Restoration Difficulty Level

[Garry]

Mine is September '65

[Rolf-Dieter ✝︎]

Bob, I like the way you think when you tell people "BCW" I have to remember that

[andyburns]

Hi Lin,  the powder coating process only heats the springs to around 70 degrees so will not effect the spring tempering or spring rate.  The first time I coated springs I went to a great deal of trouble to research this process and actually stood by and watched while they coated my parts.   Depending on the type of powder coating the temp will vary.  Some high performance coating such as what I am just about to put on my manifolds will be heated to a higher temp of around 200 but all the cosmetic coatings should be applied at much lower temps.  The coater I use has an infrared booth which further reduces the temps.

The ovens at my coater were all computer controlled reached exactly the designated temp.  Coincidentally this is a topic I know well and find really interesting.  By trade I am a software engineer and have worked for a heat treatment company here in NZ writing software to control a dozen or so large industrial furnaces.  Over the years I have worked closely with some of the top metallurgists in NZ and have picked up quite a bit of knowledge on the topic.   It come in really handy when I have needed it.  Mainly done it for strengthening and stress relief of welds to stop fatigue cracking. Check the web site out if your interested, from an engineering perspective a really interesting place.  They have helped me immensely over the years with various bits and pieces.  http://www.safegroup.co.nz/

[Valvechatter]

Andy,
Thanks for your response and for my continued education. I have to pick up some Jag parts at my powder coater soon, so I will ask about his maximum temperature. I am certainly relieved to learn what you had to share. I am now on my third, and probably getting into a fourth hobbyist restoration. It is amazing what I have learned through this hobby over the years. Thanks for sharing your knowledge and the web site. I really appreciate your restoration thread and all the work that you have done yourself. I try to do as much myself as possible, although, I am not a painter.

Thanks again and best regards.

Lin

[andyburns]

Hi Lin,  I love to share stuff I know about and soak up other people experience as well.   I was chatting with Barry the owner of South Auckland Forgings this morning and discussing with him what I had said on the forum just to be sure I was sending you in the right direction.  He has been in the heat treatment industry all his life and what he doesn't know isn't worth worrying about.  I asked him again about springs and what tempreature would start to have and impact.  He is adamant that until you get steel to at least 400 your not touching any of its performance characteristics.  He was saying that the material the spring is made from is by far the most determanant factor of how the spring will perform.   I am going to run with his recomendation and get the springs powdercoated.

I was talking to him this morning as I am just about to cut down my steering column in order to fit power steering to the car.  I dropped off a column to him previously for one of my other cars and asked him to cut and weld it.  Without even discussing he did all this deep analysis on the shaft to determine the best and safest way to weld it up.  They have a mass spectrometer which can analyse any carbon based steel as well as stainless.  Check out his OTT fix.  ->

Hi Burnsy. Please see my report below re the modifications to your steering column.
 
The existing hollow column of 18mm diameter was analysed as 0.07%C, 0.3%Mn. This indicates a soft deep-drawing mild steel. Prelininary hardness tests indicated an approximate Ultimate Tensile Strength (UTS) of 550 MPa. This result (high for this chemistry), together the low ductility exhibited during analysis, indicates extensive cold working during original manufacture.
The column was cut to required length, and an AISI 4140 high tensile Cr-Mo insert pushed into the column to join it together again. The insert had a flange in the middle of 18mm diameter, and it was around each side of this flange that the joining welds were made. The assembly was preheated to 200degC and welded using high tensile low hydrogen electrodes. Porosity was evident in some areas around this weld, and these areas were ground out then preheated and repaired using TIG process.  The insert extends 100mm+ into each half of the column, and approx 80mm along each of these inserts legs and longitudinal slot was ground in the column, then welded up per the above procedure. The purpose of these welds was to assist in torque transfer through the insert rather than just the joining weld.
After all welds were finished the welded area was post-weld heat treated at 500degC. This was to relieve welding stresses, lower any hard areas in the weld, and change structure to tempered martensite.
During fairing-out the diameter of the welded joint was reduced from 18mm to a minimum (spot measurement) of 17.25mm. This is deemed not to have any detrimental affect on the strength of the assembly, as it occurs within a region fully supported by the high tensile core. It should be noted that the smallest diameter of the column at the point where the drive spline commences is 16.6mm.
 
