Author Topic: hydropneumatic suspension leak  (Read 3751 times)

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
hydropneumatic suspension leak
« on: 17 July 2006, 07:34 PM »
Hi, I'm off to replace the return line to my reservoir, or is it the supply line?  The black chorded line from the bottom of the reservoir.....to the pump? suppose that makes it a supply line.  :P

I posted earlier about dropping at least 2litres of this expensive oil in only 4 weeks and about 400km.  This line clearly needs replacing, it's wringing wet with oil and spongy and worn because it rubs against an A/C hose. The thing is, I haven't noticed any oil on the ground.  Tracing the steel line to the rear I can't see any other leaks. 

Where's it all going!  Is the oil only dropping to the ground whilst I'm driving?  Or is it possible the oil somehow gets sucked into the engine like every other type of fluid for the car seems to find a way? 
1973 350SE, my first & fave

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: hydropneumatic suspension leak
« Reply #1 on: 04 August 2006, 08:10 PM »
This sux.  Ok, another 2.5 litres in the space of a fortnight has disappeared.  Again, no leaks on the floor and suspension's still works ok.  What's going on, is it pump like Big R says?

What'll happen if I continue driving if the system runs dry?  What should I do, what can I test, what's my next step? Thanks. :(
1973 350SE, my first & fave

nathan

  • W116 Addict
  • ****
  • Posts: 1,730
  • Location: perth, western australia
Re: hydropneumatic suspension leak
« Reply #2 on: 04 August 2006, 08:47 PM »
hi Oscar,

sorry - cant help much with the phantom oil query...
however, i just wanted to throw in my 2c re hydropneumatic oil...about 1-2 yrs ago when i last bought a few bottles of MB dealers here in Perth, it was 30 bucks a bottle (1L)...when i went in the other day for some more, they wanted 50 bucks at one MB dealer, and 70 at the other!! what a pillaging...my mums 300TE 124 wagon had a leak a few years back and i think the mechanic said we could put BP visco5000 or something like that in it as we had no MB oil? are there alternatives or can you buy the stuff in bulk?

hope you find your leak Oscar
nathan
perth wa
6.9 79 #6436
6.9 79 #6290
6.9 79 #6181
6.9 78 #4764
6.9 77 #3096
6.9 76 #1741
6.9 76 #0902
6.9 75 #0018

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: hydropneumatic suspension leak
« Reply #3 on: 04 August 2006, 11:39 PM »
Hi nathan,
Locally I was quoted $50 thru a parts shop, my mechanic 2hours away sells it for $32 Lamforder brand.  Styria, is cheaper still, although I can't quote exactly what brand or how much.  I think Big R or someone earlier said Febi is also another brand.  It's the first time I've heard anyone mention an alternative ie Bp visco 5000.  Although another parts shop in my town said he should be able to put something simmilar and cheaper in if he knew the dot number and viscosity.  Something like that.  The big thing is knowing that the oil will not corrode the seals in the struts. Or so I've read.

Well, I've degreased the engine and all the bits that were oily after I changed the hose and the last oil change.  The engine's dry now, so I've put in the last 500ml I had and will now see what happens.
1973 350SE, my first & fave

Des

  • Vintage
  • ***
  • Posts: 923
  • Location: Australia
Re: hydropneumatic suspension leak
« Reply #4 on: 05 August 2006, 12:19 AM »
shhesshh and I thought the $26 for 1ltr my mechanic charged was steep.

1977 W123 230 
1977 W116 280S *new*
1980 W123 250
VW Beetle "Oval Window"
VW Golf Mk1
Volvo 240GL
Volvo 740GLE

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Fixed!!! Hydro suspension leak
« Reply #5 on: 10 August 2006, 03:55 AM »
Well, got a replacement pump today from Styria.  Problem solved!  ;D ;D  It appears my pump was leaking thru the seals Styria speaks of.  Styria, I think you better send me a bill, I'm keeping this one.

The exchange wasn't without frustration and some choice words spoken towards the roof. Finding the right tools was a biggie, with the right spanners too long or allen keys just too hard to use.  A set of allen sockets came in very handy.   After 4 hours and checking everything was back together I thought I'd done it. Everything seemed fine after I turned the key but then heard fluid dripping onto the ground.   All of a sudden brand new hydro juice is being thrown about by the rad belts and pulleys and my clean motor is now once again covered in oil.  FUG!

With a bit of searching I found a copper gasket/washer/seal thing sitting atop the oil sump.  It was pure chance I'd seen it and I didn't know I was missing it.  It was supposed to go on the bolt of the pressure line.  There's two there, one before the pipe and one on the body of the pump.  So another litre lost, thank god I ordered 5L.

