6.9 Strut overhaul

More threads by WGB

WGB

New Member
Messages
1,289
Points
0
Location
Perth Western Australia
My 6.9 has always had a weak right front strut although it never particularly leaked externally.

The struts are no longer procurable new but I purchased two kits of seals off US E-bay last year.

I also understand Styria sells reconditioned exchange struts and this was my next alternative - and looking back on my experience probably a sensible economical one as well.

I appreciate this is his business and have no desire to tread on his toes but here is a record of what I have been up to.

StrutSeal2-1.jpg

The individual measurements of the o rings and teflon seals are given in this posting

http://forum.w116.org/mechanicals/as-rare-as-rocking-horse-poo/msg90765/#msg90765]http://forum.w116.org/mechanicals/as-rare-as-rocking-horse-poo/msg90765/#msg90765

The previous owner had also fitted wider than normal 140 Eight slot wheels and these had rubbed the right front hydraulic hose but have held up over the four years I have had the car.

In-situ with frayed hose - I have a new pair of hoses for the fronts.

DSCN1496.jpg

Strut removed and sitting in the open air after a de-grease

DSCN1500.jpg

Bottom ball joint removed with a 22mm slim spanner

DSCN1501.jpg

Markings on this strut before being attacked with a pipe spanner

DSCN1506.jpg

Top mounting clamped in vise and 18 inch pipe wrench attached to other cast end - unscrewed the top cover with some degree of difficulty

DSCN1502.jpg

Here is a picture of the top cast cover still in the vise and showing the O ring in that cover

DSCN1503.jpg

The next bit was the difficult bit strut reversed and bottom cast end clamped in vise ( with the piston removed through the top) using the bleed take-off point as a method of preventing it turning and after an hour of heaving with the pipe wrench I had only succeeded to turn the tube about 1 turn and then it was jammed even tighter and would not tighten or untighten.

Penetrating oil (probably irrelevant) - left overnight - and another 30 minutes heaving later not one skerrick of movement. At the point of "repair-despair" I remembered I had a 6 foot length of galvanised steel pipe which I placed over the end of the pipe wrench and with about 5 to 6 foot of leverage and my not insubstantial weight it started to give with a lot of graunches and moans.

They appear to use something like red-loctite to prevent the cylinder from turning and probably as an extra sealant and it is very effective and the reason it is so hard to undo. Once the threads are cleaned of the stuff the cylinder can be spun into the housings very freely by hand.

Here is the bottom teflon seal tensioned by the thick O ring in the cast end with with the bump stop - this is after the bleed off point so it is really the "seal of last resort".

DSCN1530.jpg

Here is the real shaft seal that is a push fit into the end of the cylinder and is held in place by the lower cap.

DSCN1517.jpg

Here is a view of it from the lower side with a new seal and O ring fitted

DSCN1534.jpg

Here is the piston complete with piston ring surrounding the valving.

DSCN1519.jpg

Here is a collection of the bits laid out - the cylinder has been reversed and should be the other way around.

DSCN1508.jpg

After a bit of overcomplicated stuffing around due to inexperience in the end the seal change is a walk in the park.

Lower cast end shaft seal (hat section teflon and fat o-ring) just pushes into the cast end by hand after removal of old seal

DSCN1528.jpg

External O ring as well as old teflon seal and o-ring hidden under plain teflon seal are fished out with a small hook and replaced quite easily in the mainlower cylinder seal.

DSCN1531.jpg

The new O ring is placed in the slot and then the teflon seal fed in over the top of it. The teflon seals against the shaft at the inner edge and the small o-ring on it's outer edge.

DSCN1534.jpg

And of course a new O ring is placed in the upper cap

DSCN1525.jpg

Here is a picture of the new parts waiting for "Cylinder rehabilitation" prior to assembly.

DSCN1535.jpg

I am actually inclined to think that the poor performance of this strut has more to do with the glazing of the cylinder bore than the state of the seals . This picture shows the upper part of the bore which is quite matte in colour vs the very shiny lower bore.

DSCN1523.jpg

Opinions on how I should deglaze the bore are gratefully accepted.

Bill
 

Styria

The Godfather
Moderator
Messages
8,947
Points
187
Location
Sydney
That's an excellent effort on your part, Bill. You need not be concerned that your post may be cutting across my activities - the idea is for us to share information as best as possible to enable each and everyone of us to keep our cars in the best possible condition. As I have previously said, dismantling is just about a two man job, and probably the hardest part of the reconditioning process.

