Question re: Steering Cylinder Seals

marrt · Feb 18, 2006

When I bought my first PT, I got about 150 hours on the steering cylinder seals before I had to rebuild both cylinders. The steering got progressively worse until I had to move the steering wheel quickly, or run the engine at full RPM, to steer. I have an 1845 now and with just over 150 hours on the steering cylinders, they are starting to get sluggish. I pull an Acrease wing mower and this puts extra work on the steering cylinders I believe. I was thinking about taking the front bolt lose and spinning the cylinder arm 180 degrees to see if that would get me a few more hours. Charlie, if you’re reading this, I remember you have an Acrease…have you changed the steering cylinder seals yet? I think I remember Sedgewood saying he changed one on his 1845 at relatively low hours. I’m curious to know if 150 hours is “normal” as that’s my experience with two difference machines now.

SnowRidge · Feb 18, 2006

I would think there couldn't be too many tasks that were harder on the steering than what I do, which is make a lots and lots of 180 degree turns mowing tree plantations. Most of the turns are full lock, too. So far, I haven't detected any difference in the steering of our PT-425 after nearly 250 hours.

BobRip · Feb 18, 2006

I am at 500 hours on my 422 and have not seen any problems.

Bob Rip

MossRoad · Feb 19, 2006

200 hours on the 425 and no problems. I almost always run at full throttle.

KentT · Feb 19, 2006

312 hours and counting on PT-425 and no problem with the seals... have replaced one steering hose due to abrasion.

Charlie_Iliff · Feb 19, 2006

I'm coming up on 400 hours with no steering cylinder problem on my 1845. I did lose one hose.

DHS · Feb 19, 2006

marrt,

My PT-422 has 480 hours with no external oil leakage on the steering cylinders. However, I feel my steering is slowly becoming more sluggish or I am becoming progressively weaker at faster than anticipated rate.

Am I correct to assume you had no external oil leaks on your steering cylinders just slower reaction? Internal cylinder leakage makes the cylinders sluggish? My lift cylinders are not sluggish so I have been wondering about the cause of the steering cylinders. Were the seals hard to replace?

Thanks for sharing you problem. It got me thinking about mine.

Dale

Highridge · Feb 19, 2006

I've got a PT 1430 with 238 hours and the steering seems fine. I did have to replace the steering valve at 190 hours and I replaced two worn steering hoses.

marrt · Feb 20, 2006

All, tx for the responses. DHS, yes, I was talking about internal leakage. This is usually discovered by sluggish steering response. If you have a spinner knob on your steering wheel, you can also see the problem. For example, if the spinner knob is normally at 3 o’clock and you find that it progressively moves around the dial as you mow, this could indicate some “blow by” in the steer circuit. On my 425, it got so bad that I could slowly rotate the steering wheel around the dial while the engine was idling without the cylinders moving. That’s actually the best way to test it. Make sure the hydraulic fluid is hot. Leave the machine on idle, and very slowly rotate the steering wheel while you are stopped with the tires on pavement and the emergency brake on. Increasing the engine speed or the speed which you rotate the steering wheel will reduce the effectiveness of the test. I suspect a lot of folks here with high hours would find some slippage with this test. Would be interesting to know. I think the seal kits are about $12 each. They aren’t too hard to replace. Especially if you don’t mind using a pipe wrench on the aluminum cylinder cap. /forums/images/graemlins/wink.gif

KentT · Feb 20, 2006

( That’s actually the best way to test it. Make sure the hydraulic fluid is hot. Leave the machine on idle, and very slowly rotate the steering wheel while you are stopped with the tires on pavement and the emergency brake on. )

Doesn't the emergency brake "force" the steering cylinders to bypass, at least somewhat, since it prevents the front of the tractor from moving...

pajoube · Feb 20, 2006

Thanks for the infromation, very interesting. If the weather warms up I will try the steering wheel test as I think I may have some slippage as the spinner knob will change a little.
PJ

SnowRidge · Feb 20, 2006

For example, if the spinner knob is normally at 3 o’clock and you find that it progressively moves around the dial as you mow, this could indicate some “blow by” in the steer circuit. 

But it could also be normal. All hydrostatic steering setups have some degree of steering wheel creep, even when they are brand new, since there is no direct mechanical connection between the road wheels and the steering wheel. Folks who are used to power steering on cars and trucks, which do have a direct mechanical connection, sometimes become concerned when they first encounter this phenomenon.

Just thought I would mention it before someone became concerned because his machine has a little steering wheel creep. /forums/images/graemlins/grin.gif

MossRoad · Feb 20, 2006

I've noticed that my spinner knob isn't always in the same place when going forward. I have no concerns. The thing still responds like it was new.

marrt · Feb 20, 2006

Agreed...that's why I said "could". /forums/images/graemlins/smirk.gif But if it moves around the dial like I suggested, particularly if it does this each time you use the tractor, then I would bet it's "likely" you have some blow by. In ether case, it’s not really a big deal if it doesn't bother you. And as you note, some blow by is probably normal. If it gets bad, it will be dangerous. But by then, there’d be no doubt that something was wrong anyway. My experience is that it gets progressively worse so there’s plenty of time to take action.

DHS · Feb 20, 2006

marrt,

My steering cylinders are in the beginning stage of sluggishness. I believe this summer or fall I will replace my seals. Did you purchase your seals from Power-Trac? Since they have a $50 minimum order I might have to find another source.

Thank-you,

Dale

marrt · Feb 20, 2006

Yes, I purchased from PT. In fact, PT makes these cylinders if you can believe it. I don't see how this could be economical but I guess it works for them. The hard part is getting the cap off. It screws off but mine were on really tight.

SnowRidge · Feb 20, 2006

And as you note, some blow by is probably normal. 

It's my hunch that the normal creep comes from bleed by in the steering valve, not the cylinders -- but it's no more than a hunch.

J_J · Feb 20, 2006

I am a little curious why you think the cylinders are leaking. It could be the steering valve or a priority valve in the steering valve, which lets fluid go to the lift arms if you are not steering. With the engine off, can you make the PT move left or right. At the end of steering, does the steering wheel keep on turning, very slowly?

marrt · Feb 21, 2006

The main reason I think it’s the seals is because that’s what it was before with the same behavior and that’s what I’m hoping it is this time (because the steering valve is much more expensive). I haven’t tried to move the steering with the tractor off. Before, Terry told me this put a lot a strain on the steering valve and not to try this test more than once or twice. I haven’t tried the end of steering test ether. When it warms up, maybe I should try it.