Seneca Compressor - All Quiet Now

[Mark S]

Ok, so for the final word on this. I live in humid south Florida. I am very good about maint and will drain every fill up if necessary. Do I need to install a air dryer from the get go to prevent costly damage to my system? Can I wait until a little while?

[repacs0103]

Here's some anecdotal evidence if you're interested.... my company's delivery truck is a 2003 GMC C8500 with a 3126 Cat diesel and 6 speed fuller trans, obviously air brakes. A bit heavier than your senecas, but still a similar medium duty chassis. It does not have an air dryer, but has automatic purge valves on the tanks. We run it hard daily in humid Michigan summers and then it's parked from late December thru April, much like an RV. My drivers NEVER purge the tanks... they don't do it annually, let alone daily, and in 14 years and 270,000 miles we've never had to do anything to the air system besides brake shoes, drums and 1 rear brake chamber. Our previous truck was an 89 Mack that also didn't have a dryer. It made it to 475000 with no air issues either.

I'm not saying an air dryer isn't preferable, but it isn't necessary either.


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[Mark S]

Thanks, this helps me feel better about not getting a dryer right away.

[MD3]

Originally Posted by 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?

I was worried about this noise on our new '18 37RB... Gotta love these forums for answering/solving questions like this.
Now to find a solution to quiet it down that won't cost $2500.


_

[Mark S]

That noise drove me nuts when I first got my Seneca. Once I found out it was only the compressor, I felt much better.
Same thing with the engine fan. First time it turned on we thought the engine was going to blow up. Now we accept it for what it is.
And yes, this form definitely gives me peace of mind.

[RVermont]

Originally Posted by 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.

Did you install this your self ? or did you have a service provider handle this for you. I called my freightliner service provider and they looked up my vin and they said the system says i have an air dryer. I told them that I don't and they insisted that I do. Long story short I think I have convinced them that I don't have the dryer and if it is possible to install myself i could stand on saving $800 if it is doable.

[RVermont]

I had a Meritor Wabco ss1200 air dryer installed yesterday. The unit was priced at $299. You can find them on line for $225. Labor was $825 for 7 hours. Misc parts mad up the rest for a total of $1265.

They mounted the unit on the drive shaft support rail between the rail at the battery compartment.

The conduit for the slide is pretty close and I will need to make sure that it doesn’t bind up when retracting the slide. We tried it a couple of times and it looks okay but will need monitoring.

It is pretty loud when it vents. Not sure if it is any quieter if it is up front or behind you. I did notice on the 18.5 Senecas the unit is in a similar location on the rails.

This has taken a big chunk of stress off as I will be driving a lot in the next few weeks in the freezing weather conditions and always wondering if there was going to a problem. Especially in cold rainy days with freezing temps at night.






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[brtnsnwbrds10]

Does anyone have pictures and parts of this fix? I saw the parts in a post above but it was in the post and hard to read. Do you have it in a word document or similar? That noise drives me nuts!

Also wife notices a noisey “fan” type noise when I accelerate near the side door. Doesn’t seem motor related to me? Has also done it when parked at the fuel station.

[RVermont]

Here is my work order and invoice. Doesn’t really tell you much. The unit photo is above. They start by mounting the unit in a convenient location that is with in certain distances and then they plumb in the air from the governor/compressor and into the tank. Hook up an electrical wire to run the heater. And away you go. Could be done by someone reasonably handy but since the unit is under warrantee I felt it was important to have them handle the work.


The loud fan during driving and at rest is most likely the cooling fan, watch your temperatures next time and you can see the temperature going up and the fan coming on and the temperature then will drop fairly rapidly.


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[Robbbyr]

Originally Posted by RVermont

Here is my work order and invoice. Doesn’t really tell you much.

Looks like you got a great deal compared to some folks who have posted their quotes before.

I can't remember, did your dealer tell you initially that your unit HAD to have a factory-installed air dryer? I know some have heard that!

[brtnsnwbrds10]

Thanks for the reply! Ill look into the parts. I coudn’t imagine it would be too much more difficult to install than our air horn setup? Is a matter of putting it between the compressor and the tank correct?

[Robbbyr]

Originally Posted by brtnsnwbrds10

Thanks for the reply! Ill look into the parts. I coudn’t imagine it would be too much more difficult to install than our air horn setup? Is a matter of putting it between the compressor and the tank correct?

