Hyrdostatic drive leaks

[StanS]

Fred reassured me about a leak in my 3112H hydro drive after I read here in April about problems with the pintle shaft bores/bushings. (Thanks, Fred) My nearby mower mechanic suggests that using automatic transmission fluid instead of hydraulic fluid for the hydro drive may cause or aggravate this problem. The transmission fluid attacks the bushings (bronze?) and causes leaks; the hydraulic fluid does not. My "helpful" previous owner had said to use standard GM automatic transmission fluid...! I hope this helps others avoid making this mistake!!

[Fred]

[DoubleT]

Hi Paul, I also have a 3212H and was told the same thing about the trans fuild. I really don't know for sure what the difference is from the standard hydro fuild other then the high detergent base of the trans fuild. That in it self might attack the bushings but I just can't imagine so. How much does someone want if you don't mind me asking to fix such a problem as yours? I was given a price of about $300. to put all new seals-hoses-bushings. But this did not include replaceing anything major. Best of Luck and thanks for the enformation-please if you would keep us abreast like you have of any and all problems or fixes. I did have a line on a good used one-but it may be gone now and it was not a leaker either. I think $200 might of bought it. -->Thanks->jackl-or->happyjack<-

[Les]

Proper fluid is Type F trans fluid and if I remember correctly (and I may not) the problem is an o-ring seal that is eliminated by machining new bushings.

[Les]

Paul, Jeff is correct,theproper fluid is Ford type F auto trans. fluid. It is heavier in viscosity than type A. As far as pintle shaft leaks,he's also right the only true fix is to get the housing machined for bushings to truly stop leaks.A temp fix that I used is put an o-ring on the leaking shaft,a close fitting washer behind it and a hose clamp behind that. Sometimes that "Rube Golberg" fix works for a while, but only temporarily. Regards dlc

[Guest]

"Oh what a tangled web we weave when first
we practice to resleeve."
Truly anonymous

I posted the note back in April that seems to have started the leak discussion.
I've gathered a little info. to share. I got manuals from Simplicity. For ~$25
they sent me a User's Manual on my 3112H, the mower deck, and front blade. Very
courteous and prompt. See their web site for the phone number.

The 3112H User's Manual says, "Use only Dexron A.T.F. (Automatic Transmission Fluid)
which is available from several major oil companies." The Large Frame Garden
Tractor (Landlord, Sovereign, Baron, 7000 & 7100 Models) Repair Manual has no fluid
spec. for the Vickers unit but in the Sundstrand section says, "Type A, F, or Dextron
automatic transmission fluid." I assume they mean Dexron.

So there it is from the horse's mouth. However, these manuals are old and some of the
advice offered by others may be more up-to-date.

[Al]

We have had a number of these cases redone, a coulpe of points to consider. The case wears because of steel against cast iron. It does not wear where the o-ring seals. When it is set up in the mill to bore it you need to dial in on the place where the o-ring contacts the case. Putting a ground shaft through both holes and dialing on it works. If you don't, you won't get the holes centered. Also don't use oilite bushings. as they are porus and let the oil weep through under the charge pump pressure in the case. Once bronze bushings are installed they are forever, much longer than the original cast iron. The final finish needs to be line honed with the equivalent of a Sunnen pin hone. Making the bushings about 1/8" longer than original and beveling the outer end of each bore about 2 degrees for this 1/8 th helps prevent shaving the o-rings on reassembly due to the snug fit needed. Good luck,
Al