Testing a Hydro Pump and Motor

[Richard England 1]

So my D160 blew it's orings under the pump.  I replaced them, including backup o'rings, changed the oil and filter and it ran fine for a few hours.  Now I have no forward or reverse or movement at the lift cylinder. I put a pressure gauge to check the charge pump, also one at each release valve hose under the left fender.  All read zero.  The pump produces flow, not pressure, so is that okay?  I would think the charge pump port should be under pressure to feed the piston pump.  I thought that the maybe the charge pump is not getting oil?  So I changed the filter thinking that since it does not have a bypass, it could be restricting the flow of oil.  That did not work.  Of course not, the filter is on the return side. 

 

Next step I removed the pump, opened it and I don't see any issues. (of course I have never done this before so what do I know)   Next I removed the rear end, motor and transaxle.  I made a wooden plate to cover the 2 big power ports and the 2 small suction/return ports so I can pump air into the drive port.   That did not work.  I even noticed that air would come out of the oil fill on the tran case.  Should it have?  I decided to remove the motor and take it apart, I did not see any issues.  The transaxle looks fine, I can turn the gears by hand, and all the teeths look good.

 

So I have a few questions, but I really want to know how can I test pump and motor without oil?  If pics help I can take some.

 

 

[JoeM 7,874]

There will be an hydro expert along I figure shortly. The only time i lost all oil on mine was when the coupling input coupler failed. I know you said you had the pump off, so I figure that would have been obvious. 

[tom2p 2,394]

2 hours ago, Richard England said:

 

So I have a few questions, but I really want to know how can I test pump and motor without oil?  If pics help I can take some.

 

 

I can't recall any pump or motor tests performed without oil  

 

had a summer job decades ago at a hydraulics and pneumatics distributor that also had also a service area 

 

we rebuilt Sundstrand pumps and motors 

 

we had a test bench to mount and test pumps and motors - all testing, trouble shooting, diagnosing etc was performed while testing on this test bench 

 

Edited December 13, 2020 by tom2p

[pfrederi 17,866]

Charge pump [pressure minimum is about 50psi

Did you test per the manual?? 

 

Maybe issue with Charge pump relief valve opening to easily (bad/broken spring???

 

[daveoman1966 3,762]

A couple ideas come to mind: (1) The flow and pressure are created in the GEROTOR set on the backside of the Charge Pump Housing.  These two parts (Gerotor set) set in a cavity of the Charge Pump housing and MUST be perfectly flat and smooth on both sides.  If you machine the set down by .002, then the CAVITY must also be machined down by .002 to preclude oil bypass and pressure loss.  (2)It is possible to mount the Charge Pump Housing 180 degree off, in which case, there would be no fwd or rev motion...not sure about lift pressure. Look at the PIN shown in this pic.  (3) Did you use the correct OIL FILTER.  Some after-market filters may spin on and seal ok, but the internals may  not be to Wheelhorse specs.  The correct filter is 79-5270 on for about $13.  (4) Is the RETAINING CLIP on the MOTOR shaft in tact and positioned correctly on the shaft.         

[Richard England 1]

14 hours ago, tom2p said:

I can't recall any pump or motor tests performed without oil  

 

had a summer job decades ago at a hydraulics and pneumatics distributor that also had also a service area 

 

we rebuilt Sundstrand pumps and motors 

 

we had a test bench to mount and test pumps and motors - all testing, trouble shooting, diagnosing etc was performed while testing on this test bench 

 

I need to isolate the problem, so I might have to get an electric hydraulic test pump.  Do you know what the flow rate is of the Sundstrand pump?

[Richard England 1]

13 hours ago, pfrederi said:

Charge pump [pressure minimum is about 50psi

Did you test per the manual?? 

 

Maybe issue with Charge pump relief valve opening to easily (bad/broken spring???

 

Yes, I have the manual, thanks.  I used the port on top, above the temp port, -4 BOSS.  

[Richard England 1]

10 hours ago, daveoman1966 said:

A couple ideas come to mind: (1) The flow and pressure are created in the GEROTOR set on the backside of the Charge Pump Housing.  These two parts (Gerotor set) set in a cavity of the Charge Pump housing and MUST be perfectly flat and smooth on both sides.  If you machine the set down by .002, then the CAVITY must also be machined down by .002 to preclude oil bypass and pressure loss.  (2)It is possible to mount the Charge Pump Housing 180 degree off, in which case, there would be no fwd or rev motion...not sure about lift pressure. Look at the PIN shown in this pic.  (3) Did you use the correct OIL FILTER.  Some after-market filters may spin on and seal ok, but the internals may  not be to Wheelhorse specs.  The correct filter is 79-5270 on for about $13.  (4) Is the RETAINING CLIP on the MOTOR shaft in tact and positioned correctly on the shaft.         

