6.9 front suspension not raising

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Styria

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Well Mark, I need to own up to the fact that I fell into the category of trying to hit the nail in the dark. That practice served me well right up to the time of the latest 6.9 problem. I don't really want to tell you (and probably don't know anyway) how much time I spent on this in an effort to try and get the car to come up in the front. I even went so far as to fit components from Gleaming Beauty (which had been working well) to Fontenay's 6.9 without success. It's when you get more than one faulty component in the system that diagnosis becomes tricky, or just about impossible. I guess there is the other consideration - if the parts were cheap enough and/or readily available, we wouldn't be talking like this, nor would we have to compromise and/or improvise to effect satisfactory repairs.

I also cast my mind back to B13 (Ian) and his impassioned plea to solve leakage problems on his 6.9. We were lucky enough that the guy in California, whose name unfortunately escapes me now (old age !)actually came in with his solution that obviously works well, but I have absolutly no idea if B13 has ever done anything about his problem/s. As the situation stands at the moment, I can confidently offer rebuilt struts and pressure regulators with a six months no question warranty and, of course, if there is a bulk deal in the offing, you reduce your price accordingly. The only proviso is that the exchange units offered (and required) could be tampered with - for instance, in ChrisP.'s case, the little distribution valve that he sent in exchange was worthless - some turkey in WA had butchered it beyond re-use.

As a matter of interest, Mark, are you getting any closer or further down the track with your projects ? It is unfortunate that just about none of our members are doing any work on their 116s and 107s, so there is not that much to write about. MAYBE THAT IS THE MAIN REASON FOR WANTING TO BROADEN THE HORIZON OF TK. WITH ADDITIONAL FEATURES AND INFORMATION. Make sense ? Regards Styria
 

Michel

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Excellent explanation Godfather.

Obviously, I was privvy to all of this as it was unfolding, including the frustration on the part of Styria as days went by with no results. :(

We talk about it regularly on The World on Wheels (radio programme) with our resident technician Dr Terry, who is adamant about doing a proper diagnostic before simply changing components that needn't be touched.

Well done Styria!
 

Oversize

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The suspension is just like any other system like fuel or spark. You have to ensure the supply is correct, BEFORE you start checking anything else.

One thing that a wise MB trainer told me years ago. He asked the class, what do you check when a car won't start? After various anwsers including fuel, spark etc he said you have to try to start it first! Often the customer has the description of the problem completely wrong....

And to answer your question Styria my New Year never got off to a good start. My partner's been in hospital with severe back pain since just before NYE. I had lots of time off and had big plans but they're now on hold. :(
 

Styria

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Hi Mark, I can really feel and sympathize with you regarding your partner - as you know, I have had my share uf lay-off with my accident that now goes back to May of last year. Indeed, it is only just Friday past that I have returned my four legged walking stick back to the hospital. One can only hope that your partner will recover quickly. Believe it or not, but my partner had also been in hospital and unwell for several weeks in, I think September or October, and my visits to her in hospital were hampered by a long walk from the Car Park to the wards, and that gave my left knee renewed 'curry' and caused my right heel to become very painful on account of 'fresh loads' being imposed on parts of the body that hitherto had not been affected.

Let's hope yopu can get back to your cars soon. BTW, I do think that you have come across my PDF documents that I had previously submitted to TK - do you think there is anything else that should be investigated or talked about ? Incidentally, I have come across this link submitted to TK previously - it makes good reading and credit needs to be paid to John Erbe for providing us with all the information.

N.B.Apologies for Moderator post. It just gets away from time to time. Importance is the info provided, doesn't always matter where it comes from. Also, still looking for that John Erbe post.
 
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SEL_69L

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There are two types of leaks in the hydraulic suspension system: Those you may be be able to see (external) and those you may not be able to see (internal).
It is the second sort that can occur in the struts or one of the valve bodies. I this case these components can be suspected as have having developed a fault.
It is nice to know that these components can be refurbished. Twenty years ago there was a tendency for struts to be replaced, rather than re built.
 

Oversize

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Styria

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Yes Mark, I understand. I primarily raised it because it came up as an associated link, but I am also encouraging, or trying to, get B13 back on line to see how he solved his problem/s (if he did), also leaking hydraulics vs. steel sprung suspension, remedies available etc. etc.........Regards Styria
 

B13

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Hi Styria, progress has been nil. Unfortunately life gets in the way and you know the leaks from the system aren't that bad. The whole plan to convert to springs went a bit like this:

July: I decided to put my car on club plates when its rego was up in Sept(club plates being $130/yr vs $690/yr for normal rego). But to get on club plates required a roadworthy certificate.

