While taking on the air bag swap I also decided that the 32yr old dryer and governor should also be retired and while dumping the air tanks I noticed the wet tank vent valve leaked by a bit no matter how I positioned it so I ordered a new set of those as well. During the drive home from Tallahassee to Oceanside (2300miles) the only air system issue I had was my aux compressor pressure switch developed a pin hole leak in the diaphragm, but a couple weeks ago when we went beach camping (about 20mile drive) I noticed frequent unloading of the air system (every 10-15 sec), after searching that up here I saw both the dryer and governor could be the cause.
Bags swap has been covered here a bunch, about 8hrs start to finish; the dryer is a 2.5hr job, mostly related to getting the old fittings off and swapped on to the new dryer, it took all my horsepower to get the old fittings off...be sure and get them broke loose before you remove the dryer as there is no good way to hold it secure once it's out(thanks to youtube for that nugget of info). The governor swap is 20min.
Wanting to know what the cause of my problem was I pulled my old governor apart and found the spool had been galling in the cylinder, I expect this was giving the intermittent unloading issue.
The continental bags are direct swaps...nothing to report on that, still waiting delivery of my new tank vent valves.
While leak testing I found a leak up at the valve set below the throttle, the small white covered bendix solenoid was leaking at the cover/electrical spade connection, the cover had screws holding it on so I tightened them and that solved the leak. What are those for? (I haven't pulled the air system drwg to find out myself yet).
The thing leaking was one of the two "low air" pressure switches that monitor the air pressure in the supply lines going to the throttle valve and the treadle (brake) valve. They are the sensors that will, when activated, set off the visual and audible LOW AIR PRESSURE warning signals at the instrument panel.
By the way, excellent sharply detailed photos in your writeup. ^.^d
Good clear photos really help other members understand what you did, and make it easier to follow your commentary.
What is the blue stuff visible on some of the air line fittings?
Rectorseal Amazon.com: Rectorseal 31551 1/2 Pint Brush Top Tru-Blu Pipe Thread Sealant:... (https://www.amazon.com/gp/product/B002BY02PQ/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1)
The spool shouldn't have been making contact with the cyl. The O rings keep the spool off the cyl. I haven't seen galling on any of my spools. How bad was the O ring at that end of the spool?
it was pretty flat...well past its service life.
Just a follow up on governor, I finally got around to firing up the engine today (was waiting on a new belt for the alternator/air compressor) and the new governor made a huge difference. I'm actually getting a full 125psi cut out pressure now. The best I saw before was 110psi, so I'm sure it unloading at 110psi then cutting back in a 100psi is the reason I was noticing the frequent unloads...the galled spool on the old governor was probably the cause of all that.
Another Rectorseal. One can will last for years.
Amazon.com: Rectorseal 23631 1/4 Pint Brush Top T Plus 2 Pipe Thread... (https://www.amazon.com/Rectorseal-23631-Brush-Thread-Sealant/dp/B0002YPAFY/ref=sr_1_3?dchild=1&keywords=Rectorseal&qid=1607126471&sr=8-3)
Finally got around to changing out both (leaking) low pressure switches. Was able to find a good deal on a pair of actual bendix 228750 switches (rather than aftermarket). Video in this facebook link shows how badly one of them was leaking: Redirecting... (https://www.facebook.com/len.barron/videos/245248014153045)