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MG MGF Technical - Replacing hydragas devices myself

As no qualified service nearby I was thinking replacing the suspension units of my F for myself. Would it be possible?. Difficulty degree?
Marius
M. Koetze

Marius, I have just been through the whole process of revising one of the hydra units. I would believe this is difficult job. The pipe union to the unit is very difficult to access as it is hidden behind the MEMS and other structures that need to be displaced. And then you ought to have a hydra pump available to presurize the system. Good luck. Mike
JM Vega-P.

No experience either (perhaps Dieter will know more?) - but I suspect that Mike is right: will require quite considerable disassembly (dropping of subframes etc)

Do you have access to the workshop manual Marius?
Rob Bell

Rob, Mike, thanks. I managed to get a copy of the worshop manual and from the readings replacing the units looks fairly easy. But you must be right and may be a big mess for me. I can get hold of the hydraulic pump so if somebody is experienced in doing it yourself, indications will be appreciated.
Marius
M. Koetze

Good luck with the project Marius. It may be worth contacting Mike Satur, or Bill @ the MGF Centre to see if they have any advice: this kind of work will be routine for them.
Rob Bell

Ooops, missed this, I'm sorry.

Replacement hints are at
http://www.mgfcar.de/defects/blownhydra.html
http://www.mgfcar.de/defects/blownhydra2.html
Pump and fluid mixture:
http://www.mgfcar.de/pump/index.htm

Principals of Sir Moulton's
http://www.mgfcar.de/hydragas/hydragas.htm

Notice, the manual instructions look straight forward, but there are some hints not included.
I.e just forget placing wedges between the drawn location. Let the suspension hang down as it is.
Release fluid, unbolt the fixture plates and keep all parts, special the 16mm washers between pistons and knuckle joint to put them to the same location later.
The units come out in direction wheel house, so don't worry, bend away and back missing clearance. (inner wheel house sheet metal).

Notice, the manual *thinks* static only, but the parts (front/rear) can be moved up and down by hand with some force and act as a pump themself.
*Use your brain*, the manual writer had none ;)

Do you need to change all 4 displacers ??? (why ??)

Anyway, you need to understand that the rear and front are linked together at each side and the two filling valves are at the front only. This means you can find a tricky process to overcome troubles with bleeding the system with vacuum later.
If you haven't access to a vacuum pump, then the change _is_ possible.

Steps to make the change easier:
- Work from front to rear.
- Pre-fill the units before you re-connect the pipes
- fill up and fully release the fluid several times when ready
If you have still air in the system, then lift the car at the opposit side and careful unbolt the connection joints to let off the air bubbles direct from the units.

Hope my poor description makes some sense.

Good luck and keep us posted.

Regards
Dieter
Dieter K.

Dieter, many thanks. No, I have to replace the rear left unit only. That is the one that is leaking fluid.
Any special hint for that -rear left- location?
Marius
M. Koetze

nothing, but bend the inner wheelhouse sheet metal to get it out easier.

Pre-fill when installed, then re-connect the pipe *loose*.
Lift the front left additional to press fluid and air through the loose mounted joint.
Then quick tighten the connection.
Minimum air should be left in the system then.
Let the car down, pump in, release, pump in, release and so on, several times.

No air bubble *flow noise* should be heard after all, when you bounce down the suspension front or rear. This is important, cause the unit rusts away inside if air is in them.

HTH
Dieter
Dieter K.

This thread was discussed between 15/11/2003 and 22/11/2003

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