steering box R&R: do i care about the locks and versions? - PeachParts Mercedes-Benz Forum

bricktron · #1 09-21-2016, 04:02 PM

in my '77, the steering box gave out and i bought a replacement on eBay. they are both number 116 461 04 01 with pitman arm 2350 (whew). however, 46-412 differentiates three generations of boxes by some stamped markings present under the filth. they can apparently occur in different orientations, making them super hard to read. the latter half of the codes are never even mentioned.

* 13b, 1st generation: no markings explained; "locks on steering arms or on frame cross member".

* 13c, 2nd generation: "A" means "locks in steering housing". also, "Never install 1st version of steering box instead of 2nd version".

* 13d, 3rd generation: "A" means "stop and 10.5mm pitch", "A*" means "stop and 9mm pitch", "AK" means "stop, 9mm pitch, and modification on ball guide tube".

now, the box i am removing has a marking starting with A*. perhaps this means it is 3rd gen. however, it was not original to this chassis, and i have no idea what code was on the earlier box. the box i am hoping to install seems to be marked starting with "1*". maybe it was an "A*" where the initial strike was off-center, or maybe it is another code not explained in the FSM. the only other different i notice is the much larger molded text, "YY" on the old box, "YY G" on the new one.

is it OK to install this box? should i now be determining whether my "steering arms or frame cross member" have locks on them? anything else to look out for? thanks, folks!

Stretch · #2 09-21-2016, 04:15 PM

The way I read it is that because the first configuration had steering locks external to the steering box, fitting that 1st gen box to any future systems (that have no external locks) would be "a bit interesting" when you come to turn the steering from lock to lock =>

You probably end up with a kind fo W123 owl head steering mode which wouldn't be cool.

No - really - not cool.

####

So it seems to me that so long as your steering box has internal locks then your steering system (which I assume has no external locks on the "steering arms or on the frame cross member") is going to be compatible.

bricktron · #3 09-21-2016, 06:50 PM

OK, stretch, i agree: no stops, no good.

the truth is i don't know if either the box or the frame have them. maybe both do. i thought #20 in the illustration for 13b might be the cross member stop, but after looking at the car i think it's a mount point for the skid plate.

since the "1*" marking is unexplained, and original steering box gone, any clues on checking either half for the stops that one of them must have?

Stretch · #4 09-22-2016, 05:30 AM

Quote:

Originally Posted by bricktron

OK, stretch, i agree: no stops, no good.

the truth is i don't know if either the box or the frame have them. maybe both do. i thought #20 in the illustration for 13b might be the cross member stop, but after looking at the car i think it's a mount point for the skid plate.

since the "1*" marking is unexplained, and original steering box gone, any clues on checking either half for the stops that one of them must have?

I really don't know for sure - this is all pure guess work - so you're gonna have to go check for yourself.

I assume the "no stop" steering box will spin round and round and round and never stop - actually it might not - thinking about it it might get to the end of the screw and make a nice crunching sound / feel like it gets stuck!

I know that if you have a "no stop" external steering system (the one probably 99% of all W123s have) you can twist the front wheels a long way round if you have the steering box disconnected. (Wheels up in the air or on slip plates helps...)

I assume a system with external stops on the "steering arms or on the frame cross member" would involve obvious rubber stops and extra welded on parts / big lumps on castings on the bits that move.

I assume that these special steering arms are no longer available and as common as rocking horse ****

#####

If you can't work this out yourself you might want to try

1) Posting up pictures of the steering arms you have - I'm sure most of us here will be able to say "yep seen that before" or "holy crap that'll be worth a lot on ebay"

2) Ringing up the Mercedes classic centre and seeing if they can help

3) A practical trial fit / assembly. Front wheels on slip plates - no power steering - steer to full lock one way look for parts hitting other parts - steer to full lock the other way and look for parts hitting other parts

t walgamuth · #5 09-22-2016, 06:28 AM

Quote:

Originally Posted by Stretch

I really don't know for sure - this is all pure guess work - so you're gonna have to go check for yourself.

I assume the "no stop" steering box will spin round and round and round and never stop - actually it might not - thinking about it it might get to the end of the screw and make a nice crunching sound / feel like it gets stuck!

