Sloppy fit of output bearing Sundstrand Hyd. unit

Jim1934 · August 01, 2021, 09:29:27 AM

Tried all Mike's suggestions with no cigar.
Removed charge pump casting, with shaft vertical,
and it was wet but no oil filled the gap between adjacent gear teeth.
Outer gear 'stuck' to plate below, as one would hope.
Tried rotating casting 180 deg. but did not help.
Small gear is keyed to shaft as it should be.

So now I will change filter, double RPM, and make a sacrifice to the Cub gods.
Thinking about 'warming' stuck valve. Penetrants have not worked. May drill
1/16 hole thru existing hole in top hex nut for punch access.

Doubt if oil viscosity is the culprit.
Thanks to all. Jim.

mike_belben · August 01, 2021, 09:41:29 AM

Those big hex cartridges come out for replacement dont they?

If a tow valve is open i think its gonna allow the charge pump flow to bypass the high pressure section.

Were there any valves or check balls inside when you took it apart? Hydrostatic transmissions have replenishing devices and one way checks to swap out fluid and make it do the right stuff. Any chance you lost or installed any of that wrong?

Jim1934 · August 01, 2021, 05:53:06 PM

Trying to upload pix of valves. Spent many hours.
Have had a gallery with pix for a long time.
Trying to add pix to gallery now not working like I think it should.
Service manual states the two are identical. Not mine
On one the ball is held up towards top via a spring.
On other the ball is held down by, apparently, a spring above it.
Tomorrow I will swap locations.
No guarantee these are the correct valves.
I have not modified them. Removed o ring from one in anticipation of heat.

mike_belben · August 01, 2021, 08:57:11 PM

I really dont know the answer.

I think i would run the input with a drill and no valve cartridges in place to see if oil is coming up to them. Thatd atleast tell us if the charge pump is picking up or not. Maybe spin it both directions.

Jim1934 · August 02, 2021, 09:19:41 PM

Quote from: Jim1934 on August 01, 2021, 05:53:06 PM
Trying to upload pix of valves. Spent many hours.
Have had a gallery with pix for a long time.
Trying to add pix to gallery now not working like I think it should.
Service manual states the two are identical. Not mine
On one the ball is held up towards top via a spring.
On other the ball is held down by, apparently, a spring above it.
Tomorrow I will swap locations.
No guarantee these are the correct valves.
I have not modified them. Removed o ring from one in anticipation of heat.

Took valve apart.
There is only one ball.
I am now calling the hex end in pix "down" or "bottom".
R.H. valve is defective. Spring loaded actuating rod in bottom of valve was corroded ,
stuck down, and could never push the ball upward away from its seat. Ball in R.H. pix is
sitting on its seat which is below it.
Short weak spring above ball opposes the other spring.
Will repair and see if that is the solution. Have not tried your, Mike's, last suggestion-yet.
Regards. Jim

Jim1934 · August 10, 2021, 12:02:31 PM

Replaced one valve which was stuck corroded..
Now unit will run but in only one direction. Progress.

mike_belben · August 10, 2021, 12:57:54 PM

Swap valve cartridge positions and see if you get a corresponding swapped direction.

Jim1934 · August 10, 2021, 05:12:22 PM

Would like to but after sitting 4 hours it won't run in either direction.
Thanks for responding.

Jim1934 · August 11, 2021, 12:32:54 PM

Quote from: mike_belben on July 30, 2021, 03:06:01 PM
I dont know what the banjo is.

The hose loop is fine, no you dont need a valve in there.

My cartridge valves are different than yours so i dont really understand what youve got there. I own a cub with same pump but its 990 miles away or id go llook for you. Anything that seems stuck in there nedds to be freed up.

My first guess and hope, is the charge pump guts are too dry to lift fluid from the sump at that low rpm. Like those cheap hand crank barrel pumps. They never lift oil out of a drum until you wet the pump gets, then theyre fine.

So wet your pump guts. Pull that loop hose and fill it with oil then try again. If it still wont work, pull one end of the hose and get a pan to catch oil. Run it and see if you are getting any flow. I believe the passenger side (US based) fitting is the output. It comes from the charge pump. If its not flowing oil your charge pump cant supply your drive pump.

Test that first.

