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Topic: Air Leak at Step (Read 1019 times) previous topic - next topic

Air Leak at Step

I've got an air leak coming from the step area. Both the step and the sliding floor piece work fine. The air leaks when the step is up or down and the engine is running. I don't see any noticeable loss of air when driving. At rest there is no leak.

I read the post on Barry's site (written by BarryL) but it doesn't seen to address this issue. The leak comes from the box pictured here. I took it apart and cleaned it up. I hooked it up without complete assembly and no leak, however, when I got it all buttoned up in the box the leak returned. Then I noticed that, at least a few times, changing the position of the box stopped the leak. Like a solenoid is acting up. Not sure what this box is called but I'm thinkin' I need to replace it. FT is closed today (can't say as I blame em'). Is this a part that can be had elsewhere? Thanks.
jor

I should have added that this is really more of a air exhausting rather than leaking. Should have taken a photo but there's a plastic piece that is allowing air to exhaust and that is what I am calling a leak.
93 225
95 300
97 270
99 320

Re: Air Leak at Step

Reply #1 –
I am guessing a little here, but I would be looking at the air operated vacuum pump, I just had mine swapped out for a 12 Volt vacuum pump, solved some issues.  The pump is located in your picture box under step, behind the flap.
Now when I turn on the key you hear the 12 volt pump coming up to proper vacuum.
My step and slid never failed either.
FWIW

Re: Air Leak at Step

Reply #2 –
Dave,
  What make/model did you replace yours with? I guess it is a vacuum gizmo as it works with the little canister next to it.
jor

93 225
95 300
97 270
99 320

Re: Air Leak at Step

Reply #3 –
That is the vacuum generator and it is activated when you turn the ignition on.  Mine just failed on our 2000 U320 and I got a replacement 12V vacuum pump from Mike Grimes at Foretravel for $229.13 after the Motorcade discount was applied and shipping was added.  The vacuum pump connects to the same 12V connection under the steps but you need to salvage the connector from the vacuum generator.  Remove the air line and plug it.  I plugged it behind the steps where the flexible line connected to the T at the pressure regulator.  I used a 1/2" MPT plug from Home Depot.

Monti
Monti
2015 Born Free Triumph Royal 4x4
Previous:  2000 U320 3600

Re: Air Leak at Step

Reply #4 –
Monti,

So, what brand and model of 12 VDC vacuum pump did you substitute for the air operated vacuum pump?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Air Leak at Step

Reply #5 –
Can only recommend call Mike at MOT, they had it, guess they got it from FOT, I do not know, nor the name or model number of it. It works.  No idea of cost, was included in invoice with other items, I never look, just pay the cost, that way I do not get upset.  ;D

Re: Air Leak at Step

Reply #6 –
Thanks, guys. So Monti, you do away with the air line but retain the same vacuum canister with its two lines, one from the new vac motor and the other routing through the back of the step? Thanks.
jor

Re: Air Leak at Step

Reply #7 –
FOT (or someone else) conveniently removed the label from the vacuum pump so I have no idea of the brand or model.  The invoice shows the Mfr. as FW, P/N 00840005, list price of $240.66.

Yes Jor, I used the same larger diameter vacuum line that goes into the round canister (previously connected to the vacuum generator) and connected it to the vacuum hose that comes out of the vacuum pump.  The canister continues to function as before.  The pump is activated when the ignition is turned on and it shuts off when sufficient vacuum is attained.  I am not sure if the vacuum switch that turns it on and off is in the pump or somewhere in the vacuum lines where it can control the 12V to the pump.  Either way it is automatic and works fine.

Monti
Monti
2015 Born Free Triumph Royal 4x4
Previous:  2000 U320 3600

Re: Air Leak at Step

Reply #8 –
I had a leak in one of the air cylinders for the step some years ago, was working outside and heard the leak. I still have the old cylinder and have thought about trying to get a kit to repair it. I was told at the time that they wear in the step up position as that's where they are as we go down the road.
John Duld
1995 U320C SE 40'

Re: Air Leak at Step

Reply #9 –
There must be two different versions of the step operating  mechanism.  Ours (99 U270) doesn't have a vacuum generator, and just runs on system air pressure through a local pressure regulator, with double acting cylinders on the step.  Nothing in the step box other than the operating cylinders.  Wondering what the vacuum operation adds?
Dave and Nancy
1999/2013 U270 36' Xtreme
Motorcade # 16774
2013 Subaru Outback
KD0NIM

Re: Air Leak at Step

Reply #10 –
The vacuum system is for operation of the dash heater, defroster, a/c ducts. Vacuum is used to operate the doors in the system to direct air to area you like or ask for.

Re: Air Leak at Step

Reply #11 –
Dave,

Earlier coaches have the 12 VDC vacuum pump to operate the dash HVAC system.

I wonder if the one in this thread is a totally different vacuum operated item (steps) or indeed if this is an air operated vacuum pump for the dash HVAC?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Air Leak at Step

Reply #12 –
Looking at the picture Jor posted it sure looks like it operates the steps.
1996 U270
Build #4846

Re: Air Leak at Step

Reply #13 –
Jor's picture looks just like mine and it has nothing to do with the steps.  The vacuum line goes up into the dash for the doors in the dash ventilation system.  The step area is just a convenient place to put the vacuum generator.  The air line for the step cylinder comes in from the back of the step area where it is connected to the pressure regulator.
Monti
2015 Born Free Triumph Royal 4x4
Previous:  2000 U320 3600

Re: Air Leak at Step

Reply #14 –
Some coaches use gear motors to operate the heater control doors so they would not have the vacuum system.
John Duld
1995 U320C SE 40'
 

Re: Air Leak at Step

Reply #15 –
Quote from: wolfe10 –
Dave,

Earlier coaches have the 12 VDC vacuum pump to operate the dash HVAC system.

I wonder if the one in this thread is a totally different vacuum operated item (steps) or indeed if this is an air operated vacuum pump for the dash HVAC?

Would make perfect sense that it's just for the dash HVAC, which we don't have.    I don't see why you would operate the steps with vacuum when there's perfectly good air pressure there...
Dave and Nancy
1999/2013 U270 36' Xtreme
Motorcade # 16774
2013 Subaru Outback
KD0NIM