This is the best source of automotive wisdom I know of, so please pardon the non-Mercedes part. When I bought my 1982 Bluebird Wanderlodge (Cat 3208 puller) it had a fluid leak which the previous owner thought was leveling jack fluid. Turns out it was power steering fluid and a perusal of all the maintenance records from new show it to be a persistent problem reported first in about 1983 or 4. It has a remote power steering reservoir located at the back of the doghouse where it does not get much airflow over it. It has barbed fittings for suction and return lines. Suction fitting on Eaton power steering pump has one hump instead of barbs, like a heater core. Suction line has been replaced at least once, could be 2 or 3 times. Current suction line is steel reinforced hose. Return line is original (I think) It is leaking at all suction and return line fittings. Not leaking on high pressure line.
I put my non-contact thermometer on the reservoir after about a 10 miles drive on a 75 degree day and it showed 239 degrees. Mercedes power steering runs at 150 degrees. So the Bird power steering fluid is clearly too hot. How to fix?
I plan to replace the hoses with high temperature hose (Gates rubber sells one rated for 300 degrees) and try to replace all barbed connections with threaded connections, except for the barb on the suction line at the pump since that fitting is not removable. I will also use synthetic fluid rated for higher temperatures.
Would the steel reinforcing in the current hose mean it could not make a good seal on the barbed fitting? The original return line is all rubber.
How much of a temperature drop could I expect in the fluid if I installed a cooler in the system? What is the difference in cooling ability of the tube/fin versions with an electric fan, tube and fine with no fan, and solid aluminum coolers with no fan but a row of fins? How exposed to air movement must these coolers be to be effective?
I considered moving the reservoir to a cooler location but I haven't been able to find a location on the bus higher than the power steering pump which will work.
Any advice on how to deal with the problem. It's a pain to remove the hoses but lucky for me, it has a swing out radiator so at least I don't have to remove all the coolant and the radiator to access the power steering pump.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

239 seems way, way too hot for the fuild. If it doesn't have an existing cooler, you might look at Summit Racing, I've used their street rod coolers, they are long and narrow, mount below the car tucked in a frame rail, where ever you can get air flow. Also available with barb, an or any other kind of fitting you could want. I used a cooler that was about 3 inches wide, 2 inches thick and about 24 inches long, worked great on the auto trans of an astro van. Best Wishes, Chuck

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2000 C230 Kompressor "Frosty"

2007 PT Cruiser
2001 VW TDI Beetle
1999 Landrover Discovery II
1971 Corvette

Gone: 97 Cabrio, 83 240D, 93 VW Eurovan, 95 Volvo 850, 93 Chevy Astro Van, 77 VW Bus, 99 VW Jetta, 74 VW Bus

Don't think the reinforcing will affect the connection but you do want good quality clamps to make a good tight seal. The idea of a cooler sounds like a great idea and you should expect some drop in temp. Don't know how much for sure but a fan and fin combo would get the coolest. Don't MB's have coolers with their PS lines? I know I've seen one somewhere. Lower fluid temp will help the PS pump work better since the seals won't be softened by excessive fluid temp. Hang the cooler somewhere underneath the bus. It should get lots of airflow there.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012