Yanmar 336D Power Steering Question

[farmfun]

The 3110D I purchased had a diverter valve unit that failed. its a little (aprrox 5 inch square) box - I think with 4 lines attached bolted to the engine block. I replaced it and the steering has been easy ever since, even stationary - loader full or empty. Probably serviceable but I just swapped it out - my unit originally may have been mis-shimmed.

Being the sister of the 336 if you have cleaned the hydraulic lines, filter(s) and have fresh fluid - try it.
It cost me about 150.00 if I recall and well worth the performance added.

 

[Car Doc]

My p/s is very easy also its 1 finger operation most always under most conditions. And like Winston I am cautious turning with a load and sitting still. I usually move a bit at the same time turning. And by load I mean anything close to max weight what the loader will handle with dirt in bucket or the pallet forks on like 1.5k#.

The only reason is - I know that if I never break this tractor I will never have to work on it and subsequently have to try and find possibly obsolete parts.

I would check the diverter block also and try out the 3 pt if neither is working properly it could be a stuck open relief valve in the diverter block or even a plugged hyd filter. Maybe even a weak pump but check the easy things first and a pressure test like Kenmac mentioned may be mandatory for anyone here to help further? hth

 

[S Putnik]

Thanks everyone for the great info.

The plot thickens. On further inspection, I find that only the PS and lift are on original hydraulics. The loader and some accessory cylinders used as lift arm adjusters are powered by a crank-driven hydraulic pump under the battery. It's a pretty slick addition and I didn't recognize it for what it is until I started investigating a little aux. reservoir tucked under the front.

I guess what that means is that I can't use the loader as a point of reference. The lift works well, even with a 5' HD brush mower.

Things to check:

hydraulic fluid, filter, screens
diverter valve

Where are the rear hydraulic screens located? I am without a service manual for now.

 

[winston1]

Don't have a service manual but here is a parts manual. I doubt your screen is the problem if your lift is working ok. Not saying it may not need serviceing but be ready to catch bunch of fluid. I imagine that 336 holds 5 gallons or better. Someone with knowledge can probably tell you exactly. See figure 58 for your screen location (ref #49). http://downloads.pfgaustralia.com.au/intranetwebcache/Parts/Parts Manuals/Yanmar/Y00T2140.pdf

 

[Car Doc]

Diverter block is for sure my hunch at this point or a defective/leaking steering spool valve in the steering gear or stuck open p/s pressure regulator valve. And I say the spool valve presuming this is has one and it probably does since its an all in one unit. I have the manual I will look at it and see and post back.

It should be pretty easy to tear this valve down and see if anything is stuck in its bore. Lay it out on a bench and be super careful to lay it all out and not let any springs etc get away from you.

 

[kenmac]

There is control valve within the steering column.But, the relief valve and the flow control valve are within the divider block. I would check the divider 1 st to see if your even getting flow/pressure to the steering unit Per the manual....the flow control valve in the divider block assures priority in oil supply from the mail hyd pump to the ps unit. the controlled flow to the ps system is 1.5 gal. reguardless of engine RPM

 

[S Putnik]

Priceless info. Thank you. I wish this issue had a more obvious solution. The steering has loosened up some since I started putzing around on the tractor. But it's still really stiff toward the travel extremes.

I should try lifting the weight off of the front wheels and turning the steering wheel. I suppose the issue could be mechanical binding. This tractor has been used pretty hard, by the looks of it.

 

[winston1]

This could be of interest to some and since this is a power steering thread it seems like a good place to put it. Yanmar Tractor Support Message Board • View topic - DIY Power Steering Assemblies In Stock

 

[bunick]

So what did you figure out on your steering? Just curious!!

 

[S Putnik]

So what did you figure out on your steering? Just curious!!

Having more time to observe the issue I'm inclined to agree with the theory that the issue is the hydraulic divider valve. The symptoms are precisely consistent.

It hasn't been a high enough priority to get it replaced so far. It's just annoying.