Will it fit?

[Tgtack 779]

I have an opportunity to pick up a 1077 (to restore), and two complete B Series hydro pumps and transaxles. The question is, can I swap out the 3 spd transaxle on my 857 with one of the B Series units. This would help me greatly as I use the 857 to mow with, and because of my MS, I have issues using the clutch/brake on the 857. One of the hydro units has all the various linkage needed for a transplant. 

[stevasaurus 22,881]

When you say "B" series...if it is a Sundstrand, it should bolt on and you may have to do a little sheet metal fabrication.  The input pulley needs to be on the right side of the transmission.  The reason I ask, Eaton and Peerless transmissions are also in "B" series horses and those may be for vertical shaft engines. 

[953 nut 55,874]

1 hour ago, Tgtack said:

two complete B Series hydro pumps and transaxles.

Are these tested, known to be good units? Hate to see you do all that work only to discover why the unit was removed in the first place.

[Ed Kennell 38,715]

I would  buy a running hydro   C-120  or 312.    Then sell the 857.   May be an even swap.  

[Racinbob 11,238]

Eds idea would be easier but if you're wanting to do this project it wouldn't be difficult but a fair amount of fiddling. But keep in mind what Steve mentioned. If the hydros came from a 78 or newer they are for vertical shaft lawn tractors. The B-series from 74-77 were horizontal and would be what you need.

[Tgtack 779]

They are the older Sundstrand units. One is still mounted to the frame with head stand and all linkage, so I should have pretty much everything I would need. I know I would need the smaller drive pulley with the bolt on fan rather than the large diameter pulley with fan made as part of it that is on the units. Also will need to modify or replace the head stand. So I guess it would wind up as an 877 clone. Supposedly they work, but for the additional $40 for two complete transaxles, I figure it is worth taking the risk.

Edited July 9, 2017 by Tgtack

[953 nut 55,874]

That is the correct pulley, but the engine pulley will need to be changed to the larger hydo one. Hope they are good.

[Tgtack 779]

3 minutes ago, 953 nut said:

That is the correct pulley, but the engine pulley will need to be changed to the larger hydo one. Hope they are good.

My current 1276 (no hydraulic lift) uses a smaller pulley on the pump unit. Do the Sundstrand units that also run the hydraulic lift system use the larger pulley? I am just looking to convert the 857 to "automatic" drive rather than manual shift.

[953 nut 55,874]

I guess the size relative to the drive pulley is the important thing, need to spin it fast for proper cooling. most Hydros I've seen have about a one to one relationship and the bigger the pulley the less likely it is to slip.

[Sarge 3,463]

I think up to '75 Sundstrand units will interchange , although there can be some minor differences in linkage and pulley sizes . Most of the differences are in the parking brake mechanism , but otherwise all the same parts . I may upgrade the '67 1277 to the later C-series piston to piston unit as it was much stronger and less prone to breakage than the early hydrogear version of those transmissions . The basic 4 bolt pattern never changed on the Sundstrand equipped tractors , so that helps a lot . You can spin that hydro to do a mild test with a heavy duty drill and a socket on the pulley , but be careful how much torque you apply as you can snap that small bolt off easily .

 

I say go for it if you can get complete units with all the linkage intact . It's a bit of a puzzle , but you can handle that part .

 

Sarge