Vacuum pump repeat failure
 

Ok, so less than a year ago I replaced my vacuum pump diaphram after it tore and was puking up oil into the intake. After the repair, all was well and I thought nothing more of it, but just recently it seems it tore again. I have the same symptoms (no vac/brake booster/shutoff, and oil puking out the top tube soaking my air filter. So, I am going to order another diaphram and replace it.

My question is this: What would cause it to fail in under a year? I followed this thread:http://www.peachparts.com/shopforum/sh...d.php?t=164453
I do believe I got the rounded washers in correctly, I didn't tighten the center bolt very hard, and I used a little locktite on it. So what causes the failure?

I do have a somewhat leaky vacuum system (My brake booster leaks pretty good, I believe). Does this have an adverse affect on the lifespan of the diaphram?

Please, if you have any insight let me know. It is a pain job, and I am afraid it will run me out of oil without my knowledge. Everything is soaked in oil again :mad:

Also, I am a little confused about the placement of the diaphram. Does the convex side face in or out? (away from the block or toward the block) The pictures seem to me to conflict on this.

I know how you feel; I put a new diaphragm in my '80 300 TD a couple of years ago and it didn't last two months. Neither failure seemed related to the washer. I thought maybe it could be that I caused a little stress when tightening the center screw, but I'm not sure. Fastlane sent me a new one free and it is still good. The old check valves seemed OK so I re-used them. Steve

I am going too use the RED thread lock next time on the little "center" bolt and be sure not too torque it too much;)

um, is that a good idea? 500°F is needed to take it apart next time...

I dono, guess I would find out if I ever had to take that bolt out of the 'disc', and if it didn't come apart a little heat wouldn't hurt anything, diaphragms already toasted. I think most "short lived" diaphragm repairs are caused by over torquing, although there was a guy a while back that didn't tighten it enough and it came adrift. If I was doing it for someone as a job, I wouldn't, but I would try red thread lock on my own vacuum pump diaphragm.