Airing up the tires with coach air

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Airing up the tires with coach air

March 03, 2013, 10:19:48 am

Here is a gadget I made that others might find useful. All the parts were purchased at a local Menards (similar to Home Depot) for approx $40. The coach air system cycles between approximately 85 to 120 psi. Trying to air up a tire that needs 90 - 100 psi is difficult when the coach air is on the low side, and the compressor hasn't kicked in yet. In fact, you can even lose tire pressure instead of adding pressure. With this device you can see where on the compressor cycle you are, and with the bleed valve you can release some air to get the compressor to kick in. Then, when the pressure is reaching the high end, start to fill the tire.

Re: Airing up the tires with coach air

Reply #1 – March 03, 2013, 10:22:43 am

You can also turn up the air Governor to obtain higher pressure before cutoff. Mine is set at 130 PSI. Simple to do, there is a screw in top of Governor, turn it in to raise , out to lower pressure setting.
Gary B

Re: Airing up the tires with coach air

Reply #2 – March 03, 2013, 10:25:30 am

@Peter Nice job. I've been thinking about doing one of these myself. Thanks for the inspiration.

see ya
ken

Re: Airing up the tires with coach air

Reply #3 – March 03, 2013, 10:38:41 am

Might like using a flex hose between the body and air chuck or you might have to stand on your head to read it.

Re: Airing up the tires with coach air

Reply #4 – March 03, 2013, 11:05:10 am

Quote from: Gary Bouland – March 03, 2013, 10:22:43 am

Simple to do, there is a screw in top of Governor, turn it in to raise , out to lower pressure setting.
Gary B

This sounds in reverse.
Just to be clear. You are saying "Turn the adjusting screw counter-clockwise to raise the psi"

A. Remove the top cover from the governor.

B.   Loosen the adjusting screw locknut.

C. To raise the pressure settings ,turn the adjusting screw counter-clockwise.

To lower the pressure settings, turn the adjusting screw clockwise.

Note: Be careful not to overadjust. Each 1/4 turn of the adjusting screw raises or lowers the pressure setting approximately 4 psi.

D. When proper adjustment is obtained, tighten the adjusting screw locknut and replace the cover. (Note: The pressure range between cut-in and cut-out is not adjustable.)

Haldex D2 Governor Service Data

Re: Airing up the tires with coach air

Reply #5 – March 03, 2013, 11:40:07 am

Where is the Governor?

Any down side to having a higher pressure?

best, paul

Quote

You can also turn up the air Governor to obtain higher pressure before cutoff. Mine is set at 130 PSI. Simple to do, there is a screw in top of Governor, turn it in to raise , out to lower pressure setting.

Re: Airing up the tires with coach air

Reply #6 – March 03, 2013, 12:13:39 pm

Barry, That's the right procedure.
Paul, On my 95 U280 the governor is located on the streetside at the rear. It is about 5 inches high and 2 1/2 inches in diameter. It is a D2 Governor that is available at any truck parts and probably at NAPA.
D2 Air Governor No Core, KN18530, Haldex-Midland - Ryder Fleet Products
Gary B

Re: Airing up the tires with coach air

Reply #7 – March 03, 2013, 01:57:04 pm

Paul,
On my '95 U320 the governor was mounted on the air compressor.

Re: Airing up the tires with coach air

Reply #8 – March 03, 2013, 02:06:13 pm

Peter,
Great gadget! Karma to you! Tkx for sharing!

Re: Airing up the tires with coach air

Reply #9 – April 16, 2013, 04:38:23 pm

A quote from Thomas Edison: "There is always a better way."

I have updated my coach tire fill gadget, adding a Milton truck inflator with a built in gauge that reads to 160 psi and a deflator button. This will be much nicer to not have to read the pressure with a separate gauge.

Milton 501 Hi-Pressure Inflator Gauge with 5' Hose : Amazon.com : Automotive

It's only money, right...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Airing up the tires with coach air

Reply #10 – April 16, 2013, 04:45:59 pm

The shop I use replaced my main chassis air governor? Was 90-110 before and stuck where the coach would not fill the chassis and the brakes slowly lock up.

Whatever they replaced it now runs 109 to 130. Now the brakes work better and I can fill the tires from chassis air.

I was told the valve gets sticky over years of use.

Re: Airing up the tires with coach air

Reply #11 – April 16, 2013, 07:54:05 pm

I use a similar Milton gauge that I bought at the local Parts Plus auto supply. I use another gauge to check the tires and pull out the hose and Milton gauge if I need to add air.

Re: Airing up the tires with coach air

Reply #12 – April 17, 2013, 08:04:04 am

What is the maximum safe upper limit for on board air pressure? I have been reluctant to raise mine above 115 psi since my air system is 20 years old. It seems logical that higher pressure would put stress on the system. Am I missing something?