 

(1) I will need to bust out the measuring tool for that.  Do you know of any measurements that are not in the manual that I should check?

(2) It was working before, but I will take notice of it when I reassemble it.

(3) I use the one pictured for my D160 and my D200.

(4) It was correct when I took it apart. On that note, I watched 4 video's from "CarterCreekFarm" on youtube about the motor.  When he resembles the "slipper body"(see pic) he installs the spring in it and retains it with a "round spring clip" (see pic)  My round spring clip was on the shaft.  

 

I really don't want to reassemble it just to find out it's still not working and I still don't know what part needs to be replaced.  Right now it's the pump or motor.

 

 

Edited December 13, 2020 by Richard England

[pfrederi 17,866]

If it worked after you replaced the O rings but then suddenly failed are you sure your relief valves and springs are OK both charge and implement???  if one is stuck open or the spring has failed charge pump would move fluid but it wouldn't build up pressure....

[Richard England 1]

2 hours ago, pfrederi said:

If it worked after you replaced the O rings but then suddenly failed are you sure your relief valves and springs are OK both charge and implement???  if one is stuck open or the spring has failed charge pump would move fluid but it wouldn't build up pressure....

 

I should have checked them before i pulled the pump.  I did put pressure gauges on the reliefs hoses on the motor and they read zero.   I could have used a flow meter, but did not want to spend the money.  When I disassembled them every thing looks clean (scratches/dirt).   

 

The only thing I found is that the spiral lock ring was not in the cylinder block. Now it might have popped out during disassembling or that may be the problem because it's mentioned in supplement 2 as a common issue. 

[daveoman1966 3,762]

YOUR COMMENT: On that note, I watched 4 video's from "CarterCreekFarm" on youtube about the motor.  When he resembles the "slipper body"(see pic) he installs the spring in it and retains it with a "round spring clip" (see pic)  My round spring clip was on the shaft

 If your Spiral Retaining Ring (# 200208) (your "round spring clip") was just laying loose on the shaft, then THAT very likely would be yor problem.  That Spiral ring can be had new for about $10.  It is the ONLY thing maintaining spring TENSION of the CYLINDER BLOCK (your 'slipper body') and 9 Pistons against the Valve plate.  If it is twisted or damaged in any way, it'll fail. 

The sequence is: Spiral Ring (200208), Washer(200209), Spring (200210).  From the pic, your WASHER looks ok.  If you need a NEW SPRING # 200210, they are NLA, but I have 3 of them available.  These pics may help:  NOTE..  I also have 3 of the RETAINING CLIP # 200204 available...new and NLA from Toro W/horse.  I can also order the correct oil filter 79-5270 if prepaid by you.  NOTE 2... In this color image, BOTH the SPIRAL RET RING (70) and the RETAINING CLIP (74) are JUNK...twisted and broken.  My direct email is:  daveoman@windstream.net

[Richard England 1]

@daveoman1966

 

This is a better angle of my spiral retaining ring.  I ordered a new one from mcmaster.  It looks to be the correct size.

Spiral Internal Retaining Rings for 1-1/8" ID, 1060-1090 Spring Steel 92602A160

 

 

I don't recall there being an o-ring #82 200205 when I took it apart.  I did ordered one yesterday for a whopping $20, but now I don't see a need for it.  

 

#83 83-3800 has an internal o-ring that I don't think is replaceable.  That one has some play to it, but does it matter?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited December 14, 2020 by Richard England

[daveoman1966 3,762]

As stated before, this is a source for OEM parts...the 200205 o-Ring is $13..  not $20.  The Spiral ring 200210 is $10.  

https://www.psep1.biz/arinet.asp?aribrand=TO#/s/TO//200205/1/

 

[Richard England 1]

I found some time today and put the hydro motor back together.  I was able to test it with compressed air alone, this did not work before, so it was the spiral ring.

 

[daveoman1966 3,762]

You did pre-lube that hyd motor before air-testing...right?

 

[Richard England 1]

8 hours ago, daveoman1966 said:

You did pre-lube that hyd motor before air-testing...right?

 

 

Yes I did.  Good point, I should have stated that.