Sigma Tek model-1U128B vacuum pump

[Rsmithref]

I think my vacuum pump is going out.  Anyone know if these can be rebuilt?  The $1200 price tag, bout gave me sticker shock. Or any other ideas would be appreciated.

 

[Fritz1]

why do you think it is going out? they are available new and overhauled, price difference is not that great, either way you get a core credit for returning the old one, think $20, overall these dry pumps are best replaced after 500h, lots of people go all electric, saves weight, I like to keep one vac pump for one horizon, different source of energy, will keep running with all electrical fried in case of zombie apocalypse or EMP from nuclear blast

[Texas Mooney]

1 hour ago, Rsmithref said:

I think my vacuum pump is going out.  Anyone know if these can be rebuilt?  The $1200 price tag, bout gave me sticker shock. Or any other ideas would be appreciated.

 

Buy a new Rapco for about half the price.  From the Rapco cross-ref 

MISCELLANEOUS DRY AIR PUMP REPLACEMENT INFORMATION
Bi-Directional Pumps
Sigma Tec Replace with RAP215CC or RAP216CW depending on rotation. Check IPC and eligibility to find the proper pump for your aircraft and engine.
1U128, 1U28A, B CC refers to Counter Clockwise rotation, or CW refers to Clockwise rotation as viewed from the pilot seat, or looking at the back of the pump.

https://www.rapcoinc.com/pdf/Pneumatics Cross Reference Guide.pdf
 

A new 215CC is only $454.

https://www.aircraftspruce.com/catalog/inpages/rapco_dryairpump.php

[KSMooniac]

x2 on the Rapco!

[Rsmithref]

As to why I think it’s going out;  suction gauge is about 4 or a little less, and my High/low warning light is flashing.  Nothing seems to be affected as I thought it would though.

‘thanks for the tips on the Rapco, I didn’t know I had an alternative.  I am about to start researching the correct on for my IO-360

[Rsmithref]

Still trying to figure out my vacuum issue, bout ready to start changing parts to figure it out.  I currently have a sigma tek, anyone know if the other brands are interchangeable?  Or if I change pump brand, will I need to change other things to be compatible?  Any options on quality of pump brands before I go down this road?

Thanks so much for your input 

Randy

[N201MKTurbo]

So, if you have a vacuum gauge, look for a vibrating needle. That is the usual sign of a pump failure. If your vacuum is low, it is more likely a leak in your vacuum system. Check all the hoses and fittings and make sure nothing is leaking. It is possible there is debris in your regulator holding it open. I have seen it in regulators used in deicing systems. As a last resort, I would adjust the regulator.

The pumps are kind of binary. They either work or they don’t. There is a very short window where their performance suffers before they lock up. If you have flown with this issue for more than a couple of hours, it isn’t the pump. It would have locked up by now.

[Rsmithref]

Ok thanks, I will check all the hoses and fittings again. We have adjusted the regulator twice.the low/high vacuum warning light is sporadic. But always reads low on gauge. It flashes much more than it doesn’t. No bouncing of needle , just steady low

thank you

[Utah20Gflyer]

14 hours ago, Rsmithref said:

Ok thanks, I will check all the hoses and fittings again. We have adjusted the regulator twice.the low/high vacuum warning light is sporadic. But always reads low on gauge. It flashes much more than it doesn’t. No bouncing of needle , just steady low

thank you

If you want an inexpensive replacement I have a used rapco pump I pulled off my plane when I did the vacuum system delete.  It probably has 350-400 hours on it but was working well when removed.  I’d sell it for 100 bucks with shipping included.  Message me if you are interested.  Looks to be a counter clockwise unit.