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Topic: Air Pressure won't build (Read 3268 times) previous topic - next topic

Re: Air Pressure won't build

Reply #40 –
If that hose is metal and runs to the compressor it's the one I told you about from the beginning.

Re: Air Pressure won't build

Reply #41 –
Quote from: dkeener –
Thanks for that. I was considering just the kit that was put in at FOT but have seen a few posts also recommending/replacing the whole air drier unit. So back to the store I go.

That kit is just the desiccant cartridge and maybe one or two other things. 

If this is the original air dryer, it would be wise to do the reman'd unit referenced above.  Also, don't go cheap and buy a unit that was rebuilt from other than Haldex. 

Re: Air Pressure won't build

Reply #42 –
Just a note in case, these air system parts on your coach are not motor home exclusive. All trucks that have air systems use the same so these parts can be found at Napa sometimes or ANY truck parts such as Freightliner, KW and so on. Might save you some money because you have sources and options.

Re: Air Pressure won't build

Reply #43 –
As others has said, your best option is a factory (as in the factory that made it, NOT a cheap copy sold as "replaces XXX".

That gets you not only new filters, but also valves, heater, etc.

Just pull the numbers off the old one so you get the correct one.

Re: Air Pressure won't build

Reply #44 –
Also, if you buy it locally they'll probably want the old one as a core.  Don't turn it in until AFTER the new one is installed. It's too easy to forget to remove a fitting and it's nice to see how those fittings were configured on the old unit before installing the new one.

Re: Air Pressure won't build

Reply #45 –
Quote from: Elliott –
Also, if you buy it locally they'll probably want the old one as a core.  Don't turn it in until AFTER the new one is installed. It's too easy to forget to remove a fitting and it's nice to see how those fittings were configured on the old unit before installing the new one.
To add to this its may be easier to loosen fitting before it is removed unless you have a way to hold

Re: Air Pressure won't build

Reply #46 –
Quote from: craneman  -  3 years ago
These are the 2 kits I used, seems complete except for heater.

DQ6020 - Lower Housing Repair Kit - Haldex product

DQ6026 - General Service Kit - Haldex product

Quote from: dsd –
Erratic pressure indication can be just the pressure sensor getting old also
https://www.summitracing.com/parts/SWW-82894
There is a lot to these kits but I personally would recommend getting a rebuilt. Resolves any heater issues and corrosion problems. Napa either has or will get one for you. Mine has worked flawlessly
Scott

Re: Air Pressure won't build

Reply #47 –
Same thing happened to us with our 1991 diesel U280. Worked fine until the mechanic brought our rig out to us and shut it down. We started up the engine (started just fine) but the air pressure stayed at 0. Couldn't figure out what happened ...

The repair guy was stumped. After a few days he found a solution: he clamped a hose under our rig (below the driver side gas pedal, see photo) which allowed the air pressure to build up. When he released the clamp, we could put it into gear and go. It hasn't happened since, but we keep the clamp with us at all times, just in case.

NOTE: in our case the lack of air pressure wasn't caused by a faulty air governor; we had just had the air governor replaced due to the fact that the air pressure kept rising while driving but not lowering when the brake was pushed.

Re: Air Pressure won't build

Reply #48 –
I rebuilt mine last year and the part that let go is tricky to do. I used both kits. A rebuilt one would
be easier.

Re: Air Pressure won't build

Reply #49 –
Quote from: ClassAClassy –
...he clamped a hose under our rig (below the driver side gas pedal, see photo)
Welcome to the Forum with your first post!

The photos in your post don't match your description - "below the gas pedal" - perhaps you clicked on the wrong ones?

That pressure regulator in your photos looks ready for replacement.  You can buy a replacement regulator at Lowes or HD or anyplace that sells air compressor accessories.  If you do install a new one, it should be set for about 60-70 PSI.

Re: Air Pressure won't build

Reply #50 –
Does anyone know if the spin on dryer cartridge from the DQ6026 kit is available separately?

Re: Air Pressure won't build

Reply #51 –
Keith,

Yes. If you want both filters (desiccant & coalescing) you need the DQ6036 (your best option) now if you want just the desiccant filter alone I think you will need the DQ6028.  They do make a mac daddy desiccant one that is a DQ33125.

Mike

Re: Air Pressure won't build

Reply #52 –
Do you know why thread these have v?
I think that mine needs. 39 1.50
Thanks

Re: Air Pressure won't build

Reply #54 –
Well it is fixed. A new remanufactured air dryer unit fixed the problem and pressure built as usual. Now I just need to adjust the new governor for correct air pressure. Should that be around 125 on the high side?

Re: Air Pressure won't build

Reply #55 –
A most gracious thank you to all who contributed to the success and hand holding throughout.

Re: Air Pressure won't build

Reply #56 –
Quote from: dkeener –
Should that be around 125 on the high side?
Yes - 125 would be perfect.

Anywhere in the 120-130 range is fine.  Never allow the pressure to exceed 150psi.  Your wet tank should have a safety pressure relief valve that will open at 150psi.  It will definitely get your attention if you ever hear it open.  Don't ask how I know...



Re: Air Pressure won't build

Reply #57 –
How do you know...

Re: Air Pressure won't build

Reply #58 –
I said don't ask...

One of those embarrassing times when you shoot yourself in the foot.

Most of the story is in the link below.  In that post, I said "I assume the relief valve went into action..."  Well, I was being evasive- in fact I know it went into action because it was making a extremely LOUD whistling noise that was very evident even over the running engine noise.  As soon as I closed the needle valve (and the dryer purged) the sound mercifully stopped.  I can only imagine what it would sound like if the engine was off and it opened while standing in close proximity to the tank.  Definitely something to be avoided.

Driving Tip: Scan Your Gauges!

Re: Air Pressure won't build

Reply #59 –
Ive had the unloader valve get stuck open one time.  Now it is stuck closed and purging the dryer every 30 secs.    So. Keep an eye there if you have a non air build.