Yours faithfully,
Barry Robinson
S.A.F.E  Engineering
Ph  ++64 9 2948437
Fax ++64 9 2948431
Cell   027 2864722

[andyburns]

Started ripping apart the donor car this afternoon.  Dear old girl.  In one way it seems a real pity picking its bones!  The 113 seems to have lots of parts in common with the 108.  Primarily brought the car for the power steering gear but it will no doubt have hundreds of bits and pieces that might come in handy.  Got as far as draining the oil in the dark and pulling out the radiator.  Need to get all the power steering bit and pieces off to the powder coaters.  Not looking forward to getting out the steering box and hard lines on the bottom of the engine.  If anyone needs any bits and pieces let me know.

[DaveB]

I found it hard to get adequate photos:

[DaveB]

There are a few of these early exhausts on ebay USA with photos showing some detail of the finish.

http://www.ebay.com/itm/171088497641
http://www.ebay.com/itm/380687456350
http://www.ebay.com/itm/220950632654

Do you really think they look amateur?? Pretty nice welding. It seems they used cast pieces coming off the head, welded to the tubular steel pipes, welded to the flanges. Quite a complicated exercise.

[DaveB]

I have been using a period Mercedes factory spring compressor to decompose the sub frame.  This tool is, in my humble opinion, as much a piece of art as the car is in its own right.  Superbly designed by a master tool maker.

You do have a very nice tool sir.
But, err, how does it work? I'm only familiar with those that come in pairs and grip the springs externally with claws.

And the steering column job! Yeah, OTT and brilliant.

[stickandrudderman]

But, err, how does it work? I'm only familiar with those that come in pairs and grip the springs externally with claws.

Holy carp! Do not use those spring compressors with the external claws, they are lethal.

The tool shown is a threaded telescope with keys at each end. Two plates have key-ways in them and these plates are inserted between coils in the spring and then the telescopic tool is inserted through the plates (through the middle of the spring) and then rotated  90° to lock the keys in place. The bottom of the telescopic tool has a hex machined in it with which you rotate the threaded inner section and thereby reduce the overall length of the tool and hence the length of the spring.

Simples!
Much, much safer than the external claw tool and Klann do a very nice version which I've been using for about 20 years without failure.

[DaveB]

It does sound safer with everything contained within the spring if there's a mishap.

[andyburns]

Dave,  when you see it in action you would melt, especially if you have ever used external clamps.  It makes the DIY clamps look stupid.  The overall construction of the tool is phenomenal.   Quite a strange fascination I know.

[DaveB]

Where do you find one?

[andyburns]

Think you either get lucky on ebay or know a retired mercedes trained mechanic.  I took the former route.

[andyburns]

Dave, thanks for the photos of the extractors.  The look very similar in construction to mine except obviously dont loop forward like the rhd version.  Am picking I would have horrendous trouble replacing the ones on my car.  

[DaveB]

Yep the RHD headers differ from the LHD as you say, and would be hard to replace (don't drop them). There are apparently also some accelerator linkages and bits & pieces that are specific to the header version cars.

[andyburns]

The old W108 gave up her power steering components today.  She didn't let them go without a fight.  Two stripped cap screws that needed to be drilled, and one ball joint so tight it broke the ball joint splitter!  All in all not an easy job.  Took 4 hours in total.  Will purchase some repair kits and get the pump and the box resealed before painting.  Also have to finish off shortening the steering shaft.

[GGR]

I think I read somewhere that the Pagoda steering shaft being collapsible, it doesn't need to be shortened. There may be something to be done where it collapses, but no modification to the shaft itself. I don't remember where I read that, but it was on a forum where someone was also embarked in putting a power steering in a Pagoda and was to shorten the shaft before he discovered there was no need for it.

[stickandrudderman]

Where do you find one? Smiley

Klann do a very nice version which I've been using for about 20 years without failure.

