Hydro Question, please answer....

[KB9LOR 4]

On my Electro 12 it does not have any power on a incline, but has more than enough for the lift, now would the problem be in the pump(which I don't think it is) or in the Valve body? I am leaning towards the valve body, now what do you all think? If you rebuild one what is to rebuild? the pump and valve body? is there anything else? I have a chance to buy a pump and Valve body and am thinking of doing it, but wanted to be somewhat sure of replacing those would fix the problem. any ideas? your answers are appreciated!

Brian

Okay guys, I know there has to be someone on here who has or does rebuilds on these Hydros, I have seen the posts, Don't be shy,chime in here, I could really use the help.

[wh500special 2,240]

I've never been inside a Hydrogear transmission like is on your Electro, but I've done a couple of the later Sundstrand Piston-Piston types.

Chances are your pump and/or motor is shot. I'm leaning towards the motor. You can remove the motor portion - which I believe to be a piston type - and polish all the valve plate surfaces (on the bronze face) to remove scratches and swirls. Either take the valve plate to a machine shop with a surface grinder or get a heavy piece of flat glass, put it on top a FLAT workbench, and cover it with a piece of 1000 grit or finer crocus cloth. Gently - without applying pressure - polish the plate until it is smooth a shiney.

Loss of power in a hydro is almost always a consequence of getting some dirt into the system. The first thing to wear is the bronze valving plate and if it isn't too bad it can be rejuvenated with a polish. Be sure to also polish the bottom of the cylinder block assembly too and the faces of the "slippers". You want to make sure everything goes back in the original holes when you button it back up.

You need to get a transmission repair manual to show you how to disassemble and reassemble things. Check eBay or post a "wanted" here. All of my stuff is boxed up and I can't find mine to copy/sell to you.

As far as I know, parts are NLA thru Toro. I was told recently that rebuild parts ARE available thru Sundstrand, but they can add up to $700+ pretty quickly. If you put any effort/money into the situation BE SURE to remove the transaxle housing and thoroughly clean it out so you don't repeat the process.

I am NOT an expert on these things, but feel free to ask any questions you might have. I'll help if I can.

Best of luck!

Steve

[pfrederi 17,930]

Is yours a piston to piston or hydrogear unit????

The diagnostic chart for the piston to piston calls for a pressure test. The fact that your lift works is a quick and dirty diagnostic. The diagnostic table (one of 8 pages of tables in the manual) sort of indicates if your charge pump pressure is OK it is repair by replacement of either the motor or pump valve plates (which may not be available separately from the cylinder and piston assembly).

If you have a hydrogear unit the diagnostic table is an eye chart run amok but most lead to a hydro gear tuneup as first fix....

Hydros are nice but when they go south....

I prefer my 8 speeds

[KB9LOR 4]

That is something I have not checked yet, going to go ahead and pull the trigger on a good pump and valve body and just replace both and see what happens.

Brian

BTW- Isn't the 69 sundstrands gear? I read somewhere up to 72-73 they were gear and after piston.

[kpinnc 12,707]

BTW- Isn't the 69 sundstrands gear? I read somewhere up to 72-73 they were gear and after piston.

Hydrogear, yes. Your dates are correct as well.

The Automatic Transmission Repair Manual is still available from Toro.com as a free download. It should be listed on the parts page with any of the Sundstrand-equipped tractors.

Kevin

[KB9LOR 4]

Thought it was, and did pick up the manual for it also, thanks everyone! this is why this site is so awesome!

Brian