New guy - Steiner S-20 problems climbing hills - only in forward...

[SteinerGuy]

Gents,

Long time reader, first-time poster.

We live in hilly terrain and mowing with my old lawn tractor was always a white-knuckle affair. While my other tractor, a Lamborghini Runner 450, would climb the side of a house if it had to, it's too heavy to drive over the septic system and on ag tires, it sure tears up turf, so that was out.

So, I started looking at several options and I found out about Ventrac and Steiner. I used to own a Pasquali 988, an articulated italian tractor, so I knew how handy an equal-wheel 4x4 artic tractor is, and how much tractive force they can put to the ground.

After looking around for a couple of months, I bought a rough and ragged Steiner S-20 with a blade and a 60" mower deck. Beat is an understatement. I'm slowly going through everything, rewired it, fixed a lot of bad welding, etc. Nothing too bad so far.

So, enough background - The issue at hand:

I got it running and mowing a while ago, and I tried "the hill", which is a very steep section I have always mowed downhill with conventional mowers. To my dismay, it struggled. The pump whined and I had to push very hard on the lever to keep it moving, and it finally stalled out completely, it would not move. I was a bit disappointed, figuring that the pump probably needs a rebuild.

And on we went, mowing downhill, not a huge impediment. Until today, where I tried backing up, as a fluke, and the darn thing walked up the incline like it wasn't even there, the back tires barely touching the ground.

Now, I've been racking my brain to try and figure out what's going on. The S-20 pulls fluid from the front axle, so it should run out of oil backing uphill, not driving uphill. I don't think the pump could work better in one direction than another, I figure if the pump elements are good enough to work in reverse, they should work in forward...

Any comments from you Steiner experts? Fluid level was, as near as I can tell, correct. Hydraulics seem to work well, it picks up the deck without any issues and the steering is strong (but it has trouble steering if you drive uphill, seems to steer better if you back uphill...)

I are confused!

Cheers,

Steiner Guy...

 

[pmsmechanic]

Now, I've been racking my brain to try and figure out what's going on. The S-20 pulls fluid from the front axle, so it should run out of oil backing uphill, not driving uphill. I don't think the pump could work better in one direction than another, I figure if the pump elements are good enough to work in reverse, they should work in forward...

To me it sounds like this answers your question. If you are driving down hill and the pump is pulling fluid from the front axle then this makes sense as the front axle would be lower than the rear. Therefor the pump would have a ready supply of oil.

I don't own a Steiner nor have I even looked at one so I don't have any experience in how they work. But if all the oil runs to the front axle while it's pointed down hill then it should operate the way you described.

 

[CobyRupert]

To my dismay, it struggled. The pump whined and I had to push very hard on the lever to keep it moving, and it finally stalled out completely, it would not move.

The S-20 pulls fluid from the front axle, so it should run out of oil backing uphill, not driving uphill. I don't think the pump could work better in one direction than another, I figure if the pump elements are good enough to work in reverse, they should work in forward...
...

I'm definitely not a Steiner expert, but I too am confused about why it would run out of oil if the source is on the bottom (i.e. front axle is on downhill side)?

Also, regarding your comment about pushing the handle hard and then it stalls, I may be interpreting this wrong, but you realize the less you push on the handle, the more torque it will have to climb. Or conversely, the more you push the handle, the less torque you'll have (but greater speed if on flat ground). As been said, think of the lever as gear, then more you push the higher gear you're in.
Example on my mower, reverse is a lot slower than forward (I'm not sure of the details, but in my mind I imagine that the reverse port of the hydro control valve is smaller as a safety feature to limit the maximum back-up speed). Thus at full pedal in reverse I have more torque (less speed) than full pedal forward.

 

[SteinerGuy]

I'm definitely not a Steiner expert, but I too am confused about why it would run out of oil if the source is on the bottom (i.e. front axle is on downhill side)?

Also, regarding your comment about pushing the handle hard and then it stalls, I may be interpreting this wrong, but you realize the less you push on the handle, the more torque it will have to climb. Or conversely, the more you push the handle, the less torque you'll have (but greater speed if on flat ground). As been said, think of the lever as gear, then more you push the higher gear you're in.
Example on my mower, reverse is a lot slower than forward (I'm not sure of the details, but in my mind I imagine that the reverse port of the hydro control valve is smaller as a safety feature to limit the maximum back-up speed). Thus at full pedal in reverse I have more torque (less speed) than full pedal forward.