We'll see how things go but for now case closed.

Some pics;


To test Pump (the easy way) put your finger in the out/pressure line part and blow on the supply hole.  The air that escaped thru the centre shaft area could be heard easily and felt about 6" away





The two pumps together, in comparison, I couldn't really tell if any air escaped thru the new one as hard as I tried. I'm positive that oil wont work its way thru the seals on this one.




If you're taking one off, make sure you look for that round shaped cross-holed coupling that joins the pump shaft to the engine's shaft.  By some good fortune it rolled from the engine bay onto the floor then stopped in front of me as I held the two pumps in hand.




The best pic of the "bit where the pump goes". Despite my efforts of cleaning the engine, you can see the crud outside  the area, this bit was out of sight.  No doubt it's soaked even moreso now. The rear of the car is is towards the bottom right hand corner of the pic.  The centre drive shaft is just visible and it's identical to the pump's shaft.  There's a drain hole in the bottom of the "bit where the pump goes" which is where all my oil has been going.  Btw, yes my oil level had risen up the stick by almost an inch. 
« Last Edit: 10 August 2006, 04:01 AM by oscar »
1973 350SE, my first & fave

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: hydropneumatic suspension leak
« Reply #6 on: 12 August 2006, 01:27 AM »
Hi Styria,

I'm stoked with the result from your pump.  It just seems a shame to chuck the old one.  My next step was to see if you wanted it.  PM me if you do and I'll send it straight up. 

In the other forum I thought there may be a few knowledgeable people with experience of swap overs.  Especially between 126's and 116's.  It was the manual on this site that mentioned the 126 pumps being compatible.  Without seeing the internals, both mine and your pumps not only looked the same but felt the same when turning the spindle.  No doubt if something is to wear, my pump is bound to have experienced it and is undoubtedly the original with upwards of 380,000km of travel.

It's like any job on these cars.  You do it once and you learn.  I could now confidently exchange another punp in half the time.  Now the old pump is useless and curiosity gets the better of me Iwouldn't mind breaking it up to show everyone what's in there.  Of course putting it back together again- well, say no more.  If it was a simple seal to replace, all well and good but as you say and what was said on the other forum- where do you get one?  Not at Supercheap Auto I bet  :D

I just don't know what to do with it.  I know, beware fellow 116ers of a dodgy suspension pump to appear on an ebay auction real soon. (I can't find an evil emoticon)
1973 350SE, my first & fave

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: hydropneumatic suspension leak
« Reply #7 on: 12 August 2006, 07:02 AM »
Sorry Styria, I cracked it open.  Couldn't resist.  I think it's just the rear seals to be honest.  The bronze bush has less freeplay than I thought it would, it's negligible.  Plus the oil doesn't seem to be escaping anywhere but the rear seals.  I've decided to replace them and the front seal for good measure and keep the pump as a spare. 

There's too much involved with posting the same thing in more than one forum, so the following is a copy of my post on the mbcnsw forum. There's pics of what's inside a pump for anyone interested.

 Most of you that know what you're talking about are going to cringe with what you're about to see.  But tonight curiosity got the better of me so in my dustless workshop  ::), on a lint free towel  ::) ::), I went to work on this clean  ::) ::) ::) pump.

decemberszen, I didn't get as far as the 2 o-rings you speak of, I think.  Judge from the pics.  But after inspecting where the wet areas were and blowing into the supply and blocking the out, air bubbled between the shaft and rear seals.   I think that was the only leak.  Engine oil has risen up the stick by about an inch too.

The front seal looks like an easy replacement. Even though it wasn't leaking it'll get replaced. 

The rear seals however were a pain to prize out and ended up breaking into pieces and leaving green remains on the inside of the "seal holder"  :-\, you'll see what I mean.  They both broke up but I managed to get a part number.  I need two INA G 15 - 23 - 3 single lip seals.  Found the numbers corresponding to an INA website.

Pics for reference.



Front


Front removed with shaft and 4 pistons visible.  The shaft is central with the thicker part off centre much like a cam shaft but cylindrical, (surely there's a proper term for that kind of arrangement). With bronze sleeve and metal collet, contact is made with the sprung? pistons alternating a push on each one.


Shaft pushed upwards slightly revealing more of the bronze bush.


Shaft and bush removed.  There's 2 slight indentations towards the crank end of the shaft, worn from the two rear oil seals.  I thought perhaps moving from 15mm inner diameter seals to 14mm ones might compensate but INA don't list a suitable one.


The seals all broken up


Rear of the pump with green leftovers from the seals.  Is this a sealing compund of some kind? Or just the outside of the seals fused?  It's a PITA to remove nonetheless.
1973 350SE, my first & fave