Removal of Steering Box

[Styria]

Like with most things, the more often you do them, hopefully the task becomes easier each time. So it can be with Steering Boxes, and removal thereof, and I thought I'd pass on some of my trials and tribulations, plus a couple of handy hints.

Obviously, your choice of tools and various procedures to get started are of importance. One item that is almost a must is a Miner's Lamp. if you're lying on the ground, and are trying to place the box in the correct position, you need both hands, and a strong light that will shine up the area around the steering shaft and mounting points. The lamp allows you to do that.

Accessability - quite often, it pays to move some items or some parts first which will enable one to more easily access certain areas. I know the inclination is not to touch - but it is false time saved. It really helps to move the steering shock absorber, drag link and obviously the tie rod out of the way - one only needs to disconnect those items on the steering box side only. Once they're out of the way, it is really quite surprising how much space one has to reach the 22mm and 17mm pipe fittings that attach to the box. Usually you need quite hefty and solid spanners to start undoing them, but you can then switch to short stubby, even cut-off (modified) spanners to gain easier access.

These oil feeder pipes are fitted to the box by means of additional fittings that are attached to the box first-and then the feeder pipes. As has happened to me, those fittings can turn with the feeder pipes as you are trying to undo them. You will not succeed. Remedy is to remove the feeder pipe(s) together with the box as one unit, and for that one has to cut the rubber hose that connects the two halves of the thicker pipe.

It also pays to machine up, or grind to size, a special bolt that will secure the box in the centralized position when it comes to refitting the box, and the coupling to the steering shaft. The positioning of the splined end of the connecting coupling can also take considerable time, but it is important to get it right. I also rope the steering wheel to the hand brake and height adjustment levers in such position that the self cancelling feature of the indicator is not impaired and/or compromised. Last, but not least, I have a large plastic dish to catch any of the oil that will leak from the box once the pipes are disconnected.

I hope the foregoing is useful - any furthjer queries, please post. Regards Styria

 

[Styria]

Just some further observations, particularly in relation to the centralizing of the box, the position of the steering wheel and the location of the coupling on the steering box splined shaft.

Once I had finished the installation, both front wheels were pointing to the right hand side of the car. As I said, bolt fitted to box (exact centre), steering wheel in centre position and tied down with blinker lever working correctly, and coupling installed to match the two shafts. I did not wish to change the "prescribed" position of the various components, and therefore adjusted both tied rod ends by 'looks' to the wheels straight ahead position, but I knew that I would need a wheel alignment.

So off to Accurate Wheel Alignment at Sydenham. Obviously adjustments were needed to the Tie Rods, but the mechanic centralized the steering wheel by the 'side to side' method - he says three turns, but in fact it is slightly more, so as a consequence it is appropriate to state that the only way to get exact centre is by means of locking the steering box, and not the turning of the wheel from side to side. As a result, I now have a blinker operation that does not always self cancel coming back from left to centre. The car will have to go back at some stage to reposition the steering by further adjustment of the tie rod ends. Regards Styria

 

[s class]

The centering is important because the steering box does not have a linear characteristic - it has a so-called high point in the centre of its range. This is achieved by having a smaller clearance between the sector shaft and piston teeth in the centre than at the extremes. The purpose of this high point is to give more precise steering feel in the straight ahead position.

However, 30 years down the line, most steering boxes have seen more use and hence more wear in the straight ahead position, and often the high point is hardly noticeable any more. Attempts to achieve the high point by means of reducing the clearance in the box with the sector shaft adjustment must be done with care, as binding at the extremes can easily result on old steering boxes.

 

[Styria]

Hi S-Class, I really appreciate what you're saying and it is indeed a very rare occasion when one could find a steering box with minimal wear. I have a very good relationship with the firm that rebuilds these boxes, and I know that they would not rebuild a unit if it would turn out to be unsafe, or really unuseable.

Presently, they are examining another unit for possible re-building, and it will indeed be interesting to get their verdict. Regards Styria

 

[s class]

Well you're lucky then, here some of the guys will reseal anything (and call it rebuilt).

I did an exercise a while back at my friendly scrapyard - I spent 2 hours going through about 50 W116, W123 and W107 boxes - adjusting the sector shaft on all of them. Only about 2 of the 50 had any real life left in them. I bought them as 'strategic spares'.....

 

[Styria]

Well you're lucky then, here some of the guys will reseal anything (and call it rebuilt).

I did an exercise a while back at my friendly scrapyard - I spent 2 hours going through about 50 W116, W123 and W107 boxes - adjusting the sector shaft on all of them. Only about 2 of the 50 had any real life left in them. I bought them as 'strategic spares'.....

Hi S-Class, I have had somewhat limited dealings with these steering boxes, but I have been told by the last two guys I have been dealing with that it is really not possible to get an accurate assessment condition wise unless the box is partially disassembled. I have tried the method of establishing freedom of movement by means of turning both shafts at the same time, but apparently that tells you very little. I am interested in your further opinions, and just how you assessed the condition of those steering boxes. Regards Styria

 

[s class]

HI styria,

I'm not the expert, but I have seen enough of them disassembled to have an understanding of how they work, and where the wear issues lie. I think your guys have a point that accurate assessment is only possible with the unit disassembled - but I don't think the scrapyard would have liked me if I'd left them with 50 disassembled steering boxes.....

