s class
New Member
That sounds like a sensible plan.
my 6.9 can't get it up !
- Thread starter B13
- Start date
- Thread Starter
- #122
Well well well, I made some major progress today.
On my old (previously removed) PR/DV I installed new O rings on the interface between the PR and DV, and on the cylinder which holds the small gauze filter and reinstalled the unit on my car.
Also blew out the lines to and from the central sphere and while I didn't see anything other than clear fluid come out, there didn't seem to be a blockage problem.
Primed the pump and started the old girl, after a minute the warning light went out, and the DV has prononced detents again in the N, S, and H setting. The back also lifted to normal height. The front followed after a short drive.
However like most things to do with this car there are also downsides. H setting doesn't work as yet, the car doesn't sink, it just doesn't lift. But the worst problem is the monumental fluid leak at the PR which I just can't seem to get rid of. I think its coming from the high pressure hose from the hydro pump, but I'm not sure... it could also be from any of the other connections and makes quite a mess, not to mention drops fluid on the road.
The leak could also be from the base of he PR, where it meet the plate which bolts it to the hydro tank.
Will get back to it tomorrow, however I can only work on this for so long before I run out of hydro fluid, and I don't have any spare...
What do you think the problem related to, a bad PR or DV?
........
I moved the control disc to the M (assembly) position and the system sounded (audibly) like it was depressuring the central sphere, but then when I went to undo the B2 line at the PR, there was still a large volume of high-pressure fluid trying the spray out. how many cc's is likely to come out? because I had this idea that maybe if I put my other (non leaky) PR on with the currently installed DV, we might have a solution... or at least no leaks...
I just tightened up the B2 line and gave up for the night as I don't know how much fluid is likely to come out... is it the central sphere depressurising itself?
Also my central sphere has the red dot on it so at least we know that one is in the right place. Haven't checked all the others.
I.
On my old (previously removed) PR/DV I installed new O rings on the interface between the PR and DV, and on the cylinder which holds the small gauze filter and reinstalled the unit on my car.
Also blew out the lines to and from the central sphere and while I didn't see anything other than clear fluid come out, there didn't seem to be a blockage problem.
Primed the pump and started the old girl, after a minute the warning light went out, and the DV has prononced detents again in the N, S, and H setting. The back also lifted to normal height. The front followed after a short drive.
However like most things to do with this car there are also downsides. H setting doesn't work as yet, the car doesn't sink, it just doesn't lift. But the worst problem is the monumental fluid leak at the PR which I just can't seem to get rid of. I think its coming from the high pressure hose from the hydro pump, but I'm not sure... it could also be from any of the other connections and makes quite a mess, not to mention drops fluid on the road.
The leak could also be from the base of he PR, where it meet the plate which bolts it to the hydro tank.
Will get back to it tomorrow, however I can only work on this for so long before I run out of hydro fluid, and I don't have any spare...
What do you think the problem related to, a bad PR or DV?
........
I moved the control disc to the M (assembly) position and the system sounded (audibly) like it was depressuring the central sphere, but then when I went to undo the B2 line at the PR, there was still a large volume of high-pressure fluid trying the spray out. how many cc's is likely to come out? because I had this idea that maybe if I put my other (non leaky) PR on with the currently installed DV, we might have a solution... or at least no leaks...
I just tightened up the B2 line and gave up for the night as I don't know how much fluid is likely to come out... is it the central sphere depressurising itself?
Also my central sphere has the red dot on it so at least we know that one is in the right place. Haven't checked all the others.
I.
WGB
New Member
Sounds hopeful.
I would expect the central line to have quite a lot of residual fluid in it. It will of course have more when pressurised than when flat so long as the diaphragm is intact.
Have you a good seal between the top of the reservoir and the pressure regulator as it has to deal with quite reasonable pressure and flow and may be a lot higher in pressure if you dont have a clean paper filter.
Best of luck with the leak testing.
I wouldn't worry too much about the car not lifting on the high setting as there is probably a lot of air in the system which may take a few days of running to clear. My car took about two weeks of running before it stabilized after major work.
CraigS has suggested a 30 minute drive with the car on the high setting.
Bill
I would expect the central line to have quite a lot of residual fluid in it. It will of course have more when pressurised than when flat so long as the diaphragm is intact.
Have you a good seal between the top of the reservoir and the pressure regulator as it has to deal with quite reasonable pressure and flow and may be a lot higher in pressure if you dont have a clean paper filter.
Best of luck with the leak testing.
I wouldn't worry too much about the car not lifting on the high setting as there is probably a lot of air in the system which may take a few days of running to clear. My car took about two weeks of running before it stabilized after major work.
CraigS has suggested a 30 minute drive with the car on the high setting.
Bill
- Thread Starter
- #124
More progress today.
I put back in the previous (non leaky) PR that was in before coupled to the DV I installed yesterday and the system is back to its old tricks (warning light won't go out and no feeling in the control disc) but there are no leaks, so I can at least drive the car to get to work next week.
Makes me 99.9% sure that the major problems with the system are caused by the PV so I'm awaiting to hear from godfather what way to proceed.
