As promised in my last article, we're moving into some more difficult territory now, tackling some projects that will involve a more significant investment of time, tools, and intestinal fortitude. Compounding the difficulty factor is the tight confines of the Alfa 164 engine bay, which makes a project such as clutch removal and replacement all the more difficult. Now that I've scared many of you away, bear in mind the fact that I have successfully completed this job myself, and I sell computer software for a living and have no formal training as a mechanic.
One of the most simple problems to diagnose on a manually shifted automobile is a worn clutch. By far, the most common failure involves a worn friction disc which allows the clutch to slip. Initially, the clutch will slip only when under hard acceleration, but if left unattended this problem will only get worse and eventually result in a car which won't move. Failure of the throw-out bearing is another potential trouble area, but this is much less common. Due to a variety of driving styles, 164 clutch life varies significantly - anywhere from 40,000 to 140,000 miles is possible. Like most clutch assemblies, the Alfa 164 has three primary components which should always be replaced when servicing the clutch. These include the pressure plate as well as the aforementioned friction disc and throw-out bearing. The S model uses a somewhat different spring-loaded design, requiring a different throw-out bearing and pressure-plate. Otherwise, the procedure is similar to the Base/L R&R.
I'll assume you have the factory service manual if you're planning on completing this project - it is a requirement. The version from CarDisc (CarDisc@aol.com), is a cost-effective alternative to the hard-copy original version. What I'll discuss here is the deviations from the manual which make for a quicker job.
The biggest challenge of this project is the required removal of the starter from the bell- housing. The manual suggests removal of the rear exhaust manifold is required to get access to the three bolts which secure the starter - not true. From underneath the car, the top bolt (towards the head side) can be accessed using a 13mm socket with a wobbly extension. The other two bolts are more readily accessible. If you get frustrated trying to get access to these bolts, removing the starter heat shield will provide better access. With the three bolts removed, just move the starter out of the way, still leaving it electrically connected (battery disconnected, of course).
Both half-shafts do need to be unbolted (but not removed) at the CV-joint and the driver's side strut assembly removed. This is truly a ten-minute job with an air-wrench. The intermediate shaft needs to be removed as well, but not until you remove the three bolts securing the shaft flange, not the ONE bolt, as pictured in the manual. A gentle rap to the flange with a hammer may be needed to pop the splined shaft free from the gearbox.
Instead of removing the gearbox out of the car altogether, it can be separated from the motor and rested on the subframe. This will allow adequate clearance to get access to the flywheel, should you want to remove it for resurfacing (highly recommended, but I didn't bother since my flywheel measured true and was unmarked).
The final item to consider replacing is only applicable to `91 model year Base and L models. These cars use a roller bearing on the input shaft which is prone to failure. Later cars and all S models use a more reliable needle bearing which is the replacement part for all cars. Unfortunately, access to this bearing can only be accomplished with the gearbox removed from the vehicle, so this doesn't exactly fall into the no-brainer replacement category. I've known of people who have put 150,000 miles on their 164 without this part failing; however, I just recently heard from someone who had this bearing fail two weeks after replacing the clutch with only 50,000 miles on the odometer. The choice is yours - do you feel lucky?
You didn't really expect me to just replace with the stock Alfa clutch, now did you? Off the shelf, there is no replacement option other than the stock Alfa parts. Fortunately, Centerforce (http://www.centerforce.com / info@centerforce.com / (520) 771-8422) of Prescott, Arizona will take the stock friction disc and rebuild it to their "Gold" specification for a modest fee. By using advanced friction material in a "hockey-puck" configuration, Centerforce claims a 30% increase in holding capacity and an increased longevity of the friction disc.
Installing the new clutch disc is most easily done if you can borrow the Alfa clutch centering tool #1.820.124.000. I've yet to find an after-market tool which has the 164's unique spline configuration. In a pinch, a shortened broomstick handle will suffice.
As I write this, Project 164 has been back on the road for all of about 24 hours (we'll talk about the performance results from the head upgrade next time). First, the most immediate difference is the dramatically reduced pedal effort to deploy the clutch. It's so easy I initially assumed it wasn't working properly! Once on the road, the clutch functions extremely well. The grip as the input shaft locks up to the flywheel is solid and assuring. The lockup occurs with the pedal lower to the floor, as it should.
Next time we'll talk about removal of the heads, and the subsequent overhaul and upgrades.