[Mike, 92 Country Coach]

I copied and pasted your questions below:

I’m confused. While the parking brake is engaged and the engine running, I build pressure in the Front, Rear and Aux systems. Overnight, say 10 hours, the Front and Rear air pressures do not drop at all and the Aux system drops 20psi.

Mike-This means your Suspension Norgrens (air bags) are holding air but you have a leak somewhere else in your system that uses aux air.

When I start up the bus and I release (turn off) the parking brake, in neutral and the engine running, I loose air pressure in all three systems quickly.

Mike- Not related to the previous question, this leak is in your brake system

In a matter of maybe 60 second the Front, Rear and Aux systems will drop from 117psi to 96psi with my foot on the regular brake. I take my foot off the brake, still in neutral, the engine running, and all three systems quickly drop to 88psi, then 77psi and the parking brake light comes on.

Mike-Aux and Brakes are 2 different system, you have leaks in both systems.

Still in neutral, no brakes applied, I run the engine rpms up and no air pressure will build up.
Only when I engage the parking brake will air pressure build up and it builds up quickly.

Mike-Same answer as previous, you have a leak which should be substantial enough to hear.

What happens in the Front, Rear and Aux systems when the parking brake is engaged and what happens when the parking brake is disengaged ?

Mike-They have nothing to do with each other, two independent systems. It is going to be hard for you to hear these with the engine running, plug a compressor into your port in the back above the batteries, you should be able to hear a leak that is dropping that quick.

[George]

Mike’s replies are accurate and the rear air access is the way to go. Your leaks may be multiple locations in both systems.

[Michael]

Mike and George;

Thank you for your replies.

I am currently at Prevost – Ft. Worth. The bus has been here for almost two weeks now.

Here is what they told me would solve my problem and if I approved or disapproved the repair –

• Driver side wheel seal leaking – APPROVED
• Replace tag shocks – APPROVED
• Generator service – APPROVED
• Level 3 Service – APPROVED
• 2 red rear marker lights out – APPROVED, HOWEVER THEY DID NOTHING, telling me they could not match my marker lights with LEDs. My marker lights are ALL LED.
• Air system service – APPROVED
• Replace engine air compressor – APPROVED
• Fuel leak near Webasto preheater – APPROVED, however, I told them to just cap off the leak
<strike>• Replace upper control arms</strike> – NOT APPROVED
•<strike> Replace lower control arms</strike> – NOT APPROVED

I drove up to Prevost – Ft. Worth Tuesday, July 8th and spent the night so I could be ready for my 6am APPOINTMENT. After spending Tuesday night at Prevost Ft Worth and getting up at 5:30am for my 6am APPOINTMENT, it was 6 HOURS, close to NOON, before anyone came out to the bus to help me.

• 6:00AM – I spoke to the Lot Walker and he said, we’ll send someone right out to you.

• 8:10AM – I called my Service Writer and he said, we’ll send someone right out to you.

• 9:15AM – I called and my Service Writer was in a “Meeting”. The Front Desk said they will ask the Lead. He told the Front Desk to tell me, we’ll send someone right out to you.

10:15AM – I called my Service Writer and he said, we’ll send someone right out to you.

• 11:55 AM – A Tech finally wondered to my coach and took my bus in for inspection after I described the parking brake / loosing air pressure problem.

• 1:30PM – I was told I needed a new D/S drive axle inner wheel seal, the brakes had over heated, and the engine compressor had failed, etc.

• 2:00PM – I was told it would be Friday before all repairs would be complete and I could not stay in the bus

• 2:30PM – I was told in would be Monday, July 14th before all repairs would be complete and I could not stay in the bus. I had my son in Dallas drive me three hours home.

• Monday, July 14th – I was told it would be Tuesday or possibly Wednesday, July 16th before all repairs would be complete. I told Prevost I would drive up and sleep in the coach Wednesday night.

• Wednesday, July 16th – I arrived at Prevost at 7pm and they were still working on the bus

They continued working on my bus until Friday, July 18th, finishing at 3pm as they were closing.