Sept: Put the car in for its roadworthy test and they decided the car needed 4 new tyres, lower and upper front ball joints, three hydro struts, and rear level control valve.

Oct/Nov: procure parts and data to convert to coil springs, I also bought new lower ball joints and a new set of 215/70-14 tyres. Finding out the upper links with ball joints were NLA was making me even more frustrated.

Dec: as the 3 month grace period from when your rego expires and you can still pay it was fast running out, I shelled out the $690 and paid up another years rego.

Jan: you know in all honesty the leaks from the suspension don't even bother me, its so minor its just 1 litre of Penrite MB15 suspension oil every 4 months. It's the authorities which have the problem. This leak has been more or less present for the 5 years I've had the car and I've just learned to live with it. The steering is still a bit ordinary because all those ball joints need replacing and I don't see the point in replacing the bottom two without doing the top two. However now I've gone back to 215 series tyres on 14" rims instead of 245 series tyres on 17" rims, the steering feels much nicer to use now.

So I'm back driving the car around normally with its nice new tyres, I've paid its rego, topped up its suspension fluid, and enjoy the ride. I'm at a point where if the car sits for 7 days or more it needs to have the suspension pump primed prior to pressurising and just smile at it that the car has character. If I drive it every day, or every 2nd or 3rd day I'm greeted by the suspension warning light which goes out after 20 seconds.

I'll try again this August to get it through a roadworthy again. Never know my luck if I wash under the car before presenting it.

I.
 

Styria

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Hi B13, thanks for bringing us up to date. I had wondered how you had fared in the end. Leaks from the suspension system need not always spell the end of a 6.9, but it does depend to some degree on what part is leaking. Poor Chris, whose experience is responsible for this thread, was unfortunate to be the victim of some overzealous Inspector, and his subsequent problems can be sheathed home to mechanics not familiar with the system - and he's been suffering ever since.

I think it needs to be stressed that hydraulic oil will find the slightest source of leak, but it doesn't always mean that the system will not work. I have had no end of trouble curing leaks around the pressure regulator area, and unfortunately the stuff spreads like wildfire underneath a car. In your case, Ian, if the system works, and works well, the system should not lose pressure. If it does, there is a weakness as far as pressure is concerned. You often get the situation where the back will work, but the front stays down - all to do with systems pressure - the front is heavier, isn't it, and there just may not be enough pressure to lift the front. One needs to find the source of the pressure loss.

Also, one often reads that "they're running the engine to 2500rpm for a couple of minutes to build up pressure. That may work, but I have found that with a "good" system the pressure starts building up almost immediately, and without having to rev the engine unduly. Anyway, I am glad that you have the car running again - BTW, I do have replacement upper links - genuine 6.9 (cast iron), but only on exchange basis with similar material. I cannot accept alloy units. Regards Styria
 

john erbe

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Styria, as I've got no use for the hydro system I'm complelled to maintain a low profile. Nevertheless, lot's of luck to those that continue the endless battle.
 

Styria

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This is an old topic, but nevertheless one that needs to be understood as to its workings, and what actually makes the system work. I do the work and testing with a fellow 6.9 owner who is an engineer and is also able to interpret the instructions and descriptions advocated by Mercedes Benz to have the system working properly.

We have come across a new set of circumstances that hitherto we had not come across, and it is related to the workings and pressure values of the Pressure Regulator. For it to perform its function properly, there have to be cut-in pressure points, as well as cut out points. We had the situation where there was sufficient pressure to raise a car to the high level. It took a bit of time as the cut-in pressure was no better than marginal, but the car did raise to the higher level once the disc was moved accordingly. However, lo and behold when we returned the disc to the lower setting, the car did not come down to normal. What was happening was that the Pressure Regulator was unable to release the high level setting as it could not de-activate the pressure required to activate the lowering values.

We changed the Pressure Regulator to one that I had serviced, and which attained the required high pressure reading. The result ? The car came down to its normal height within a matter of ten seconds.

All this takes time, patience, testing equipment and a full understanding how each component, at various settings and functions, and functions interact with each other. Don't worry, some five to six years ago we spent two days before we managed to get a car to its normal level. Regards Styria
 

Oversize

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So why was the pressure reg faulty? Poor seals, scoring, spring tension?
 

