The new mess. Exmark Laser HP 23hp with weak hydraulic drive.

[tomplum]

That's a nice looking machine. Seeing as though it is new to you, you may want to run it just to confirm that you didn't have an oil spill from the last guy. Or can you actually see the source of the leak?

 

[DK35vince]

I have the same HG pumps on my Cub Cadet Tank. What I would do before anything else is change the fluid on both pumps and change the filters at the same time. HG recommends 30 weight motor oil. I'd stick with that.

I have Hydro Gear pumps and Parker wheel motors on my Hustler Super Z and my manual calls for 20w-50 motor oil.

 

[5030]

I have Hydro Gear pumps and Parker wheel motors on my Hustler Super Z and my manual calls for 20w-50 motor oil.

My HG pumps and wheel drives are integral with each other. HG actually sells a kit with filters and oil for them along with a fitting that goes in the pump casting on top that facilitates the changing of the fluid.

 

[Rock Crawler]

That's a nice looking machine. Seeing as though it is new to you, you may want to run it just to confirm that you didn't have an oil spill from the last guy. Or can you actually see the source of the leak?

The right hand pump is the leak source. I cleaned all and ran it 0.6 hours and the right side is soaked.

View attachment 827087

 

[5030]

If mine leak (and they have in the past), they always leak on the bottom where there is an aluminum pressure die cast bolt on cover (bottom of the charge pump) and under the cover is an 'O' ring.

What I did was I replaced the 'O' ring but first I took a flat file and filed the removable cover flat as the casting(s) were a bit rough and bolted it back on. If you do that, you need to mark it as to orientation (I used a small punch to mark the casting and the body so I installed it correctly. If you install it backwards, the pump won't work. Neither of mine leak any more.

 

[Rock Crawler]

Temperatures settled at 170-175 for left and right pumps and 155-160 for left and right hydraulic wheel motors. Temps rose consistently left to right. So, nothing with the temp gun said that there is an obvious issue. I may look for a local dealer and have them spend an hour or 2 diagnosing it to see if they can tell me for sure.

Another minor issue is the hydraulic damper attached to the hand control levers. The one on the right side is completely dead and not offering and dampening. The left one has the working damper, and it also does better at returning to center/neutral.

It needs chains on the tires or needs ATV or ag style tires. I almost died a few times. Turf tires are scary and dangerous and should be legally relegated to the flat lands of the USA.

 

[RandyT]

Probably going to have to test hydraulic pressure to see if it's the pump or motor. I'd guess that's specific test equipment at a dealer.

My local hyrogear distributor has one that they will send to the dealers as a loaner. We pay for it and then get a refund after sending it back and we are out the freight for return. Don't price a hydraulic flow meter and pressure test set. The price will scare you

I have the same HG pumps on my Cub Cadet Tank. What I would do before anything else is change the fluid on both pumps and change the filters at the same time. HG recommends 30 weight motor oil. I'd stick with that. I have well over 1K hours on mine and no issues at all but I change my oil and filters every year. Both mine are driven by a common Vee belt with a spring loaded idler btw.

The Hydrogear factory oil is 20W50

If mine leak (and they have in the past), they always leak on the bottom where there is an aluminum pressure die cast bolt on cover (bottom of the charge pump) and under the cover is an 'O' ring.

What I did was I replaced the 'O' ring but first I took a flat file and filed the removable cover flat as the casting(s) were a bit rough and bolted it back on. If you do that, you need to mark it as to orientation (I used a small punch to mark the casting and the body so I installed it correctly. If you install it backwards, the pump won't work. Neither of mine leak any more.

Hydrogear came out with a replacement charge pump cover kit because the aluminum cover warps causing the leak that you describe.

And to @Rock Crawler It looks like the leak is low on the pump. Could it be the line coming from either the filter line or the return line to the tank. Could be cover leaking but would check everything to find the leak. And also as a side note your bypass valve is activated on the right pump which could be part of your drive issues. the bolt through the hex with the plastic cover needs to be turned closewise matching the one on the left.

 

[5030]

Hydrogear came out with a replacement charge pump cover kit because the aluminum cover warps causing the leak that you describe.

Actually, for me, it was an easy fix that I described. Additionally, last time I changed the oil in my HG units, I used 15-40 Rotella T6. The Tank is going away, anyway. Getting a diesel powered Kubota F20 in the spring as I really need the front mount deck as well as better economy as the Kawasaki 24 horse engine is a gas hog.

 

[Rock Crawler]

So, I watched a couple really informative YT videos of breaking these pumps down, what to look out for and getting them back together and sealed up. There really is not a lot going on in here, they are fairly simple creatures. I think I am going to order the seal kit and tear into the right pump. A common issue is that the pistons that ride on the swash plate get buildup in the bores and the pistons stick up inside. If you get 1 piston stuck, sounds like you may not realize it... but get 2 or 3 stuck and you really drop in flow and performance. They can be easily removed and the bores scrubbed with brake-cleaner and some fine Scotch-Bright. But you have to inspect it all and if if you have gouges or other hard part damage, you may as well toss the pump and buy new.

But I spoke to a fellow yesterday (chatted) on FB market who is selling this same model and he broke down the pumps, cleaned and reassembled at 780 hours and they have worked fine ever since. May as well at least try that with the $40 seal kit and some winter labor.

Right now I am still involved with a JD LA125, machined the crank and the aluminum sump last night from the previous owner running it dry with a failed head gasket. Next is get a brass sleeve machined to make back my dimensions and get that turd rolling. Then move to this Exmark and finally get my fathers 900 hour 2011 Craftsman Excellerator GT with locked up Kohler Courage 26HP V-twin in here and decide what I am going to do with that. It did not window the block, so I may be able to buy a new rod/piston assembly and bring it back. I hate mowers. They are all near junk quality today and made to last 10 years or so. Then there is the 1986 Cub Cadet that I have that still runs... back when they were made to last a lifetime.

 

[D&D]

. They can be easily removed and the bores scrubbed with brake-cleaner and some fine Scotch-Bright. But you have to inspect it all and if if you have gouges or other hard part damage, you may as well toss the pump and buy new.

Doesn’t cost anything to look and you cant break it worse since it’s already broke