Power steering issue

[draw54]

Having power steering troubles. Has to be related to cold temperatures. Did not have this problem last Winter. The tractor is housed in a lean-to shed, before starting I blanket it with a large tarp and place a milk house heater under it to warm things up for an hour or so before startup. Last couple of times the steering is frozen tight. I raise the the front tires off the ground with the FEL jiggle the wheels and gently tap with a sledge hammer after about 10 minutes or so the steering slowly responds and then starts acting normal. Just wondering what might have happened to cause this and possible maintenance remedies?

 

[Peter 315]

You might have water in the hyd oil or the front axle

 

[winston1]

You might have water in the hyd oil or the front axle

Ditto. Loosen plug #16 and see what comes out. 4WD EXTERNAL ^: Yanmar Tractor Parts

 

[rScotty]

Your tractor is giving you a fair warning. Yes, it sounds like water. In this cold weather I'd do the easiest thing that might work - and that would be to drain the front axle and put in new front axle oil. Use any regular multiweight detergent motor oil. Motor oil is more than good enough, & the high detergent will help scrub out any remaining water.
Some Yanmar front axles didn't come with dip sticks. Is so, fill the axle housing up until oil is up to the level of the rotating axle inside the housing. That axle is the first thing you will encounter by sticking a screwdrive down the filler hole.
Luck,
rScotty

 

[California]

Motor oil and not GL90?

 

[draw54]

I'll drain the front axle oil first off. I got 75-90 wt gear oil on site also plenty of motor oil so think I'll use the gear oil. Be a few days before I can get at it away for a few days. I do appreciate the input/suggestions.

 

[rScotty]

Motor oil and not GL90?

Yes, motor oil. The evidence is pretty strong that we are dealing with water in that front axle housing. My judgement is that getting every drop of water out of those convoluted bevel-gear housings is a whole lot more important than what oil we end up running in that axle housing. After all, if you look at old factory literature, Yanmar themselves never could decide which oil should be used.

Motor oil will do fine. It has the detergency to help form an emulsion to hold any remaining water in suspension until we can drain that out, too. As for the multiweight aspect, that's an advantage we also get with motor oil, and it's a big advantage if we are trying to deal with changing axle oil this cold winter. For you tropic birds, it's winter here in the non-california USofA. When the temperature drops into single digits, GL90 just doesn't flow well enough in the cold to even get it reliably into or out of the axle housing. Then try to figure out where the level should be when the GL90 has roughly the viscosity of honey. Add a sprinkling of wind-blown snow, and motor oil is easy to deal with by comparison.

We mentioned on this forum before that the whole subject of what lube for the 4wd front axle never was never really resolved by Yanmar. Reading through twenty year's worth of their technical publications, they are quite proud of having invented that type of 4wd front axle, but in their shop manuals they quite often recommend two completely different oils: using either a light oil and a heavy gear lube in the front axle ---and they do so without any word of explanation as to which to use or when. The only way that makes sense is that they thought chosing one over the other was simply common sense. So I'm sort of agreeing with the Yanmar designers . I personally think that those guys got tired of debating which oil to use in their new fancy axle and just ended up solving the problem by specifying two completely different oils. You don't have to be a lubrication engineer to see the problem: their nifty axle has lots of sliding bevel gear friction (GL lube indicated), and some ball and roller bearings (light oil recommended). The axle assembly also has some seals which operate "wet" continuously. Those seals will benefit from some of the motor oil additives & the combustion additives won't matter. There are good arguments in favor of a multiweight high detergent oil with additives there - and motor oil is an easy way to get it.

Bottom line is that a real front axle failure is almost unknown in Yanmars as long as the axle has any kind of lube in there at all (although leaky seals are common enough). Just get the water out - that's the important thing. Consider changing it several times.

End of rant. And btw, California....thanks for asking question.
rScotty

 

[California]

That makes sense.

I didn't realize motor oil will form an emulsion - easy to drain out - more readily than gear oil. Also didn't realize that some of the engineers considered motor oil acceptable.

Thanks for broadening our understanding!

 

[rScotty]

That makes sense.

I didn't realize motor oil will form an emulsion - easy to drain out - more readily than gear oil. Also didn't realize that some of the engineers considered motor oil acceptable.

Thanks for broadening our understanding!

A lot of engineering decisions are compromises. No surprise there.
Normally you don't want a detergent type emulsion-forming oil in a gear case - partly because you don't want any "wear particles" to be held in suspension. Without filtration, it's better if those particles just fall to the bottom and stay there. But water is a special case. Motor oil isn't perfect, but IMHO it is handy and good enough.
rScotty

 

[Billrog]

When you put heat for only an hr. or so your driving the moisture in cause frost on the inside of your housing. I don't know how cold it is where you are but when real cold it would take many hrs. ( 24 or more)to thoroughly warm everything up. Trans hydraulic oil would work well to replace gear lube in the front axle.