New Hydrospeichers and Pendelstutze

[oscar]

After saying and recommending to everyone to get the original metal sway bar links, today I picked up my two new Pendelstutze.

They're PLASTIC

So, unwillingly, I'm doing a biased experiment on how crap these links will be.  Lemforder brand, part number 123 320 09 89.  They easily twist without much force.   They look shite but I'll give them a go and for the greater good get back with a report then send Lemforder a damning letter on what I think of their plastic part.

I also picked up new spheres or Hydrospeichers also Lemforder, part number 123 320 02 15 plus some more Lemforder oil.  No Blue, green or red dot on the spheres, just all black with a 123 part number.  I'll check with the old ones to see if they're the same.  The SLS system will be up to scratch and in a way I hope I'm wrong about the strength and longevity of this plastic part but what was wrong with the original sway bar link that they had to change it to plastic.  Mind you, Lemforder could very well be just the aftermarket and Meyle was OEM metal.   Anyway we'll see what unfolds.

2nd 3rd and 4th photos are of:
-original sway bar links
-a variation of the original
-and the plastic ones

[WGB]

Maybe the metal ones were over-engineered?

I guess time will tell.

Bill

[oscar]

Maybe the metal ones were over-engineered?

Exactly. That's the whole essence of these cars and it's why I hate the thought of putting these plastic parts on a functional part of my car.  Up to about a fortnight ago I started cutting into the shell of that 280 I'm pulling apart.  The thickness of the sheet metal and frame is fantastic.  I was unbolting and cutting and all the meantime muttering "wow".  So solid.

[nathan]

oscar, when you were cutting through this uber thick steel, are you sure it was wow you were muttering or something else...me, i was dropping the f-bomb a few times when i was trying to remove the front quarter panels of rusty goldie a couple of months ago,...those damn germans, they make sure stuff stays on!

[oscar]

   Don't know which thread it's in now but yeah, the quarter panels gave me grievance.  When I'm finally done, I think it may be the first and last time I completely disassemble a w116.  It takes sooo long, especially when you keep finding useful pieces, (more like Needful Things), and suddenly the wrecking ball momentum grinds to a halt.

[oscar]

Any advice for putting the new spheres on?  Is it just a matter of jacking up the rear off the ground, unscrew, unbolt then attach the new, drive away?

Just wondering if I need to prime anything before starting the engine or does the circuit purge itself?

[koan]

Just wondering if I need to prime anything before starting the engine or does the circuit purge itself?

Be aware there maybe pressure in the lines so some protection for eyes is wise.

Just remove and replace using the proper flare nut spanners on the connections, a few taps with a hammer helps sometimes.

Some previous posters have spoken of the requirement to bleed the full hydro setup,  I've never had to, there's nothing in the books about it.

Only thing to bleed is the pump if it ever sucks air.


koan

[oscar]

Thanks Koan,

Well, 3hrs up until 9:30pm tonight and the car's been reborn.   Man you don't know how bad some things get until you replace them with new.  They were a bugger to get to especially the right left hand side with the exhaust in the way.  The biggest hold up was getting the 11mm flare wrench onto the nut which had already been rounded.  Flare wrenches are great so long as the nut is in good shape too.  Took me ages but I got it.  I also noticed a bleed point in the line near the right hand side but I attached everything, added a litre of hydro fluid to the reservoir then went for a spin.  Incredible difference.  The car floats.

Unlike the new spheres, the old ones looked like a cave and the valve or stopper or whatever it's called on the end of the bladder, was retracted way inside.  Each old sphere held about 450ml's of hydro fluid when I emptied them.

BTW, didn't bother with those plastic sway bar links.  The metal ones on there look near new so they're staying.  The only thing I have to fix now is adjust the ride height.  The cars standing much taller in the rear.  Kind of aggressive looking and better than a sagging rear but parallel with the ground is the way to go.

[s class]

Well you've listed two key indicators that the old spheres were gone :

a) the diapragms were retacted
b) the spheres still held fluid even after being disconnected from the system. 

[WGB]

Sounds like they needed replacing a long time ago Oscar.

The pundits on the M-100 site do recommend bleeding 6.9 systems but it is really only necessary if you have to prime the pump after  it has been disconnected as Koan has said.

What I noticed after I first changed the spheres in my 6.9 and didn't bleed anything was that the handling firmed up after several days of driving which was presumably all the air in the lines working itself out and back to the reservoir.

A lot is made of the fact of residual pressure in the system but if the car is raised the pressure should disappear and particularly if the spheres are empty - very early on in the jacking process.

Where people get into trouble is when they jack it up without running the motor first, the check valves come into play and lock pressure into the struts and spheres waiting for the next lucky sucker.

