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Art Love

Australia
6226 Posts

Posted - 03/31/2010 :  03:02:37  Show Profile  Reply with Quote
You don't have to get them from Germany. Geoff Summers, an aeronautical engineer at the Gold Coast has had a lot of the brass housings reproduced. The steel levers don't wear out and are reusable. The problem I had with Geoff's units when I visited him back in 1995 was that he was using a round profile O ring rather than a square profile one in his toggle rebuilds. The square profile ones fail soon enough. I have no experience with any of Geoff's rebuilt valves, so my objection was theoretical rather than based on any hard core evidence. I know Geoff is still rebuilding valves 15 years later, so maybe I was wrong. In fact he has done 2 of the 3 valves I am going to use on my LWB Finnie sedan (he could not get the third one apart), but they are a totally different design.

I also believe that Neil Dubey has had new brass housing made if my memory is correct. The housings have to be swaged around the rod at their lower end once the new seal is inserted as Chris has already alluded to.

I was still able to buy new toggle units from Bosch in 1995 as well as seals. Here is a picture of some of the packets and a copy of the old faded invoice. You probably can't read any of it, but it is dated 29th June 1995 and it is for seals and two toggle units which cost me A$145 each back then, 15 years ago









Unless someone has some questions, I shall leave my discussion on how the valves work at this stage. Chris will cover it as well in his Lode Star articles better than me. What I did want to talk about a little was all the sorts of trouble I have had trying to rebuild these valves. I have already said the Geoff Summers could not get one of the early version valves apart. This was because someone had glued/Loctited it together. People who have not got a clue as to how these valves work and who don't want to spend money having them repaired properly do all sorts of dreadful things. Alex Black also told me that his biggest problem in repairing valves was trying to deal with damage caused by other people. I recall that when I visited Geoff Summers back in 1995, he had a pile of aluminium housings 3 feet tall against the wall at the end of his room. Neil Dubey had the same thing. Alex is running out of good housings.

So, I believe that we should all save the housings that we have and not do dreadful things to them, but send them to good people who repair them properly, several of whom have been mentioned here and elsewhere on this Forum. Here is a list of some of the problems I have personally had.

Unable to remove the inlet and outlet valves from their threads because of glue, Loctite, etc. The end of the valve has a small square recess in it. This recess is the only thing that you can use to unscrew it. The end is fine brass. I cut down a small flat screw driver to fit the recess perfectly and still got nowhere on more than one occasion. The brass broke before the valve moved.

As already said, unable to drive the steel locking pin out of the aluminium housing - end of story.

Unable to move the toggle unit up to release the small bottom shuttle between the pins of the inlet and outlet valves.

Having pushed the toggle unit up to release it at the bottom, being unable to get it back down. I have one sitting on the bench in an otherwise good body where the top lip of the brass housing just refused to come down into the bore - end of another story. You need special tools. I modified a pair of needle nose pliers to grab the lower ball on the toggle shaft, but there were still times that I could not move it.

Locating the toggle shaft at the top against the strong spring is tedious.

I have no way of rebuilding the inlet our outlet valves which I am told contain 13 individual bits/seals. I've never pulled one apart to find out. Ditto the high setting unit.

So, I am quite happy to pay someone who knows what he is doing $350 a valve to repair them, both from a time and cost point of view, and certainly from a piece of mind point of view.

I think it is interesting to have had a crack at it in 1995 and to have managed to rebuild valves that have done 10 years of service, but I don't want to do it again and I don't think people new to these cars, unless they have special skills and tools, should try to reinvent the wheel.

Questions and comments cheerfully accepted.
Art
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wbrian63

USA
900 Posts

Posted - 03/31/2010 :  08:08:41  Show Profile  Reply with Quote
Art / Chris

I have a question about how the valves handle transient inputs. If this is to be covered in Chris' upcoming article, I'll wait until then.

