I have just put new seals in my steering gear box and put it back in and the steering is much harder to turn than before. Also after a 6 mile test drive the steering box heated up, so hot that it was uncomfortable to touch. Is that box supposed to get that hot? I had never put my hand on it when it was steering properly but am thinking it should hardly heat up at all. I am thinking that I may have done somthing wrong when I put it back together. Any comments appreciated. Milt.

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Milterino
76 450 S.E.L.

It sounds like new seals have pushed the gears closer together, hence friction and heat.

What about adjustment - usually a 19mm locknut around a 6mm allen. Clockwise on the allen loosens the gears and Counter-Clockwise tightens em up - opposite of what you'd expect.

Fiddle with the steering box adjust nut, that's what i'd do..... even back it off (clockwise) 1/2 turn for starters. Then tighten it up 1/8 turn intervals (counter clockwise) in between 10 mile test runs. That's fragile adjustment and paint marking the original settings with help. Even 1/4 turn is helluva lot for steering adjustment.

Diesel: Thanks for your reply. I found the adjustment(19mm,6mm) but I had done nothing to that. You referred to the "steering box adjusting nut". Is that the large spanner type nut (has two holes for spanner wrench) that is about 2 1/8" OD. I will try loosening the spanner nut a tad and see if that eases turning and cuts down the heat. One interesting sidelight for me was that the steering was very tight in the sense that there was no radial play in the steering wheel. Thanks, Milt.

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Milterino
76 450 S.E.L.

Milterino, by "steering box adjust nut" am referring to the allen/19mm combo. And hell yes, mark the allen to steering casing for point of reference.

Tendency is to tighten it (counter-clockwise) too much and then toast the gears. That's why i say back it off (clockwise) 1/4 - 1/2 turn for starters. Doesnt matter if you've never adjusted it before.

That's chunky work - reinstalling steering box - where splines can be lined up too tight. Am thinkin gears got nudged in the process. How many times was it hit with hammer to wrastle in place? That's another idea - you might want to loosen the collar and smack it again if the steering wheel shaft splines are set too tight.

And I'll betcha it was bogus oil (tranny fluid?) with solvents that scorched your seals in the first place.

Well now I have the subltitute box back in. It turns easier than the original so I have done something to the original when I put the new seals in it. Funny, this one runs hot also. I never noticed that before but they must all run hot. After a 6 mile test run its so hot you cannot hold your finger on it and the pump is likewise. I never had a car that ran at such high tempetures and I can see that after 29 years of heat it must take its toll on something. I do use tranny oil in the pump. I think that that is what destroyed my bushings as it was leaking for who knows how long and blowing back on the rubber bushings. They were rotted out.
As far as adjusting the box, I won't do that as I didn't touch that as the play wasn't a problem. As for reassembly, it's relatively easy if you loosen the steering shaft and move it back, assy. the box and then slide the shaft down on the box. Thanks for your input. Milt.

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Milterino
76 450 S.E.L.

Question: Don't these cars use ATF in their power steering? The PS reservoir on my 107 has a yellow warning on it to use only ATF. The owner manual also specifies ATF. I put MB PS fluid in my old 114 when I changed it out last time, a long time ago (need to do this again, I guess), but my 107 uses ATF. The approved product list shows the SL class uses one type of MB PS fluid, or an approved Dexron III ATF from the list; twelve are listed. There are two MB PS fluids shown on the list, and one of them is equivalent to Dexron III ATF. (Now that I think about it, I'd bet my old 114 probably has the PS fluid in it that is the same as Dexron III ATF. I'm going to check the part number when I get home tonight)


230/8

Are you sure it's Dexron w/additives and not Ford Type ATF that's closer to MB specs from 30 yrs ago??

I've heard nothing but bad news about putting modern tranny fluid in vintage steering boxes. I think this is one case where buying $9 pint of MB dealership PS fluid pays off.

And as i'm sure you know from experience, the approved procedure for draining the fluid is hilarious isnt it? Basically you pull the PS pump return line and crank the engine till the system runs dry. And then there's that little $3 pancake filter hidden in the bottom of the PS pump.

