4000HD digs but doesn't steer

[mike bruns]

I got my hydraulics working good with help from John Bud and guys on here. Adapted a new front hyd pump and sealed all the leaks on the power steering. After a few hours working good the steering is heavy.It still has some power but not effortless like when I first got it going.Maybe debris in the relief valve?
Thanks,
Mike

 

[souNdguy]

pressure test the system.

soundguy

 

[john_Bud]

What fluid are you using in the PS system? It is not normal car PS fluid. I am using a trans/hydro fluid in mine. There isn't much in the way of cooling and as the fluid heats up, it thins out. The result is exactly what you describe. You can thicken up the fluid a bit too.

However, i would first flush the system out completely. It's a PITA and messy to boot! Take the cap off the PS pump. Take the return line off and direct it to a collection bucket or jug. Cap the line at the pump. Then crank the engine over until the PS reservoir is about empty. Refill. Do that until the fluid coming out is clear. Then Crank the steering wheel all the way to the left and hold it there against the stop. (It helps if you were smart and lifted the front end up with the loader before starting...). Then do the crank the engine and fill the reservoir dance. When the fluid is clear, crank the steering wheel to the right and hold it against the stops and flush.

Repeat that after about a week. It should be mostly clear this go round. If you are getting a lot of "stuff" out you may have seals failing in a cylinder or inside of a hose. If it is cloudy, it is water in the system. Can also be rust.

After doing the flush - it should be better. If not, try the thicker fluid.

 

[mike bruns]

I'm using the same fluid as the hyd system. M2C41. It's mostly new because it blew a couple of hoses but it's cloudy so i'll try flushing it.The filter is clogged ruined so i'll change it to.What is a heavier fluid to try?
Another question...When running the hoe the tractor likes to be almost full throttle to dig the best. Is it designed to run that way? The engine and hyd pump stay cool, I just feel sorry for the old machine.Amazing how much dirt this old dinosaur will move.

 

[sotxbill]

pressure test it and consider adding a cooler.

 

[john_Bud]

If cloudy, definitely flush it out and put in a new filter. Smart things to do. You may have to flush it more than once if it has particles in the flow. The clearances in the control valve (in the column) are tight and don't like floating garbage. Remember that you HAVE to hold the steering wheel over against the stops while cranking the engine and keep doing that until the flow going out is clear. Two people makes the job pretty easy as one can stand there and keep the PS reservoir full, but I do it alone with a LOT of getting on/off. The system is not really sealed very well and it likes to be flushed every year or so.

I use hydraulic fluid of a higher viscosity to thicken it up. The spec on the M2C41 is about 48 iso or around 30wt (IIRC). A 60 iso or even 100 iso can be used or blended. It will help seal a system that has some wear and restore operability by reducing bypass loss. Sure, a better solution is to rebuild the entire system, but that's a lot of $$. This does help, but you have to be aware of how thick it gets in the winter and may have to change the fluid spring/fall.

I can use the hoe effectively at 1500 rpm. It get's a bit "twitchy" at 2000 and used a lot more fuel at that speed too -- without being much more productive. Most of what I do is at 1500-1700 rpm with the hoe. For the FEL, the throttle is set to about 1000-1200, and use the foot throttle to modulate travel speed and lift speed. But, there is a rather steep climb up / down to where I dig. Slow speeds give give better control and make it more comfortable as the hoe feels pretty tipsy with all that metal sticking up.