Thanks for the replies guys. I too am new to this Steiner thing so I may be missing a piece of the puzzle. The thing has two transaxles that act as reservoirs. The pump pulls fluid from the bottom of the front transaxle, near the rear. The rear transaxle is plumbed into the front by way of a small 3/8 drain hose. The individual motors leak a bit of fluid into the transaxles, so an excess gets moved back to the front by gravity.

So, on a hill, all the fluid in the front would be moving back towards the pickup, I can't see it running out of oil. One question I had was how the system returns oil to the tank. It looks like there is a drain on the pump, that goes to the front transaxle, so the really should be nearly all the fluid that gets sucked out returning to the front transaxle.

Regarding it "stalling" - It's more of a slip than a stall, it just stops moving. In reverse, I have very little resistance on the control lever and I can feel the governor loading up and working the Onan hard. In forward, it seems like it just cavitates or leaks internally. It makes a lot of pump noise and I can feel resistance on the lever, which I don't see in reverse.

The next thing I try will be to replace the draw hoses, the ones that are there look really brittle and there is a kink that might be collapsing under high loads, but that still wouldn't explain why it works better backwards than forwards...

 

[pmsmechanic]

Unless one of the hoses is collapsing internally and it only draws form the one reservoir.

 

[Raw Dodge]

Ok,here is my 2 cents,having owned and operated these machines for 25 hrs,my educated guess is your rear motor is worn,you need to remove the rear motor and polish the s eat he's and grooves out is the rear fixed plate and polish the plungers then reassemble it all,and do high pressure loop flush..Another thing,make sure both transaxles are in low range when climbing...the S20 should easily climb anything in low range with strong hydraulics.IF your lift and steering are weak once the hydros heat up,that's another sign your rear hydraulic motor is weak....

 

[SteinerGuy]

Thanks Raw Dodge I was hoping you would chime in, read a lot of your posts about your early Steiners and the one you made about them relocating the feed line to the rear transaxle is what had me confused, since you said it would normally run out of fluid on downhills..

I think the rear motor definitely could be the culprit, if I understand correctly it would just bypass and lose all the oil into the rear transaxle if the valve plate was grooved up... I am familiar with the pumps and I think the motors are nearly identical (but with a fixed swash plate/cam).

How do you guys polish these? Do you send em out for power lapping or just do it yourself with plate glass and 1500 grit?

On the low range, the stickers are long gone, it has a lever on the rear near the seat, on the front on the right side. I think I have both in low, the shift shaft is pushed in for low on both. I have tried it every which way and that seems to work best...

Thanks again

 

[SteinerGuy]

Just to add to this, I decided to swap the lines at the pump tonight, to reverse them. I figured it would be the easiest way to figure out if it's a motor issue or a pump issue. Other than the controls being reversed (which took a few minutes to get used to) it performs the same, so it's definitely a motor problem.

Another thing I didn't mention - The previous owner had all the hoses replaced a while ago, and they may have screwed it up. Right now, the lower port on the pump goes to the rear motor, to the front motor, back to the upper port on the pump. I am not sure if this is correct or not...

 

[Raw Dodge]

Just to add to this, I decided to swap the lines at the pump tonight, to reverse them. I figured it would be the easiest way to figure out if it's a motor issue or a pump issue. Other than the controls being reversed (which took a few minutes to get used to) it performs the same, so it's definitely a motor problem. Another thing I didn't mention - The previous owner had all the hoses replaced a while ago, and they may have screwed it up. Right now, the lower port on the pump goes to the rear motor, to the front motor, back to the upper port on the pump. I am not sure if this is correct or not...

My advice is to never open the system unless necessary ,swapping the lines will allow contamination into the system,and yes you have areas motor problem,and you are correct the fluid simply blows past the swash plate and plungers instead of spinning the motor on steep hills. I usually use a nice peice of glass I got from an old home audio cabinet,and start with 320 and work my way to 1000 grit ,it can take 15-20 minutes of time easily if it's really bad. Luckily the rear motor is the easiest to get to and the previous owner probably didn't filter the closed loop system after replacing the lines. I know it's time consuming and costs a few bucks to put together a high pressure one way filter,but this is something you want to have on hand before you open the system again,if you do the work on the rear motor and reassemble odds are about 1 in 5 for success past 1 hour of operation...and next time you will have to remove both motors and the main pump and do them all,and buy a filter anyway. Right now your pump and front motor seem to be ok,so get a filter put together and fix it right once.

 

[prs]

Raw Dodge; do you know of any instructions for creating such a filter for future reference?

prs