Hey dog, you know that don'tcha --its' under the "steady plate"?!!?

I think one of your posts is what lead me to it about a year ago.

Yep, i flushed and messed with my own steering box about that time.... figured new ps fluid and pancake filter oughta be maintenance each 125k miles or so.

You still in the 108? Can remember you fightin rust, but i say drive it everyday and keep it on the road until the wheels fall off.

Well:

According to the MB service products list, SLs, and most other MBs, should use MB PS fluid #000 989 88 03, or one of the approved Dexron III fluids. For some reason the C class cars use a different PS fluid. I checked the part number for the PS fluid my dealer sold me for my 114 and, as I suspected, it is PN 000 989 88 03. So, looks like MB is selling a pretty expensive PS fluid which is basically Dexron III ATF, without the red color.

This accounts for the warning on my 1972 350SL that only ATF should be used.

Now, if you are working on a very old model, I believe some of them used a Type A fluid, which is or was similar to Type F. This is where the original owner manual becomes very important. Type A is no longer available in my area. I suppose folks will have to use one of the "universal" fluids that are on the shelves now. I saw a Quaker State universal fluid at KMart a few days ago. Type F is getting scarce except at the Autozones of the world. Goofy lubes usually only carry DexronIII/Mercon fluids which are basically the same except the Mercon has a higher temp specification. If I have my local Goofy do a whole-trans flush and fill on my 68 Mustang I have to bring the Type F fluid for their machine.

All that said, it seems highly unlikely to me that using Dexron III ATF in the 450SEL's steering would have caused a problem. Sounds more like a problem of adjustment. Of course, I'm always prepared to be proven wrong, that's called learning from the experiences of others.

FWIW,

230/8

FWIW, I have the "Owners Manual" for my 76 450 SEL and it specifies for the power steering, "Automatic transmission fluid (ATF) Dexron type. Of course this was in 76 and a lot of things have happened since then. Milt.

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Milterino
76 450 S.E.L.

I just re-sealed the PS box and pump on a '66 250S. I refilled with Dexron. It didn't get hot or stiff.

Happy Motoring, Mark

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DrDKW

Yeh, dog still using the 108 as my daily driver 3/4 of the year. Never really had a rust battle, just filled in a few old paint chips. The frame, floorboards and rockers are rock solid -- obviously hasn't seen much Ohio salt

Milterino:

If you have filled with Dexron III (all you can get these days) then your fluid is correct. Go back to Dog's post on the adjusting nut. This is the sector tension adjustment that is located on the top of the box. It is a 19mm lock nut that holds a smaller, 6mm, allen screw. These are a bugger to get at on SLs, so may be equally tough to get at on your SEL. If you have a manual then check job 46-480 for a thorough description of of how to set the friction torque on the streering gear. It must not be too tight. Some folks really crank down on the adjusting nut to remove play. I would hazard a guess that being too aggressive with this adjustment, or failing to check this adjustment after re-sealing the steering, could cause the box to run hot from high internal friction. If you adjust the allen screw, remember CW is looser and CCW is tighter.

I cannot speculate on how hot a gear should run. My SL gear is tucked up tight with the exhaust manufold, so I know it runs hot.

230/8

Puzzled. According to my table a "bar" is equal to .9869 atmosphere and an atmosphere is equal to 14.7 lbs. so I figure a bar is equal to 14.5 lbs. Now I have a power steering pump which has an "opening pressure of relief valve" of 65 bar so does this mean that to open the relief valve it takes (65 x 14.5 or 942 lbs per sq inch) to open the relief valve? That's a bunch. The CD also says the circulation pressure is a max 5 bar or as per my figuring or about 72 lb per sq inch. If you will, tell me if I am thinking correctly.
Also I apparently have a replacement pump on there as it says 65 bar and as per the CD I should have an 82 bar. I do have an 82 bar junk yard spare. Wonder about the ramifications of putting the 82 bar in there? Any comments appreciated, Milt.

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Milterino
76 450 S.E.L.