Seneca Compressor - All Quiet Now

[LSA376]

I have a '16 37TS with air brakes and seats. The air compressor was so freaking loud it would scare our 110lb Bernese Mountain dog when it would engage while traveling down the highway.

After digging into it I noticed no air dryer. I called Freightliner to get a parts list and the parts manager tells me " it has to have an air dryer." I tell him no it does not. Again, he states " any truck with air brakes MUST have an air dryer." He tells me I don't know what I'm looking for... Really.

He asks for the VIN #, after a few minutes he tells me "it doesn't have an air dryer." No @*%$!

Jayco wanted to save a few bucks I guess.

Long story longer, $1,500.00 later in parts the dryer's installed and low and behold... Compressor nice and quiet. Without the dryer the compressor sound is directly transmitted into the first air tank making it extremely noisy. Oh, and as a side note, I won't stress out about the water content in my brakes... As much.

I also found a leaking air line on the rear air bag. It would sag the rear end overnight, now the bags hold tight for nearly a month before they lose air.

[Robbbyr]

Even though I don't have air brakes I am seriously considering adding one. In my coach wet air will just cause eventual corrosion of some components, but in an air brake-equipped unit moisture can freeze and cause serious safety issues. I still can't believe Jayco didn't spec a dryer on the newer units. To think Senecas would never be out in freezing temperatures is ridiculous IMHO.

Helpful to also know it quiets things down! Thank you for the feedback.

[Mark S]

Is this something new or do all Senecas not have a drier?

[Robbbyr]

I can't speak to whether the newest (2017+) Senecas have an air dryer or not. But certainly the pre-air brake units did not, and neither do the first model years that included air brakes.

All do have an automatic moisture ejector valve on the wet tank, but it isn't the same level of moisture removal that a true desiccant-style air dryer provides.

[RogerSwann]

If not having an air dryer is a safety issue, forget puzzling over why Jayco did not order them.
Why would Freightliner build them? The parts manager seemed to think a non air dryer version didn't exist. How many operators of the vehicles do not have air dryers? Plenty of these units in service, has the lack of a dryer been an issue?

[Grumpy]

When I was buying trucks for our fleet, air dryers were always an option. I always added it to the specs.

[Robbbyr]

Originally Posted by RogerSwann

If not having an air dryer is a safety issue, forget puzzling over why Jayco did not order them.
Why would Freightliner build them? The parts manager seemed to think a non air dryer version didn't exist. How many operators of the vehicles do not have air dryers? Plenty of these units in service, has the lack of a dryer been an issue?

For decades air brake-equipped trucks did without what are (modern) desiccant-style air dryers. Generally daily (especially in freezing weather) the driver had to manually drain the accumulated water and oil residue from the air tanks. Water forms when the air is heated and compressed into the air tanks where it then cools, condensing the moisture in the air. Oil is carried into the airstream by the air compressor which is engine oil lubricated. These liquids in the air are not what you want going through the air system degrading the internal components, and you especially don't want the water to freeze blocking a portion of the system and possibly creating safety issues. Before today's desiccant dryers some rigs had alcohol injectors to keep things from freezing.

Most of us here remember cars before ABS and we learned how to drive without it, but most can agree it does save lives. When you add the additional components to give an air brake-equipped truck ABS (like a Seneca) you add numerous additional pieces that can (eventually) malfunction because of contaminated air. A properly working air dryer will likely extend the lifespan of those components. Why aren't newer Seneca owners having issues? In my opinion it is likely because those units are still fairly "new", and most RV owners don't drive them extensively in sub-freezing weather. But 10+ years out I wonder what things might look like? Those brake control components that corrode and fail will be very expensive to diagnose and replace.

I spent my career in a municipal fire department, the trucks we had when I started on the department did not have air dryers. Every day we drained the air tanks at shift change, and twice a day we did it when it was below freezing. You would be shocked at what comes out of an older truck! Those older trucks without ABS had brake components that would fail periodically, including the air tanks failing because of rusting through from the inside! Once we started ordering any new trucks with air dryers and retrofitted the older trucks, problems such as those decreased significantly. Once ABS became available on fire trucks, air dryers were standard equipment to protect the components of the ABS system from contamination.

In my opinion this is a case where I believe Jayco is "penny-wise and pound-foolish" on the backs of current owners who will absorb the higher maintenance costs later. To build a truck with a modern air dryer might cost just a few hundred dollars. Considerably less than what it will cost to replace just one air brake ABS modulator valve down the road. If I had an air brake Seneca I would definitely install an air dryer, and I probably will anyway even though I have a hydraulic brake unit to better protect my suspension leveling valves, parking brake, and engine cooling fan components.

Does an air dryer add an additional maintenance step? Yes. But I think the costs of periodic desiccant cartridge replacement outweigh the other possibilities 10+ years down the road.

[jimclawson]

To LSA376;

We just bought a 2016 Seneca 37RB, and we have a loud rhythmic noise that almost sounds like metal on metal right after starting the engine. Goes for a few minutes than suddenly stops as if a switch was turned off. Could that be the same sound that you were experiencing?

[stmccormick]

What you are describing is exactly what we had on our 2016 HJ. I did add an air dryer and that sound went away. The trade-off is we now occasionally get a big puff of air release. Frieghtliner told me that was the safety valve they added with the dryer to ensure the system never over pressurizes. This sound doesn't bother me like the metal on metal clicking.

[RyRoRyan]

I heard there was a way to silence this without putting an air dryer in. I recall a thread on this, but cant find it at the moment. I live primarily in a dry climate (New Mexico) so I am not in a huge rush to add a dryer unit, but would like to make the noise go away if I could. Anyone know what needs to be done to do this?