Specifically, what I'm talking about is what is used to delay the actual inputs to the valves from the levers actually causing air to be injected or released from the bellows? I would think one wouldn't want there to be a constant process of injection / releasing as the car bounces up and down the road during normal travel.

As an aside, I read with interest how the valves are designed differently to deal with the inlet and exhaust pressures present in the valve body. Years ago, while rebuilding a level control valve for my now-gone '66 Cadillac Fleetwood, I was amazed at the technology implemented to provide a mechanical control of air into and out of the air shocks. To be sure, this was not a full air suspension, but rather an air-assisted suspension, and only in the rear. However, the issues were the same - how to vent air when required to lower the car, and how to add air when needed to raise the car and keep it in the system, and also how to prevent constant +- activity while in motion. Cadillac's solution involved 2 Schrader valves - the type used in tire valve stems. On the inlet side, the valve was mounted with the actuating stem towards the inside of the valve - seal towards the pump. Since the pressure on the pump side was always higher than the pressure in the system, that kept the valve closed. When air was needed, the stem was depressed, allowing air to flow into the system. The exhaust side of the valve was a bit more ingenious. It used a modified valve, with a stem attached to the seal side of the valve - the stem had a head on the end. The natural pressure in the system (along with the spring inside the valve) kept the valve closed. When air needed to be vented, the stem was pulled, opening the valve and releasing the air.

The actuation of the valves was handled by a lever - one end resting on the inlet valve, the other, with a notch to slide over the valve-side stem of the exhaust valve, under the aforementioned head. The lever was connected through a viscous damper to the outside of the valve where another lever was attached to one of the cross-link members that supported the top of the rear axle. Movement of the arm on the outside resulted in movement on the inside, but because of the damper, only in a delayed fashion. Additionally, because there was no mechanical connection from the outside arm to the inside lever, large movements of the arm still only produced the small (about 3/16" either way) movements of the lever.

Air for the system was provided by a diaphragm pump that ran off engine vacuum. It had a reservoir tank of perhaps 1.5 quarts volume attached to it. The diaphragm was about 5 inches in diameter and they acted upon a piston about 1/4" in diameter. Stroke was perhaps 1/4 inch. 14" of vacuum was more than enough to produce amazingly high pressures in the tank - albeit very slowly. I attached a 200psi gauge to the test port of the tank and the gauge was pegged most of the time... A fully exhausted tank took about 10 minutes to fully pressurize at idle. There was a regulator on the tank to limit the air going to the shocks to about 125psi - the limit of those devices. The air inlet to the pump was off a hose that attached to the air cleaner, inside the perimeter of the air filter. Unfortnately, there was no drier fitted to this system, so most of the reservoirs failed due to rust.

Sorry to divert the thread...

Regards

W. Brian Fogarty

'02 S55 AMG (W220)
'92 300SE (W140) - sold
'76 450SEL 6.9 Euro #1164 - parted & gone
'76 450SEL 6.9 Euro #521

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter VII
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Chris Johnson

USA
3751 Posts

Posted - 03/31/2010 :  11:00:58  Show Profile  Reply with Quote
Hello Brian,

This system does operate with potentially constant inletting and exhausting of air. On a rough road, the system will be very busy.

This is a large part of the reason why the system uses a constantly operating, high reliability air compressor and has a relatively large air storage tank. The system has a number of throttles, in the form of small diameter bores, to slow down the transfer of air though.

There is some small amount of "dead play" in the height control valves, but this is frequently misunderstood to be to furthur mitigate the amount of air flow in the system. This is not true, and the amount of dead-play is generally set to a much greater value than is actually needed, or desirable.

Note that this system is truly an extremely reliable system, with failures occuring in the rubber seals, not the mechanical parts.

Chris Johnson
If you aren't constantly impressed with your car, then it needs fixing.
100.012-12-000790
100.012-12-000867
www.300SE.org
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jeen

Netherlands
10 Posts

Posted - 03/31/2010 :  13:34:20  Show Profile  Reply with Quote
http://w-100.de/cms/index.php?option=com_content&task=view&id=9&Itemid=23

It seems like this company selling the single parts.