Many air dryers also require the installation of a small diameter air line from the air compressor governor (top of compressor) to the dryer, and the inclusion of an ignition-switched 12-volt feed to the dryer drain heater. Still not monumental, but factors to consider.

[RVermont]

Robbbyr You are correct. Simple but several items to hook up laying on your back on the ground. There is the main line from the compressor then the small line from the governor to control the air blow off at compressor cut out and the ignition feed for the heater.

The unit they used has a pretty good installation manual and I saw the unit on amazon for $225.

When I originally spoke to the repair center they ran my vin and said the unit should have an air dryer and he would not order the parts as he thought I did not know what I was talking about. It took quite a bit of arm twisting for them to believe me and they took great pride in crawling under the unit to show it to me. When he could not find it he apologized and called freightliner who again said it had to have one. After another 1/2 hour they decided that it was ordered without a dryer. They said this is crazy to use the unit in the freezing weather without a dryer.
The great thing about this site is the amount of knowledge we can gain from each other.


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[Glenn Meredith]

Jut had my 2018 HJ at Freightliner for the sway bar service bulletin, transmission reprogramming, window switch and fuel gauge calibration. I also asked for a quote to install an air dryer. The dealer would not install an air dryer unless they had drawings from engineering to the location, plumbing and electrical hookup. They wanted 9 hours labor to complete the drawings. Then the dealer could quote the parts needed and labor. They told me that warranty would be void unless they had drawings. I also asked about connecting a horn. I was told that if i did it would void the warranty on the whole brake system. Has anyone else hit a wall with trying to improve their ride?

[Glenn Meredith]

I forgot to mention at the dealer I was told I have an air dryer. All air brake vehicles have air dryers. They sent a mechanic to check it out. He spent no more than 5 minutes. I was charged 1/2 hour labor.

[ready2retire&drive]

The price they charged me and a breakdown of parts is earlier in this thread but here is a picture of where freightliner mounted it. The bracket and mud flap I installed to keep the road rash off the unit, does not get as dirty/mudpacked now. Since these are all freightliner parts will not cause any issues with warranty. As for the compressor being quieter did not really notice a difference. Last trip into dealer when they replaced the sway bar links under warranty, they said that is the way the compressor's sound on these units ? Time will tell, they mentioned in the third paragraph in my extended warranty sheets the compressor has a Cummins part number so therefore is covered until April 23/2021. Hope this helps.

[RVermont]

Glenn, it sounds strange that your dealer has these issues yet there are several people who have gotten this done with no problem. Where are you located maybe someone will have suggestions as to different service locations that can get this done.

Good luck


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[RichP]

Originally Posted by 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.

That air release you are hearing is the dryer purging moisture out of the desiccant it will do that every time the compressor charges and reaches the governed cut out pressure which is between 125 and 145 psi depending on application. It has nothing to do with over pressurization the head of the air compressor has a safety relief valve that opens at 150 psi to vent any access pressure. Also any truck with an engine driven compressor that does not have air brakes does not need a dryer and the moisture ejector valve on the tank is more than enough. Adding a dryer would be an in necessary expense. The tinny clanging noise is just How the compressor sounds since it is gear driven off the rear of the engine it is slightly amplified in the cab and there is nothing you can do about it.


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[Nogara]

Took my 2018 TS to the local Freightliner service center and enquired about the compressor noise, told the service manager about the airdryer fix. He said adding an inline check valve will mute the noise and that the tanks have an automatic dump that should keep things dry. They installed the check valve on Warranty, did not think that would be a warranty item but it was. It worked, compressor rattle is almost undiscernible. I'm very happy with the fix since my wife was ready to trade it in because of the noise. Even if you have to pay it should be a lot less than an airdryer installation.

[javamon]

Originally Posted by Nogara

Took my 2018 TS to the local Freightliner service center and enquired about the compressor noise, told the service manager about the airdryer fix. He said adding an inline check valve will mute the noise and that the tanks have an automatic dump that should keep things dry. They installed the check valve on Warranty, did not think that would be a warranty item but it was. It worked, compressor rattle is almost undiscernible. I'm very happy with the fix since my wife was ready to trade it in because of the noise. Even if you have to pay it should be a lot less than an airdryer installation.

If you have an invoice for this work that details part#, etc, it would be very helpful if you could post it. Would like to discuss this with my Freightliner shop. Thanks.