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Discussion Starter #1
Hi All, I am trying to help some travellers who have problems with their 2000 2.0L 156 and are 'broken down' in my area.

Problem is car wont select a gear from Neutral, however if you start pushing or towing the car it will then grab a gear and so long as you do not stop will continue to operate.

If you are in non city mode and stop in say 2nd gear it will clunk a bit and then go back to N and from there you need a push to keep going

Also the selespeed oil res was empty, its been topped up with LDAS Penrite, bled but still no good.

After perusing this forum, I decided that a trip to an experienced ***** man with a diagnostic unit was in order

After 6 phone calls...usual mechanics rubbish.... the owners are informed that the clutch operating piston is leaking, a new unit is $3K and they cant find a second hand one etc etc ...sure you blokes know this round-about well.

My research on your forum shows some pics of the piston/cylinder/ actuator call it what you will, have 2 o rings on a spool.

Is it possible to buy some viton o rings and repair the cylinder, I am a very handy person and would like to help these folks out but dont want to reinvent the wheel in process.

The picture is from this forum, can anyone confirm that this is indeed what I should find in this ***** when I pull it down, also the o ring sizes were mentioned in the same thread (well the picture I cant upload is http://www.alfaowner.com/Forum/gallery/files/1/2/9/0/7/2/2012-12-20_14.26.30.png)

http://www.alfaowner.com/Forum/alfa...eak-from-selespeed-on-a-156-need-o-rings.html

Any helpful information would be greatly appreciated.John
 

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The Selespeed unit is a hydraulic system with electronic controls. To attempt troubleshooting the system might be quite involved but you can check all the basics first.

- Does the reservoir keep emptying? You need to know how to check it. Open the driver's door and switch key to 'on' position but do not start the car. Check that the dipstick in the tank is not below 'min'.
- If it keeps emptying check whether there are any leaks around the actuator. If you cannot see it leaking anywhere it might be leaking into the gearbox.

- The hydraulic system needs pressure to operate.
- Does the pump runs? It will run again for every 2 gear changes assuming the accumulator is healty.
- You will need diagnostic tool to monitor whether the pressure is normal.

- If the hydraulic seems ok you need to check that the clutch rod position is set between 28-28.5mm.
- Run clutch bleed rountine and the actuator calibration routine.
- Clean the big connector next to the battery. This is the actuator wiring loom connector.

So, was the car sent to an experienced mechanic or the troubleshooting done over the phone only? Are you certain that the clutch piston is leaking and not the solenoid is leaking?
I have never dismantled the clutch piston because there is a rod jammed into it to move the sensor arm. It seems a little difficult to remove and to put it back might be even harder.
The trouble with the "O-ring" is that actually some of them are not O-rings but actually hydraulic seals.
The difference between O-ring and hydraulic seal is that O-rings are meant to seal off gap where the surfaces are not moving; whereas hydraulic seals will seal gap where the surfaces are moving. If you mistakenly use O-ring where hydraulic seal is called for, the O-ring will twist and tear and the sealing action will fail.

I have heard of hydraulic seal kit for the actuator repair but I've not been able to find it. Viton O-rings on the other hand are easy to find.
 

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Discussion Starter #3
OK we now have driven back the car from the mechanic w/shop, like I said once it is rolling it will change gears OK but will not select a gear from stop.

I will hopefully get some time in the next day to pull out the faulty part and I shall report back.

Tx
 

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Discussion Starter #4
PS not sure what you mean by a solenoid leaking, a solenoid is an electrical coil that drives a rod or core.
 

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Discussion Starter #5
pps all the other things you have mentioned, I understand and am pretty sure they are working ......done a couple of hours reading on this forum!
 

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The position of that clutch piston is controlled by a solenoid that is designated EV0. A hydraulic valve is integral to the solenoid so that the current applied to the solenoid will result in a certain fluid flowrate across the valve. The valve contains three O-rings on the outside for sealing. If they are not sealing well it will give quite a bit of problem as you can imagine.
 

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Discussion Starter #7
Can you confirm please the best way to approach this unit, from top? thru wheel arch? or from underneath?

Does the whole selespeed unit need to be removed or does the clutch cylinder detach, for service?
 

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Discussion Starter #8
Are you certain that the clutch piston is leaking and not the solenoid is leaking?
Having dismantled the unit I understand what you were trying to ask me now, you were referring to the Solenoid operated proportional flow-rate valve marked EV0, yes I am looking at that as well

Yes, I have removed the clutch actuator roll-pin that drives the position indicator potentiometer, I will keep you informed of the degree of difficulty in re-installing that pin.
 
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