Jeen
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styria

Australia
231 Posts

Posted - 04/09/2010 :  02:28:07  Show Profile  Visit styria's Homepage  Reply with Quote
What a fascinating subject this is, and the many headaches it seems to create. For anyone interested, I can supply fully rebuilt valves for the later 109 models at a price of $380.00 each on exchange, plus postage. They are fully warranted for a period of twelve months.

For oversead customers, i.e. US and Europe, there is a core charge of $A 200.00 or, preferably, if you send your old valve first for examination to suitable reconditioning, there would be no core charge. But the valve taken in exchange should not have been interferred with in any way.

I read Art's post with a great deal of interest. I have just fitted two front valves, but waht my work somewhat more difficult, was the fact that all the fixed steel pipes had been removed as well. So really I started off from scratch and just fitting the steel pipes temselves that connect the two valves is frustrating, as well as time consuming. As Art says, you must not cross thread any of the fittings.

You can also contact me on my webpage, namely 'topklasse.net.au' - some M100 members are already contributors to the site. Regards Styria

"My Gleaming Beauty"
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Art Love

Australia
6226 Posts

Posted - 04/18/2010 :  02:21:53  Show Profile  Reply with Quote
I've been removing the three axle valves from the W112 300SE coupe to send them away for rebuilding. The rear stays up, but I'm sending it anyway. So I took the oportunity to use my little Kodak camera to take some shots as I went along in the hope it will be useful to someone. The car is back home here, so it is on stands, not the comfort of the hoist at Justin's. We also have a jack under the front subframe to give it and the motor a bit of support while the stands hold the body.

The left front valve is the worst to get off and worse still to get back on. The W112 is easier by far for this valve than the 6.3 which has steel pipes to all 7 connections. The time to do the 6.3 valves is when the front subframe is out of the car for any reason. It is a dog of a job on the car.

Further down is a picture of the left front valve after I removed it. It has two high level connections to the brass part. It has an end inflow connection on the left and a lower inflow connection on the bottom side at the left. In the middle on the bottom is the connection for the left front air bellows. On the right are the two outflow connections, one at the end and one at the bottom. In contrast to the 6.3, in the 300, three of the connections have hoses attached rather than steel pipes making life easier. The two end fittings and one of the high level fittings have the hoses.

I undid the end E fitting first. You can see the threaded fitting in the middle of the picture at the top. The hose allows the end to move a long way out of the way. I then undid the three bottom fittings, doing the E nearest the camera first, then the B in the middle and then the A last. At the time I took the picture, I had just started on the far A fitting with my 14mm open end spanner on the brass attachment on the valve and the pipe spanner (flare nut wrench) on the pipe fitting. Squeezing the two spanners together cracks the thread. Then you have to use an open ended 12mm spanner to undo the rest.





This is RHD but you can see how the steering mechanism is in the road. I've undone the two high level lines as well. You can't use the two spanner technique on them, because there is nowhere for the 14mm spanner to go. There is not much room up there. You can see it better in the pictures I took on the other side. You can see that I still have the ball joint for the control rod intact. That was not deliberate, it just happened that the lower ball on the lower control arm let go before the one on the valve arm.

This picture is a bit fuzzy but it shows the bottom E,B and A pipes undone across the bottom of the valve unit.





This is similar from a bit further back.





I shoved the camera up behind the steering damper to take this. I didn't see it from this perspective myself. Note the in the past, someone has had trouble with the nut on the A fitting rounding off and has filed it down to a square 10mm.





You can also see that I have the valve retaining bolts loose and in fact, the right one is out. A 13mm long socket spanner did the job for them on this side as there was plenty of room.

