1977, B7100, front driveshaft looseness

procraftmike

Member

Equipment
1977 B7100DT w/B219 FEL
Jan 27, 2016
277
10
18
Neenah, WI
I have noticed play in the front driveshaft. At first, I assumed I had a bad u-joint. But after further inspection, there appears to be play between each of the 2 upper yokes and the splines. There is a little play at each yoke, which adds up when you factor in both on top and possibly both on the bottom. The yokes are held onto the shaft by a single roll pin.

Should I be concerned about this play? Is there an easy fix for it? The u-joints appear to be just fine. I assume I have the same issue on the lower end of the shaft as well, as the parts listing shows the same arrangement.

This tractor is built like a small tank, but I can't same I'm impressed with the front driveshaft arrangement.
 
Last edited:

Lil Foot

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Lifetime Member

Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,297
2,250
113
Peoria, AZ
Recently rebuilt my front axle & didn't have any play I would consider excessive for a 37yr old machine. I will check it next time I see it, but it's 150 miles from here now.
 

North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
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Sandpoint, ID
Probably play from worn coupler / shaft splines.
You could change the couplers for cheap enough and see if that takes the play out of it. ;)
 

procraftmike

Member

Equipment
1977 B7100DT w/B219 FEL
Jan 27, 2016
277
10
18
Neenah, WI
It is hard to say if the wear is in the yoke (coupler) splines or the shaft splines. I have no idea if one is of a harder material than the other to limit wear on one of the items. I suspect the splined shafts are probably hardened, not sure on the couplers. I think if there were 2 roll pins installed, 90 degrees from each other, it would help combat the "teeter totter" affect that probably developed over time. My guess is it would be a real pita trying to drill for additional roll pins though.

I guess I will have to drive out the roll pins and disassemble the shaft to investigate further. Changing the couplers doesn't appear that difficult. The splined shafts on both ends would be a different story.