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Topic: Dash Air Stuck on Defrost/Vacuum Pump Replacement (Read 3214 times) previous topic - next topic

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #20 –
There is a 1/4" air line that runs from the step/step cover valves to the front (left) air tank. That one is indicated on the air schematic. I still can't find this pesky vacuum generator. I thought I knew what everything is on this thing but how about this? What is it? It's above and forward of the ride height valve. Thanks.
jor

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #21 –
jor - If I remember correctly, the vacuum generator on mine was about a 4" cube, made of sheet metal covering the actual vacuum generator.  It had an air supply line and a vacuum line attached.

Don't recognize the item in your picture.

Rich

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #22 –
I believe it will also need to have two 12v wires attached to activate a solenoid that controls the incoming air from the air line.

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #23 –
Quote from: Rich Bowman –
jor - If I remember correctly, the vacuum generator on mine was about a 4" cube, made of sheet metal covering the actual vacuum generator.  It had an air supply line and a vacuum line attached.

That describes what I removed years ago.  After removal, I dissected it as is my usual habit.  It was very simple inside, no moving parts.  Replaced it with a 12 volt vacuum generator. 

Richard

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #24 –
All I did was replace the check valve inside the box, still going.



obsolete vacuum generator

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #25 –
Craneman,

I probably should have done the same as you.  However, I had already bought a 12 volt vacuum generator and I destroyed the metal box which contained the guts of the original vacuum generator. 

Richard

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #26 –
Elliott and hdff

I did this today, thank for the write up. When I turned on the ignition, it was a whomp whomp coming from the pump. How does your sound? Mine did not sound right, I wonder if I got a bum pump?

Side note, the fitting on the back side that has the air hose has been a bear to remove. I had to take the regulator off, put it in a vise and I still cannot remove it with a pipe wrench,, guessing the PO put on some loctiite or something. I will try more tomorrow.  Not that I am too disappointed, the regulator gauge is shot so I am going to replace regualtor too. I am chasing an air leak so hope a new regulator may fix it.

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #27 –
Quote from: Jason –
Elliott and hdff

I did this today, thank for the write up. When I turned on the ignition, it was a whomp whomp coming from the pump. How does your sound? Mine did not sound right, I wonder if I got a bum pump?

Side note, the fitting on the back side that has the air hose has been a bear to remove. I had to take the regulator off, put it in a vise and I still cannot remove it with a pipe wrench,, guessing the PO put on some loctiite or something. I will try more tomorrow.  Not that I am too disappointed, the regulator gauge is shot so I am going to replace regualtor too. I am chasing an air leak so hope a new regulator may fix it.
Regarding the womp womp: no. Mine is a constant fast waaaaa. Like an air compressor.

Check the air cylinder that moves the step cover too. It's known to leak where the arm exits the tube. I'm getting ready to put a solenoid in line to those regulators you mention because that whole corner of the coach is known to be problematic

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #28 –
Thanks Elliot. I looked at this again. Between the hose going from the pump to the new Dorman amplifier, I put in the check valve that hpff showed. This caused womp womp. With it removed, the pump ran like a compressor for a time, then cycled off and on as it should. I have double checked the valve ensure it is going the right way, but I am confused why the valve would do this? Is a check valve needed?

I will be looking forward to when you do the solenoid!

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #29 –
My vacuum pump was shot so I have a new one. My problem is one of the control
valves is leaking. Does anyone know what they are out of.

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #30 –
If you have the slider on the heater/AC control, the leak may be when the slider is in the far left position. I put a small stop on ours so it blocks the last quarter inch. Otherwise, the vacuum pump ran all the time.

Pierce

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #31 –
I have found the control valve that is leaking and it leaks most in the defrost position.
The pump doesn't run steady. It burps about every 5 seconds. So I would like to
know if anyone knows other equipment that they were installed in.

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #32 –
FOT had both the actuators and the solenoid valves in stock.

Rich

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #33 –
Thanks Rich if I can't find it locally I will try Foretravel.

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #34 –
Quote from: oldguy –
I have found the control valve that is leaking.
I would like to know if anyone knows other equipment that they were installed in.
You probably already know this, but just in case, I have had good luck searching for mystery coach components by:
1.  Removing the component and seeing if it has ANY kind of ID number.
2.  If ID number present, searching that number with Google.
3.  If ID number missing, doing a Google search for the best physical description I can come up with, for instance:
      "vacuum heater control valve".
4.  When Google returns results of search, go to the "Images" category, and compare the pictures to what you have on hand.
5.  You may not hit gold on the first pass, but you can always refine your search parameters and try again.  It often works for me!

vacuum heater control valve - Google Search

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #35 –
Thanks Chuck, there is a number 2-27106 but I couldn't find anything with it. I went
through what you sent, no luck. I'm trying to find what I need in Canada as the courier
companies are charging big brokerage fees. I paid more for shipping on something I
bought than I did for the item. When the border is stable I will go back to shipping
items to Point Roberts and go there to pick up the items.

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #36 –
Quote from: oldguy –
Thanks Chuck, there is a number 2-27106 but I couldn't find anything with it.
Post a few sharp photos of the doohickie, and also the front view of your A/C/heater control panel.  I'll try my luck at searching.

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #37 –
I found a photo of the climate controls on a '99 U320 (see below).  Is this the same as your coach?

I was looking around online and found reference to Evans Tempcon being the manufacturer for many RV climate control systems.  Found the website linked below.  The photos of the control panels they sell show control knobs that look very similar to the ones in the photo.

If you don't have luck anywhere else, you might try contacting Comfort Air to see if they can help with parts or information.

HVAC Control Panels - Evans Tempcon - Comfort Air Inc. -


Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #38 –
Chuck the second picture is the item I am looking for.

Re: Dash Air Stuck on Defrost/Vacuum Pump Replacement

Reply #39 –
I downloaded this and refer to it often https://www.foreforums.com/index.php?action=media;sa=album;in=593  it's the parts manual for a 2000 and 2003.  Your 99 will most likely be the same as the 2000.

Look at page 252-253, it's section 1280 .