851 Power Steering Issue

Quick Summary - Power steering quit working in the winter of 2007. Once the weather warmed up it started working again after turning the wheel locked-to-locked a few times. Ran all of last summer without an issue. Backed it out of the barn in December, it worked, pulled it forward and power steering quit again. I had a leak at one of the lines. Tighted the nut and turned the wheel back and forth to try to get any air out. If I turn the steering wheel slow, the power steering seems to work as I can turn the steering wheel with 1 finger. If I try to turn the wheel at a normal speed, it does not work. Pulled the reservoir apart and discovered the filter was slightly off its seat so all of the return fluid was not going thru it. Any ideas would be apprecitiated. Thanks.

Hmm, water in PS oil?

Jim:

You really need to thoroughly flush the PS system and replace the filter in the reservoir. I expect you will vew surprised at what you find. Use CNH 134D oil.

Dean

I had the exact same symptoms. PS didn't work when cold, worked when turning slow in warmer weather, had to fight the thing when turning faster. The culprits were a combination of bad oil, rotten filter, and a leaking reservoir that soaked the PS belt, making it slip like crazy regardless of tension.

I cut myself a cardboard gasket to go under the rubber one, which enabled me to seal the reservoir cap without bottoming out the screw. I put a new filter in and cleaned out the gunk the best I could. I added new oil and cleaned the belt with degreaser. The belt still slipped for a while, but eventually dried itself out after several hours of dusty bush hogging and the unit is working fine now.

I would empty and clean the reservoir then flush the system out with fresh fluid and a new or cleaned filter. It's messy. You disconnect the return line from the pump and direct that fluid to a collection bucket. Put a small hose cap on the pump to keep fluid from going out. Then fill the clean reservoir with fresh fluid. With the wheel turned all the way to the left, crank the engine over until the reservoir is empty. You can disable it from starting if it is a gas or diesel engine - just different methods. You CAN let it run, but it will empty the reservoir in about 2 seconds. Refill and repeat until clean fluid comes out. Then fill the reservoir and crank the wheel all the way to the right and repeat. It will take a fairly large amount of fluid, maybe up to a gallon. Then reconnect the return hose and you should be good to go.

I suppose a clever guy or gal could rig up a way keep the reservoir full with a deal like those water bottles in gerbil cages. That would make it go a lot quicker, but still messy!

You should do this when you change the fluid in the hydraulic reservoir, transmission, differential. Typically every 500-600 hours or 2-3-4 years. The fluid will get water in it and the inside of the system will suffer if you don't get it out.

jb

Thank you all for your feedback. I will order up the new filter and give it a try. Thanks again.