[ready2retire&drive]

I have a 2015 37rb and had to install an air dryer, When I asked Jayco about it they said they do not spec their chassis with them so in our cooler climates needed one to keep the moisture out

[RyRoRyan]

Can someone post the parts list that was used?

[ready2retire&drive]

Here you go a nut and bolt breakdown of all it took to put in hope it helps, they mounted it infront of the right front tire behind bumper
ord INSTALL AIR DRYER MOUNTING BRACKETS. INSTALL AIR DRYER. REMOVE COMPRESSOR DISCHARGE HOSE,AND REROUTE. INSTALL NEW COMPRESSOR DISCHARGE LINE TO AIR DRYER. INSTALL AND ROUTE NEW SENSE LINE FROM GOVERNOUR ,TO DRYER. MAKE HOSE EXTENSION . HOOK OP TO TANK LINE,AND ROUTE TO DRYER. SECURE ALL LINES. TEST SYSTEM. PARK UNIT OUT FRONT. CORRECTION QTY EXTD PRICE UNIT PRICEDESCRIPTIONITEM
850.00LABOR (1) 002F/A12-25425-000 TUBE-COMPRESSOR DISCHARGE,META 176.82 -176.82 1 002X/PH 209P 8 6 BUSHING (G0816B-08-06) 1.59 1.59 1 002X/PH 48F 10 8 CONNECTOR (G1416-08-10) 3.36 3.36 10 002X/GLH G1212-04 1/4" NYLON AIR BRAKE HOSE 0.51 5.10 1 002X/PH VS68NTA4 2 COUPLING (G7016-02-04) 1.66 1.66 1 002X/PH 149F 10 6 MALE ELBOW(G1496-06-10) 6.87 6.87 1 002X/PH VS68NTA4 4 CONNECTOR (G7016-04-04) 2.04 2.04 10 002F/GRO 83 6021 TIE STRAP-11.75X.18,BLK,NYLON, 0.16 1.60 10 002F/GRO 83 6029 TIE STRAP-15.25X.3,BLK,NYLON,1 0.34 3.40 2 002X/PH 20620 8 8 FITTING (3505-08-08) 13.25 26.50 2 002X/PH 42F10 UNION (G1414-10-10) 3.74 7.48 2 002X/GLH G7ETM-04 CLAMP 1.38 2.76 1 002F/BW 065660 AD-9 AIR DRYER 768.63 768.63 1 002F/12-21552-000 BRKT-RH FWD FRAME M2 74.42 74.42 1 002F/12-21551-000 BRKT-FWD FRAME ADPTR AD9 97.26 97.26 1 002F/A12-11593-094 HOSE ASSY-AIR,DISCHARGE,TEFLON 129.28 129.28 1 002F/A12-25425-000 TUBE-COMPRESSOR DISCHARGE,META 176.82 176.82 1 FRT FREIGHT 60.00 60.00
JOB#6 EXPRESS ---- PARTS: 1,191.95 -- LABOR: 850.00 -- TOTAL 2,041

[jimclawson]

LSA376 and RyRoRyan,

Glad to hear I am not alone with this issue. We are in Scottsdale AZ so nothing out here ever needs drying! But I do want to get rid of the noise. If there is some other remedy that works, I am open ears, but I'll go with a dryer if need be.

[ready2retire&drive]

Not sure on another remedy. The problem with compressing air it heats up, when it cools sometimes creates condensation=moisture creating the water in the system. I know on our shop air compressor's we have automatic unloaders at the bottom of tank that spits a little air whenever they fire up or shut down, not sure how to apply this to a truck.

[LSA376]

Unfortunately without a dryer the sound of the compressor is transmitted directly into the first air tank amplifying the noise as the dryer is to be installed between the two. I don't know how it can be quieted down any other way.

[Mark S]

I have been off the job for several years so I checked with my son who drives fire engines here in south Florida. He is unaware of air driers as he drains the air tank twice in a 24 hour shift. Is this a cold weather thing? We definitely have more than our fair share of moisture here so I wonder about the driers?

If we need the driers to quiet things down, how big a job is installing drier and what is an approximate cost?

[stmccormick]

In cold weather, the issue you can run into is the moisture inside the system freezing. If it does and the brakes can't pressurize, you're stranded until you thaw them out. The other advantage to the dryer is you don't need to constantly drain the tanks to prevent rust on the inside.

I had frieghtliner do my air dryer, but I also added a couple extras -- auxiliary air connection so I can fill my tires and toys from the RV and a couple of purge valves. The cost was right where my trucking friends and this forum said, about $2,500. There are some posts on the forum where a few guys indicated they did it themselves.

[RyRoRyan]

Since I was intrigued by this, I decided to give Freightliner corp a call and talk to their tech support team. He has had numerous talks with his coworkers and even tried going up the chain on this. In his opinion, unless your rig stays in states like AZ, NM (yea me), or TX, then he recommends it should have an air dryer on it...especially if it has air brakes. He has tried to pass it up the chain that units with air brakes should come standard with dryers, but obviously that has not happened yet. He did state that the automatic purge valves on the bottom of the tank do a pretty good job at expelling a good amount of the water, but you will never get it as clear as a dryer will. I am going to live without a dryer for next year or two as I know I prob dont really need it but I am sure I will get one at some point. Those of you though that are not in the SW, should think about getting one yourselves or hammering on Jayco a little bit to figure out why they omitted this item especially on 16'+ units with the air brakes.

[ready2retire&drive]

It would have been nice not to have to install my own. Just a point on compressing air it will heat up and when it cools creates moisture. If you are cycling your compressor a lot when driving it may still get water in system. As for the automatic purge valve I would still run a remote manual drain to an accessible location and still drain it your self to make sure you are getting most of it out. I tee'd into my tank and ran a remote drain and mounted it on the frame of my generator so I can drain it without crawling underneath