Clutch actuator disected

[WhiteNBlack08]

OK, I promised that if somebody sent me a bad actuator, I would disassemble and show you what makes it tick. So, here it is. Thanks to Chieftmc for letting me have his old actuator.

First is the complete actuator:



We've all seen this before. Start by removing the 5 torx screws holding the cover on with a T20 bit driver:



After removing the cover and the rubber bellows, this is what you see:



Next you disengage the pushrod by inserting a screw driver and prying slightly to pop it loose. The ball end just snaps into the socket:



Next you can remove the motor by removing the two T30 screws from the mounting flange:



Continued in next post....

[WhiteNBlack08]

Once you have the motor out, you can see it is sealed to the case with a rubber O-ring:



The case of the motor is held together by two tabs bent over the mounting flange. See following pictures:





Once you bend out the tabs and separate the motor, this is what you see:





It's just a simple DC motor. I have not had time to pin out the connector, but I will post that once I have time.

[WhiteNBlack08]

You can then work on taking out the cam that operates the pushrod. Start by removing the spring clip holding it on the shaft. Note: you will break the clip trying to remove it. It is very brittle:



This is the view through the opening the pushrod goes through:



You can insert a screw driver under it and pry it out of the case:




There is a plastic cover over the actual cam that appears to act as a shock absorber at the end of travel for the cam. In the following two pictures, you can see the spring mounted inside. It engages two tabs on the back of the cover and the cover has pads on each end that contact the case:

[WhiteNBlack08]

Next I disassembled the pushrod itself. Not sure the purpose of this mechanism, other than it seem to take up slack and keep the pushrod constantly engaged with the throw out arm for the clutch:





Next is a couple of pictures of the cam & helper spring removed:





And here is the empty case:

[BARNEY O]

Very interesting ... what was actually wrong with this actuator??

[WhiteNBlack08]

Next you will see the culprit behind the failure of this unit:



As you can see, the pivot shaft has rusted. Chief had posted previously that he found moisture in this unit. It worked it's way down the pivot shaft and caused it to rust which bound up the cam.

I am going to attempt to clean this unit up and see if I can get it working again. I couldn't find any issues with the motor. It was nice and clean with smooth bearings.

I am hoping to be able to pin out the connector. It uses a 6 pin setup. Although, I'm not sure what for. It's a simple DC motor, so I only see a need for two, + & -. There is no sign of any kind of resolver or encoder to tell the TCU positioning, so i have to assume it works off of load sensing.

The actuator holds either end by over centering the cam. The coil spring will hold it at each end. I'm assumng that the motor is there just to get it over the center and the spring does most of the work????


Anyway, I will update this thread as I discover more info. It's getting late, and I have to be up a 5 am to go to work.

[Kermit]

I was about to ask if you'd attempt a rebuild, its exactly what I'd have tried too.

[rubyg]

must have some hall effect sensors for position sensing info to the computer.

[a2jack]

Thanks to WT+Blk and to the Chief for doing this for our forum.

The activator, overall , Looks like typical Euro over-engineering and way too complex. It will remain a weak spot in our cars.

With the 451's demise in sight, those of us who plan to keep our cars long term as collectables, would do well to buy an extra activator and set it aside while they are still available.

As we say in aviation "It Ain't If, It's When" . A2Jack

[WhiteNBlack08]

I had an aweful time getting the cam off the pin. I used every type of tool I had to wedge underneath it an pry. It was bound up extremely tight.

By the way, anybody still wondering about the teeth, the ones on the cam are plastic, molded right into the part. The output on the motor is steel, looks to be chrome plated, since it didn't rust.

If I have time, I'm going to try and futher disect the motor today. Hopefully get a pin out of the connector.

I managed to clean up the shaft this morning, and now the cam pivots beautifully.