So here are the options, keep in mind that my studs are flipped so I can change the slave without removing the transmission.

1. New OEM slave cylinder, may as well buy from FCP($580) for lifetime warranty. ECS would be the same. BMW NW $522
2. Rebuild from MLR $380
3. Rebuilt kit with viton seals & new pistons $150
4. Rebuild kit seals only $75

With the proper derilin pivot pin the problem will be solved.

 

90mins, dang... Should open a shop haha.

 

Then it would take longer than 90mins 🤣😂

 

Please go with option 1 it has been discussed. This is forum conclusion, at the end nothing work effectively but BMW extensive research for parts and material on this platform.

 

@platii I know! Your comments have been burning a hole in my brain since the discovery.

It seems so easy to pull the trigger and walk away. In my defence I may be the best person to experiment. Obviously I'm not going to give up. My son at this point could carry on after me, he has been there through all of my struggles with both cars.

I have a spare clutch and the transmission itself si bullet proof.

 

There is another option, the e46 smg2 slave. They're for the most part identical save one ridge that from memory can be left as is, or shaved if you prefer.

 

An interesting idea, going to check the sensor plug and see if the PLCD is the same. The physical clutch and movement may be different too causing the scale to be off?

SMG III Clutch Slave cylinder 23017838938 - New - MLREng

NEW replacement BMW SMG slave cylinder. This replacement unit does not include the position sensor. The position sensor on this transmission is sold separately as part of wiring harness for HPU. Vehicles over 100k miles and performing clutch change should replace clutch slave or rebuild with our...

mlreng.com

SMG II Clutch Slave cylinder 21522229841 - Complete Unit w/ Sensor - MLREng

This genuine BMW SMG II Clutch Slave Cylinder, featuring the part number 21522229841, is a perfect fit for various BMW models, delivering the performance and reliability expected from the brand. Trust this component to uphold the integrity of your vehicle's transmission system, allowing for a...

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So I have decided to throw in a spare slave cylinder and a delrin pivot pin. Inspect the pump seals, motor and replace the o-rings on the clutch solenoid. The clutch has ~30k miles on it, staying in.

I will get some pump cycle times & temperatures. Then put in a rebuild slave cylinder with MLR viton seals and repeat the tests. As the platform ages some good data will aid in a higher survival rate at a lower cost. I hope?

I enjoy the whole journey, including the wrenching. I just have to remember that when things fail. The brass pivot pin made sense at the time and I just barely missed the discovery the last time the transmission was out. I knew it going in this time and it was confirmed.

 

So I have decided to throw in a spare slave cylinder and a delrin pivot pin.

Would this work:

Unicorn Nipple v3.0 - Billet Stainless Steel Clutch Fork Pivot Pin

Where Unicorns are Born and Bred

www.einhornindustries.com

I’m running it in the e30 and e28. Can’t remember if it’s in the e60.

 

Well @Fiftytwoeighty based on my observations between the SMG & manual car I have noticed little to zero wear on the pivot pin. If it isn't broke?

When the engine comes out of the manual car I can have a look and I know I installed it.

 

Metal against metal will wear. That hardened pin may not wear but guess what's going to wear now?

Also the SMG2 slave has been documented here. You use / reuse an e60 PLCD with the new e46 slave. We know it works but no long term data IIRC.

 

Metal against metal will wear. That hardened pin may not wear but guess what's going to wear now?

True

 

Another concern now is, the clutch fork been rubbing on the clutch pressure plate rivets.

IMO, the issue with rebuilt slave is the inner diameter of the slave body wears out, makes the repair fails shortly after.

 

I'm curious if the SMG/clutch has a higher force and thus wears the pivot pin faster. I've always run the Delrin on other manuals but on this build I chose to use the E31 850 steel pin - we'll see how that wears over time.

 

Well the car went about 70 miles before failure. The pin has been in for a few thousand miles. I got the yellow gear and then the red gear. Parked the car stuck in gear.
View attachment 985578
View attachment 985579
View attachment 985577
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It took Matthew and I about 90 minutes to get the transmission out.

I have always hated those brass pivot pins. They cost a lot more than the genuine plastic one, marketed as being better yet they seem always fail and disappoint. When I did my trans out service this past January, my genuine plastic had minimal wear at 107K miles lots of city driving. I could have thrown it back in there for another 100K miles especially since now I do more highway miles. With this much wear, it could easily cause premature slave failure (over extension) and soon after possibly a contaminated clutch and other mechanical issues. I fear those things LOL

 

Back on the tarmac, for now. Plans for the future. All of the SMG software shenanigans will go in another thread. Looking for a spot for a cooler?

Inspected the pumps seals because of other problems people have had. They look new.

 

For what it's worth, the SMG2 slave that I put on my car has been flawless, and I didn't have to file anything down at all. I have a post up about it but (that part of) the car has been running great.

Cheers