Step air leak

Topic: Step air leak (Read 1644 times) previous topic - next topic

Step air leak

December 31, 2017, 10:22:57 pm

At the coach today with the engine running and noticed the step was not going up. Did some checking and found an air leak in the area behind the step coming from a little box. In the box are some wires going to a switch and some air tubing to this device where the air was leaking from( yellow arrow pointing at it) . I know it has to do with the air to the step but that is about it.. also there is a vacuum can that has 2 spots to hook a hose up to, 1 has a hose hooked to it but the other one doesn't, but there is a loose hose nearby and it is going to the leaking part in the box. I assume it attaches to the vacuum can ( just an educated guess ).. I'm figuring the part leaking needs to be replaced???

Re: Step air leak

Reply #1 – January 01, 2018, 01:37:47 am

Kieth, maybe because I have had a few Champagne's due to the time of year but could you take a picture of the whole area as I have a 2000 and I cannot make you picture out. On the right it looks like a lot of rust but the rest does not mean much.
Sorry.
JohnH

Re: Step air leak

Reply #2 – January 01, 2018, 03:53:32 pm

Well damn, the pic I took it to big to download, let me figure out how to size it down, it's in the area behind the step when it comes up behind the pleather cover..

Re: Step air leak

Reply #3 – January 02, 2018, 02:52:27 pm

resized them to work. this is located behind the step that goes up and down

Re: Step air leak

Reply #4 – January 02, 2018, 03:44:22 pm

Put the hose on the CAN.. should stop

Re: Step air leak

Reply #5 – January 02, 2018, 03:50:03 pm

That should work but if that doesn't work, may be time for a new vacuum generator - it is the thing in the box.

Most folks have gone to an electric one. There are several posts on the forum. I got mine and a new plastic can (it is a round plastic ball shape) from NAPA for less than the cost of a new air driven vacuum generator from FOT.

The step is probably not working because the air leaking out also goes to the step solenoid valves to power the step.

Rich

Re: Step air leak

Reply #6 – January 02, 2018, 04:08:01 pm

Sorry... the step has nothing to do with the part you showed with the pic.. The CAN goes to the dash for the vents ie.. dash/floor/defrost

The steps are ran from a solenoid on the back of the step that pushes and pulls the air shaft..

Re: Step air leak

Reply #7 – January 02, 2018, 05:02:28 pm

Quote from: DavidS – January 02, 2018, 03:44:22 pm

Put the hose on the CAN.. should stop

by putting the hose on the can should stop the air leak coming from under the box where the yellow arrow is pointing in the pic in the 1st post?
I understand now what you are saying about the step solenoid not having anything to do with the vac can or little box, what is the little box called and for,,,,,, why in the heck is a dash part located down there anyway???

Re: Step air leak

Reply #8 – January 02, 2018, 05:58:08 pm

Quote from: hdff – January 02, 2018, 05:02:28 pm

by putting the hose on the can should stop the air leak coming from under the box where the yellow arrow is pointing in the pic in the 1st post?
I understand now what you are saying about the step solenoid not having anything to do with the vac can or little box, what is the little box called and for,,,,,, why in the heck is a dash part located down there anyway???

For some reason that is where they fit the dash vacuum.. prolly for noise level not being in the cab...

Look behind the step on the outside of the box and you will see how the air lines come out and into a rectangle shaped valve body with a couple hoses and 2 exhaust ports.. approx 1.5" x 3" tall

That valve is what tells the step to open or close depending on air flow.. you will see 2 of them valves.. 1 is for the steps and 1 is for the step cover slide.

If you have a leak in the step area it is probably the cylinder leaking .. what happens it wears the shaft out and air escapes around the shaft in the open or closed position.. some have filled with grease and fixed but I replaced mine when it leaked .

check with a water bottle and soap to find the exact spot and update and we can go from there..

Re: Step air leak

Reply #9 – January 02, 2018, 09:04:45 pm

If I remember right mot replaced both those solenoids when I bought the coach. The air leak is definitely coming from the end where the yellow arrow is pointing, I can put my finger over it and feel it and that is located under/in the small metal box by the Vacuum can behind the step. And the step won't come up.. I'll go piddle with it when it warms up a bit , (you guys up north don't throw stones at me) it barely got above freezing today

Re: Step air leak

Reply #10 – January 02, 2018, 09:30:33 pm

Keith,

This is to expand on what Rich has posted it reply #5.

Try to remove and plug the air supply to the vacuum generator (the square box that has the air leak) and see if this will cause the step to operate. On some coaches the vacuum generator and step shuttle valve (Norgen valve) get air from the same regulator. If the air leak in the vacuum generator is too much the regulator won't flow enough to operate the step. Report back with results.

Pamela & Mike

Re: Step air leak

Reply #11 – January 02, 2018, 09:34:13 pm

I am not sure what the box is or does.. but I see what you are saying now.. that square box has an exhaust port in it..(pic was a little to close to see it at first)..

