1992 pete, we swapped engines and I can't find where this line should go. Air governor gets a control line from tank, but where should the exhaust line feed too? There is no air dryer on the truck.
Shouldn't be connected to anything. At least I have never seen that. That port needs to stay open to allow the unloader pistons to operate properly.
Thanks Rzucker, the old compressor on the engine had a fitting on it also, and I looked all around for a line to hook onto it. Then I got to thinking about it and couldn't figure out a place where that air should have to go, its just to allow the air on the other side of the governor piston right?
Yep, just a vent. Somebody may have run a few feet of line to help keep dirt and dust out. Not a bad idea in really dusty applications.
Did some of the old alcohol kits use that port or was it strictly the curly line to the air compressor intake? Seeing that just got me thinking.
I doubt that, the exhaust port only pops air out when the compressor needs to start pumping.
Well, I haven't seen one in 20+ years. So my memory is a bit foggy on this. Thanks for clarifying
Well, on another note, the only alcohol systems I have seen were the bubblers after the air dryer outlet. But I could see a system on the compressor intake. Had a GMC service truck with out an air dryer that got a little drink now and then right though the intake filter in the winter.
When I went to school on this stuff I remember no end of papers and bulletins telling you not to block this or that exhaust port. I say put a screen on it, though, to keep mud wasps out. I thought I remembered that alcohol added to the compressor inlet will be stripped out by an air dryer. They also said that if you put it in after the dryer, alcohol removes the very expensive barium grease from the valves that is supposed to stay there for their lifetime.
Normally your governor will have a signal line from the ping tank (wet tank). The exhaust port will be open. The unload port will go to the head of the compressor. It will also have a line going to the purge valve on the air dryer. Yours does not seem to have a line to the purge valve.
OP mentioned the truck has no air drier...
I believe I'd consider installing one. Modern air driers work extremely well keeping water out of the tanks, valves and brake chambers. And in winter most have a heater kit to prevent the purge valve from freezing.
No argument here. A good AD-SP is a good addition to any truck or machine with an air system. I have added them to several twin engine scrapers that had to have air to control the rear engine.
I hate those spin on style dryers they expensive and don’t last long! I like older 10 bolts dome style, they are PITA to replace filter element but more reliable!
Paging Mr. Truck Shop. I want to know what your thoughts are on these. When I started the AD-1 and AD-2 were already obsolete but the teacher told us they were still available as some fleets liked to use them. Very big and bulky. Will you have one on your Mack? The AD-4 was kind of nice because the cartridge was held in by bolts instead of a central thread so easier to get off than having to chuck the whole mess in a vise and get the element out with a big chain wrench risking damaging something like the AD-9 but the AD-9 seemed much more popular. I don't know if I ever had an AD-SP but did have at least one truck with the Haldex equivalent. Not a big fan of that one because it seemed to use a lot of air from the wet and front air tanks each cycle (special front tank check valve), leading to another early compressor cycle. The AD-IP seemed to be the modern equivalent of the AD-9. But the spin-on AD-IS seemed to be the most popular in later years and that is probably the one being mentioned above.
A air dryer is probably in its future, I'd like to get it running up and down the road a bit to get some of the kinks worked out of it, before adding and changing a bunch of stuff. It seems like if I add everything I want right away, then if I have issues, I need to figure out if its something I've caused, or if its a previous problem. It will probably get a AD-9, just because that's what I have put on the cranes, and that's what I'm familiar with. Thanks for the help guys.
Ad-9 is my favorite one, although it’s little uncomfortable in service, depending on location sometimes you have to take the whole dryer off to get to bolts on the back of the dome.
You rang-BV. Air dryers-I like ones that work, that means I'm idle for the moment. AD-9's are best for add-on systems and reliable plus cheap to rebuild. The AD-IS models have become popular because most are bolted right to the end of a air tank. For fleet maintenance the AD-IS spin-on is best because it's quick to service, just make sure and build air til purge valve pops before loosening cartridge. The purge valve for the AD-IS is about $85 to 88 bucks but it's easy to clean and service. Had a interesting one last year with a AD-9 on a new airport Oshkosh snow plow. They were in a panic and needed the plow going like right now at 1:30 am. It was showing only 60 lbs in system but the pressure relief valve on dryer was popping off. Removed from plow, removed cartridge housing and tightened cartridge down on O-ring-when assembled at Bendix someone failed to spin the cartridge down tight and it finally bypassed internally. Truck Shop
I only had one AD-9 purge valve failed on very old truck - replaced it and it was good to go again, had several AD-SP with brocken snap ring groove that holds purge valve, AD-IS had only couple, constantly leaking and very expensive on parts. One time needed only governor for that one and dealer was hell bent on selling me the whole thing for more then $500, claimed that you cannot put regular $40 governor on that one. Frankly I didn’t investigate weather you could or not, because it was something like third time I had problems withi it - threw it away and plumbed $145 AD-9 in place of it moved governor to the compressor where it belonged! Yes it took more work and buying some air lines and fittings, but that one was a long haul truck, and I was not about loosing money on tow changes and being late because of something stupid like this. Same thing with replacing all push in ( especially plastic ones ) connectors with brass threaded ones, if it leaks it goes straight to garbage can, and threaded goes in place of it! And another thing with these - it pissed me off when they give you problems and seems to pick the worst weather possible, so you have to crawl under the truck in mud and wet snow!
I like the AD9 just because they are so common that parts are cheap and plentiful. Seem to be pretty hardy, though the aluminum base plate will eventually corrode and fail to seal. Seen 1 million plus mile Kenworths with the dryer mounted right in front of the steer tire getting sprayed with all the crap from the road and still going strong with a new dessicant element every year or so.
Yes you can install a regular governor on the AD-IS dryer, it's not scary. Wow broken snap ring groves that hold the purge valve, never seen that problem. I guess I don't get around as much as I use to. Truck Shop
I’m pretty sure you can put regular governor on that, I think the parts guy was stupid or playing stupid, trying to sell me more expensive thing, but it wasn’t the first time I had problems with that thing - so I didn’t trust it anymore! Yes, that snap ring groove thing was a strange one, I drove that truck myself when it happened, it’s scared me good! Was loud bang, then loud hiss and all the air was gone in 3 seconds!
My only bad experience with an AD-IS wet tank-governor combination wasn't even the air drier... It was the unloader O-rings in a single cylinder Cat/midland compressor, it would pop the unloader and drain the little wet tank and re-cycle in 20 seconds. Local dealer replaced it twice under warrantee and never fixed the problem. "Become one with the air" was my reply. Air loss didn't show on the laptop I guess.