6.9 front suspension not raising

[Styria]

Hi Bill, I'm all for leaving well alone - in other words, if it ain't broke, don't bother to fix it. It could well be that driving the car for a few days may get the suspension to settle down and get rid of possible 'Air Locks', but I have some doubt. Generally, if the system is working well, half to one minute to pump up with hardly any revs required, and whilst some sinking overnight is quite acceptable, it should always pump up quite quickly.

At this stage, Chris, try and leave well alone - there is not a lot of substance in dislodged steel balls affecting the workings of the pressure regulator. Regards Styria

 

[chrisp]

Thanks Bill / Styria,

I'll leave it alone for now and try driving it again on Sunday when (hopefully) it stops raining over here.

Yesterday I drove the car to work (30 kms or so), then into the city and back for a meeting, then to the in-laws, then home. Probably a round trip of about 80 kms. In the morning the car performed well (was the first time I had driven it since Wednesday night when Bill came round and fixed the leak) on the way to work. The warning light came on a couple of times while sat in traffic but went out again when I pulled away. The car was level and everything seemed ok-ish.

Into the city and back in the afternoon the car was also working nicely, with fewer warning light incidents than the morning.

After work I spent some time in the car park playing around with the height via the control disc settings. Some observations:

• Moving the car to the high setting always results in the rear lifting
• Moving the car to the high setting resulted in the front lifting once out of four attempts; the other times it didn't move at all

I then drove the car to the in-laws' house on the normal setting and it behaved perfectly, no warning light at all.

However, two hours later when I came to drive home I couldn't get the front the raise at all again. Even after five minutes of 2500 RPM the front wouldn't come up. In the end I started driving gingerly home and while riding low, the front did eventually rise about 1-2 inches and I felt like a Top Fuel funny car driver without the performance. More worryingly the warning light was coming on even when driving normally and only going out under hard acceleration.

This morning the car was as I had left it: not down to the very bottom at the front, just 1-2 inches up, and checking the control disc for resistance, I had pressure and clicking through the positions resulted in hissing as the circuits switched.

Regards,

Chris

 

[chrisp]

Thought I might give you all an update on the continuing saga of my suspension not working.

For the last little while my car has been sat at The Star Shop here in Perth. They managed to get everything working again for a matter of minutes only to find that - presumably - some bits from the bottom of the reservoir managed to get stirred up which have now taken out the valve that sits atop the reservoir. Are these even available?! I hate to think what the cost might be but if anyone has one, please let me know since one is proving hard to procure. I will list a separate "wanted" thread elsewhere... For the record, the guys at the garage tell me the part number is 126 320 0658.

Regards,

Chris

 

[WGB]

I was wondering what you had got up to with your car Chris.

It is possible that there is still a piece of the shredded o-ring that I removed or some other collection of crud in the guts somewhere.

I must say I would be inclined to remove it and get it stripped or serviced by someone who knows about hydraulics.

I know s-class stripped one and there is a pictorial on the other site about what he did.

If it was mine it would be pulled to bits and sitting in a bowl by now.

I am off to NZ tomorrow for 8 days but if you are brave on return we can pull it to bits and clean it and see what happens if you haven't found a replacement or solution by then.

The other trick would be to PM Nathan or TJ450 and see if they have any answers.

Bill

PS - S class would be worth a PM as well as he seems to know a little about the internals.

 

[chrisp]

Thanks Bill (and Styria for your phone call and post on the other thread),

I spoke to Sean at the Star Shop this afternoon and he has clarified for me what is broken. It seems it is not the pressure regulator itself that is damaged but the aluminium box (adjusting switch of the valve unit) that the control disk sits on.

They cleaned out my front levelling valve and pump and got the system repressurised, the car rose and then a hammering noise came from the adjusting switch and the car would sink again. When they dismantled this they found a piece of o-ring (probably the bit you are referring to, Bill) but apparently the needles are damaged and the main bolt that goes through it sheared when they tried to remove it.

I am going to go down there on Monday (unfortunately I can't get there before then) and take some photos and assess what's happened with my own eyes.

Thanks again to Styria and Bill for the advice.

Regards,

Chris

 

[Styria]

Hi ChrisP., I must admit to being confused - very little of all that's happened is far from patently clear - I can hardly wait for Monday. Regards Styria

 

[chrisp]

Hi ChrisP., I must admit to being confused - very little of all that's happened is far from patently clear - I can hardly wait for Monday. Regards Styria

You and me both!

 

[motec 6.9]

Hi Chris send me a PM as i have a spare parts 6.9 geoff

 

[chrisp]

Hi Geoff,

That's excellent news! PM sent...

