Air Dryer Bypass Demo

Topic: Air Dryer Bypass Demo (Read 9300 times) previous topic - next topic

Re: Air Dryer Bypass Demo

Reply #25 – August 03, 2014, 08:04:41 pm

Does anyone have the part number for the control line flare plug?

Re: Air Dryer Bypass Demo

Reply #26 – August 03, 2014, 08:06:59 pm

I'm trying to get the pieces together, but without access to my coach for a couple of weeks.

Just what are the wrench sizes needed for the two large hoses?

Re: Air Dryer Bypass Demo

Reply #27 – August 03, 2014, 08:22:27 pm

If I remember correctly (it was five days ago after all

), 1 ⅛" on our coach. If you need to take the connecting block off on the input side (which has the line going to the wet tank and the line going to the governor as well as the hose, that was 1 ¼".

Quote

I'm trying to get the pieces together, but without access to my coach for a couple of weeks. Just what are the wrench sizes needed for the two large hoses?

Re: Air Dryer Bypass Demo

Reply #28 – August 03, 2014, 09:18:32 pm

Tom, only use pipe tape or pipe dope on NPT ( national pipe thread) If you use the tape, leave the first two to three threads bare. That would go for the dope also. JIC fittings are self sealing

Richard B

Re: Air Dryer Bypass Demo

Reply #29 – August 03, 2014, 09:20:52 pm

Tom,

I will be back under my coach tomorrow morning. I'll take some measurements of the various hose end fittings and get back to you on the wrench sizes. As for the flare plug, it would be good to have several different sizes: perhaps 1/4", 3/8", and 1/2". Never know when you might want to plug off a air line somewhere on your coach.

Re: Air Dryer Bypass Demo

Reply #30 – August 03, 2014, 09:26:18 pm

Chuck, would be nice to have ALL the wrenches a person might use, but hate buying a set of 15 or so just to use one or two. With the hex wrench having a very narrow head, and you having used them, you know how they can get into some very tight places.

Richard B

Re: Air Dryer Bypass Demo

Reply #31 – August 03, 2014, 09:39:31 pm

Quote from: rbark – August 03, 2014, 09:18:32 pm

Tom, only use pipe tape or pipe dope on NPT ( national pipe thread) If you use the tape, leave the first two to three threads bare. That would go for the dope also. JIC fittings are self sealing

Richard B

That is what I figured. I was hoping you would chime in on this.

I also figured leaving the threads bare would be plenty good enough for this purpose.

(and I thought NPT was New Process Technology, oh well)

Thanks, Tom

Re: Air Dryer Bypass Demo

Reply #32 – August 03, 2014, 09:53:44 pm

Actually, Plan "A" is to service or replace with factory reman the dryer every two to three years. Will substantially reduce the likelihood of dryer failure.

Plan "B" is a good fall-back position, but Plan "A" is preferred.

Re: Air Dryer Bypass Demo

Reply #33 – August 03, 2014, 09:59:54 pm

Brett, + one on that!

Re: Air Dryer Bypass Demo

Reply #34 – August 03, 2014, 10:01:57 pm

I'm in, with both plan A and plan B.

I had my air dryer completely rebuilt six months ago, and just bought the parts for the bypass kit on eBay.

Re: Air Dryer Bypass Demo

Reply #35 – August 03, 2014, 10:19:30 pm

Not an expert, but this is what I use for air lines...
50ml Tube Loctite[REG] 567 PST High Temperature Thread Sealant | Fastenal
Don

Quote from: Tom Lang – August 03, 2014, 07:38:07 pm

Thai being true (?), what, if anything, should be used to seal the threads?

Re: Air Dryer Bypass Demo

Reply #36 – August 03, 2014, 11:04:38 pm

If you buy the "really big wrenches"™ from Harbor Freight you can use the one of the other wrenches as a cheater bar. If you can get the box end of the wrench on you can wedge the box end of another wrench on the open end of the wrench. If you can only get the open end of the wrench on you can use the box end of another bigger wrench over the box end. I've only had one bolt I couldn't get off using this method and that one came off with the addition of PB Blaster and some heat.

Hope that makes sense!

see ya
ken

Re: Air Dryer Bypass Demo

Reply #37 – August 03, 2014, 11:27:57 pm

Isn't it possible to keep the D2 governor in the system with the air dryer bypass? Maybe have a small hose fitting on the bypass so the governor stays, to open the compressor output when max or to restart compressing when min psi is sensed.

Our air dryer has a brass valve fitting on one port that has several hoses. I think it is needed to keep from pulling oil from compressor. This valve would need to be part of the bypass to protect the compressor.

