Hydraulic Fluid for Radiator Fan Motor & Steering

[robbyray]

I need to add hydraulic fluid to the engine compartment reservoir that supports the radiator fan hydraulic motor and hydraulic-assisted steering. I can't find anywhere in my 2008 Alpine 36' FDDS manual/drawings what grade or viscosity hydraulic fluid was factory installed in the engine compartment hydraulic reservoir. Any information or suggestions would be appreciated.

[Dale777]

robbyray,

The owner's manual for the 2008 Alpine Coach states,

"Power Steering Fluid -- Replace Fluid every 10K, Use Valvoline Premium Blue Motor Oil".

If you don't have this manual, go to the Alpine Coach Association web site to download it at this link:

http://www.alpinecoachassociation.co...s%20Manual.pdf

You will need Adobe Reader to read this PDF. The referenced Adobe Reader page number, for the fluid to use, is page 105. Although the manual does not say what weight to use, WRV confirmed for me that it should be the same as the engine oil - 15W40 Valvoline Premium Blue.

Also, there have been a number of posts questioning what fluid to use in this reservoir that you might want to read:

Cost of having the Hydraulic fluid changed

How much oil needed to change out hydraulic fluid

Brake pedal pressure

[robbyray]

Thanks, Dale, your iRV2 forum references were very helpful. Do you know what the standard operating pressure is or what motor is used to generate the hydraulic-assisted brakes and steering pressure? The relatively small, rectangular aluminum box with welded ends under the very rear of my '08 coach, driver's side to the rear of the radiator, looks like the welded aluminum ends on the box are slightly bowed out suggesting that the pressure may be high in this hydraulic system, perhaps when braking.

Did learn from an '09 Alpine owner that his unit came with Chevron Rykon Premium 46 hydraulic fluid in the hydraulic reservoir in the rear engine compartment (passenger’s side) for the hydraulic-assisted brakes, steering and radiator fan. A Chevron Lubrication Specialists (lubetek@chevron.com) told me that Chevron Rando HDZ 46 hydraulic fluid has replaced the Rykon Premium 46. I located a 5-gallon "pail" or bucket of the Rando HDZ 46 in Yakima WA at Wondrack Distributing who told me they used to supply Rykon Premium 46 to Western RV. The Rykon and Rando products have a higher viscosity index higher than Valvoline Premium Blue 10W/40 motor oil by about 10% to 30%.

According to Cummins NW in Yakima, it took about 4.5 gallons of the Rando HDZ 46 to replace the fluid in the reservoir and lines. My manual says to replace the hydraulic fluid in this engine compartment reservoir every 10k miles and the filter (Nelson P/N 84220-A) every 6k miles. Seems like a pretty frequent change-out schedule, especially for the filter. Have put the fluid and filter changes on my periodic change-out and maintenance lists. Again, thanks for pointing me in the right direction on the Alpine Coach forum, ray

[Dale777]

robbyray,

I don't know the details of what motor is used to generate the hydraulic-assisted brakes and steering pressure, but it is the power steering pump. I've never investigated the power steering pump, although I would guess that the pump is powered by a PTO off the transmission or engine. I think the earlier coaches used PTO off the engine, then somewhere in the later years switched to PTO off the transmission. Since yours is a 2008, then it might be the PTO off the transmission.

However, the hydraulic brake system itself is a HydroMax Hydraulic Brake Booster. The HydroMax Booster gets its power either from the hydraulic power steering pump or, as a backup, from the 12-volt electric boost pump.

Try this link for the technical manual on the brake booster: http://rb-kwin.bosch.com/us//pool/us...ter_Manual.pdf

Perhaps, someone else on this forum knows more about the power steering pump and how it works - PTO off transmission or engine and what pressure???

[HeapBigEngin]

Not sure if this info will help or even applies to your MH, but here it goes. We have a 2003 F/wood Revolution 40' DP with an 8.3 ISC Cummins on a Freightliner chasis, side mount radiator. Last summer, the MH developed a serious leak at the hydraulic fan motor...replaced it with new; reman not available. Also had weird steering "feel" at times after driving 10 miles or more. Turned out the power steering pump was losing pressure when hot. (Our pump is engine-driven.) Since both units on our MH operate from the same hydraulic fluid source, not sure if there is any relationship between the 2 repairs....I doubt it. (Previous owner had not had any hydraulic system maintenance performed, as recommended by Cummins, in 36,000 miles.) Pressure specs for our pump are 2100 psi, cold; 2400 hot. My pump pressure specs were 2100 psi, cold; 1900 hot. Not good. Pressure after the repair were 2150 psi cold; 2450 hot. Those are some serious pressures....

Not sure how much fluid you are adding. Maybe the hydraulic fan motor is leaking? Also, I suggest you check the power steering lines for proper routing from/to the pump. Ours had rubbed on the framerail for sometime, although it didn't require replacement. The techs re-routed it and covered it well back there with wrapping foam and tape. They told me it is not uncommon to see the lines like that....just something to think about.

[Old Scout]

Lots of discussion on types of hydraulic fluid to use-- old coaches used trans fluid, newer ones use engine oil or something more exotic. See the thread on Generator Exercise, yearly change-over of non-combustion related fluids [ie, other than engine oil] seems like a waste of time and money.

[robbyray]

Thanks all for great feedback. From inspection yesterday, looks like hydraulic assisted brake/fan/steering motor may be a Chelsea 267XGFJW and pump a Sauer Daufess (difficult to tell spelling). Will try to contact motor manufacturer or distributer to get pump specs. Checking out PTO today. Looks like there was a leak in the recirc pipe where it clamped to the intake. More later. Thanks a bunch. ray

[TerryM]

Do a search on this forum with "pto transmission" and check out the posts by Engineer Mike. He even includes pictures. Should apply to your coach.

[takepride]

Quote:

Originally Posted by robbyray My manual says to replace the hydraulic fluid in this engine compartment reservoir every 10k miles and the filter (Nelson P/N 84220-A) every 6k miles. Seems like a pretty frequent change-out schedule, especially for the filter. Have put the fluid and filter changes on my periodic change-out and maintenance lists. Again, thanks for pointing me in the right direction on the Alpine Coach forum, ray

My Alpine Coach Owner's Manual says to change the filter every 10K and says only to inspect for leaks and fluid levels regularly, with no recommended frequency of fluid replacement.

[EngineerMike]

Alpines prior to the Diesel Particulate Filter engines which started on 08 rigs have a Sauer Danfoss (earlier called Sauer Sundstrand tho my spelling is probably off) pump that is shaft-driven off a shaft extension on the air compressor. Air compressor is right side, upper level, and in front of the "rear" flange of the motor, and it is driven off gears from the crank shaft.

Alpines from say mid-08 on w/the DPF engines have a Chelsea brand PTO w/recirculating lubrication off the tranny driving a Sauer Danfoss pump, located inboard and slightly forward of the battery compartment. Some time after the change to PTO drive for the pump, WRV changed to the Rando hydraulic fluid as their standard OEM fluid. Prior to that they used diesel motor oil, the same as was used for the Cummins engine, and prior to that (05-ish model year and before?) they used red tranny fluid.