I try to leave the next morning, Saturday, I press on the Service brakes to stop twice, once at the Exit Gate and once in front of their office and brake pressures drop from 115psi to 77psi & 72psi. Parking Brake light come on.

I am still at Prevost – Ft. Worth for the same problem I brought the bus in for repair to begin with.

I have driven this bus 272,000 miles and been a Prevost – Ft. Worth customer for around 25 years. My brake air pressure would only drop a few psi when the service brakes were applied. A drop of 20psi is unacceptable and dangerous.

Prevost – Ft. Worth drove my bus 11 miles and had the engine running for over 6 hours while my bus was in their possession. How could they miss this drop in air pressure ? They told me my problem had been repaired and were letting me drive the bus home in this dangerous condition.

While everyone has been very polite and professional to me, the lack of progress, the time to solve and repair my service request is appalling. It used to be much better here.

The Air Service is supposed to check for air leaks, check service brakes system, check park brake system among other items. Did they actually check the brakes since that is why I brought my bus in to begin with. I caught the problem after just stopping twice.

I am still here for the same problem that brought me here to begin with.

• What is going on with my parking brake and what is allowing me to lose all that air pressure so quickly ?

MICHAEL POWER – 1998 Prevost XL-40 Country Coach Conversion, Original Owner

[Michael]

Prevost – Ft. Worth is replacing my R-14 valve as we speak. They think this is the problem. They said it was leaking air and the diaphragm failed. They showed me the valve and it looked ok, no water or rust inside the ports.

[George]

Michael,

I recently had a similar sounding leak issue. It turned out to be a braided air line to the VPOD which I had never heard of. Replacing the line cured the leak.

Good luck with a frustrating problem.

[George]

Michael Power,

Did you previously have a signature with “ Country Coach the World’s Most Luxurious Motor Coach” ?

[Joe, 98 Country Coach]

Michael,

I replaced a leaking R-14 valve this Spring. The symptoms were as you described. It fixed the problem. Let us know how this turns out.

Joe

---

Joe Wilhelmi

1998 Country Coach

Dixon,IL

[Mike, 92 Country Coach]

Unless the initial description of the problem is incorrect, or someone made some bad decisions on plumbing there is no link between the two systems. This is designed by Prevost this way for Safety

[Michael]

Prevost-Ft. Worth has now replaced –

• Engine Air Compressor

• Air Dryer Cartridge

• R-14 Relay Valve

• Driver Side, Tag Axle R-12 Relay Valve

• Air Governor

• Check Valve from the Wet Tank to the Primary Tank

• Check Valve from the Primary Tank to the Secondary Tank

I have mentioned several times other Prevost Community Members have had problems with the air line leaving the Engine Air Compressor. They told me that air line was ok.

Replacing the R-14 and R-12 valves took them 12 hours. The Prevost R-12 valve was a different shape from my original and there was one line that was a smidge short and would not seal. They spent five or six hours trying to make it fit.

Three times Prevost-Ft. Worth told me the problem was fixed and three times, I left for home only to return. The 1st time, last Saturday, I did not even make it out of their driveway before I saw my Front and Rear Air pressures ahd dropped to 72psi and 77psi with just two brake applications.

Then they replaced the R-14 & R-12 valves and told me I was repaired. I made it 18 miles away before the Rear air pressure dropped to 80i while I was driving, applying no brakes and the Engine Air Compressor would not kick in. I returned.

The third time they found oil in the Air Governor and replaced it. That was Tuesday. I made it 8 miles this time before the same thing happened and I had to return.

The fourth time was today. They replaced both Check Valves and when they test drove my bus, they did not make it but a mile or so before having the same problem. I had to have these two Check Valves overnighted from New Jersey because in all of the Prevost Parts System, these were the only two available in America.

My bus has been at Prevost-Ft. Worth for over two weeks now with the same problem. I have been here for eight going on nine days. I drove up LAST WEDNESDAY to pick up my bus because the told me it was ready. So I only brought one change of clothes.

The problem is the Rear Air System looses air while driving and the Engine Air Compressor is not kicking in. I think Prevost-Ft. Worth is trying hard and is as stumped as I am.

Very Frustrated – Michael Power