Aug 11 Noon.
Did the above a few days ago.
Removed both valves, ran charge pump and oil came out the top of one. Reversed dir of charge pump and oil came out of the other. Wary of the loop to aux. ports. Jim

mike_belben · August 11, 2021, 04:56:54 PM

QuoteAug 11 Noon.
Did the above a few days ago.
Removed both valves, ran charge pump and oil came out the top of one. Reversed dir of charge pump and oil came out of the other. Wary of the loop to aux. ports. Jim

Well thats good news with respect to your charge pump charging and your swash plate swashing.

If this fluid flow from the charge pump to the drive pump can now be directed to a load (the drive motor) and maintain pressure (by not having any relief cartridge problems that allow leakage back to tank) then you should be in business.

In between the valve positions are some pipe ports facing the sky. One is the charge pump regulating valve. Just a little BB or pellet with a spring. Have you been in there? If one of those is stuck open or pitted real bad the charge flow will have a path to tank and wont pressurize the drive pump.

I believe for the circuit to work you are going to have to take that flow out of the passenger side jic fitting and loop it back into the driver side fitting. You wont need a hydraulic valve in it.

Jim1934 · August 11, 2021, 08:54:44 PM

Have not been in those cavities plugged with hex socket heads. Will do so.
Loop (open) always installed. Did try closing it with C clamp but no difference.
To repeat- won't run in either direction regardless of swash plate movement or gear
pump rotation dir.

If that fails I will probably open the two main valves for inspection.
May destroy them buy that is ok. I tried repairing one by soft soldering
bottom can on with a Certainium alloy, 5x strength of normal solder and a
melting point of 420F. I was not careful with alignment but joint was ok.
I am aware of repair services. Thanks, Jim

mike_belben · August 12, 2021, 08:39:43 PM

Google this up.

sm2093 (Jul-73).pdf

Its a manual for the JD140 that i have. My phone is too low on memory to go finding the section but its a big file and should have a good theory of operations abd troubleshooting section on the sunstrand 15 pump

Jim1934 · August 15, 2021, 08:15:20 PM

Quote from: mike_belben on August 12, 2021, 08:39:43 PM
Google this up.

sm2093 (Jul-73).pdf

Its a manual for the JD140 that i have. My phone is too low on memory to go finding the section but its a big file and should have a good theory of operations abd troubleshooting section on the sunstrand 15 pump

Thanks. Will do so.
Internet been down for four days.
Removed 1/8 pipe plugs and nothing in cavities but oil.
Removed plug with 5/8 hex, also between main valves ,and it contains a spring and short rod but no ball.
However it looks obvious that the conical shaped end of the rod rod is pushed into a mating shaped hole by the spring
to accomplish the same thing.
Unit will only run in one direction and then only by one combination of the two main valves.
So far it will only run in one direction of gear pump. CCW looking into pump from normal drive side.
Conclude at least one valve is defective. It will only run when an original valve is nearest the flow
control handle. Used one I purchased is in the other spot. The letter "P" is stamped by valve nearest
flow control lever.

mike_belben · August 15, 2021, 08:34:47 PM

Without having known good cartridge relief valves, its hard to say whether they are the issue or something inside didnt go back together right. Ive never been in one and cant be of any help there. But i hope that manual has something inside thatll help.

The spring and little plug valve should be doing the same thing.. I cant honestly remember if mine was a BB or something else. I know i had to try many springs in mine to add on the aux high pressure pump fed by the charge pump. I kept blowing out the front seal on the addon pump, until i got that circuit down to about 10psi with a pen spring. Nothing to do with your setup. You want 500-700 i that circuit if i remember right.

The empty ports are for pressure gauges. A good next step for you in my opinion.

Jim1934 · October 02, 2021, 05:02:34 PM

Pressure at test port for gear pump measures 50 psig when
driving pump at about 1000rpm max. No provisions to run it faster.
Aux. ports jumpered open (passing oil) with a hose.
Output shaft does not rotate.
Had both check valves rebuilt and advertised as tested in a tractor after rebuild.
Changed oil.
When hydro is removed, I can rotate output gear with difficulty but it won't spin at all.

The 17 hp Kohler two cyl. runs ok on test bench.
Will build frame for the combo and assemble and if Kohler doesn't cause hyd. output
to rotate I will be looking for another hyd.

JIM.