Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 07, 2025 ...

Mystery air filter on 2004 U320...

April 08, 2025, 07:40:28 pm

I found a mystery Donaldson  spin-on air filter #549458. It's on the pass side, under the AC compressor. Foretravel didn't have any info on it and there's none in stock.....

That part # crosses to: 
Baldwin BT9408 'Air Coalescence Spin-on Filter'.
CARQUEST 83458,
Fleetguard AF26113,
Luber-finer Luberfiner LAF6113,
DONALDSON P566130.

I searched the forum for these part numbers and came up with....nothing.

What say you?

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Re: Mystery air filter on 2004 U320...

Reply #1 – April 08, 2025, 08:01:28 pm

Can you post a photo of the filter in situ?

Seeing the location in a photo will help folks identify what would normally be (or not be) in that location, and if there's some sort of aftermarket system installed.

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Re: Mystery air filter on 2004 U320...

Reply #2 – April 08, 2025, 09:40:57 pm

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Re: Mystery air filter on 2004 U320...

Reply #3 – April 09, 2025, 12:09:28 am

Google this:
air filters on the outlet side of big truck air compressors

Tim

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Re: Mystery air filter on 2004 U320...

Reply #4 – April 09, 2025, 08:19:26 am

Tim,

I tried your suggested Google search, and got nothing relevant.  Can you provide a direct link to whatever you found?

I'm trying to think of why a filter on the outlet side of air compressor would be a good idea...  Isn't the air dryer supposed to catch any oil that comes from the air compressor?

I wasted an hour last night looking at photos of big block Cummins junkyard engines, hoping to see a photo of an engine with a mystery air filter similar to that in the original post.  No luck.

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Re: Mystery air filter on 2004 U320...

Reply #5 – April 09, 2025, 09:11:39 am

@StevenOrlando,

The two lines in your "black & white" photo - can you tell where they terminate?

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Re: Mystery air filter on 2004 U320...

Reply #6 – April 09, 2025, 09:40:28 am

My guess is upper one goes to compressor.  Lower one goes to air dryer.

This filter must be used alot since there are so many options of filters

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