I have one horrible problem. My power steering system all the sudden started puking ATF of of the reservoir on my 1970 280SEL 2.8L, 108 chassis.

I started the car up yesterday morning, which was the first below-freezing morning that I had started the car all year. I let the engine warm up and then drove about a mile to work. When I parked, I heard this bubbling sound and saw a puddle of ATF under the car. The power steering was bubbling over out of the top of the reservoir. It appeared to start as soon as I shut the engine off. My father helped me bleed the system using the bleed screw while we refilled the system. As a side note, I replaced the PS filter about 3 months ago and it has been working fine since. After bleeding and refilling the system, the power steering worked fine for the rest of the day.

I started it up again this morning and it did it again. Once again I cleaned up the engine compartment and started looking for leaks. The hoses are all original, but I cannot find a leak in them. Also, the PS pump is not leaking any fluid. Normally, if you have a leak that lets in air, it must also let oil through, right? I'm stumped as to what the problem could be. Any ideas, and has this happened to anyone before? If so, how do I fix it?

I'm hoping it's just the hoses somehow going bad, but with my luck. . .

Thanks!

did you remember to put back the circular metal cover on top of the PS filter, and put the vertical spring on, before you capped it?

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1970 280S M130 engine- good runner
1971 250 M130 engine- #2 rod bearing, gone
1971 280SE (blown engine,parts car)
1977 German 280S W116-only 33 years old

Yes, I put everything back in like it should be. It appears that the system is sucking in air somewhere and it all bubbles back up as soon as I shut the engine down. I haven't lost power steering function yet, so as of now it is a major annoyance of a problem rather than something that would stop me from using the car. Right now, I need to drive it back to school, and I can start tearing things down two weeks from now when the quarter is over. There is definitely something wrong because it's never had any air in the fluid before. Any suggestions on where it's coming from? It has to be some place where air could get into the system, but oil couldn't leak out. Also, it seems to happen only when the weather is cold.

Return line is loose, it's as high as the reservior.

Also check for water -- if it freezes, the pump will howl a little and make slush, PS fluid everywhere (this happened on the old 62 Olds, very similar system).

Bad seal between reservior and pump inlet will do the same thing.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Recommend a new seal kit for the PS pump. In my '72 250C, the front pump seal was letting more air in, than leaking fluid out.

Happy Motoring, Mark

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DrDKW