Power steering question

[Tiffindreamr]

Do motorhomes with power steering use hydraulic or air power steering? This is a general question, but I'm specifically wondering about Tiffin. Since large RVs already have the air compressor anyway, it would make sense to have air power steering, UNLESS you lost your air pressure!! Lack of air pressure on a Tiffin (40 psi or less) would result in locked up brakes, but lack of air would drastically affect steering as well.

[Skip426]

To the best of my knowledge, they all use hydraulic assist P/S.
I'm new to the air game, but I've never heard of air assist P/S, and considering the amount of lubrication required in the P/S box , I can't see air assist being possible; unless the assist was external to the box( air rams on the steering linkage ) then control of the direction and amout of assist would be compex . To say the least.

[H. Miller]

Air is used on large military trucks (duece & a half). Should a leak or heavy usage occur, there is a "shut off" valve that maintains a minimum air pressure for brake operation...

[Gary RVRoamer]

I don't know of any RV chassis that uses air for steering assist - Freightliner, Spartan, Roadmaster, Ford and Workhorse all use hydraulic for power steering. Newell and Prevost too, as far as I know.