Yahoooo ... finally someone managed to solve the leaking actuator for us SMG/SSG owners out there :rock::rock::rock: :
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How to repair your SSG clutch slave using BMW parts
I have been suffering with a worsening leak from the hydraulics on my SSG gearbox for a while. This is what I did to remedy the problem; the car is a UK spec SSG 330i Sport.
Firstly, check that it is the clutch slave that is leaking, it will most likely be running into the inside of the bell housing and out of the the drain hole at the bottom, it will also probably be moist around the three multi plugs on the left hand side of the gearbox; you will notice that the fluid that is leaking is lime green and smells sweet. Once you have established that it is this that is leaking I'll tell you what you need to do.
Go to your nearest BMW dealership or BMW independant and order a seal repair kit for a manual clutch slave (they do not do a kit for the SSG) this will be a special order from Germany and will take 7-10 days as it is made to order, you will also need 1litre of CHF11s fluid. The kit consists of a new cap, new rubber gaitor and new piston complete with piston seal.
Start the job by disconnecting you battery, then you will need a ramp as you will be under the car for a considerable amount of time; from under the car strip the frame holding the hydraulics and pump on the left hand side, two hydraulic pipes, the gearbox saddle and lastly the reservoir; most of the bolts are T27 and T45 torx head and are fiddly to get to but achievable. You may need to remove two 18mm bolts from prop shaft coupling to get to reservoir bolts The pump is hard wired in, so don't try to unplug it just prop it up on the something safely.
You will then be able to remove the clutch slave very easily.
When you remove the slave, take off the clutch position sensor via 2 4mm allen head bolts - you do not want to damage this!
Then put it in a vice and remove the black cap by peeling it out, then pull out the rubber gaitor and you can then pull out the piston rod, then remove the spring circlip with circlip pliers; there will then be a washer and voila! your piston with seal, there is also a spring behind the piston.
Now you will notice that the piston you have removed and the piston in the kit are different, the seal however is exactly the same, take your old one off (it will probably break apart as it will have become brittle) carefully with something blunt remove the new seal and put it on your piston TAKE NOTE OF THE ORIENTATION OF THE SEAL. Lubricate the seal and push the pitson back in, there will be some resistance but it will go. Refit all the parts and press the new cap in - use a long 18mm socket or something similar and vice.
Refit all your parts reverse of removal, and refill your reservoir.
cycle your ignition a couple of times to prime the pump, this will partly bleed the hydraulics, fill the reservoir again to the top mark, you can start the car and you will probably get no warning lights but this is all you can do, you will then need a BMW tech guy with diagnostic gear to run the bleed procedure, this cannot be done manually as the ECU needs to learn clutch position, slip, gear position etc. DON'T BE TEMPTED TO DRIVE THE CAR UNTIL THIS IS DONE.
This realistically takes 2 hours and the battery on your car must be FULLY charged or the ECU will not perform.
I took a chance at the kit fitting, but in the end it paid off.
Any reasonable mechanic can do this job, and you DO NOT need to remove the gearbox. Once you have the seal out it really is a piece of piss . Budget for £27 for kit, £10 for fluid and £45-£120 for bleed procedure and a full day. You will save at least a grand by doing this yourself.
Good luck and I hope I have been useful in writing this."
Original info
http://www.bimmerfest.com/forums/showthread.php?p=5851787&posted=1#post5851787