The Ford Barn

Alaska Jim · 03-09-2021, 11:55 AM

Has anyone bought one of Shoebox Central's new driveshaft yoke's ? They show a new one that is for 49-55 Ford and Mercury. I bought one and went to put it on the driveshaft last night and it seems as the U- joint "eyes " are a bit oversize and the cup will just push in with just the pressure of your hands. I was just wondering if anyone else has had this problem, or did I just get a bad one. I have not contacted the vendor yet, I was just wondering if anyone else has had any experience with this part from them. all of the stuff I bought from them in the past has been fine. I will post this on the early v8 forum as well. thank you for any input.-----Jim

55blacktie · 03-09-2021, 12:01 PM

There's a good chance that your replacement yoke was designed for a 1310 u-joint, the most common size. If that's the case, you'll have to get a u-joint that is 1310 on the yoke side, and whatever size is required on the driveshaft side. I had to do that when I replaced the pinion yoke on my 55 T-bird, having changed the rear-axle ratio.

55blacktie · 03-09-2021, 06:35 PM

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rotorwrench · 03-09-2021, 07:52 PM

There were two front knuckles used. The 8M-4841-A was used prior to the introduction of the Merc-O-Matic. The 1M-4841 was used for the Merc-O-Matic so there is a difference but I don't know what it is. There were also two U-joints, The 8M-7042 and the 1M-7042-A respectively. My big problem now is that I don't know if the MOOG & SKF 507 or the Spicer 253242X are replacements for the standard or the automatic transmission since I don't have much info to go on. The damn things may be interchangeable but I just can't verify that.

A lot depends on if it's for standard or automatic applications. It's been a while since I looked all this stuff up but if my memory serves, the bearing diameter for all 4 caps was 1-inch. I think the 1310 UJ has a 1 & 1/16-inch size bearing cap. The OEM ones use C-ring internal snap rings that fit between the cap & knuckle bore. These will usually hold a push fit as long as it's not a real loose fit.

The Ford car book that I have that's up through 1953 only shows the 1M-4841 knuckle & plug since that part number likely replaced the part made prior to 1951 for the Ford cars.

Alaska Jim · 03-10-2021, 03:26 AM

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rotorwrench, I had my brother ( he is a machinist by trade) measure the new yoke against the old one. the u-joint does have the 1 inch caps. the old yoke has a 1/2 thou. press. and the new yoke is 1.5 thou. oversize, allowing no press at all. the original yoke and the new yoke both take the internal c-ring clip. we went digging through the conex today and found 1 used yoke that I think will work. It has some minor rust pitting, but no grooves from the oil seal or wear from the output shaft bushing. I still would like to find a better, or new one, so I will keep looking. in the mean time I will probably use the one I dug up today, and I will call Shoebox Central about the one I purchased from them, tomorrow. Thank you for your information.--- Jim

03-09-2021, 11:55 AM	#1
Alaska Jim Senior Member Join Date: May 2010 Location: Palmer, Alaska Posts: 1,575	drive shaft yoke Has anyone bought one of Shoebox Central's new driveshaft yoke's ? They show a new one that is for 49-55 Ford and Mercury. I bought one and went to put it on the driveshaft last night and it seems as the U- joint "eyes " are a bit oversize and the cup will just push in with just the pressure of your hands. I was just wondering if anyone else has had this problem, or did I just get a bad one. I have not contacted the vendor yet, I was just wondering if anyone else has had any experience with this part from them. all of the stuff I bought from them in the past has been fine. I will post this on the early v8 forum as well. thank you for any input.-----Jim

03-09-2021, 12:01 PM	#2
55blacktie Senior Member Join Date: Aug 2020 Posts: 442	Re: drive shaft yoke There's a good chance that your replacement yoke was designed for a 1310 u-joint, the most common size. If that's the case, you'll have to get a u-joint that is 1310 on the yoke side, and whatever size is required on the driveshaft side. I had to do that when I replaced the pinion yoke on my 55 T-bird, having changed the rear-axle ratio.

03-09-2021, 06:35 PM	#3
55blacktie Senior Member Join Date: Aug 2020 Posts: 442	Re: drive shaft yoke northerndrivetrain.com

03-09-2021, 07:52 PM	#4
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,431	Re: drive shaft yoke There were two front knuckles used. The 8M-4841-A was used prior to the introduction of the Merc-O-Matic. The 1M-4841 was used for the Merc-O-Matic so there is a difference but I don't know what it is. There were also two U-joints, The 8M-7042 and the 1M-7042-A respectively. My big problem now is that I don't know if the MOOG & SKF 507 or the Spicer 253242X are replacements for the standard or the automatic transmission since I don't have much info to go on. The damn things may be interchangeable but I just can't verify that. A lot depends on if it's for standard or automatic applications. It's been a while since I looked all this stuff up but if my memory serves, the bearing diameter for all 4 caps was 1-inch. I think the 1310 UJ has a 1 & 1/16-inch size bearing cap. The OEM ones use C-ring internal snap rings that fit between the cap & knuckle bore. These will usually hold a push fit as long as it's not a real loose fit. The Ford car book that I have that's up through 1953 only shows the 1M-4841 knuckle & plug since that part number likely replaced the part made prior to 1951 for the Ford cars. Last edited by rotorwrench; 03-09-2021 at 08:00 PM.

03-10-2021, 03:26 AM	#5
Alaska Jim Senior Member Join Date: May 2010 Location: Palmer, Alaska Posts: 1,575	Re: drive shaft yoke Sponsored Links (Register now to hide all advertisements) rotorwrench, I had my brother ( he is a machinist by trade) measure the new yoke against the old one. the u-joint does have the 1 inch caps. the old yoke has a 1/2 thou. press. and the new yoke is 1.5 thou. oversize, allowing no press at all. the original yoke and the new yoke both take the internal c-ring clip. we went digging through the conex today and found 1 used yoke that I think will work. It has some minor rust pitting, but no grooves from the oil seal or wear from the output shaft bushing. I still would like to find a better, or new one, so I will keep looking. in the mean time I will probably use the one I dug up today, and I will call Shoebox Central about the one I purchased from them, tomorrow. Thank you for your information.--- Jim