Anyone that would want to take on the job still has to purchase the special seals, and as my pricing structure had been very reasonable, the saving for the 'do it yourselfer' is not all that substantial, plus one runs the chance of damaging or destroying the strut in the end, despite their robustness. In any case, I still have yet to work out some way to replace/supply new bump stop rubbers for the front units. As well, the bottom mounts are worth their weight in gold. Bill, also, I have taken the liberty to reposition the thread in the 'ARTICLES' section - this term is a bit of a misnomer, and that part of the website is badly in need of some sorting and re-grouping, as well as re-naming. In the meantime, until all that is done, it does become a question of 'having to walk your eyes to obtain some of the relevant information'. As you can imagine, as the site continues to, shall we say, build a repair library, the task is becoming just that bit more difficult. Regards Styria
 

Oversize

Master
Messages
5,196
Points
191
Location
Melbourne
So the big questions:

Where are the seal kits available? Is someone remanufacturing these now?

How thick is the main tube?

Could it be badly damaged in a vice?

Can it be honed easily?

Surely there's a better way to secure the tube or caps while it's disassembled? I'm not keen to have a huge pipe spanner biting into the housing.... Anyone have some other ideas?

Can the bump stop be separated from the lower end?

If the bump stop are NLA (or were never available separately), could a newer style (yellow foam type) be fitted?

Would yellow foam (progressive) bump stops be resistant to hydraulic oil?

Are all the valves in the piston?

Could the valves be modified to mirror the high performance (heavy duty) AMG stuts?
 

Oversize

Master
Messages
5,196
Points
191
Location
Melbourne
Any answers for this one? :(
 

Styria

The Godfather
Moderator
Messages
8,947
Points
187
Location
Sydney
Mark, I hadn't seen your post, but will reply to it as best as possible, and as soon as possible. Probably some time late today or tonight. Regards Styria
 
OP
WGB

WGB

New Member
Messages
1,289
Points
0
Location
Perth Western Australia
I would be interested to hear how anybody else removes the end caps but most of the damage is superficial and easily filed out.

Judicial heat reduces the turning torques by a factor of 100 and there was no visible deformation of the cylinder other than exterior markings.

The kits I purchased off e-bay and I have already supplied the dimensions if anyone else wants to fabricate their own.

All the valving is in the piston and does not need to be touched.

Bill
 

Oversize

Master
Messages
5,196
Points
191
Location
Melbourne
It sounds like the guy you bought the kits off might still have one left? Any chance you could give me their details (PM), or buy it on my behalf? Having the set in my hands might make it easier to have sets remanufactured here in Melbourne (along with the basic dimensions).... And I wouldn't get just one set done!

What about the rears???
 

Styria

The Godfather
Moderator
Messages
8,947
Points
187
Location
Sydney
Mark, Bill has answered it pretty well. I can only add a little bit. Without heat (as advocated by Bill in the end) it is just about a two man job to separate the the top and bottom sections from the main body. We used a reasonably large vise, but also two very large adjustable tools (I don't know what you call them - should take photos for illustration) to separate all items.

The tubes themselves are quite thick and very solid - German steel. I think it is not inappropriate on my part to say that Bill was very fortunate to find those old seals on ebay. From what he has said, they weren't cheap to buy. The rebound rubber is a troublesome item - I really don't know how a replacement could be sourced, nor do I know of anyone that could manufacture them. Another potential problem part is the bottom ball joint. Possibly NLA, but if they are, worth a lot of money. Nothing else fits. I try and have mine refurbished, but that source is becoming unreliable.

As Bill says, the valving is in the piston by means of solid discs, retained by peened over nuts. In other words, they don't want you to dismantle them. I think I did try, but cannot remember the outcome, nor what I achieved. Best left alone. I do think that under hard cornering, the strut that is put under pressure by body roll will respond to additional hydraulic pressure. It is for that reaso (I think) that new seals in the struts will considerably improve cornering and road holding. Hope that helps. Regards Styria
 

Oversize

Master
Messages
5,196
Points
191
Location
Melbourne
Ok looks like I'll be headed to a hydraulic specialist and now that I think about it, I seem to remember tracking one down in Keilor East. At that time it didn't appear to be a problem for them, but that was a long time ago; they may not be in business now.... Just recently I was canvassing wreckers and the second MB place on my list (from the phone book) was GOA and the factory was for lease! No forwarding address as they just stopped trading; damn. :(

I spoke to Pedders in FTG and it seems all they've done in the past is hydraulic to conventional conversions... Not interested. They may be able to assist with the bump stops.

As you mentioned Styria the ball joints may be a problem and I'm not even sure if MB had them listed as a separate part to the struts. Then there's the upper mounts... Does anyone know the part numbers for this stuff??
 

Styria

The Godfather
Moderator
Messages
8,947
Points
187
Location
Sydney
Mark, the bottom ball joint does have a separate listing, but last I heard it was very expensive - and I mean, very. The top mounts are still procurable, and I'd recommend that you contact abl567 to procure that part for you, i.e. if you want it and need it. Regards Styria.