Cheers,

Chris

 

[chrisp]

So today I went to see Wilhelm. The part that's broken is this one:



Apparently the innards are toast. Everything else is working fine now, thankfully. So, I'm not sure exactly what this part is called (height adjuster, valve-that-the-control disk-is-mounted-on?) but it's what I need. If anyone has one, or knows if/how they can be repaired, I'd be very grateful to hear from you!

Regards,

Chris

 

[Styria]

So today I went to see Wilhelm. The part that's broken is this one:



Apparently the innards are toast. Everything else is working fine now, thankfully. So, I'm not sure exactly what this part is called (height adjuster, valve-that-the-control disk-is-mounted-on?) but it's what I need. If anyone has one, or knows if/how they can be repaired, I'd be very grateful to hear from you!

Regards,

Chris

Well, what can I say ? More confused than ever ! It's just not fitting together. Regards Styria

 

[Oversize]

If this was me, I'd be looking at what was recently replaced... Pump & front valve. Assuming the rear is operating normally (high & low, plus maintaining height overnight), it seems clear the problem lies in the front circuit. Perhaps the front valve wasn't adjusted correctly, or it has crud inside (less likely)?

However, the intermittent warning light activation seems to suggest a pressure supply problem as well. Without the manuals, I can't be sure what the lamp is designed to indicate; I thought it was for locked, high position, or lack of pressure?? Anyone care to add info here?

Now it sounds like your mechanics are adding to your woes by breaking things whilst try to diagnose the original problem.

Worst comes to worst, clean out the reservoir thoroughly, check the pump for flow & volume, make sure the valves are adjusted correctly, bleed the system, then do a leak down test.

 

[motec 6.9]

Hi Chris PM sent i have that valve

 

[Styria]

Chris is the person and fellow member that bought my Astral Silver 6.9 - in rebuilt condition, such as valve grind and de-coke, complete re-spray, a host of interior work - there are pictures of the valve grind in the Technical Section (as referenced by workshop tasks on the home page), plus many other pictures elsewhere on the website. The car came up well - we resprayed for Chris prior to purchase and much other work was carried out.

In due course, in fact not long after purchase, Chis and his wife re-located to WA as indicated by him earlier in the thread. I guess it's almost appropriate to state that from the car's point of view, the move was a virtual disaster. A slight leak from the front regulator valve was picked up when he changed rego. details to WA. The car was taken to a mechanic for replacement of the valve and he has had problems ever since. I last spoke to Chris about two months ago, and I believe that he has not, or is not able to, used the car for perhaps the best part of twelve months. At that time, he replaced the two Power Steering belts in his garage at home - not an easy task if you don't have appropriate tools. Anyway, apparently he did manage. So that brings us to perceived problems with the suspension on his car (6.9 of course), but I am guessing a little as I am not up to speed with any latest developments - if there have been any.

I came across Chris' thread whilst in the process of re-organizing and re-classifying various threads and transferring them to different locations on TK. It just so happens that I have just spent an inordinate amount of time on a 6.9 that refused to raise itself in the front. It started off almost exactly the same as Chris' problem - a slight leakage of oil from the front regulator valve. Sure, I thought, this is no real problem, but I have been involved in an unbelieveable learning curve since that initial thought. More of that in the follow-up post. Regards Styria

 

[WGB]

Chris was at the recent WA meet and when both of us are finished with our respective holidays I am pencilling in a day to have a look at his hydraulics.

Bill

 

[Styria]

Hi Bill, I am pleased to hear that. BTW, may 2013 be a good year for you, such as it can be. Also, I am glad that you are coming in on this thread - for Chris' sake, but I am also keen to share some of my thoughts and impressions on what I have experienced and/or discovered when dealing with the latest issues I was confronted with. I should point out that my observations and remarks should not be treated as gospel, but there are some rules that should assist as a guide in dealing with 6.9 suspension problems. I would also draw attention to the fact that a comprehensive workshop manual procedures have been submitted to TK by way of PDF documents. It is hoped that once a long awaited library feature becomes part of TK, those procedures will be transferred into the appropriate section. More to follow. Regards Styria

N.B. Apologies for Moderator logged post.

 

[Styria]

In my view, the hydropneumatic suspension system, has been unjustly maligned and criticized and, many times, by the unknowing and I can include myself to a certain extent as one of the critics as well.I have owned Gleaming Beauty for the best part of sixteen or seventeen years, and it is not that often that I have had suspension issues that have actually prevented the car from being used. Call me lucky or smart, but my 6.9 has been just about the most reliable of any 6.9 I have been involved with.

