E300 Estate 124 Rear shock bottom mounting problem

[harpoonlouis]

Just found that the lower end mounting on the rear shock absorber on my E300 has parted company.

It appears to be a ball and cup arrangement and the ball has pulled free of the cup causing a load bang from the shock over sudden drops ( speed bumps in my village!)

Can this be re-attached or is this a new shock job?

It has a hydraulic connection. If I swap out the shock is this system under pressure and will it need re-filling? Any clues apperceiated.

PS only been a member on here for a while but it has been very very worthwhile, many thanks to those who have hlped me so far.

 

[Bolide]

It's not a shock absorber it's a suspension leg. You can replace them individually. If the mounting that's broken is part of the leg you'll need a new leg. There is a joint down there - maybe it seized then failed

Don't drive it till it's been fixed. Only have it done by someone who knows what they're doing

Nick Froome
www.w124.co.uk

 

[harpoonlouis]

Hi Nick

Thanks for the info and the warning.

You describe it as a suspension leg but it obviously isn't the spring/shock combo used on front struts which I am very familiar with. This one is a damper of sorts with a hydraulic connection indicating that it is part of a active suspension system.

It is the ball and cup arrangement at the bottom of the unit that has separated.

The cup is held in place by two transverse bolts and the ball apperas to be an integral part of the damper/suspension leg. I can't see how I could not change out both parts as corrosion is evident on the ball and the cup has stretched or failed mechanically.

Sounds like a swap out of the unit including the cup mounting at the base. Is the hydraulic connection for fluid transfer or is it pressurised in it's own right?

In case you are concerned I am a Chartered Engineer and very familiar with hydraulic systems etc. I just have never needed to look in detail at this suspension system before.

Thanks

 

[star]

you need to change the shock, easy to do if the pipe comes undone. top mount is under carpets between seat backs. beware lots of pressure in pipe.

 

[Bolide]

The leg is pressurised by the underbonnet pump & height is set via the height corrector. The damping & springing are provided by the suspension spheres. There is pressure in the system but I couldn't tell you how much

The system is basically the same as a Citroen BX but with the addition of a helper spring to maintain the ride height when stationary

Andy K has written a good how-to on replacing parts of this system - have a look on the two forums and you should find it

Nick Froome
www.w124.co.uk

 

[harpoonlouis]

Hi Nick

Thanks for that, now I understand.

Had a BX as a company car once, ugly as hell but probably the best handling of any car I have ever driven, wasted on such a car!

Will have a serach for that post.

Thanks to all who replied.

 

[Bolide]

Looking at the diagrams on Detali.ru

http://www.detali.ru/cat/oem_mb2.as...GM=717.433&CT=F&cat=44R&SID=35&SGR=075&SGN=04

it looks as though the joint is on the foot of the hub and the leg uses a fixing bolt as a pivot. If that's the case, and the pivot has sheared off the leg, the leg will need to be replaced. I would expect the bolt seized solid and the flexing sheared the pivot / boss off the leg

It's not a failure I've heard of before. I have replaced the lower joint below the hub on one car - it creaked and we found that was the cause. Neither is a common fault as far as I know

Legs are expensive from a dealer and cheap in breakers yards. Because they are not shock absorbers (damping being performed by the spheres) they can be replaced individually

Nick Froome
www.w124.co.uk

 

[harpoonlouis]

The bolt number 29 in the drawing has a second identical bolt 2-3 inches inboard and the two of then anchour quite a substantial casting. ( not shown on drawing) The casting has a central hole with a plastic cup insert which should hold the ball that is on the end of the leg/strut. It looks as if the cup has become weak and has lost it's grip on the ball end of the leg. The surface of the ball has suffered quite a lot of corrosion so maybe there was a failed seal or dust cover on there at some time.

Looks like I need to get a replacement leg because of the corrosion and the cup because it has lost it's grip ( know how it feels!)

Presuambly the system is pre charged with fluiod so swapping out the leg needs to be done by a workshop with the charging pump. Reminds me of the ill fated Allegro, remember that, with the square streering wheel? Learned to drive in one of those Ha-ha!

 

[Bolide]

AFAIK the system is self-bleeding. See Andy K's info

Nick Froome
www.w124.co.uk