And, after all that and the nice pictures of the two spanners, the pipe spanner just rotated on the far A fitting, so I gave up last night when I did that job and started again this morning with the vice grips to release that fitting, again with the 14mm open ender on the valve end. So that will be another thing to fix before the unit goes back in. Here is a picture showing where it came from. At the top you can see the two high level lines above and in front of the end E hose fitting. The three lower pipes are obvious with the B line sticking up more than the other two. At the far end you can see the A hose end fitting. In the middle is the bracket with the two welded nuts at the top.





This gives a good view of the two high level pipes (the inflow one from the master valve is a hose). That's the B line tracking up to pass inside the trunion where it should be protected by two thick rubber hose spacers.





The set up is the same on the 6.3, you just don't have the luxury of the rubber hoses. Here is another general view.





And it is out





Now the right side. This should be pretty straight forward on LHD cars. On this car, the steering box and arm are in the way. There are three less lines, one high level and the bottom A and E lines. You can again see the B line tracking up behind the subframe to go across the top to the bellows, missing its rubber protective hose. I've bought a metre of the hose to fix this up as well as to use on Justin's and other projects.





Here is a close up. I've got the control rod off the correct end this side. That's the front of the power steering box and steering arm protruding in from behind. No room for a socket here. You can see that I have got the B line started. If it won't undo with fingers, it is tedious, because there is only enough room for a part turn of the 12mm spanner which has to be repeatedly reversed. This applies a lot doing this. The E line just above the control arm is straight forward on this side.





I've cracked the high level line with the pipe spanner and have managed to get my hand up in there to undo this line with my fingers.





Now I'm working on the A fitting at the far end. That funny looking yellow thing is the palm of my hand squeezed in above the steering arm in front of the power steering box with my trusty 12mm spanner. I've already done the two spanner trick to crack it. You will notice that the rubber spacer is missing from the bracket holding the three lines to the back of the subframe in the distance. That is another job for me. If it were there, I would loosen it anyway while working on this line, particularly when reinstalling this valve.





I've decided to release the unit before I finish undoing the A line because I can't get it free enough to use my fingers, and there is no room to swing the spanner. So now I am undoing the two bolts, outer one first. With the power steering in the road, I cannot fit a socket and am using a closed 13mm spanner. You can see the end of the released high level line above the end of my thumb.





Here is another view of the same thing.






Now I'm onto the inner bolt. I remembered when I changed this valve recently that the bolts had to go into the unit before the unit went into place, because with the unit in place, there was insuffient room to get the bolt into its hole because the power steering box was in the way. I don't know if that is the case on the left in LHD cars, but it is worth bearing in mind.





Now with the unit free, I can get my hand in to undo that A fitting with my fingers. That's the brake line ruining the picture. There really is not much room.





And it's out.





Couple of shots of where it came from.









Now the rear one.









This is very accessable with the exception of a problem I recall having before. That is getting the high level fitting undone. The two spanner trick works easilly here on the A,B and E lines. As at the front, there is nothing on the valve unit for the 14mm spanner and I found there was only one way I could apply the pipe spanner (flare nut wrench I think you call it) and that was in the most mechanically disadvantagous position for my hand. You have to undo the fittings before you undo the two bolts, and at the rear, the nuts are not welded, so you need a 13mm socket and a 13mm spanner.





When the units come back, I'll complete this thread with some words and pictures on reinstallation. Hope it is all helpful for someone.
Art

Edited by - Art Love on 04/18/2010 02:37:59
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werminghausen