Styria

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Mark, don't know at this stage as we merely removed it and replaced it with one that was giving excellent (well, close enough) cut in and cut out readings. Will have to pull apart the faulty Regulator to determine what needs replacing. Regards Styia
 

Styria

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In another thread, I have talked about an apparent faulty strut that seemed to be by passing all of the oil pumped out by the Oil Pressure Pump, and then returned (shall we call unused) back to the Reservoir. It took me some time to organize and rebuild a replacement strut as there were other jobs that appeared more urgent and better paid (well, less expensive) and quite frankly, tiredness would just catch up to me. So, the other day, I bit the bullet big time, rebuilt another strut and fitted it the following day. Hard yakka as the car was on a slight decline and I had no support for my back. In addition, it is imperative that the position of the top mount is close to 100% correct to enable reconnection of the oil supply and plastic bleeder hoses without putting undue strain once they are connected to the corresponding hoses from where they had been disconnected. That as all done, sturdy engine stands back under the front hubs to simulate static pressure, wobble (yes wobble) back to the driver's door and reach in to start the car. Of course, as probably 200 times previously, GB started and ran with that glorious burble (how often have I referred to that), back to the front of the car (engine running) and observed the position on the front valve lever to return to the centre (perpendicular 90 degrees to the other side of the car) position expecting the car to raise slowly from the suspension's static (wheels on the ground) position. Guess what ? Zilch, absolutely zilch and I find myself picking up my heart and fast disappearing patience. Yes, there was no change from the status quo originally experienced with the pump working continuously, and the suspension not raising.

As with most malfunctioning components, there had to be a reason. Unfortunately, with suspension issues, you don't always know what is the problem because you simply have no visual evidence and even though one might be utilizing the test equipment, you still may not be able to pin point the problem. In this case, with the valve in the "Filling" position, again the oil was just going through the valve (we didn't know this), and back to the reservoir. In desperation, I disconnected the valve adjusting lever from the self levelling bracket on the firewall, returned the lever back to the central (static) position, and the car quite quickly raised itself to the normal level without having to rev it out to higher RPM - just normal idle. When a system is working well, that is all that's required.

The problem was that the pressure attained was higher in the distribution valve (next to Pressure Regulator) than when compared to the pressure in the front valve, This in turn meant that the various ball valves could not be released (insufficient pressure), and as a result the valve would not operate. Once the pressure was high enough, the ball valves were released and the car started to raise. Simple, isn't it ! Regards Styria
 

Styria

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So right now, as at yesterday Friday, GB was again functional suspension wise. Thanks for that. Whilst the going was good, and I was on a "high", I decided to fit on a temporary basis at the moment, four genuine 14" chromed (quite nice) original Bundts together with the appropriate size, namely 215.70.14 B. F. Goodrich Silvertown tyres in place of the 17" 235.45.17 Speedy Rims with Nankang tyres. I did this at the request of the new Car Club I have joined - it is called "My Car Club" and it is run by true enthusiasts, that are not interested in Club Politics and personal villification and bias as practiced by a certain individual now in charge of the Mercedes Benz Club of NSW. Simple assertion is that I was accused of assault during a Club meeting in March of 2020, and I was shown the door by that person by way of email fifteen months after the alleged incident, and at no stage was I informed of any action pending, at no time was I given the opportunity to address any Committee members or Executive of the Club, and this is after 28 years of membership. For the time being, I am awaiting two letters of support from fellow Club members and I will request a re-opening to clear myself of a charge (without proof) that could be construed as a criminal matter.

Quite frankly, I am quite glad to be no longer associated with this person that is now heading the NSW Club. With the replacement wheels that I fitted, I have of course the correct size tyres that are extremely difficult, and expensive, to attain any longer. The original XWX tyres can be bought as full imports at about $650.00 each. I have taken a couple of photos, namely the original 14" Bundt on the front, and the original 17" Speedy on the back. My preference is the Speedy unit over the Bundt, but it will be interesting to see how Gleaming Beauty handles the "original" set up. Hopefully, here are the pics: Regards Styria20211119_073523.jpg20211119_073512.jpg

20211119_073512.jpg
 

Oversize

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The hydro can be very temperamental & even when things all appear ok it can malfunction especially with a lack of use! I know Dora was refusing to cooperate when recommitioned but despite that I took her for a short drive. Whilst I wouldn’t advocate such practise the resulting forces seemed to unlock the sticking valve & all was good once more!
 
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