[w113dude]

I think I read somewhere that the Pagoda steering shaft being collapsible, it doesn't need to be shortened. There may be something to be done where it collapses, but no modification to the shaft itself. I don't remember where I read that, but it was on a forum where someone was also embarked in putting a power steering in a Pagoda and was to shorten the shaft before he discovered there was no need for it.

I just finished doing the conversion on mine, my car did not come with power steering either, after a couple of hours of struggle i was able to make it work, it had to be cut no other way to do it, the steering shaft has two notched lock settings even then i had to extend the notch to make it fit perfect.

[andyburns]

Guys, I am not certain about the 113 shafts but the W108's started life with a solid shaft in 1967.  There were a couple of terrible frontal accidents where the solid shaft was forced into the cabin and speared the driver.  I have read they even called it the 'spear effect'.  Within one year they had redesigned it to a two piece collapsible shaft.  At the steering wheel the shaft started off round but was extruded down to a box section 3/4 down the shaft toward the pedals.  The second half of the shaft slipped into the box section with quite a tight tolerance.  In an accident the two pieces simply slide over each other.  If you are lucky enough to be doing a conversion on a car with this system and need to shorten it to take power steer, you simply give the short piece of square tube that fits up to the steering box a bit of a thump with a heavy hammer and it slides into the other section by an inch or two.  I suppose you are shortening the travel on a safety item which isn't too flash but unless you have a critical frontal it probably will be just dandy and save you a whole swag of time and effort.  One thing I am big on is saftey and think that if you ever undertake anything like this and it fails then someone could loose a life.  I dont think welding is a good idea on a component like this unless you have a very high level of knowledge on how to produce a 'strong' weld that is equal in strength to what you have just cut.  I have heard stories of people with limited abilities cutting and welding these shafts in their back yards.  In New Zealand the law is quite clear on this as well.  Any modifications to ANY steering or suspension components away from the manufactures design have to be certified by an engineer who understands the physics behind the modifications.

[andyburns]

Guys, would love some help on this one.  Before I go head first into shortening my steering shaft I am a bit worried about a few things.   The first is if I cock it up in any way how hard would it be to get another shaft.  I have a left hand drive shaft available to me in the states but am wondering if its the same as my RHD version or if its an early or late one. 

Second concern is that I have done all the measurements this afternoon and it looks as if I need to shave exactly 40mm off the shaft.  This would push the coupling right up into the shroud that bolts to the inside of the car.  I am really worried that it would make access really difficult.  For a start you need to get a spanner onto the coupling clamp that holds it onto the spline.  Secondly when in place and the pins are slipped into the mating steering box there are a couple of tiny clips that slide over the pins in order to prevent the coupling from coming apart.  Even when they were away from the fire wall by 50mm they were little buggers to get your fingers into.  What the hell will it be like now with as little as 5 to 10mm of finger gap?  If anyone could shed some light I would be most appreciative.  Someone must have done this or have removed a factory 230 system and seen exactly how its done.

[andyburns]

Another pic I wouldn't mind floating is a telescoping W108 shaft.  The early 108's had a round shaft much the same as in my early 230sl.  The were definitely not telescoping and had to be cut and welded.  The latter ones changed to the pictured configuration and were square which made them easy to identify.  Are the latter W113 telescoping shafts square/rectangular as well.

Also has anyone had the end of an early shaft re splined rather than having to resort to cutting and welding.  I would prefer to go down this track if possible.  Seems a cleaner solution.

[GGR]

Yes, the coupling end up into the shroud. The way I did it was to keep the shroud loose up the steering column and fasten the coupling from inside the foot well. Then lower and fasten the shroud.

[andyburns]

Thanks GGR.  Now you have pointed that out I feel stupid for not picking it.   I thought the shroud was welded to the shaft and didn't move.  The clamp should have been a giveaway.   Next piece in the puzzle solved.  All I need to figure out now is how to pull the shaft out of the column.  The 108's are easy as its a single rod but this one must be in two pieces as its bent in the middle.  Can you easily just pull out the low shaft somehow.  If anyone can describe this to me I can take photos as I go for anyone else thats keen.