USA
771 Posts

Posted - 05/23/2010 :  11:48:46  Show Profile  Visit werminghausen's Homepage  Reply with Quote
I offered to share my limited experience on air valves.
For the story: I have bought a 'sinking' 300SEL and was reading about the valves and decided to take them apart because I am just interested if they are repairable.
I took the 3 valves completely apart and was machining 'sleeves' for the 3 valves stk, e and a.
before taking the valves apart I was analyzing them. I built a test stand and did pressure tests in order to figure out what the problems are. I found stk faulty in all cases and also the e valve is suspect. a valve was good in all cases.
I wanted to figure out what the tolerances were in operation. I mean when the car is standing and I press it down by my weight at what tolerance does the valve start adjusting: some people said 1cm but have no reliable source. 1 cm could be translated into an angle difference of the main lever on the leveling valve. I expect the angle difference less than 1 degree before the stk valve will operate the e or a valve?
I am collaborating with a friend in Germany (he is working for Bosch in Stuttgart) who has access to a tiny lathe because the valve bodies are so tiny and relatively precise that a regular lathe can't be used. Also the tools for machining the parts need to be special. So i understand today why remanufacturing these valves is expensive and why there are some mystical tales around these valves.
Right now I have machined all new valve bodies according the old bodies which need to be destroyed if you want to harvest the inner parts. Precisely the flanging of the parts is the reason they need to be destroyed.
stk is the most challenging part of the 3 and the main cause for our sinking cars. I changed the design of the custom Bosch o-ring, therfore changed the original design in detail at the ball seat to a standard seal ring and did tests. The first pressure tests at 10 bars were sucessful.
If you are interested I can tell you more. Martin
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Ron B

Australia
11612 Posts

Posted - 05/23/2010 :  18:50:17  Show Profile  Visit Ron B's Homepage  Reply with Quote
yes please!

quote:
12-14-2004, 11:49 PM #8
Tom Hanson
MBCA Member

What the heck, try to stuff a MB 6.9 liter V8 in it. What a machine that would be..
__________________
Tom Hanson
Orange County Section
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Art Love

Australia
6226 Posts

Posted - 05/23/2010 :  18:57:33  Show Profile  Reply with Quote
Keep going Martin.
Art
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werminghausen

USA
771 Posts

Posted - 05/27/2010 :  01:18:06  Show Profile  Visit werminghausen's Homepage  Reply with Quote

My questions to the knowledgeable people here is: When I assemble stk, e and a valves into the valve body back- what are the correct adjustments. What 'play' has the toggle before it activates a or e?
I would appreciate your comments here. Martin

Edited by - werminghausen on 05/27/2010 01:23:15
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Art Love

Australia
6226 Posts

Posted - 05/27/2010 :  03:50:44  Show Profile  Reply with Quote
Martin,
I'll have to undo the B fitting on one of my spare valves to answer that. Not sure when that will be, but I will do it for you.
Art
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werminghausen

USA
771 Posts

Posted - 05/28/2010 :  17:11:37  Show Profile  Visit werminghausen's Homepage  Reply with Quote
quote:
Originally posted by Art Love

Martin,
I'll have to undo the B fitting on one of my spare valves to answer that. Not sure when that will be, but I will do it for you.
Art



Thanks Art
My 2 questions are:
1) What is the set angle for the exterior lever for Neutral (no activation for e or a .
My guess this angle is 15 degrees (+ 1 degree according my analysis) down from the horizontal. Please confirm.
2) What is the tolerance of lever movement when e and a valve are activated? The tolerance is +/- 2.5 degrees according my analysis of the 3 valves I took apart.
I heard Michael Brockhoff saying that the air valves are adjusting at a height difference of 1cm! I need to get these 2 questions confirmed before I put the valves back together.
Any help here is good. Martin
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Art Love

Australia
6226 Posts

Posted - 05/30/2010 :  06:10:27  Show Profile  Reply with Quote
15 degrees seems correct to me. I had trouble working out the other measurements. It is hard to tell when the valves open and close without an air feed and with the shuttle in place, I can't see when the toggle engages the A and E valve pins via the B port. By feel, what you say seems close, but I had no way of measuring it. In reality, the sensitivity of the lever is dependent on how far in the A and E valves are screwed. I don't know and never did know whether they are screwed in to the limit of the thread in the valve body, or whether there is a set position. The other problem I have had is that with the exception of the two front valves on #1702 which I bought new, I have no way of knowing whether the settings on the valves I have are factory.

