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  #46  
Old 6th January 2013, 10:57 PM
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SEL_69L SEL_69L is offline
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Default Re: 6.9 front suspension not raising

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.
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  #47  
Old 7th January 2013, 08:59 AM
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Default Re: 6.9 front suspension not raising

Quote:
Originally Posted by Styria View Post
This is the post started by SELfour50, and contributed to by John Erbe in California. I am just hoping that John will call in and contribute from time to time - his info is most valuable.

http://www.topklasse.net.au/forums/showthread.php?t=257

Regards Styria
That link is talking about lowered springs....
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01 Ford AU 5L (Deep Blue)
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87 560L#2020 (Dora 2)
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78 6.9#4248 (Skye)
79 6.9#3686 (Moby Dick)
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  #48  
Old 7th January 2013, 06:45 PM
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Default Re: 6.9 front suspension not raising

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
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  #49  
Old 24th January 2013, 09:08 PM
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Default Re: 6.9 front suspension not raising

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.
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  #50  
Old 25th January 2013, 06:08 AM
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Default Re: 6.9 front suspension not raising

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
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  #51  
Old 22nd February 2013, 11:25 AM
john erbe john erbe is offline
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Default Re: 6.9 front suspension not raising

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.
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  #52  
Old 22nd May 2020, 06:11 PM
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Default Re: 6.9 front suspension not raising

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
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  #53  
Old 23rd May 2020, 04:33 PM
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Default Re: 6.9 front suspension not raising

So why was the pressure reg faulty? Poor seals, scoring, spring tension?
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01 Ford AU 5L (Deep Blue)
88 420L Euro#-P
88 420L#-P
88 420L#2477-P
87 560L#2020 (Dora 2)
87 560L #9987
87 420L#4309-P
87 420L#-P
86 560L#5896-P
79 6.9#5541 (Red Bull)
78 6.9#4248 (Skye)
79 6.9#3686 (Moby Dick)
78 6.9#1776 (Dora 1)
77 450L#7010-P
75 450L#8414 (Gold Nugget)-P
57 Buick 73A (Titanic)
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  #54  
Old 23rd May 2020, 05:17 PM
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Default Re: 6.9 front suspension not raising

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
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