18 Auto-Hydro Failure?

["Manic-Mechanic" 1,266]

Hello,

    I lost power to my hydro both forward and reverse and up and down. Can the squash plate in the transmission motor go bad and cause both of these symptoms?

 

Edited August 21, 2017 by Oldman

[R. L. Addison 299]

No, the swash plate controls only direction, the lift pressure is supplied by the charge (or make up pump which primary purpose is to replenish lost oil due to leakage of the closed loop circuit) pump which has it's own smaller volume circuit. The open-center control valves allow this system to make up any shortage of oil when the valves are in center position (oil goes into closed loop [drive] system, or if no make up is needed,  back to tank (transaxle). I would check for a stripped coupling, broken coupling, or something similar. 

["Manic-Mechanic" 1,266]

Thank you. I replaced the pump and coupling when I rebuilt the engine. I thought the squash plate was for forward and reverse only but a Toro mechanic told me otherwise. I have the tractor up on jack stands and run it, moving the control levers and barely hear the pump and no movement, could there be that much air in the lines? Exhausted.......

[pfrederi 18,647]

There is a swash plate in the motor but is fixed.  it provides a hardened smooth surface for the piston block slippers to push against.

 

Do you have access to a hydraulic Pressure gauge (at least 200 PSI???)  Charge (makeup) pump pressure is first test.  Acceleration valves are always suspect.  You say you replaced the pump did you open it up??

 

see this thread..similar problems in a piston to piston unit.

 

[R. L. Addison 299]

Did you fill the pump case with oil? I do if they sit more than a day after service. The one on the table now I have filled, and it will be filled again before I start the engine. Three plugs in top of the pump /valve body, & I put a fitting in the center plug & pour oil in. Seems to me that goes to the charge pump & hopefully into the case also. I have to look again, but I think that's the way I did it last time.

["Manic-Mechanic" 1,266]

Well, I replaced the pump as all things pointed to this being the issue, now it's been noted that it's in the hydro motor? My original pump was still working when I swapped it out.Then she caught fire when the ammeter failed! I think this relationship wasn't meant to be.......I mentioned I  do this for therapy, now it seems it's the cause for anxiety!

 

Edited August 22, 2017 by Oldman

[pfrederi 18,647]

The joys of pump replacement on a D series...

 

Did you look inside the new pump before you installed it??  I have purchased several pumps and motors over the years...all claimed to be from good working tractors.  All of them had issues when I opened them up...some of them must have been towed to the junkyard they were so bad.

["Manic-Mechanic" 1,266]

Well, no, I didn't. As I said, the original pump was still functioning when it the hydro quit, just the spline on the shaft was deteriorating so I replaced the pump. I have the original and a shaft if need be to rebuild. I was thinking maybe the hydro motor is faulty? In any event, the hydro motor should be examined and or repaired then put back in. I had hoped to get some good results this way? Your probably correct though, I should remove the pump again and rebuild all of it, then it's a done deal. I am just getting worn down as I have been rebuilding this entire machine for several years now.......It took two years to find a good clutch and PTO parts, people will sell you junk-knowingly, as I have many "spare" parts on the shelf! Ha ha ha!

Thank you

["Manic-Mechanic" 1,266]

I am trying to find a good replacement for the seal part 102817, can anyone tell me the best replacement for that seal? Also, the pre-load may be in question on the hydro motor, the clip that is notorious for breaking, what clip is that, what part number? I never had the hydro apart so rather wait to find out I had hoped to order that in advance with the O-rings and such.......

Thank you.

[pfrederi 18,647]

The spring clip is 200204.  Where are you seeing the seal 102817??  I didn't see that on the piston to piston listing.  You do not have the external brake band on your machine do you???

["Manic-Mechanic" 1,266]

102617 goes under the head of the one bolt, securing the manifold. Nope, no brake band. Thanks for identifying the clip.The seal is item 4-67.

[pacer 3,177]

Those seals can be had from Mcmaster, but they come in 100 lots. Paulf (pfredri) bought a bag of them and has been very good about sending out 2-3 to the guys needing them (I'm one of em!) No doubt he'll be along soon and confirm this.

 

Dang, oldman, you really have had a run of bad luck!! I'm just coming off rebuilds on 2 of my D's and I am well aware of the pain on getting at that unit in the D's.

["Manic-Mechanic" 1,266]

Yes, it comes in three's! I am growing tougher for it, but still wine like a baby over my horse's........I am fairly new to D's, only had this @ four years. Well, if he is so inclined to send one then I will make good use of it!

["Manic-Mechanic" 1,266]

I did receive an envelope, many thanks going out to pfrederi. The hydro unit was sealed pretty good, needed some good o'l German persuasion, "push good & hard"! I failed to realize the top two bolts were case bolts! Da-hah! See the gear shaft protruding over 3/16ths, and it turns with some difficulty. Perhaps a broken spring clip? The strainer was semi-attached to the old gasket, good thing I didn't knock off  the hydro unit completely......

["Manic-Mechanic" 1,266]

Well, that was the culprit! The replacement hydro motor works nicely. Many thanks to forum members that helped me through the repairs! I ran the unit tow valve off, all directions and then closed the tow valve and again all directions, works wonderfully! Quiet too........