View Full Version : Repairing an Oil Plunger on a Pacemaker

07-06-2008, 11:36 PM
Hey Guys - This is the last part of the apron repair. After this repair, the last majors issues to address (that I currently know about) are the compound and tailstock. I've already made all the parts for the compound, I just need to reassemble it.

Ok, so on this 1945 Pacemaker, the oil plunger was stuck in the "depressed" posistion. Here is a picture of the buggered up oil plunger:

Here is the oil plunger and the arrow highlights the begining of the oil passage that feeds the carriage. The other plunger supplies the apron. In this passage, there is a .2500 check ball. Don't loose it if you decide to blow out the oil passage with an air gun ... ;-)


The only difficulty in this repair was the apron dissassembly. I already described most of the process in my other posts, but the last major component that needs to be dissassembled is the half-nut.

It took me a little while to figure out how to get this apart. I decided to try taking a little video of how it came apart. I have to applogize now for the extremely shoddy camera work. I was trying to film with one hand and disassemble the half-nut with the other...

I will post the video here in 20 minutes or so.

07-06-2008, 11:37 PM
Alright, so I've pulled the pins and slid the two halves of the half-nut apart. I've also removed the half-nut engagement lever, gave it a few gentle taps and bumped the shaft out of the "cam" mechanism. Then, the "cam" mechanism was rotated and tilted to remove. (Note that I'm using cam in the broad sense here: a cam is a mechanism that translates rotational motion to linear motion)

Now, the bottom of each oil plunger assembly was clearly visible. To remove the plugs, I had to first make a special jumbo screw-driver that fit nice and snug in the slot. Also, there is a thread-sealent/locker on these plugs. I twisted a 5/8" diameter piece of sucker rod with a 1' cheater bar trying to twist the plug out. After that, it occured to me that they had likely used some sort of thread locker and after some careful heating with a torch, it screwed out nice and easy. In fact, you probably could've used an ordinary large (like 3/8") screw-driver to remove the plugs... oh well!




And finally, here is the the plunger assembly:

Pretty simple! I just had to shine up the plunger a bit so that it slid back and forth nice and easy.

07-06-2008, 11:46 PM
One last "oops" - While disassembling the plate, I cracked the oil passage and had to repair it. This is the passage before the final repair, but after a failed attempt ;-)


Here you can see the old pipe cleaners in the oil passage. They prevented swarf from plugging up the passages and controlled oil flow so that all parts of the apron recieved a sufficient amount of lubrication. Some were so dirty, they were like a solid plug, so I replaced them:


And that's all there is to that!

07-07-2008, 03:09 PM
very interesting. How much do you think the carriage weighs ?

07-07-2008, 05:46 PM
Oh... probably 500 lbs or more. The carriage, after removing the apron, compound, cross-slide and taper attachment, probably weighed about 350-400 lbs. The apron weighs another 150 maybe 200 lbs. So I'd put the whole thing at 500+ lbs. I can dead lift 150 and my brother-in-law can dead lift 250 and it took us both to remove the stripped down carriage and there was no way we could lift it to our chests.