I am not sure what the box does to start with so I cant help at this point.. take the box out and see if you can clean it.. if not see if it has a number on it.

Re: Step air leak

Reply #12 – January 03, 2018, 11:30:07 am

The box is an air driven vacuum generator like the one used by HWH to deflate the slide room bladder. The vacuum is used to control the vents in the dash. It is connected to the solenoid valve behind the step box that also controls the step. If it is leaking, it is very possible that your step will not be getting enough air to operate.

I disconnected the line to the vacuum generator and plugged it. Replaced the vacuum generator with an electric one and also the vacuum can with a new plastic vacuum ball. I'm pretty sure that I just used the 12V that was going to the old box to operate the new pump. Mounted both on a piece of plastic cutting board and then just slid it into the step box and made the final connections. See attached photo.

Re: Step air leak

Reply #13 – January 03, 2018, 11:32:46 am

Rich,

Looks like the standard 12 VDC pump used on Ford diesel PU's (for the same purpose-- to "power the dash HVAC system").

Re: Step air leak

Reply #14 – January 03, 2018, 12:27:35 pm

Yes, I think that's what it is. I found it through another thread on the forum. I'd have to go out in the 8 degrees we have here to try to find the documentation.

Rich

Re: Step air leak

Reply #15 – January 03, 2018, 12:37:50 pm

Rich,

No need, it is one of the less costly and more widely available 12 VDC vacuum pumps.

Re: Step air leak

Reply #16 – January 04, 2018, 10:30:27 pm

Quote from: Rich Bowman – January 03, 2018, 11:30:07 am

Mounted both on a piece of plastic cutting board and then just slid it into the step box and made the final connections. See attached photo.

I'm always finding ways to use those old cutting boards. Have yet to throw one away that wasn't cut to pieces or had lots of holes drilled in it. (as a backer board)

see ya
ken

Re: Step air leak

Reply #17 – January 05, 2018, 06:20:26 am

I found this on on a beach in Alaska ;-).

Rich

Re: Step air leak

Reply #18 – January 30, 2018, 03:27:30 pm

Rich -

Can you advise the part #s and your sources for the plastic ball and vacuum generator.

I have found the air generator sourced in other threads here. but would like to verify.

Thankx.

Re: Step air leak

Reply #19 – January 31, 2018, 10:34:04 am

Scott,

Here's what I have been able to reconstruct from my memory and also a receipt:

Vacuum Ball: Napa https://www.napaonline.com/en/p/NDP7301605
Vacuum Pump: NAPA https://www.napaonline.com/en/p/NVP641509
OR
Vacuum Pump: Amazon https://www.amazon.com/Dorman-904-214-Mechanical-Vacuum-
Connector: Amazon Amazon.com: Dorman 645-740 Vacuum Pump Pigtail: Automotive You will need this to power the pump.

I think the Amazon pump would work just fine and it is cheaper than NAPA. Looks like the same pump. I think I got mine from NAPA.

I also ordered a new check valve but the original seemed to work better than the new one so I didn't replace it.

If I remember, the old air driven vacuum pump had 12V power so I just used that to power the new pump. The new pump has a cutoff switch when vacuum is achieved. I can hear it run (about 60 seconds) when I first turn on the ignition key and it also seems to run about one minute, 3 times/hr when the vacuum gets low.

You will have to cap or plug the air line that supplied the old pump. I was doing this while on the road so had limited flexibility. I tried to remove the supply end of the line but didn't want to damage that connector (it was really tight). I ended up cutting the line back to about 3 inches, putting a screw in the end of the line and then a JB Weld epoxy cap to hold it all together. It worked out so well that I haven't gone back and messed with it. Maybe this Spring.

Good Luck and PM me if you need any more info.

Rich

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Step air leak

Reply #20 – January 31, 2018, 01:32:01 pm

Thanks Rich. Will start to problem solve in a few days when we get to Tucson. Looks like my v. generator has been replaced by our PO. Will verify functionality b/4I buy any thing. May b in touch.

Tx again.

Re: Step air leak

Reply #21 – January 31, 2018, 02:47:07 pm

Scott, Check this out for a vacuum pump. A bit less $$ I have one of these for vacuum bagging. Works great!

Vacuum Pump - 12V - ROB-10398 - SparkFun Electronics

And while you are there explore this amazing electronics toyland. If you can think of something to do there is a way here.

Re: Step air leak

Reply #22 – January 31, 2018, 03:07:29 pm

Roger _ Think it has enough guts?
Interesting web site. Tx.

Re: Step air leak

Reply #23 – January 31, 2018, 03:18:53 pm

Roger,

I'd worry about it being exposed to the weather mounted behind the step.

Rich

Re: Step air leak

Reply #24 – February 05, 2018, 11:27:14 pm

Rich I got the Dorman that you got, I haven't hooked it up yet but just to test it I touched the wires to the + & - on my truck battery and the unit only ran for about 1 second and acted like it tripped out. Did you have any problems with yours?

Affiliate Notice