BTW, as far sa Air Cells go, did you want a price and/or availabiity for the Lemfoerder brand both front as well as rear ? I couldn't get hold of the company this morning. Will try again tomorrow.
 

Oversize

Master
Messages
5,196
Points
191
Location
Melbourne
Styria I'm after the cells that're as close to the originals as possible. Not sure if they were Lems; the heavy ones seem to be the best, as long as they haven't been sitting on a shelf for years!!!

Yes I need the front top mounts. I think the rear top mounts are ok, but I'll have another look.

At this stage I'm just after the front cells and the central one.

I got in contact with my seal guys today and the next stage is removing a front and rear strut followed by disassembly. I'll then send all the info I have along with the parts and oil specs to either match up seals with existing ones, or have some/all remanufactured. They also have several contacts for hydraulic specialists and machinists. If it all works I'll be recommending them to everyone!! :D

I know there are some very knowledgable people in WA who actually developed the hydraulic suspension for the Lexus LX570 :):

http://www.lexus.com.au/lx570/features/performance
 

Oversize

Master
Messages
5,196
Points
191
Location
Melbourne

Oversize

Master
Messages
5,196
Points
191
Location
Melbourne
Well that does sound interesting!!! :cool::rolleyes:
 

abl567

Super Moderator
Moderator
Messages
2,092
Points
125
Location
Sydney
Welcome Martin! Nice to see you here, we must catch up
 

PvD

Mountain Dweller
Messages
46
Points
0
Location
Kurrajong Heights
After replacing all the hydrauliy spheres, front lower struts ball joints, high pressure flexible hoses between spheres and struts, some small flexible return lines from struts, hydraulic pump hoses, cleaning the tank, replacing the hydraulic oil filter, replacing the front level control with a reconditioned unit and link between fron level control and torsion bar (which disapeared by its self) I expected to ride nicely and be leak free. Not so the left rear strut area still showed a slight leak from high up on the strut. The ride was brilliant. The small flexible return line which was not replaced previously was replaced, still a small leak. We removed the strut. The hight pressure hose connection was so tight and since the washer was renewed when the hose were replaced this was unlikely to be the leak. We un-screwed the top cap from the strut tube which was not difficult. The 'O'ring seal appeared damaged. The 'O'Ring was removed a metal swarf was found embeded in the 'O'ring. These struts were replaced with new strust in 2007 by a reputable mechanic who specialies in european cars including Merceded. Sourcing new 'O'Ring and will put it back together. One could consider this a partial 6.9 Strut overhaul. Photos included are leaking strut, strut top seal inside cap showing damaged 'O'ring and 'O'ring with metal swarf sticking in side of removed 'O'ring.
 

Attachments

  • DAMAGED 'O' RING.pdf
    138.1 KB · Views: 9
  • STRUT TOP SEAL.pdf
    190 KB · Views: 10
  • LEAKING STRUT.pdf
    216.3 KB · Views: 14

Oversize

Master
Messages
5,196
Points
191
Location
Melbourne
Lets hope there's no more bits floating around in the fluid! Do you believe the metal was there from manufacture? Sounds like a straight forward fix though. I wish someone was making a repair kit so I didn't have to start from scratch like others have done before....

Where did you source the lower ball joints? And how did you clean the tank?
 

PvD

Mountain Dweller
Messages
46
Points
0
Location
Kurrajong Heights
Mark, upon further investigation (with a magnet) the swarf was some of the thread locking material. The damage to the 'O'ring must have been from when the strut was manufactured as I doubt removing the cap could have caused the damage the 'O'ring.
Have now installed the new 'O'ring. We had the stop tightning about half a turn from bottoming out the tube in the top cap to ensure the inlet and drain hoses alined correctly.
Now waiting for the thread locking material to fully harden before pressurising system.
Peter
 

PvD

Mountain Dweller
Messages
46
Points
0
Location
Kurrajong Heights
Mark, got the ball joints from some place in Germany with eBay name of matron1 the total cost was about AU$300.
I have kero, petrol, turps, thinners, acetone and rag on the end of long screw driver, can't remember how I cleaned tank . With the valving mechanism removed and the tank being steel you can hardly damage anything. I got it spotlessly clean and repainted the outside.
Peter
 

PvD

Mountain Dweller
Messages
46
Points
0
Location
Kurrajong Heights
Sorry Mark, Change computer and can now send correct info re-ball joint the previous name was spelt with a 'n' at the end incorrectly. Info attached now with correct name 'matrom1' hope this helps.
Peter
 

Attachments

  • Strut Ball Joint.pdf
    51.1 KB · Views: 6

Similar threads

Top