I had a few old distributors laying around, so I decided to set up an assembly line and rebuild them over the weekend. Thought I'd share a lesson that I learned.
You know that distributor grease cup that we all take for granted? I learned that lack of maintenance with that assembly creates the most amount of wear on the distributor.
The grease cup screws on to a fitting that screws into the distributor. The fitting is easily removed with a 7/16" wrench once you clean the crud caked on it. Once you remove the fitting, you'll see a spring can be removed with needle nose pliers. Then there is a little solid Bakelite disk that is about 1/4" diameter and 1/8" thick that rides against the inner shaft with pressure from the spring. The disk will look like a plug of hardened grease when you first take it out. Here is a picture of the assembly--
http://s844.photobucket.com/user/ma...2001_zpsujgiczys.jpg.html?sort=3&o=0If the Bakelite disk is missing because it wore out or because it wasn't installed, the spring rides directly against the inner shaft. This creates a noticeable groove on the shaft. Two out of six dizzies that I took apart were missing the Bakelite disk and had heavy wear on the inner shaft.
Many of the grease cups had fresh grease in them, but the grease had hardened inside the fittings so that no grease was making it to the inner shaft. This was true with four out of six.
Lesson learned is to not take the grease cup for granted and to check it when doing a tune up. Remove the cup, remove the fitting, remove the spring and take out the Bakelite disc with a small screwdriver. Clean everything well. (I found that a pipe cleaner dipped in kerosene did a great job on the inside of the fitting.) Reassemble packed with fresh grease. DON'T FORGET THE BAKELITE DISK!
If the Bakelite disk is missing or worn, I'd replace it with a nylon spacer from the hardware store. Since the spacers I'm familiar with have a hole in the center, I'd fill it with JB Weld to make it solid. Maybe someone knows where a comparable solid nylon plug can be found, but I've just seen the spacers with center holes at the hardware store. I figure the disk is supposed to be solid if that is how the GM engineers designed it.
Another learning...by working on the grease cup assembly in my vise, I learned that when it is packed correctly and tightened, it is designed so that excess grease will flow out between the cup and the fitting so that not too much pressure is put against the inner shaft. I will look for the grease overflow in the future to know when to stop tightening the cup.
Easier to do on a bench, but out of curiosity I tried to take the assembly off the distributor on the 235 in my '57. It came out and went back in easy (would have been easier if my arms were about 6" longer!). Mine was OK, but it gave me peace of mind to check it out.
Yes, I do give my grease cup an occasional twist as part of regular maintenance. But I won't take it for granted in the future after seeing the wear on several disassembled distributors for lack of proper assembly or maintenance.
Matt
