100, and...
This is the same 'Spicer type' as the front u-joint used on: 1965/73 289/302 Mustang / 1970/77 Maverick/Comet and a gazillion other 1942/80's FoMoCo vehicles.
So, there's no need to buy u-joints in Lockport NY (Mac's) and pay shipping charges, when you can buy them at local autoparts stores. Just take the original along to match it up.
Note: Ford changed the u-joints basic part number from 7039 to 4635 sometime after 1956.
This is the same 'Spicer type' as the front u-joint used on: 1965/73 289/302 Mustang / 1970/77 Maverick/Comet and a gazillion other 1942/80's FoMoCo vehicles.
So, there's no need to buy u-joints in Lockport NY (Mac's) and pay shipping charges, when you can buy them at local autoparts stores. Just take the original along to match it up.
Note: Ford changed the u-joints basic part number from 7039 to 4635 sometime after 1956.
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Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
I now know that it was dumb to order the universals from Mac's but I was ordering some other stuff and thought it would be easier to just add then to the order. I took both original parts with me the other day to compare to what was available locally. Both NAPA had the drive shaft shop had replacement parts (Ross - I don't recall the brand) that were listed as the same 4635 however, none of them had enough clearance.
My 1975 Ford O-S-I (Obsolete-Supercede-Interchange) catalog shows that B7AZ-4635-A was replaced in 1963 by C3AZ-4635-E. All 4 of these cups are #1310 size.
But FoMoCo sez this u-joint will work on 1948/52 F1's and 1953/56 F100's. If you want what is listed in the 1948/56 catalog:
B7AZ-4635-A =
CARPENTER NOS OBSOLETE PARTS in Concord NC has THREE = 800-476-9653.
ANTIQUE AUTO SUPPLY in Arlington TX has FOUR = 817-275-2381.
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Joined: Dec 2009
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From: Central Connecticut
I found a solution that might work for others if they have the same problem. I popped out the plug at the end of the knuckle and replaced it with a 1 5/16 " freeze plug that I got from NAPA.
This gives quite a bit more clearance for the replacement universal joint.
This gives quite a bit more clearance for the replacement universal joint.
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Joined: Dec 2009
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From: Central Connecticut
I can't really tell although I don't think it goes far enough to pot the plug out. I've been thinking about trying to put some epoxy down at the end to hold it in. The guy at NAPA suggested that I tack it lightly with a welder.
Fleet Owner
Joined: Jul 2004
Posts: 27,299
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From: NM
I went to replace my front joint today and got it in about 1/4 of the way before I saw the same problem -- DUH!! It isn't just that the center of the U-joint is thicker, the big difference is the length of the axles the cup go on. Ford essentially shortened them and moved them outboard. I was going to try to put new cups on the old axles but they aren't at all the same.
So I'm off to NAPA for a freeze plug!
Edit: I got plenty of clearance by beating on the stock cup with a ball pein hammer.
So I'm off to NAPA for a freeze plug!
Edit: I got plenty of clearance by beating on the stock cup with a ball pein hammer.
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Joined: Dec 2009
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From: Central Connecticut
