The Stovebolt Site Forums The Shop Area Engine Shop Distributor rebuild lesson

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=0

If 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

I would not fill your nylon plug with JB Weld since it is a "steel reinforced epoxy"

There is a seal of some sort between the cap and the body of the grease cup which would probably have sealed much better when it was new.

Very nIce write-up, Matt,

Here is an earlier thread on this topic. Denny Graham has posted a nice description and a lot of nice photos.

I double if a sealant was used around the grease plug threads (into the distributor), but I doubt that using a sealant would hurt anything.

I have never seen grease come out around the threads. It seems there would not be enough pressure in there to force grease out around the threads?

I was thinking about this as I typed yesterday and had the same questions that 1866yb and Tim raised as I was typing.

I have seen the plug that goes against the shaft referred to as both a fiber plug and a Bakelite plug in different GM manuals. I don't think that replacements are available, so that is why I suggested the nylon spacers. I don't like my idea of filling the spacer hole with JB Weld for the same reason mentioned in the above post. The link Tim posted has some good ideas for a replacement. I'd also consider a nylon spacer filled with regular epoxy, not JB Weld.

I took a closer look at the fitting that the grease cup screws into. It has a gasket (leather?) fitted to the end to keep grease from leaking out. So my thoughts about grease oozing out when tightened as a good thing are incorrect. The grease is oozing because the gasket is worn and needs to be replaced. Funny, I couldn't get grease to ooze out of the grease cup on the 235 in my '57. Now I'm glad it doesn't!

My apologies for any confusion,

Matt

Just wanted to add that I used the advice from one of Tim's links and wrapped some teflon tape around the grease cup threads. This solved the oozing grease issue when tightened. Rather than fight the issue with a worn leather gasket, this provided a nice, easy solution.

Matt

Is this something I can do with the distributor installed? I didn't know this grease cup even existed before I read this thread. Now I'm a little concerned seeing how other maintenance items on my truck were in need of attention. I saw the location of the grease cup today, and am not sure I'll be able to tell if the fiber plug is present or not. I'm sure I can remove the grease cup, but am not sure if it will do any good to add grease if that plug isn't present and the spring is riding on the shaft.

Removing the distributor is a simple one-bolt and one-wire operation, plus disconnecting the vacuum line. If you don't turn the engine, and mark the position of the rotor as you remove it, you can simply re-insert it the way it came out with minimum changes in the timing. Everybody needs to master distributor removal and replacement- - - -it's a LOT simpler to get the points installed correctly if the dizzy is on the workbench, instead of trying to do it while leaning over a fender!
Jerry

Hoff,
Pull the cap and remove the rotor. Attempt to move the distributor shaft side-to-side. If there isn't any movement between the shaft and the distributor body, you passed the first test.
Remove the cup. If the spring and plug are gunked up and won't come out, you can unscrew the entire grease cup assembly from the distributor and push the plug and spring out on the bench. Once you remove the assembly, look for the plug. If you don't see it, shine a light in the hole in the distributor to see if it is against the distributor shaft.
Carl

Interesting post.I just replaced my old dist with a new one. Have not sent the core back and would like to rebuild it. Looks like the shaft is worn as there is wobble at the top. So bearings may need replaced. Is there a way to do this with out a lathe and expensive tools?
One other note. The new dist was aluminum casting, the grease cap hole is 1/4 and not threaded.So no cap or grease fitting. Had to take the points out to change the screw thru the plastic insulator as that was backward and the eccentric that moves the point gap was missing. I am debating a letter to The co but my Mandarin is weak.

It is easy to do without any fancy tools. Go for it. All you'll need is a Dremel to grind the end of the factory pin that holds the gear to the shaft (replaced with a tension pin from the hardware store), a punch to drive the pin out, screwdrivers, pliers and wrenches.

There aren't any bearings in it. The distributor case acts like a long bushing for the inner shaft to fit through.

There is good info about how to do it at Deve's website--devetechnet.com. Look under the '59 235 rebuild and you will find instructions how to tear one down and do a rebuild. My 1957 shop manual also had great step by step instructions.

Simple and fun. If you have a good core to start with, you'll probably be happier (and prouder) of your rebuild than the repop you bought.

Good luck,

Matt

, Thanks for the info. The core is only a few bucks and I gota pay the freight back. The old dist has the date code for my era truck . I have done a few v8 dist so this may be a good summer project.