Won't move when off

[wrg]

A friend has a PT 1418 that he rebuilt the engine on, that seems to be hydraulically locked when shut down. The engine was bad/apart when he purchased it. Checked that the front brake pins are disengaged, but don't see how to relieve hydraulic pressure to the wheel motors circuit. Unit goes fine forward, reverse, etc. when running, but can't be moved when "off".

He didn't get a manual with the tractor when he bought it, and I haven't been able to find much relevant info on line.

All the smaller general purpose lawn tractors I've seen seem to have a hydraulic bypass that can be activated to move the machine by hand when not running.

Is this condition normal for this particular machine, or is there a trick I need to learn about in order to move the machine when not running. Operating any of the hydraulic levers doesn't seem to release the hydraulic lock condition (at the moment non of the PTO connections are in use, so I'm not sure that's even a valid approach to the problem since it appears the drive motors and PTO hydraulics probably use separate pumps).

Any guidance would be appreciated. Thanks in advance.
Bill

 

[KentT]

It is hydraulically locked when not running. That is normal. Do NOT try to force it!

You'll likely need to put a bypass hose on the drive (often called tram) pump.

Was he given a short section of hydraulic hose -- approximately 18" to 24" long -- when he got the tractor? This is used to bleed air out of the system when changing the hydraulic filter and to bypass the tram pump. I don't know about the 418, but on my older 425 the ports to connect the bypass hose are on the front, right side of the pump, down below the hydroback control linkage that changes the pump volume.

My owner's manual is a few hundred miles away, or I'd offer to scan in what little it says on the subject. I suggest you call the factory. Terry in the service department should be able to walk you through it.

 

[ClintBlake]

I seem to remember being told there is a bypass valve that can be opened if you need to move the tractor with it not running. I was told this 7 years ago when I picked up my PT-422, but have never had a reason to need it so my memory is very sketchy. A quick call to PT should provide the answer.

 

[MossRoad]

As others have said, there should be a bypass valve on the pump. You have to locate it, and turn it with a wrench, I believe. It is either a nut or a cap screw. I can't recall. Call Power Trac and they will be able to quickly tell you where it is located on your model.

Also, as others have said, do not attempt to move the tractor with force unless this bypass valve is opened. You can damage the tram pump.

Welcome to TBN!

 

[Robert259]

On my 1430, directly behind the seat, there is a valve to which the hydraulic purge hose is connected when purging the hydraulic system. This is under the fuel tank at about the centerline of the tractor.

Directly behind this is the towing valve and two ports. Page x of my manual titled "Towing Instructions" says the following:

"The variable volume pump mounted to the bell-housing end of the engine is also the pump used to tow the machine. Open tow valve two turns if equipped. The tow ports shown below have 90-degree fittings screwed into the ports. Attached to the 90-degree fitting is another fitting with a steel cap. Remove the caps from the fitting in each port and screw the jumper provided into the fittings and connect the two ports shown in the following diagram. Note: Tow slowly, also note these ports can be used to check high pressure."

I have never towed my tractor, so I can't comment further.