Re: Air Dryer Bypass Demo

Reply #38 – August 04, 2014, 12:09:45 am

Barry,
D2 Governor has 3 unloader ports.
1 for air dryer
1 for compressor intake valves unloader
1 not used (at least the way mine is plumbed)
Stopping the control signal air leaking to the air dryer (after "control" flexible tubing has been removed) is necessary in order for the governor piston to fully complete its travel. That will allow the control signal outlet pressure to build and send the high pressure control signal to the engine compressor intake valves unloader. That unloads the compressor allowing bypass flow until the governor low press setpoint (wet tank pressure) is reached and the cycle starts over again.
Neal

Re: Air Dryer Bypass Demo

Reply #39 – August 04, 2014, 12:18:45 am

Dan, you can get the parts from Billy Jack, I did about two months ago when this topic began. I guess cheaper elsewhere but getting direct from FOT I though I would get the right fittings. So is you heading to Nac soon, that one option

mike

Re: Air Dryer Bypass Demo

Reply #40 – August 04, 2014, 07:56:51 am

Michael: Assume Billy Jack is in service at FOT. Tks I will look him up as I had rather pay more for the correct parts than purchase a lot of possible parts. Be there on the 11th Monday. DAN

Re: Air Dryer Bypass Demo

Reply #41 – August 04, 2014, 10:26:44 am

@Dan Billy Jack is in parts.

see ya
ken

Re: Air Dryer Bypass Demo

Reply #42 – August 04, 2014, 12:23:33 pm

Thought he was service writer?

Re: Air Dryer Bypass Demo

Reply #43 – August 04, 2014, 12:58:34 pm

Barry, are you suggesting that instead of just using a 1/2NPT coupling that maybe use a "T" instead with the centre being say 1/8"NPT and a flare fitting on that to connect the control line too??
Did I read this right?
JohnH

Re: Air Dryer Bypass Demo

Reply #44 – August 04, 2014, 05:13:28 pm

Dan, as was answered by Ken, yes, Billy Jack is FOT

As the other question, he is in Parts......I shoulda put all that.

Just FYI Dan, he had to order for me but it is in their routine. I got three sets, one for me and one for Norm and another for Tony (deengineer). Perhas Dan you call him in advance, get him to hold a set for you or get on order (it was though a quick delivery)

By the way, the suggestion by Bret is new to me. I am new to the RVing so not much history to have made the dryer change out every two or three years. Need to put on my schedule for Annual Maintenance review topics.

Mike (Michael H.)

Re: Air Dryer Bypass Demo

Reply #45 – August 05, 2014, 12:05:24 pm

Aside:
The elbow spec'ed by Chuck is in the NAPA computer - just wasn't availiable in Marquette
Part #2501-12-08 3/4 M-JIC / 1/2 M-NPT / 90 DEG $5.30EA
Part #5000-08-08 1/2 F-NPT / 1/2 F-NPT / COLLAR $2.96EA
Part#s and prices not NAPA - From Chuck's post
The pertinent part is "12-08" (3/4 by 1/2) for size and "JIC" for coupler type

Main:
I have studied Chucks pics of the new device and I get that part..
however... On my '96 8.3 the line coming into the rear side screws into a big brass block which also has two smaller hoses attached.
(Pictures attached)

A year or so ago Barry talked about some device to keep oil out of (or inside) the compressor.
Something else suggested a different device was used in later years.

How does the magic pitch fork (the EDB) fit into this?

Re: Air Dryer Bypass Demo

Reply #46 – August 05, 2014, 02:27:36 pm

Quote from: TheBrays – August 05, 2014, 12:05:24 pm

A year or so ago Barry talked about some device to keep oil out of (or inside) the compressor.
Something else suggested a different device was used in later years.
How does the magic pitch fork (the EDB) fit into this?

Is this the thread you are referring to?
Air Dryer

Re: Air Dryer Bypass Demo

Reply #47 – August 05, 2014, 04:43:11 pm

Quote from: Barry Beam – August 05, 2014, 02:27:36 pm

Is this the thread you are referring to?
Air Dryer

Yes it is thanks.

So the question is, to bypass the dryer do you just connect the hoses or does the by-pass include the isolation valve?
I can almost read the referenced thread either way.

Re: Air Dryer Bypass Demo

Reply #48 – August 05, 2014, 05:46:58 pm

This post has been edited to reflect new info just received from Don (Acousticart) on his experience with the bypass procedure.

Elliott,

You disconnect the big air line that attaches to the isolation valve. You disconnect the big air line that attaches to the bottom of the dryer. You connect those two hoses together with the EDB. That takes the air dryer (with isolation valve still attached) completely out of service. The next step is to plug the line that runs from the D-2 governor to the dryer. The last step is to plug the black nylon air line that is attached to the Isolation Valve. That completes the bypass procedure.

Tom Lang,

I crawled under my coach to verify the wrench size needed for the big air lines. They take a 1 1/4" (1.25") open end wrench. It would be nice to have 2 of this size wrench - one to hold backup on the hose (so it doesn't twist), and one to loosen the connection. I was wrong when I recommended getting the 6-piece wrench set at Harbor Freight. You don't really need that set, unless you're like me and just like buying tools. (I have edited my original post)

Re: Air Dryer Bypass Demo

Reply #49 – August 05, 2014, 05:59:33 pm

Quote from: cajk – August 03, 2014, 07:37:07 pm

I think you may find fittings bigger than 1 5/8" on your coach

Wrong again...

I crawled around under my coach looking at all the hose fittings I could find. As I mentioned to Tom (above) the air hoses on the dryer take a 1.25" wrench. The only other bigger connection I could find was on a couple of hydraulic hoses - that one is slightly larger than 1.5", which is the biggest wrench I had in my kit. I'm guessing it is 1 9/16", but it might be 1 5/8". I would say that is the biggest wrench you would ever need, at least on my 1993 model coach.

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