I know that if you have a "no stop" external steering system (the one probably 99% of all W123s have) you can twist the front wheels a long way round if you have the steering box disconnected. (Wheels up in the air or on slip plates helps...)

I assume a system with external stops on the "steering arms or on the frame cross member" would involve obvious rubber stops and extra welded on parts / big lumps on castings on the bits that move.

I assume that these special steering arms are no longer available and as common as rocking horse ****

#####

If you can't work this out yourself you might want to try

1) Posting up pictures of the steering arms you have - I'm sure most of us here will be able to say "yep seen that before" or "holy crap that'll be worth a lot on ebay"

2) Ringing up the Mercedes classic centre and seeing if they can help

3) A practical trial fit / assembly. Front wheels on slip plates - no power steering - steer to full lock one way look for parts hitting other parts - steer to full lock the other way and look for parts hitting other parts

I'd go right to #3. The newer boxes all have the internal locks, right?

DeliveryValve · #6 09-22-2016, 11:52 AM

I've always wondered, but have not a chance to research, does anybody know what pitch means? i.e. 9mm pitch and 10.5mm pitch. I found in the FSM the pitch of the first gen and 2nd Gen Boxes are 10.5.

Now getting back to the steering stop. I have not tried this yet, and at some point I do want to try it because I have a very tight non "A" box sitting around. But I believe if you have the bushings for the external stops, the box will work.

These pictures don't have the bushings, but you would add them to the triangle piece on the crossmember...

And to the casted tab (where the hole is) on the idler arm and pitman arm. Idler arm shown.

EDIT:

Found pictures of a steering box with what looks like an adjustment screw instead of a bushing. The FSM calls them "stop lugs".

At this point, I don't know the part numbers for these external stops.

.

bricktron · #7 09-22-2016, 03:52 PM

thanks rich, those pictures are very helpful. it sounds like the first gen box needs those different pitman and idler arms with stop lugs at the end. the fact that the replacement box's pitman arm does not have the lug (it is identical to the installed one) tells me that it does not depend on external stops. great, done! now to continue with the swap job.

FWIW, on my workbench, the arm rotates about 75 degrees from stop to stop.

DeliveryValve · #8 09-22-2016, 04:23 PM

Being curious, I dug out a couple of boxes out of storage. On further review the box I thought without an A, A* or AK is actually an A*. The ID was not stamped straight.
I removed it from a car with pitman arm 2350 (no steering stop lug tab) installed (left on pic below).

It's interesting AK box (right in pic below) came with a pitman arm 2355 (with steering stop lug tab) and that is original to the box.

Aaron, I would imagine you are correct with the assumption on the pitman arm if it's original. But that would be easy to find out once you start using it. I've read if you did a sharp turn on an early box with no external stop, it would cause the tires to rub on the wheel well.

DeliveryValve · #9 09-22-2016, 04:32 PM

Quote:

Originally Posted by DeliveryValve

I've always wondered, but have not a chance to research, does anybody know what pitch means? i.e. 9mm pitch and 10.5mm pitch. I found in the FSM the pitch of the first gen and 2nd Gen Boxes are 10.5.
....
.

What I gathered is pitch in a steering box is just like a screw pitch. So in a recirculating ball steering box, the pitch of 9mm or 10.5mm is how much the ball travels around from one crest of the thread to the other. My assumption is the 9mm pitch would be faster steering.

Quote:

Originally Posted by bricktron

...
FWIW, on my workbench, the arm rotates about 75 degrees from stop to stop.

Good info. I put everything back in storage, I'll need to check the boxes next time.

.

bricktron · #10 09-23-2016, 01:55 AM

Quote:

Originally Posted by DeliveryValve

What I gathered is pitch in a steering box is just like a screw pitch. So in a recirculating ball steering box, the pitch of 9mm or 10.5mm is how much the ball travels around from one crest of the thread to the other. My assumption is the 9mm pitch would be faster steering.

it's a "more indirect ratio" (46-412:13d), whatever that means. the "ratio in center position" and "total ratio in center position" also differ, but don't ask me to explain what they are.

it would be nice to know if they included the years or chassis number when these changes occurred. both my boxes's part numbers start with 116 -- not even mentioned in the article. oh well!