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Hydro. Pump - Lazer Z

4K views 15 replies 9 participants last post by  Sharpcut 1 
#1 ·
I had one of our 2000 Lazer Zs brought in today. Said was mowing and heard a bang and then he noticed fluid leaking and it wouldn't move.

They brought it to me and we had to pull it off the trailer with a Gator because it would only freewheel a short distance and then the left rear wheel would lock up. Then maybe it would loosen up again and freewheel for a bit then lock up. I was able to drive it using the right wheel only up onto the hoist. If I tried to use the left stick, I would get a rapid clicking and I could feel it through the stick.

Ended up finding the seal on the pulley shaft for the left pump blew out. Leaked all fluid out. It seemed to spin the same as the other by hand. I put a new seal in and reinstalled the pump. Filled with the proper Mobil 1 15w50 oil. It still just clicks louder and won't move. I am guessing the pump is shot. The clicking is coming from the pump and not the wheel motor. But I don't know why I could sometimes push it and other times not be able to.

Any thoughts?
 
#5 ·
I'll give this a try,

Since the pump is clicking I'd venture to say it's imploded inside, The wheel motor will act as a pump when the pump is not supplying fluid flow.

So, Even with the bypass valve open if the pump does not let fluid pass through it (broken parts plugging internal ports) the wheel motor will hydro lock and prevent tire rotation.
 
#7 ·
I would get a rapid clicking and I could feel it through the stick.
Ended up finding the seal on the pulley shaft for the left pump blew out. Leaked all fluid out.
Any thoughts?
@ the least you will need a pump and the most a pump and wheel motor depending on what you find when you open that bad pump.
 
#9 ·
Thanks guys for the info. I guess I will be removing the pump, again, and take it apart to see what grenaded.

I can't screw it up much more since it probably already needs replacing.

Unfortunatly this mower is set up with our bagger for leaves and so now I also will have to convert the other Z to allow for the bagger to be used while this one is down. All while my supervisor is on me about getting snow stuff ready. I guess I should have started that back in July. I might be ready now.
 
#10 ·
anytime that input shaft seal starts to leak on the pump there is usually always something going wrong with the bearing right behind forcing it out and leaking. Unfort that has been hydrogears achiles heal on these pumps for years. You will need to replace the pump, and also flush your lines, reservoir, and pull your wheel motor apart. replace hydro filter and of course fresh oil. If you dealer has any, get the new Exmark hydro oil, its even better than the current Mobil 15w50 for hydro systems. The old 15w50 was awesome, but they have definately cheapened it down some in the last few years. Check for debris and damage sitting in the motor and either replace it if its damaged bad enough or clean/flush it really well and reassembly with a new seal kit.

I cant tell you how many times i have heard in 15 years i just put a new pump on and now the new pump is damaged along with the motor. As they ask for wty on the new pump, unfort we have to deny it because all that debris from the first pump failure came right back into the new pump from the motor/system that was never flushed or replaced.
 
#11 ·
I just pulled the pump apart. The actual pump itself looked fine. No wear, no debris, no damage. I pulled the rest apart and the all the pistons fell out of the piston block. No problem. I put them back in but one of the pistons does not want to fully extend back out when compressed. There was also small metal pieces on the parts and in the oil. Not good. The plate the piston block rides on was worn considerably. Althought the unit does have probably 2500 hours on it.

My next step is pulling the wheel motor and disassembling to check for damage. They might not want me to fix this machine since they want to buy another new one this spring. We'll see.
 
#15 ·
The almost has to be some scoring in the pump.
Yeah, the one half of the pump plate was worn and had a couple little chunks missing.

I ended up replacing the left pump and left wheel motor. Used Exmark Hydro Fluid. Everything seems to work fine now. Now the question is, when is the other side gonna go?

Thanks to everybody for your help.
 
#16 ·
I bet the inside of the wheel motor let go and wiped out the pump. Even if the pump was wiped out, once the dump valve is opened up, it should freewheel no problem. Sounds like the shaft broke in half, and now it is coming around and catching,then seperating.
Your shaft got wiped out in your wheel motor. Baggers put a lot of stress on the hydro's. You need to make sure the gas dampners are working correctly. One that is bad is like putting 5000 psi through your hydro's. At least thats what an Exmark engineer told me at a trade show yeasrs ago.
 
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