Tried to change my power steering pump filter today but the nut holding down the spacer tube wouldn't spin. The rod that it is screwed onto IS spinning and appears to be threaded into the pump itself. Can I just unscrew the rod? What is it screwed into?

Thanks

1992 300SD

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Have your tried forcing the rod to stay stationary while you try to free up the nut? Maybe try some penetrating oil on the nut.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
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Screw a couple more nuts on the rod and lock them together by turning them in opposite directions toward each other. Put a wrench on the top nut and turn it clockwise while you turn the one you're trying to remove.

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84 300SD
85 380SE
83 528e
95 318ic

I put a pair of needle nose pliers on the shaft below the nut by first pushing the plastic piece down the shaft towards the bottom 1/2" (compressing the spring below the shaft)...then removing the nut. Needed to hold onto the shaft as the nut was removed.

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1986 300SDL 440,xxx

Thanks all. I didn't have two nuts to lock together. I had tried holding the stud but it just slipped.

Guess I'm off to the store for some nuts and maybe needle nose "vise grips". I'm guessing those are M6 nuts.

Anyone know if the stud can be safely unscrewed? no extra parts (washers) to fall down in the pump? I've got some diagrams and nothing is shown but I'm a little leery of their completeness.

Just spin off the shaft. It just screws into the casting, not a big deal.

That's how I did it on my OM606 W124, worked fine. I've done it a few times like that now, just make sure the shaft gets back where it's supposed to and the cap will snug down tightly when everything is bolted back up.

You should have pushed down on the plastic piece so the spring wasn't acting on the nut. Now that the stud is loose you could remove the whole assembly, but you will need two nuts to screw the stud back in tight. But not too tight, since you sure don't want to strip the threads in the aluminum casting.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I made a store run and got two M6 nuts to lock together. Even after it broke loose, I had to use the wrench most of the way. I noticed a small bit of something (looked fibrous) in one of the nut's thread. Putting it back together, I was able to spin it all the way down by hand.

And - indeed the stud just screws into the pump and could have been taken out without removing the nut.

Thanks everyone.

I wonder if someone installed a locknut or something.

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'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
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It didn't look like a locknut. The threads on it and the stud looked OK too. It probably had just been on there a long time. The fluid I am pulling out to flush it has a red tint - I'm wondering if the previous owner used ATF fluid.