So the next best thing is to check externally. If you grab hold of the pitman arm and jiggle it, any free play that can be felt is most likely due to wear in the teeth of the sector shaft and teeth of the piston. This is the clearance that is adjusted with the external adjustment. When assessing a box on the bench, it is necessary to adjust the sector shaft to establish if the play is due to misadjustment, or excessive wear. The ideal is if you can identify the high point. If you can, chances are good that the box has minimal wear.

The next check is to put a vise grip on the input shaft and jiggle it looking for free play. Any play felt here is most likely due to wear in the recirculating ball components, and there is no adjustment possible for this.

It is a bit of a gamble still - the steering box in my 280SE has only a hint of a high point left, but it is still very tight and precise in use. In the blue 6.9, I fitted a box that I had been very careful and meticulous with, and once I had assembled it, on the bench, these basic external checks looked very promising. I was therefore a bit disappointed that in use, it appears to have more slack in it than I would have expected. To be fair though, the car still has poor suspension bushes - and the ball joints are probably suspect too.

 

[BenzBoy]

Are new steering boxes available?
Regards,
Benz-Boy

 

[s class]

I'm not sure Benzboy, but I do know that MB can supply a new piston and sector shaft as a matched set - these are the components most prone to wear - but the set is expensive at around US$1000.

 

[Styria]

I have never checked on the price, but at $1k. US it is not cheap, especially as one still has the additional expense of seals and labor for the cost of dismantling and rebuilding - at least another $300.00 on top of it which may not even include the seals. Regards Styria

 

[BenzBoy]

No - not cheap but I keep hearing of issues with steering boxes so is it the only way to go to get a really first class unit? Given that many boxes have done high mileage and are getting on in years maybe it is the only alternative. If a box has lasted 30 years then in fact it is quite cheap.
By the way, how many of you have priced a rack for a modern car?
Regards,
Benz-Boy

 

[Styria]

Hi BenzBoy, the closest I can come to a steering rack for 'a modern car' is our Statesman, and my price for a rebuilt rack is $200.00 on exchange. Regards Styria

 

[BenzBoy]

Hi BenzBoy, the closest I can come to a steering rack for 'a modern car' is our Statesman, and my price for a rebuilt rack is $200.00 on exchange. Regards Styria

I guess that rebuit price is seals and fresh oil. I mean a quote on a worn rack where either the rack itself or the pinion needs replacing?
Regards,
Benz-Boy

 

[Styria]

I guess that rebuit price is seals and fresh oil. I mean a quote on a worn rack where either the rack itself or the pinion needs replacing?
Regards,
Benz-Boy

Oil is excluded as the guy only reconditions/repairs with removal/replacement carried out separately. The exchange cost includes renewal of bushes etc. and I would imagine that a worn out unit would never see the light of day in view of the fact that there would have to be hundreds available to choose from, unlike Mercedes items that were never sold in Australia on the same scale as a Commodore or Statesman. Regards Styria

 

[TJ 450]

An exchange rack for a Volvo 850 was $1000AUD a couple of years back. Dealer fitted it was about two grand... It makes the MB parts seem pretty reasonable to me, seeing as the Volvo had only done 130,000km!

Tim

 

[s class]

Benzboy, it may not be the only way to get good results. I have heard about a shop here in my neck of the woods that claims to be able to rebuild, re-machine, re-harden, and rechrome as necessary the worn teeth in sector shafts and pistons. I haven't given them a try yet, but I have some excessively worn steering boxes at home. Perhaps its worth a shot to see what these guys can achieve.

 

[BenzBoy]

This morning I went through all the past invoices for servicing on the Spirit and a new steering rack was fitted in 1997 by the proevious owner. The cost was $3995 for the rack plus 2.3 hours of labour. It was covered under warranty as the car had done only 30,000 at that point.
I guess that all helps put the costs associated with the steering box of a W116 into perspective.
Regards,
Benz-Boy

 

[SEL_69L]

Interestingly, I got hold of a completely new steering rack for my daughter's Pulsar for $250; they would not register the car until it was replaced. Not surprisingly, the steering is now the best feature of the car which is really quite good mechanically, but has a very obviously feral looking body on it. Her reasoning is that because of it's appearance, nobody would want to steal it.

 

[Michel]

Interestingly, I got hold of a completely new steering rack for my daughter's Pulsar for $250; they would not register the car until it was replaced. Not surprisingly, the steering is now the best feature of the car which is really quite good mechanically, but has a very obviously feral looking body on it. Her reasoning is that because of it's appearance, nobody would want to steal it.

The girl has a very valid point.....

 

[BenzBoy]

I raised this because Styria asked me for a price comparison.
Regards,
Benz-Boy