PT-180 Clicking or thunking from wheels under stress

[James23]

I would think if it was the Lovejoy slipping, it would also slip when he deadheads a hydraulic cylinder since all the pumps drive through each other.

But one way to test that theory would be to see if the loader will raise when the drive is ratcheting. If the coupler was slipping due to operator calling for drive torque then the hyd pump would also stop turning in unison.

I will give this a test this weekend before I tear it apart.

 

[MossRoad]

So forgive my ignorance here, I'm not an expert in hydraulics. The other hydraulic systems all seem to work fine and have full power, so I don't think it could be a filter / cavitation issue?

Either way, I will be attempting to tear it apart this weekend, hopefully that goes well....

The filter only feeds the charge pump in the tram pump. What they're alluding to is that if the filter is plugged/restricted, maybe the charge pump isn't making up the fluid for the tram pump, so when it attempts to build pressure as you push the tram pedal, it can't.

The other hydraulics aren't filtered, so wouldn't be affected.

 

[MossRoad]

Good luck on your tear down.

Remember, with hydraulics, cleanliness is key. So if you're going to crack open fittings, be sure they are clean before you do it, and be sure you have a way to plug the open fittings with something clean, and that you don't drop a hose lower than the tank, as you don't want to siphon your oil tank overnight. Common sense, that's all.

 

[ponytug]

So forgive my ignorance here, I'm not an expert in hydraulics. The other hydraulic systems all seem to work fine and have full power, so I don't think it could be a filter / cavitation issue?

Either way, I will be attempting to tear it apart this weekend, hopefully that goes well....

Ooops. I see that @MossRoad beat me to it.

So the filtration on PTs is different than many other hydraulic systems.

First a little background. The main drive pump system for motion is a variable volume pump that can send, you guessed it, variable amounts of oil out to the wheel motors in forward flow or reverse flow. It is basically a closed loop system. Some the oil circulating in that circuit leaks out in the variable volume pump and is returned to the tank. That would leave a shortage, except that there is a small pump that pressurizes (charges) the variable volume pump with oil. It is called the charge pump. The oil suctioned from the oil tank is filtered before going into the charge pump, and thence into the variable volume pump, and the wheel motors.

So,...it is possible that the suction oil filter has a problem, causing problems in just the wheel drive circuit, and not affecting the other systems. Does that make sense?

Again, my bet is on Terry.

All the best,

Peter

 

[m5040]

So is Terry telling you to remove the tram pump and ship it to Tazewell?

 

[James23]

So is Terry telling you to remove the tram pump and ship it to Tazewell?

Yep. My current plan is to tear it down and if that lovejoy connector looks good, ship the pump off to him for a rebuild.

 

[m5040]

For a 75 hour pump, I would lean to fix the problem. Everything else should be almost new unless foreign material ran through it.

 

[cqaigy2]

When i bought my PT, i had it for something like 2 months and noticed a lot of oil leaking out of the tub, it was coming from one of the pumps. I think it was the variable volume pump. It was a nice stream coming out of the shaft area. Sent the pump back to Terry/PT and they shipped one probably the same day i had my pump out of the PT.

I'm probably one of the people that Moss alludes to, about draining oil out on the ground, as i'd not plugged one of the hoses, just put a plastic bag over the end with rubber band. It slipped off what i had it propped up on, and drained a few gallons of oil on to the floor of my shop. It was such fun to clean up.

 

[ponytug]

For a 75 hour pump, I would lean to fix the problem. Everything else should be almost new unless foreign material ran through it.

Power-Trac will know once they open the case whether it is worth servicing. As it is functioning and not making noise except under load, I think that the odds are favorable.

All the best,

Peter

 

[James23]

When i bought my PT, i had it for something like 2 months and noticed a lot of oil leaking out of the tub, it was coming from one of the pumps. I think it was the variable volume pump. It was a nice stream coming out of the shaft area. Sent the pump back to Terry/PT and they shipped one probably the same day i had my pump out of the PT.

I'm probably one of the people that Moss alludes to, about draining oil out on the ground, as i'd not plugged one of the hoses, just put a plastic bag over the end with rubber band. It slipped off what i had it propped up on, and drained a few gallons of oil on to the floor of my shop. It was such fun to clean up.

Terry recommended I cap all the lines. I am hoping the local tractor supply store just has them in stock.

 

[oldnslo]

Do you have a hydraulic schematic for your machine?

Any idea on how the pump is controlled? Direct connection to the swashplate pintle or separate hydro- mechanical control? If separate hydro-mechanical where charge pressure is used to bring pump on stroke then loss of charge pressure could cause the fluttering but would usually provide some reduced drive speed.

Are the wheel motors geroler - geroter style? These are sometimes called Char-Lynn motors.

 

[m5040]

Terry recommended I cap all the lines. I am hoping the local tractor supply store just has them in stock.

I never seen hyd caps there. If not, look for a hydraulic hose making shop (you made be a future customer there anyways and it will be good to know where they are).

 

[James23]

I never seen hyd caps there. If not, look for a hydraulic hose making shop (you made be a future customer there anyways and it will be good to know where they are).

Thanks for the heads up. Just ordered a JIC 04 06 08 10 12 14 cap and plug kit from Amazon. Tractor is in a rural-ish location, I might end up spending half a day tracking those down, which wouldn't be fun.

 

[m5040]

I kind of said that because I just used mine today and the hose going to the bottom of the lift cylinder started to leak where they make a loop and tie it to the cylinder. Looks like fun to get at the hydraulic control valve end.
I have always thought of putting a electric diverter valve on it to give it that extra circuit like the big Power Tracs. Maybe the time is coming quicker the I expected.

 

[washita 425]

if the lovejoy coupler is slipping at 3600 engine rpm would it make a ratcheting noise?

 

[1944woodpecker]

Both forward and reverse. In reverse, the back wheels start doing it.

 

[MossRoad]

if the lovejoy coupler is slipping at 3600 engine rpm would it make a ratcheting noise?

I doubt it.

 

[1944woodpecker]

just wondering.... have you checked for possible loose lug nuts on your wheels? I had a problem with that on my Kubota when it was fairly new...

 

[MossRoad]

just wondering.... have you checked for possible loose lug nuts on your wheels? I had a problem with that on my Kubota when it was fairly new...

Watch his video and turn up the sound. The wheels aren't turning and you can hear the clicking when he applies pressure to the treadle peddles.

 

[James23]

Do you have a hydraulic schematic for your machine?

Any idea on how the pump is controlled? Direct connection to the swashplate pintle or separate hydro- mechanical control? If separate hydro-mechanical where charge pressure is used to bring pump on stroke then loss of charge pressure could cause the fluttering but would usually provide some reduced drive speed.

Are the wheel motors geroler - geroter style? These are sometimes called Char-Lynn motors.

I do have a schematic. Basically there are wheel motors, the treadle and the pump and the filter. nothing else of note (as far as I can tell).