The clutch release bearing on our BMW Bavaria started grinding about a month ago, so it was time to take the transmission out and replace the bearing.
I bought the bearing a while ago, before I started taking everything apart. I held off getting a new disk and pressure plate so I could check the thickness of the friction material on the clutch disk. It was 8.5mm, while the minimum thickness (for the outboard release lever) is 7.8mm. I ordered a new clutch disk (21 21 1 223 125) anyway and pressure plate (21 21 1 202 052).
Russ Neely, Brian Shorey and Stevan Thomas, people that I’ve known for years only through the Alfa Digest, all recommended that I get the gears lightened on my Alfetta’s transmission.
I’ve had the transmission apart for a while (to replace the clutch) and finally got around to having the work done.
Two people were recommended, Tom Sahines and Merrit Carden. Tom Sahines was too busy and he gave me Merrit’s number. I sent my gears and input shaft to Merrit at the end of July and went to pick them up 10 days later.
Merrit’s house is in sort of a cul-de-sac. There was a front-ended Kia in the driveway – his son’s car, waiting for an insurance adjuster.
His garage was his machine shop. It was packed with junk in addition to a (if I remember correctly, and old Bridgeport) mill, drill press, hydraulic press, etc. It was one of those shops where the owner knows where everything is, but if you moved one thing two feet, it would take him a month to find it.
I picked the gears up at the beginning of August. Merrit carefully unwrapped each gear to show me his work. In some cases, the gears were not only drilled for lightness but the walls were also machined – all this on hardened steel. The quality of the work was clearly apparent. Look at the photographs – they speak for Merrit’s beautiful work. More pitures here.
To contact Merrit Carden:
7475 Shady Hollow Dr
Newark, Ca 94560
I finally started taking apart the transmission. The main shaft has over 50 parts rotating around it – 1st – 5th gears, synchro hubs, synchro sleeves, bearings, etc.
This is where doubt started whether this would actually work again.
Common Alfa transmission wisdom indicates gear lightening for better shifting response and as a cure for a crunching 1-2 shift. It makes, sense, having less rotating mass and the accompanying reduced intertia would wear the syncros less. Better acceleration too, but me losing 20 lbs. would increase the car’s performance more.
This is a close-up of 1st gear and the worn syncronizer ring.
That wear is the cause of the crunching gears in 1-2 upshifts in the Alfa. You can see the wear in the triangle shaped shiny areas on the synchro ring. A new synchro ring has a rough surface. To tell you the truth, I didn’t know what a synchro ring looked liked before I took this apart.
In the process of replacing my Alfetta clutch, I also removed the transmission and final drive – it’s all one unit.
My idea was to just to reseal the case with Hylomar between the final drive, spacer and transmission. But I guess I have to clean up my bench and take a good look at the synchros and dogs.