So, where should one begin ? Firstly, I have now come to realize that the testing equipment as referred to in the workshop manual is a 'must have item'. I am fairly certain that the details are already on TK, but if not, the manual will be PDF'd in the immediate future - I'll just have to check. So, I went out and bought a 'copy' of the equipment, which required the making of some special flexible brake hoses, and also some metal brake lines, as well as gauges reading to 250 bars - I bought two to enable readings to be taken at more than one point in the system at a time. Getting the right connections was a major headache - whilst I managed to stop most leaks whilst checking, the pressure is immense and hydraulic oil will just about find the slightest leak in the checking system. The prescribed tools in the workshop manual feature a pressure relief valve when measuring hydraulic pump pressure, and that tool I have not been able to replicate. As a result, I could not measure the pressure values of the pressure pump. Connecting the gauge straight to the pump, with ALL fittings and washers in place, only resulted in leakages at the fittings, and in fact destroyed one of the gauges. As a consequence, I had to make do with checking the amount of flow per minute - I obtained 0.5 litre per minute (at idle, but the engine should have been run at 2000 rpm) and substituted that pump (in due course) with one that flowed at 0.7 liters per minute. As I said, not a totally correct procedure, but better than not checking anything. Additionally, the outputof the pump can be measured further along the pressure supply lines. I should also add that it is handy to have two persons checking and assisting each other - I was lucky in so far as I was able to call upon the help from a friend and fellow 6.9 owner who is able to read and, more importantly, translate drawings into practical applications. Those schematic drawings as in the workshop manual are of immense assistance. More to come. Please bear with me.





As above - testing regulator valve PRIOR to installation.















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[Styria]

In the course of getting the suspension to raise, it was soon obvious that there was not enough pressure in the system to raise the car in front. The fact that the rear would respond to low normal and high adjustments tended to confuse the issue. Why is the back working, and the front not ? Replacing one component after another, and one at a time, components that I removed from my own 6.9 (Gleaming Beauty - and they had been operative) only resulted in the suspension coming up to a certain height and then.....nothing. It just would not come up to the desired level. ALL TO DO WITH INSUFFICIENT PRESSURE IN THE SYSTEM. We had replaced the pressure regulator, the pressure pump, the front regulator valve - all to no avail ! By this time, after almost three days, the loss of at least five liters of hydraulic oil, and we were just not getting anywhere. The maximum pressure we could achieve was about 135 bars - we needed at least 180odd. We had also replaced the Master Air Cell (fitted a new one) and no success. We were able to establish that the oil was pumped right through the system and back into the tank - so it wasn't staying in the system building up pressure. In the end we decided to separate the front struts from the system completely and once we had eliminated one at a time, the car started to raise. Clearly, the problem lay with the strut - it wasn't holding the pressure, allowing the loss of the 50bars we were short of. Once that faulty strut was closed off from the rest of the system, the car rose immediately - we then connected it up again, and the strut blew the bottom seal big time. It had to be replaced - once done so, the car stayed up.

Just to summarize a little. I have already stressed the importance of the test equipment. It is also important to conduct a leak test on all four struts to establish that leak down leakage is within specifications. That is a time consuming process - all four wheels off, then the car needs to be lowered again to rest on its suspension components, and it is then necessary to disconnect the thin plastic line from the system (not the struts) and check for leakage over a period of some six hours. It is also possible, and almost essential, to check your regulator valves prior to instalment - the check can be carried out with the valve "freed from the car", but connected to the system in general. By trial fitting the valves, one can establish that they are free of leaks, and that they perform the height adjustment functions.

Once you get every component working to its proper capacity, or very close enough, the car will respond almost immediately to any variations in attaining height and also attaining high and normal levels. I have found that there is no need to rev the system unnecessarily, and air locks are also just about non-existent. Even when all components have had to be dismantled and refitted, half a minute of idling, or slight rev increase, will lift the car to its correct level.

Hereunder, pictures of the height level front and rear of Gleaming Beauty - after rectification work on the Pressure Regulator, and a period of standing for two days. I hope that some of the foregoing will destroy some of the myth and criticism levelled at the 6.9. Sure, it can be a little finicky, but once sorted, it will operate very efficiently. In Chris'case with his Astral Siver 6.9, a pressure check should be the first step in sorting the car. It helps to have spares, it helps to be able to understand the system and to follow certain procedures and then have the parts on hand to make the system work. Regards Styria

 

[Styria]

I hope this info lifts the mystery from various aspects of the 6.9 hydropneumatic suspension system. It is os some importance to couple this information to the workshop manual section already within TK. I will just make sure that the relevant information has been stored. Regards Styria

 

[Oversize]

It seems there are two types of mechanics in today's society. Those that take the time to diagnose the problem using test equipment and those that attempt to diagnose using the symptoms as a guide and then start replacing parts in the hope of hitting the nail on the head in the (figurative) dark. Unfortunately the vast majority are in the latter category.....

Well done Styria; the system is really quite logical and armed with the right equipment, some time and common sense and the problem almost reveals itself.