Almost invariably, someone has pulled them apart at some time in the past trying ignorantly to fix the air leak that is usually due to failure of the centre seal in the pivot. When I pulled a spare valve apart yesterday to see if I could answer your questions, I found a cast of the valve body bore in silicone sealant in the A valve housing. At least the valves had not been Loctited in as I have found in the past and unscrewed without damage. Hopefully your friend at Bosch can access this information for you.
Art
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werminghausen

USA
771 Posts

Posted - 05/30/2010 :  13:44:25  Show Profile  Visit werminghausen's Homepage  Reply with Quote
quote:
Originally posted by Art Love

15 degrees seems correct to me. I had trouble working out the other measurements. It is hard to tell when the valves open and close without an air feed and with the shuttle in place, I can't see when the toggle engages the A and E valve pins via the B port. By feel, what you say seems close, but I had no way of measuring it. In reality, the sensitivity of the lever is dependent on how far in the A and E valves are screwed. I don't know and never did know whether they are screwed in to the limit of the thread in the valve body, or whether there is a set position. The other problem I have had is that with the exception of the two front valves on #1702 which I bought new, I have no way of knowing whether the settings on the valves I have are factory.

Almost invariably, someone has pulled them apart at some time in the past trying ignorantly to fix the air leak that is usually due to failure of the centre seal in the pivot. When I pulled a spare valve apart yesterday to see if I could answer your questions, I found a cast of the valve body bore in silicone sealant in the A valve housing. At least the valves had not been Loctited in as I have found in the past and unscrewed without damage. Hopefully your friend at Bosch can access this information for you.
Art


Hi Art,
as I mentioned before I have built a test stand in order to test the operation of 3 old valves. I built a jig for in order to know at what angle the lever is during testing, then I connected the E /A /Stk with a special fitting in order to apply air pressure. For air pressure and measuring pressure I was using my A/C gauge set.
The setting I described (15 degrees +/- 2.5 degrees) are about what I tested on the 3 valves I have taken apart.
I am very sure that e and a valves were adjusted by Bosch - therefore the locking screw with the cross in the middle.
Unfortunately all knowledge about these air valves has faded within Bosch. The only sources are a handful of people on the planet trying to keep the secret.
Martin
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Art Love

Australia
6226 Posts

Posted - 06/02/2010 :  06:15:54  Show Profile  Reply with Quote
I promised to continue this thread when the rebuilt valves came back. Well, they have.





So, I decided to start wth the easiest one. It's about 10-15 years since I last this this job on a complete car and it has not got any easier. It keeps me humble and every time I think my mechanics are charging me too much for labour, I think of this job and feel better. So lets start as I did this afternoon. Let me say that it is easier to take pictures of someone else doing a job than taking pictures of yourself while upside down under a fuel tank, so don't complain about the quality of the shots. I'm getting too old to be under a car on jack stands as I have said before. Here is where I left off.









Here is a useful ingredient that you have seen before in my postings from Justin's shed. This is to show that I have a can in my garage as well.





I think it is sensible to start with the most difficult line, or the one you released last. On the rear valve, that is the high setting line. I also think it is essential to have the valve free when you are trying to fit these lines. If you bolt it to its bracket first, it is my experience that it is next to impossible to line up the pipes and get them started in their threads. So, leave the valve loose and connect up the lines then mount the valve. You'll see this as we go along. It is also essential to start all these lines with your fingers. The threads are very fine and particularly with the high setting line, you are screwing a steel thread into a brass thread and it is very easy to cross thread and cause permanent damage. Take your time. when you get jacked off and angry, take a break. And I can assure you you will get jacked off doing this job.

So her we go with the high line. At least at the rear, there is only one high line.

















Have to go up and have dinner or I'll be even deeper in the manure. More later.
Art
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