Finally starting to feel that I'll have this thing sorted.
I.
I put back in the previous (non leaky) PR that was in before coupled to the DV I installed yesterday and the system is back to its old tricks (warning light won't go out and no feeling in the control disc) but there are no leaks, so I can at least drive the car to get to work next week.
Makes me 99.9% sure that the major problems with the system are caused by the PV so I'm awaiting to hear from godfather what way to proceed.
Finally starting to feel that I'll have this thing sorted.
I.
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WGB
New Member
At least you seem to be narrowing it down.
I hope the end is in sight.
Bill
I hope the end is in sight.
Bill
s class
New Member
Cool, this is major progress.
- Thread Starter
- #127
Its just about fixed, in fact its fixed, except for the height adjustment.
A marathon effort while TK was offline saw me replace the hydro tank, the PR, the rubber hoses between the tank and pump, the high-pressure hose between the pump and PR and new fluid. After a few minutes the warning light went out, the back raised, and shortly after the front raised, though not very high.
The hose was re-manufactured from a good used (but leaky - it had been previously re-made using 1200-1500PSI power steering hose) hose using 3000PSI hose and it worked a treat. I used my original PR (which I termed "leaky one" in previous posts) which turned out not to be leaky, but I couldn't seal the high-pressure hose due to a PO having rounded the 14mm flare-nut.
I also put a new O ring between the PR and DV. While the hydro tank was out I also replaced the rubber hoses with new EFI fuel hose. In my hydro tank, while the fluid was relatively brown-but-clean, I did see the same black sludge in the bottom of the tank that everyone elses had. I figure this must be a good thing... The replacement tank was cleaned of dust and installed, my gel-sealing ring looking in good(ish) reusable condition.
(To empty my old hydro tank I considered various ways to empty it without making too much of a mess and then just decided to run the engine and use the hydro pump to empty the tank.)
While the hydro tank was out I also took the time to replace both windscreen and headlight washer motors and the annoying leak mentioned in the other thread. Turns out my headlight washer pipes aren't connected but at least when I'm ready to tackle it I know there is a working washer motor and don't have to remove the hydro tank again.
After driving the car for a short while it became obvious that there was a leak at the front level control valve, from the output shaft. Not dire, only maybe 1 drop every 5 minutes, but annoying. I put this down to the level valve not being put under proper pressure for such a long time which is why it has been (externally) dry all this time. After the 3rd day of driving like this the next morning there appeared to be a lot more hydro fluid on the ground under the car.
We removed the front level control valve, transferred its rubber boot from this leaky valve to my spare one and re-installed it back into the car. No leaks and when the system became pressurised the car lifted VERY high at the front. I put this down to the connecting rod being made very short to compensate for the inadequacies of the leaky level valve. Lengthening the connecting rod lowered the front back down to a more normal W116 height which is to say its slightly higher at the front than the back. No leaks, no warning lights, and each night now no sinking.
The high setting is the next thing to tackle when I can be bothered. I've also covered a few hundred km now so maybe all the air in the system will have been purged and the system will lift again. I've lost the circlip which retains the cable in the control disc which makes using the control a little harder (it pops out).
Finally the car is starting to move away from its perceived reputation as being a bit of a headache.
Ian.
A marathon effort while TK was offline saw me replace the hydro tank, the PR, the rubber hoses between the tank and pump, the high-pressure hose between the pump and PR and new fluid. After a few minutes the warning light went out, the back raised, and shortly after the front raised, though not very high.
The hose was re-manufactured from a good used (but leaky - it had been previously re-made using 1200-1500PSI power steering hose) hose using 3000PSI hose and it worked a treat. I used my original PR (which I termed "leaky one" in previous posts) which turned out not to be leaky, but I couldn't seal the high-pressure hose due to a PO having rounded the 14mm flare-nut.
I also put a new O ring between the PR and DV. While the hydro tank was out I also replaced the rubber hoses with new EFI fuel hose. In my hydro tank, while the fluid was relatively brown-but-clean, I did see the same black sludge in the bottom of the tank that everyone elses had. I figure this must be a good thing... The replacement tank was cleaned of dust and installed, my gel-sealing ring looking in good(ish) reusable condition.
(To empty my old hydro tank I considered various ways to empty it without making too much of a mess and then just decided to run the engine and use the hydro pump to empty the tank.)
While the hydro tank was out I also took the time to replace both windscreen and headlight washer motors and the annoying leak mentioned in the other thread. Turns out my headlight washer pipes aren't connected but at least when I'm ready to tackle it I know there is a working washer motor and don't have to remove the hydro tank again.
After driving the car for a short while it became obvious that there was a leak at the front level control valve, from the output shaft. Not dire, only maybe 1 drop every 5 minutes, but annoying. I put this down to the level valve not being put under proper pressure for such a long time which is why it has been (externally) dry all this time. After the 3rd day of driving like this the next morning there appeared to be a lot more hydro fluid on the ground under the car.
