Hydraulic leak - mower deck will not stay up

Mon Nov 11, 2013 7:46 am

Good morning gentlemen -

I spent an enjoyable afternoon yesterday dragging the lawn sweeper around with my LoBoy 154 - until it was time to put it away.

As I was cleaning everything up I noticed that suddenly the blade would not stay in the "up" position. Pulling the lift handle allows it to raise but almost immediately would drop back down to the ground. Holding the lift handle caused the blade to stay up and allow me to get everything parked and put away. (I should clarify that this is with the engine running; not engine off).

I don't see any visible (outward) signs of leakage. I've reviewed the "Hydraulics" section of the owner/user manual but didn't see a troubleshooting guide.

Does the hydraulic system have it's own fluid circuit? Or does it use the same fluid as the transmission/rear axle? Sound like a pump going bad? Is there a check valve in the system?

I have both lift items attached currently (both the mower deck and the snow blade are installed), which is the way I have run for the last couple winters.

Appreciate any input on where to start.

K

Re: Hydraulic leak - mower deck will not stay up

Mon Nov 11, 2013 8:09 am

The transmission is the oil reservoir for the hydraulic system. (one oil, shared use)
The valves are between the dash and the engine. Pull one of the side panels to access it.

Re: Hydraulic leak - mower deck will not stay up

Mon Nov 11, 2013 9:09 am

Not the hydraulic pump, if it were you wouldn't be able to raise the mower deck.

If you are not leaking hydraulic fluid on the ground, the problem is in the control valve or perhaps the external relief valve, depending on tractor serial number.

Check the control lever and linkage action - see if the spool valve returns past the center (hold) position when control lever is returned to neutral position.

Re: Hydraulic leak - mower deck will not stay up

Mon Nov 11, 2013 1:42 pm

Thanks, guys - I'll take a look.

One other thought that may or may not be relevant: I had the trans apart a couple weeks ago replacing a shift fork and dumped (and replaced) all the trans/diff fluid.

Any chance that an incorrect fluid level (either too low or too high) could cause this new problem?

K

Re: Hydraulic leak - mower deck will not stay up

Mon Nov 11, 2013 2:20 pm

Any chance that an incorrect fluid level (either too low or too high) could cause this new problem?
The hydraulic fluid level is easy enough to check. Remove plug on back differential plate and fill to that level. However, since system is working, don't think that is the problem.