Problem with '87 300d Steering Gearbox

Hey gang,
I'm wondering if I should attempt to fix/replace the steering gearbox on my 1987 300d.
First a bit of history:
I'm leaking power steering fluid at the rate of about a pint a month.
Noticed the problem when terrible groaning sounds began and I popped the p/s pump cover, and behold -- ZERO fluid in the reservoir! Since then I've topped it off a couple of times and it no longer makes noise.
However, there's a pretty noticible play in the steering wheel, on the order of 25 or 30 degrees, or about 4 - 5 inches. I thought it was the alignment at first but that's been checked (just put on 4 new Bridgestone Turanza EL400 tires today). The guys at Firestone said that the steering gearbox was probably going out and that they couldn't do that repair at their shop. When I bought the car in October the steering was pretty tight, so this has been a progressing problem in the last few months.
So I guess my question is -- on these 124 models, how much of a pain is it to replace a steering box yourself? I've done a lot of work on 123s -- replaced alternators, a/c condensors, water pumps, glow plugs, brake master cylinder and calipers, and the like. So I'm no stranger to spending a lot of time and elbow grease to repair something on my own.
But with a rebuilt pump running $475 alone, I just wonder if I should leave it to a mechanic, or if I could just get away with topping off the fluid and seeing how things go?
Anyone swapped out a gearbox on a W124 before?
Thanks. Chris
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This sloppiness should not happen within a few months - unless someone "fixed" it before you bought the car.
Suggest you have a helper turn the steering wheel back and forth while you watch two views:
1. the steering wheel's input TO the box vs. the box's output via its pitman arm and;
2. under the car the pitman arm's action onto the tie rods and how the idler arm a/k/a "drag link" transmits the steering force to the right wheel (without lifting).
After these observations you'll know if 100% of "the problem" is in the steering box or elsewhere or both.
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I will certainly follow your suggestion to get under the car and watch the various rods/arms behave.
T.G., if the box itself isn't damaged, then why I am losing so much fluid? Perhaps the p/s pump is bad? I drove the car for at least 10 or 20 miles while the steering was making those horrible moaning sounds, until I refilled the pump. I believe that is when the excess play started happening. I just assumed I had damaged the ball bearings or something.
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Well, you need to get under the car and find the leak!
Suggest you look at (and clean) the PS pump, the PS hoses and, of course, the steering box. The leak is probably just a slow ooze.
As to the sudden play, IMHO it's either the steering wheel shaft to steering box coupling OR it could be that some air is trapped in the steering box that needs to be expelled - try cycling the wheels from extreme right to extreme left and back a few times.
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That's the part that usually goes first, yes.
If memory serves the rebuild kit is like $1.50 or something...
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
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