Life of Hydraulic Fluid - AW ISO 32

[BHopkins]

I recently bought a used motor home. It has 95,000 miles on it, and no service records, so I'm planning on going through all the mechanical systems and replacing all fluids and filters.

The Power Steering uses A/W ISO 32 hydraulic fluid. The total capacity for the motor home p/s system is 44 quarts, 16 of which are in the reservoir. The system is plumbed in such a way that the hydraulic fluid does not circulate through the reservoir, so there are 28 quarts in circulation, which includes two radiators in series.

What is the life of hydraulic fluid? In my cars, I typically replace p/s fluid every 30k miles. But with such a large capacity, it could cost $150 - $300 to do a full p/s fluid change. If the fluid wears, or ages, or gets contaminated, I have no problem replacing the fluid. Hydraulic fluid has to be a lot less expensive than what a p/s pump or steering rack must cost on a rig like this.

Second question. Is anyone familiar with Miles Lubricants? They offer A/W ISO 32 hydraulic fluid at a good price. And looking at the PDS, it should be a good product. Buying hydraulic fluid is new to me, so any advice will be appreciated.

 

[bullwinkle]

Does it have a filter? That would be a good thing to add if it doesn’t have one. Fluid analysis might be a good idea too, to give you an idea if the OVER TWO PAILS of fluid need to be changed or not.

 

[BHopkins]

Does it have a filter? That would be a good thing to add if it doesn’t have one. Fluid analysis might be a good idea too, to give you an idea if the OVER TWO PAILS of fluid need to be changed or not.

The Owner's Manual says that there are three filters inside the reservoir. I haven't opened up the reservoir yet, to see what these filters are like. Since the hydraulic fluid lines only connect to the bottom of the reservoir, and do not circulate through it, I'm not sure how these filters do much filtering, except to filter any new fluid put in the reservoir.

I like your idea of a fluid analysis. The cost of a fluid analysis is only a fraction of what 11 gallons of hydraulic fluid would cost. I'll have to see if there is an easy way to get fluid from the circulation lines, instead of the reservoir.