Bill

[s class]

Where people get into trouble is when they jack it up without running the motor first, the check valves come into play and lock pressure into the struts and spheres waiting for the next lucky sucker.

This has caught me out on the 6.9's - what should I do when I want to lift the car?

[WGB]

It depends on how you are lifting it.

I use a two pillar hoist with lifting on the chassis points so all four wheels are off the ground.

The manual says just to lift it without doing anything to the control valve and on lowering it I hold the weight with the hoist, start the motor and when it lifts itself I drop the hoist completely. The suspension is totally depressurized and easy to work on.

If you are jacking only the front or rear and relying on the other end to hold itself up you will need the second position but I am sure four axle stands and start the motor before lowering it woud be safer.

The "M" position with the cable released is for all four wheels off the ground only - but it will release any central pressure if the pump needs to be uncoupled.

Recently when I did the front suspension (without opening the hydraulics at all) as I moved  the front sway bar down I heard the central sphere pressurise the system and the front rams then extended and stayed locked in full extension as the ball check valves locked in position.

Fortunately it took a few days for some parts to arrive and in that time normal wear had made sure the system had lost it's pressure and the rams could be moved again. I will depressurise with the "M" position before I next dismantle any part of the suspension.

Bill

[koan]

I've been caught a couple of times with the full hydro suspension, both stupid mistakes with unexpected effects.

First was replacing the rear transmission mount, front wheels on ramps and a trolley jack supporting the transmission. Overnight the front suspension leaked down and I ended up with the transmission jammed against the body and a lot of car weight on the trolley jack.

Another "moment" with the suspension was when I had the rear trailing arms out and jammed the sway bar out the way with a wedge. I fired up the engine for a weekly warm up, after a while I felt the rear rising. How can this be?  Had a look, both struts had extend and lifted the car on the timber I'd used to support the trailing arms, about 100 mm off the jack stands.

Either of these mistakes could have caused injury in slightly different circumstances so I'm a lot more careful now.

I now assume all lines have pressure in them unless depressurised, by disconnecting the control arms on the level controllers and moving them to emptying position - with the engine running and then moving the control valve to "M". Now the suspension can't do anything unexpected, can't pump or sink down no matter what levers or valves are moved.

koan.

[oscar]

Sounds like they needed replacing a long time ago Oscar.

I honestly can't remember when they went bad.  I do remember before xmas going over a speed bump thinking "that didn't feel right".  Then I had that incident not long after whereby one sway bar link fell apart.  The ride improved after I replaced it.  But it wasn't until I posted about what the spheres do a month ago that I knew something was definitely worng.

Anyway, keen to know more about what's going to keep costing me $500 every few years in the name of a smooth ride, I took a grinder to one of the spheres from the wreck earlier today to see what was inside.  Apart from seeing no obvious holes in the diaphragm (apart from the one left from the angle grinder) the thing that strikes me the most about these things is that they should have a shrader valve or similar attached to the diaphragm side so they can be recharged.  If not from factory, I can't see why one can't simply drill, tap and throw a schrader valve in, get the sphere pressure tested and then recharged.  Anyone know what sort of pressure these things are charged to?

Shaped metal ring holding the diaphragm's integrity and helping to form a seal against the sphere's inner walls.


Profile of the ring


From the left, back wall of sphere ends where the small rust spot is. Then there's a channel seen holding water and I'm not to sure if the lip of the diaphragm gets caught there or what. Moving to the right is a section that rises to the faintest of humps presumably the ring and diaphragm lip will not go past this hump.  The rest is a uniform finish up to the fluid opeing.


This is basically what the ring and diapragm looks like in the sphere when fatally deflated.  Inside the sphere the diaphragm's lip would ordinarily be folded back over the ring.  I can't imagine that the ring touches the inside of the sphere.  Only the rubber diaphragm's lip does.


Going back the other way to a charged normal sphere, the diaphragm is pushed towards the fluid opening of the sphere.  Most noticeable is the two channels on the disc connected to the diaphragm.  It pushes against the fluid opeing of the sphere and the channels provide the dampening effect by restricting how much hydro fluid goes back to the struts following a bump.  Interstingly, the new spheres I got a had a cross pattern, ie 4 channels.


If I could find a fault at all I would be thinking this manufactured "hinge" in the diaphragm would become infamous for sphere failure.  I couldn't see any probs but I've no way to test its integrity without  pressure test of some kind.

[CraigS]

That's exactly what the Citroen spheres have (Schrader valve). Th epressure in the system is around 2000 psi, but not sure whether this is uniform across the spheres.