We removed the front level control valve, transferred its rubber boot from this leaky valve to my spare one and re-installed it back into the car. No leaks and when the system became pressurised the car lifted VERY high at the front. I put this down to the connecting rod being made very short to compensate for the inadequacies of the leaky level valve. Lengthening the connecting rod lowered the front back down to a more normal W116 height which is to say its slightly higher at the front than the back. No leaks, no warning lights, and each night now no sinking.
The high setting is the next thing to tackle when I can be bothered. I've also covered a few hundred km now so maybe all the air in the system will have been purged and the system will lift again. I've lost the circlip which retains the cable in the control disc which makes using the control a little harder (it pops out).
Finally the car is starting to move away from its perceived reputation as being a bit of a headache.
Ian.
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Bandolero
New Member
Good to see you are sorting the problems out.
I see you used 3000 PSI hose. Do you realise that the system runs about (or up to) 3,200 PSI and the low pressure warning light comes on at about 2,900 PSI. Carefull the hose doesn't blow.
I see you used 3000 PSI hose. Do you realise that the system runs about (or up to) 3,200 PSI and the low pressure warning light comes on at about 2,900 PSI. Carefull the hose doesn't blow.
- Thread Starter
- #129
For a minute there Bando I thought you were were going to say you were able to help me with the missing circlip....
Anyway, the hose is made of: Gates 1/4" R1/ISN EN853 3275 PSI hose. The published max figure capable of the hydro pump is 200bar which is 2900 PSI. I think it'll hold up.
Sent you a PM, btw.
Ian.
Anyway, the hose is made of: Gates 1/4" R1/ISN EN853 3275 PSI hose. The published max figure capable of the hydro pump is 200bar which is 2900 PSI. I think it'll hold up.
Sent you a PM, btw.
Ian.
Well done Ian,
I can see it took you a long time but you finally managed to 'fix' it and get the thing up and running far better than before..
I stil have to sort out the rear on the 690SEL....
Oh well, sometime in the not too distant future I hope.
I can see it took you a long time but you finally managed to 'fix' it and get the thing up and running far better than before..
I stil have to sort out the rear on the 690SEL....
Oh well, sometime in the not too distant future I hope.
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s class
New Member
I'm glad you stuck with this to sort it out.
WGB
New Member
Pleased to hear it Ian.
Hopefully the suspension can return to drive and forget.
I am waiting to rebush my suspension but waiting until the present bushfire danger has receded so that I deon't end up with a wheelless 6.9 and an approaching bushfire.
Bill
Hopefully the suspension can return to drive and forget.
I am waiting to rebush my suspension but waiting until the present bushfire danger has receded so that I deon't end up with a wheelless 6.9 and an approaching bushfire.
Bill
'scuse my ignorance, but what is achieved by replacing the hydro fluid tank? I thought it was just a steel can, so providing it doesn't have a hole it or such, should play no part in repairing a faulty system.
Having said that, I'm spending more time cleaning out the engine bay of the blue 6.9, and finding more fluid leaks around the hydro pump / tank area.....
Having said that, I'm spending more time cleaning out the engine bay of the blue 6.9, and finding more fluid leaks around the hydro pump / tank area.....
- Thread Starter
- #134
Hi Lukas, the tank is just a big can, but it has two small threaded posts which take small 8mm nuts to hold the PR/DV combo to the top of it. The thread has stripped on one of the posts on my old tank, leading to an unsatisfactory seal of the PR to the tank.
Driven normally this didn't cause so much of a problem, but when driven enthusiastically, it was possible for the fluid to splash around in the tank and leak around the seal, then when the car was parked you'd come back there would be a small but embarassing puddle under the front. Being very thin oil it doesn't take too many drops to make a noticable puddle. People at work would walk past my car and say "yo Merc is bleeding again".
So as well as trying to get the system to function properly, I'm also trying to get it as perfect as possible - something previous owners haven't been successful in doing.
Driven normally this didn't cause so much of a problem, but when driven enthusiastically, it was possible for the fluid to splash around in the tank and leak around the seal, then when the car was parked you'd come back there would be a small but embarassing puddle under the front. Being very thin oil it doesn't take too many drops to make a noticable puddle. People at work would walk past my car and say "yo Merc is bleeding again".
So as well as trying to get the system to function properly, I'm also trying to get it as perfect as possible - something previous owners haven't been successful in doing.
WGB
New Member
B13 has the extra problem of the stripped thread and i guess the whole exercise just goes to show the how tiny the leaks can be that then make the whole system malfunction.
There is a very rational reason for removing and cleaning the reservoir as the oil is only filtered on return from the suspension (by a spring loaded filter that can be bypassed when clogged) and whatever clears this filter is held as a sediment in the base of the tank by virtue of the design of the outlet back to the pump being raised above the bottom of the tank.
The result of this design is that about a litre or so of oil is not circulated but gradually fills up with black rubbery goo and will be sitting in the base of every tank that has not been cleaned thus far - no matter how clean it looks on the dipstick.
I am pleased you have perservered B13 and hope you will continue to enjoy the drive from here on in.
Bill
