Hi everyone! In my quest to find any potential areas of trouble I discovered one that I felt should be pointed out.

The SS airline from the compressor to the dryer on my Barth was routed over the top of the metal radiator crossover tube and against the oil pan. I noticed that the SS braid had been compromised in these areas. After I removed and replaced the dryer to replace the desecant the system would not build pressure. Found the SS airline had been sawed nearly thru where it was against the sharp edge of the oil pan and by moving it, the teflon inner material fractured. I also notice that the radiator matal crossover tube was noticed by the SS line and will have to be removed and welded. (or a new one)

Had this happened on the road, I would have had big trouble. I suggest inspection of this line and replacement if the SS braid has been damaged in any way!

BTW, the SS airline from the pump to the dryer must be 30 inches long to meet DOT regulations for heat disapation.

Good catch. That SS (stainless Steel) line can also be changed out to a Copper Line in a pinch. That would have been an expensive roadcall for sure.

We have done a couple of roadcalls where changing out the line was "not an option" and have installed a hose clamp and a piece of rubber over the rub thru area. After getting it back to a local garage it can be changed out without any ill effects.

As far as that metal tube for the coolant line is concerned you can also get an exhaust shop to duplicate the bends. If the rub thru is on a straight area just "whack" (NY Term) it off and install a section of radiator hose between it.

If the reason you rebuilt your airdryer was a leak that kept pumping with the cadence of the motor then chances are your "unloader line" had some ice in it. You still might have a problem later on.

Take that little line off at the air dryer and at the middle port of the D-2 Governor and add a couple of drops of alcohol/airline air guard down the line until it comes out at the dryer line. Now would also be a great time to replace the "air governor" as this should be done at the same time you do a dryer.

If the air doesn't flow and ice keeps the pressure down the little line the dryer will stick open. Many people replace or bypass a perfectly good air dryer because of ice.

There are two little lines on the air gov. The middle one is the unloader line - this tells the air compressor to stop building and it sends the air dryer a signal to vent moisture. The other little line is the signal line from the airtank - once the air gov gets the air psi up the signal line that it is set for the piston moves inside of the gov and opens up the unloader port for the other line. Your air dryer unloads and the compressor stops building

Turning the set screw in (under the rubber or plastic disc dust cover) lowers the psi cut off. Turning it out increase psi. Anything between 120 & 125 psi is good.

Thanks Bill:

I did indeed replace the governor and all associated lines, I still need the plastic neck on the bottom water blow-off port but it is all done now and functioning perfectly. Pressure was a bit high on the dash gauges but a check with a precision gausge shows 127-126PSI. I'll leave it 'till it settles in.

For now I have put a piece of radiator hose over the worn area so that I don't have any surprises on the road.

We had a similar failure to the one Ed found just this past week. On our 94 Breakaway as we attempted to leave a campground near Plymouth OH, We couldn't get air pressure to build enough to release the brakes. After tracing the "hiss" I found a stainless braided line worn through in 2 places. I pulled the line off and took it to a local NAPA store where they fabricated a replacement (no steel braid). Once I installed it with a couple of layers of sheathing to protect it we were on our way. I suspect that it had been leaking for some time since the operating pressures are now higher than I've seen before. We're lucky it happened where it did. Anyone else who has our vintage Breakaway should check that hose before it fails.
Stu Allen

quote:

Originally posted by stuallen:
I pulled the line off and took it to a local NAPA store where they fabricated a replacement (no steel braid)...

Is this the line that goes to the head of the air compressor? Does the end of the hose you removed attached directly to the head of the compressor?

You need at least 3-4 foot of stainless or copper discharge line, some people say a min. of 6 foot. The most heat comes from the head of the compressor and cools down the farther down the line it goes. If you leave a regular steel braided cloth hose or rubber hose it will fail.

This line goes from the head of the compressor to the drier and uses the heavy duty hydraulic type fittings. The original line appears to be about 3' long and was braided stainless over a flexible plastic? hose so any cooling effect would have been minor.

DOT specs require 3' minimum, copper can be shorter, but not recommended. I would take the old line to truck shop (that has the capability) and duplicate the line with identical material. Replace and be careful of the routing.

Mine sawed thru because it was against the sharp corner of the oil pan. Check the metal coolant cross-over pipe, mine had been abraded nearly thru by the SS line

quote:

Originally posted by MWrench:
DOT specs require 3' minimum, copper can be shorter, but not recommended...

I checked with the DOT inspectors today and 3' is the minimum for an air compressor discharge line.

The line you have will work, but, it will fail. The heat being produced will blow out the hose or it will overheat it to the point of causing air to seep out thru the line.

Yes, seep out thru the line. When it get too hot the inside of the hose will start to melt and cause little cracks in the hose. Enough cracks will cause the hose to be porous to the point of little or no air psi making it to the air tanks.

If that doesn't happen the hose will melt and cause pieces to flake off and go into air valves and tanks. Enough melted rubber could block off the compressor discharge line or an air valve.

Go ahead, ask me how I know. I see it all the time. Do yourself a favor and replace the line with the correct type of hose.

I know your thinking "what's it matter?" or "yeah, ok, I'll get right on it". Don't do it and the next time you won't be sitting in a parking lot or KOA but on the side of the road.

This is one of those times when you'll look back and say "I should have listened to ..." Replace the line with the correct hose, do not think that it's going to be ok!

Don't believe me? Ask a trusted truck or Rv mechanic. Please, do it sooner, rather then later!

We made it home safely (1500 miles or so) with the rubber hydraulic line. Bill, you are recommending going back to the stainless braided hose? Would it be OK to make a longer one and avoid the rub point that caused the failure? It also looks like putting an elbow fitting at the compressor aimed down would eliminate a stress point on the hose. Does that sound reasonable?
Stu

Yes, go back to the stainless steel braided line!

Longer is better to a point. Do not have any low spots between the output of the compressor and the input of the air dryer. A low point will allow moisture to sit in the drooping area of the hose. In the winter time this low spot will freeze causing a blowout of the line or the head gasket on the compressor.

The air dryer has a psi relief valve but most air compressors do not have one built into the head. If it was me I would make it a little longer and install a psi relief valve (made for compressors) in one of the spare air ports at the head of the air compressor.

As far as the elbow is concerned, if you must use one try to use a 45 instead of a 90 fitting and make sure the male threads are thick enough. Use the fitting from the compressor and check thread thickness. Too thin and the fitting will snap off.

quote:

Originally posted by stuallen:
I suspect that it had been leaking for some time since the operating pressures are now higher than I've seen before.

Would you please explain the psi readings your getting now.

Thanks for the advice, Bill. I'll see iif I can work out a routing that will prevent a low spot in the line.
Stu