Re: Airing up the tires with coach air

Reply #13 – April 17, 2013, 09:03:44 am

Thanks Barry for the Haldex adjustment info. My upper end pressure seems to run around 110 psi. I can rarely get front tires over 100 psi. Based on weighing the coach front and rear axles and the tire manufacturers recommendations I should be about 105 psi in the front.

My question is where is the Haldex governor?

Thanks

Roger

Re: Airing up the tires with coach air

Reply #14 – April 17, 2013, 12:53:32 pm

I never have aired my tires with the compressor, but I did watch a Country Coach air up a completely flat tire by clipping on the chuck, start the engine and bada bing.....it filled right up. Maybe 10 minutes at medium idle.

Re: Airing up the tires with coach air

Reply #15 – April 17, 2013, 05:53:02 pm

Kent,

We would set our systems up for 120 psi with a max of 130 psi. You are OK at 115 psi. Low pressure warning will come on at about 60 psi and spring brakes activate at about 45 psi I believe.

Keith

Re: Airing up the tires with coach air

Reply #16 – April 17, 2013, 07:15:17 pm

Roger, I had similar problem. Needed110, but seemed to max out about 96 on one tire. Found over trial and error that I had a problem with the chuck. Some reason it just did not work on that tire, did not fit right versus the others.

I routinely can still all the other five to 95 and 110, and that was after my governor was adjusted downward from 130 to 120 psi. It works though, so encourage you keep trying. I think, as aside, that the D2 governors come in at least two pressure range designs?

There is a Youtube on airing tires, might be of interest.

HOW TO: Inflate High Pressure RV Tires

Re: Airing up the tires with coach air

Reply #17 – April 17, 2013, 07:33:33 pm

My 23 yo coach states 90 in front and 85 rear. My electric compressor kicks on at 80 and off at 100, but it doesn't like filling tires. Before rolling the coach, I use the engine compressor, which kicks out at 120 - 130. Haven't checked it accurately, but with the engine running, I was easily able to get the tire pressure right for all 6 in about 10 minutes. They were 75# each when I bought it. Feels like a better ride with recommended pressure.

Does anyone know of a chart relating air pressure in tires to the weighed load on each axle ?

Re: Airing up the tires with coach air

Reply #18 – April 17, 2013, 07:39:11 pm

Quote from: sgwynn – April 17, 2013, 07:33:33 pm

Does anyone know of a chart relating air pressure in tires to the weighed load on each axle ?

It depends on the tire, brand, load range, size, etc.

Here is Michelin's http://www.michelinrvtires.com/michelinrv/tires-retreads/load-inflation-tables.jsp

And better than axle weight will be weight at each axle end, then inflate all tires on that axle for the heavier end. That way you won't risk being under inflated if your weight isn't exactly the same at both ends. See RV Safety & Education Foundation or the Escapees' SmartWeigh program.

(ETA - corrected the RVSEF URL)

Re: Airing up the tires with coach air

Reply #19 – May 05, 2013, 10:06:59 pm

Quote from: Paul Smith – March 03, 2013, 11:40:07 am

Where is the Governor?

Quote from: Home2fromHastings – April 17, 2013, 09:03:44 am

My question is where is the Haldex governor?

For benefit of those who have asked (and those who haven't but wondered - I was one), since we learned where the governor is on our coach today I thought I'd share - follow the smallest air line off the air dryer. As you're looking at the engine from behind the coach ours is on the right side of the engine at the end of that small air line (you'll probably find the line is in a tie-wrapped bundle with other lines).

Michelle

Re: Airing up the tires with coach air

Reply #20 – May 06, 2013, 07:01:53 am

It helps when it says "governor" in red on it! Can you write that on ours so we know where it is? Ha ha ha!

Re: Airing up the tires with coach air

Reply #21 – May 06, 2013, 11:02:37 am

Quote from: txforetravel – May 06, 2013, 07:01:53 am

It helps when it says "governor" in red on it! Can you write that on ours so we know where it is? Ha ha ha!

That photo wasn't posted by me - I suspect Barry B. has been sneaking in and improving posts

He's like the wind

Re: Airing up the tires with coach air

Reply #22 – May 06, 2013, 11:09:33 am

Also the black cover comes off and there is a screw you turn to adjust max air pressure. If the diaphragm gets stuck turning it all the way and opening it again can get you off the road but you will need to replace. Very common part but make sure you get the one that cuts in at 90-95 psi.

Re: Airing up the tires with coach air

Reply #23 – May 06, 2013, 12:19:27 pm

Speaking of the air governor, for the mechanically inclined, be sure you have ALL the right tools to replace it and that you can get to it. For the non mechanical types, I would recommend having it replaced every 6-8 years and don't play with it, just enjoy it.

Re: Airing up the tires with coach air

Reply #24 – May 06, 2013, 12:26:54 pm

Quote from: Michelle – May 06, 2013, 11:02:37 am

That photo wasn't posted by me - I suspect Barry B. has been sneaking in and improving posts He's like the wind

Chief photo improvement moderator at large

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