Discussion Category: Lab Pumps
Welch Vac pump Rebuild
Hello fellows techs. Has anyone rebuilt a Welsh Chemstar 1402N . I'm sure I put it together right, but now it won't turn by hand. I'm suspecting the E-Clip or Thrust Washer in front of intake rotor. Any ideas? Thanks
Reply byHi Leon,
I have rebuilt a Welch 1400, a 1400N Chemstar and also a 1376. I encountered a similar problem to what you are describing with the 1376. When I disassembled it, there was a thrust washer but no thrust discs installed. Since I was "rebuilding" the pump, I installed a new thrust washer in place of the original one. The original was thinner with visible machining type wear marks. After I had everything back together and torqued, the pump would turn over by hand, but it was difficult and obviously not correct. I removed the end plate and also the new thrust washer, then reinstalled the original thrust washer and torqued everything back together again-then it turned over smoothly. That was about a year ago and this pump is still running happily.
Hope that helps,
Brian
Reply byThanks for replying and the information. I'll give that a try.