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Topic: Vacuum Generator finally quit (Read 2159 times) previous topic - next topic

Re: Dash air problem

Reply #25 –
John, did you have to put a check valve in the line to keep it from running all the time?
I am changing mine out ( 93 U300 ) and it runs till 24 psi ( vacuum), shuts down, and starts again in about 2 minutes.
The vacuum pump is the cause, but cannot not find a good check valve

bill
1993 U300, 6v92
build 4366
USAF retired, Flight Engineer, C124, C130
 ATP, A & E.  & ex AI

Re: Dash air problem

Reply #26 –
Quote from: John Sichenze –
I just had to change mine too. I changed it to the DC vacuum pump and you will hear it if you turn the key and have the door open and say, wow what is that noise.  Once you are started though you do not hear anything.  Mine was under the front step behind the flap.

John,  please provide details.  In addition to the question about check valve, part # & where purchased;  what wiring/plumbing changes did you make;  etc.  I have changed the vacuum reservoir and took apart and cleaned the pump itself.  btw, anybody guess if the performance would change if the psi of the air to vacuum pump and step were increased??

Regards to all,
John Lang
John Lang
Crossville, TN
07 Nimbus

Re: Dash air problem

Reply #27 –
On mine (99 U270), there are three little electric motors that move the flaps in the air box.  No vacuum motors, no vacuum tank, no electric or venturi vacuum generator.  The motors seem to run to their end positions (either one), then stall at that position until the polarity is reversed.  from the dash.
Dave and Nancy
1999/2013 U270 36' Xtreme
Motorcade # 16774
2013 Subaru Outback
KD0NIM

Re: Dash air problem

Reply #28 –
I called mot and had them send me the part.  I think it already had a check valve I will have to look out at the coach.  It was not that difficult to do. Talk to parts and to there service writer or mike and they can walk you through it. I talked to Weaver when I was there for other service and did it in there shop. Best way for me as I could just go get parts as I needed the. It was in the shop with the slides pulled for the delamination fix.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Dash air problem

Reply #29 –
A while back someone noted that they found the diaphram in the vacuum pump had cracked and that was the source of their vacuum leak.
I have mentioned before that I removed all the vacuum motors and replace them with good old fashioned push/pull cables and disconnected the vacuum pump.

http://www.foreforums.com/index.php?topic=8959.msg39610#msg39610
Rick

Re: Vacuum Generator finally quit

Reply #30 –
Well the good news is that you had plenty of time to get ready for it..
And maybe the best choice is the electric vacuum pump, I have not had the issue yet, but have been thinking hard about it.  Hope I get off the fence before I am stuck.  I am as guilty as anyone on the hind sight issue.
Good luck.

Re: Vacuum Generator finally quit

Reply #31 –
Our vacuum pump kept cycling on and off every 10 or 20 seconds. I clamped each hose off until I found the source of the vacuum leak. Really easy to do in several minutes with a simple clamp like a ViseGrip. Just start at the vacuum pump and go out from there. Turns out it was the heater control slide on the instrument panel, close to the radio. I slid the lever to the right about a quarter of an inch and that stopped the leak. Has worked great since then. I just remember to stop before I get all the way to the left when shutting it off. If your pump is out, you can also easily find the vacuum leak with a MityVac  hand vacuum pump. Cheapest $24.95+s/h online. Hope your fix is simple also.

Pierce & Gaylie Stewart
'93 U300/36
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Replacing Vacuum Generator with an electric vacuum pump

Reply #32 –
Have a 2002 with air activated  vacuum generator located under the step to operate the hac controls.  Has anyone replaced the air activated generator with an electric vacuum pump.  If so is the current electric circuit heavy enough to carry the load of an electric pump.

Re: Vacuum Generator finally quit

Reply #33 –
Hi Chuck,

As a temporary repair I installed an electric vacuum generator (motor) from a 1974 Cadillac and it worked just great on the existing wiring. As long as the vacuum cut-off switch still functions and the vacuum canister has no leaks,  a replacement pump should work quite well. Necessity is the mother of invention!

Jim
2002 U320
Jim Frerichs
2002 U320 42'