Looking for some quick hydraulic help!

[aaytay]

I just finished a major rebuild of a CCC 2072 (basically a 982 with power steering and Kohler Mag 20) and we're having some difficulties I'm hoping someone can help with.

Here's what's been done to the tractor:
Hydro pump rebuild
Driveshaft bushing replacement
Power steering valve rebuild
Added electric fuel pump

Now that the tractor is back together, I'm finding that there is no hydraulic function at all with the engine running. The power-steering is not power assisted, the lift valve doesn't move when you actuate the lift lever, and the tractor itself will not move when the hydro lever is moved. (I have confirmed the shift linkage is correct and in place as it should be.)

This is the second hydro I've rebuilt, so I immediately suspected the charge pump was put on upside down, so I pulled the hyd. lines, and was able to spin the charge pump 180-degrees (without removing the driveshaft....never knew you could do that!) with the thought that maybe I installed it upside down. Not only did that not help, but once we restarted the engine, it began spitting hyd fluid through the tiny vent hole in the hydro dipstick cap, so I knew that wasn't right and I spun it back the way it was. I've also jacked the front wheels off the ground and cycled the steering back and forth many times with the engine running, hoping to purge some air from the system, but that didn't help either.

So, the tractor doesn't move and snow is on the way (this is my snowblower rig). What could be going on here? Is it possible this could be an issue with one of the automatic hydro check valves?

Any thoughts are appreciated...

 

[kmcconaughey]

Art, sorry to hear the 2072 is having issues. Wish I had an answer for you.

 

[aaytay]

Thanks Kraig. I'm sure I'll figure it out.

 

[jstorma]

aaytay,

That's not a good feeling at all after all that time of going thru it.

I'm not a hydraulic pump guru, but did you happen to check and set the relief pressures with a gauge for the charge pump and lift? They could be set so low they are opening and just recirculating hydraulic oil. Might be a good check to start the engine for about 10 seconds, shut it off un-thread the filter and see if there is oil in it. At least you know the charge pump is working.

 

[kmcconaughey]

Maybe send Steve B an email, he’s probably encountered something similar.

 

[mgonitzke]

Take out each release valve and pour Hytran into the holes until you can see it coming up to the depth of the valves, and then screw the valves back in. Turn the driveshaft in the direction of rotation a couple dozen times. That *should* prime the pump. At the same time, I'd also verify everything is connected correctly at the steering unit.

I would not mess with relief valve settings. If it was correct previously, it probably still is now, or at least is close enough to correct that it's not going to cause issues.

 

[aaytay]

Thanks for the thoughts Matt. I appreciate it, and I tried that tonight. Pulled the release valves, dumped in some Hytran and reinstalled. Unfortunately that didn't help. Still no action from the entire hydraulic system.

Is there anything I can do to test the functionality of these (auto) release valves? (With the older style you can at least push the plunger down and make sure it pops back up.)

I also pulled the hydro filter just to make sure it was getting fluid and can confirm, yes, it's getting fluid! LOL

This showed up in today's mail. After this storm blows through I hope to get the necessary reducer and check the pump pressure. That should be telling about what's going on here.

Dad came over last night and we pulled the mower deck off the 1872 and slapped the blower and turfs with chains on so we're good for this storm.

Keep the thoughts coming!!

 

[mcafone]

you can still check those automatic valves. You can take a small nail and push that ball down from the tip. It should move a little less than a quarter inch. It should then spring back up on its own. If the ball doesn't move there's your problem. But I've never seen one freeze up and not leak.

 

[ccarney]

Art I wish I could offer expert advice but being more of a clutch-gearjammer cubber I can only offer sympathy. Will keep posted to see how your diagnosis turns out.
Craig

 

[kmcconaughey]

Wasn't there someone years back that left a rag inside the rear end after cleaning it out and it plugged up the outlet to the suction tube?

 

[dschwandt]

When you say you rebuilt the hydro...
What exactly did you do??

 

[aaytay]

Wasn't there someone years back that left a rag inside the rear end after cleaning it out and it plugged up the outlet to the suction tube?

You're not helping McConaughey!

When you say you rebuilt the hydro...
What exactly did you do??

New seals.

 

[balbrecht]

Art,
Can you cap off the lines coming out of the pump and basically isolate various components? i.e. see if it moves with the lift and power steering out of the loop. That might help isolate where the issue is.

 

[aaytay]

Art,
Can you cap off the lines coming out of the pump and basically isolate various components? i.e. see if it moves with the lift and power steering out of the loop. That might help isolate where the issue is.

Thanks Brian. That's a great idea!

Having said that, I think I may have found the problem. This is with the engine running:

So, either Kraig is correct and there is some kind of blockage, or there is some kind of internal issue inside the pump. I'm guessing the pump needs to come out. Grrrr....

 

[mgonitzke]

DO NOT cap the ports on a ported hydro. They should be connected together with a small loop of tubing, if one is wanting to test things without the tractor hydraulics connected.

The only way it'd be 100% safe to do that without causing damage to the transmission would be to swap in the relief valve parts from a manual lift tractor that had the ports capped off. There are some different parts in the implement and charge relief valves on those.

 

[ibyers]

My brother in law just had the same problem after changing fluid and filter on his 1863. Problem was using the wrong filter (Automotive oil filter) After replacing it with the correct filter, and cycling each hydraulic component a few times to purge the air, it worked fine.

 

[mmasheris]

Make sure the hyd lines on the steering valve are not reversed been there done that it will give you a condition like you have

 

[aaytay]

MYSTERY SOLVED!!!

I decided to bite the bullet and pull the hydro pump from this tractor to see if I could figure out what the problem was. First the charge pump got pulled off the front of the pump, and that looked perfect, so it was time to separate the pump halves. That's when it was obvious...

Look at the center of each "cylinder". Notice how the lower one on the right is missing its center?

Left:

Right:

It turns out the center spring got pushed out when I was installing the pump. (Facepalm!)

Here it is with the "guts" pulled out. Without this spring action, the cylinder cannot keep in contact with the plates, so that makes for a total loss of hydraulic pressure inside the pump. This happened when I was installing the pump and didn't get the pump output shaft to mesh with the gear inside the transmission.

Luckily there is another hydro pump here in the shop, so I opened it up and pulled the cylinder from it as this set up has a wonky split ring that is almost impossible to reinstall.

This entire issue came about because this tractor has a hard cab on it. Because of the hard cab, you can't pull the fender deck. That normally wouldn't be a problem, but this tractor also has a rear PTO, so when you're reinstalling the pump (with one hand because the cab is cramping your style) you're needing to thread the pump output into the transmission while at the same time get the rear PTO shaft to hit it's mark on the top output shaft on the back of the pump. I managed to get the PTO shaft to find it's home, but apparently the pump output didn't mesh with the bull gear in the transmission.

Needless to say, I've already reevaluated the install procedure once I get a new gasket and reassemble the pump.

 

[kmcconaughey]

Art, good to hear you found the issue.

 

[dschwandt]

Art,
You still have that unit apart?
If so, could you post a picture of the back side of the unit and tell me if it looks like this one, with no holes in the mounting flange?

Picked up this ported unit a few years back and just now got around to checking it out.
Unknown what it came from originally, it has remnants of grey paint on it but no sign of any yellow.
Numbers on the tag say 90-1225-CCW and A-88-49-14816
No idea what those mean either except the CCW probably means counter clock wise.
Thanks!