Both air tanks lose air together

[GoWestMan]

7 hours ago, Frank McElroy said:

Doug, from what you are saying, the duty cycle of your air compressor is 100%. You already replaced the compressor once and with this duty cycle, you'll be replacing it again soon.

I can't stress enough that if you are not able to perform and pass an air brake pre-trip safety check and you are not able to find the leak(s), then your best solution is to find a truck repair shop to perform an air brake pre-trip safety check and repair the leak(s) in your air brakes.

Very good point. Dont really want to pay for another compressor. Gonna have to find a good shop in town to look for the leak. Ive been at two but neither seems to be big fans of working on old RV's but there is a semi trailer shop that must be very familiar with working on air brake systems.

[Kevin Wald]

I had same a month ago, 2006 Signature Commander  

A 90 degree air fitting below the park brake push-pull on-off button was leaking.

My tanks would leak down in 30 minutes, now hold for three days  

 

[bmulvenna@hotmail.com]

On 6/29/2024 at 11:39 AM, bmulvenna@hotmail.com said:

Found a leak in the air dryer. Will order a new one. Not sure if this is the total solution but will find out.

I again checked for leaks in all fittings on both front and rear tank, door seal, air horn, park brake, dash guages, all 3 6 packs, tag pressure, govenor, drain valves, step, brakes, air bags, etc and found no leaks. Only the leak in the dryer. Will report back if new dryer fixed the issue.

Thanks for all the suggestions.

Mike

Leaking air dryer replaced with a new one. 

 Tanks leak slowed but not eliminated. The hunt continues. Will check shuttle valve per Ivan's suggestion.

[RoadTripper2084]

On 6/30/2024 at 8:02 PM, GoWestMan said:

Demonstrate to whom? Maybe its different here but we have an initial inspection when you bring in an RV from out of the province (bought it in California, drove it back to Alberta) but after that, as long as it stays insured, there are no more inspections til you sell it to someone else.

Doug, FYI if you're in AB (as I am), you are required by law to have a "Q" endorsement on your driver's license to drive your coach.

Quote

The "Q" endorsement on an Alberta driver's license indicates that the driver is qualified to operate vehicles with air brake systems. This endorsement is required for drivers of vehicles that have an air-only braking system or a combination of air and hydraulic brakes. To obtain the "Q" endorsement, a driver must complete an Air Brake Program, pass a test, and demonstrate the necessary knowledge and skills to inspect and operate vehicles with air brakes safely. The "Q" endorsement applies to both commercial and motorhome drivers in Alberta.

This involves taking a long one-day course where you'll learn all about the air brake system on your coach, which will also help you to debug these types of issues, and of course, avoid possible safety issues. The wife and I both did ours a few years back, it was kind of fun, but I'm a bit of a systems freak. 😉

 

Edited Thursday at 02:54 PM by RoadTripper2084

[96 EVO]

15 minutes ago, RoadTripper2084 said:

Doug, FYI if you're in AB (as I am), you are required by law to have a "Q" endorsement on your driver's license to drive your coach.

This involves taking a long one-day course where you'll learn all about the air brake system on your coach, 

 

Two 8hr day course in B.C!

[GoWestMan]

24 minutes ago, RoadTripper2084 said:

Doug, FYI if you're in AB (as I am), you are required by law to have a "Q" endorsement on your driver's license to drive your coach.

This involves taking a long one-day course where you'll learn all about the air brake system on your coach, which will also help you to debug these types of issues, and of course, avoid possible safety issues. The wife and I both did ours a few years back, it was kind of fun, but I'm a bit of a systems freak. 😉

 

Ive had my Q endorsement since I first drove a transit bus in 1990. Have owned and driven air brake buses for several employers as a bus driver plus my two of my own RVs.

[Ivan K]

In TX I needed a Class B license at a minimum. It is like a mini CDL, noncommercial license, written test and driving test with precheck demonstration including air brake system test. No class attendance is required and the study materials are on line. Outside of busy scheduling it was useful for me.

[GoWestMan]

16 hours ago, Kevin Wald said:

I had same a month ago, 2006 Signature Commander  

A 90 degree air fitting below the park brake push-pull on-off button was leaking.

My tanks would leak down in 30 minutes, now hold for three days  

 

Good tip. I'll check that.

Mines booked into a shop next week if nothing turns up.

[c210pa18]

I’m am chasing air leaks as well.   I fixed two on the front tank, they are not leaking now.  But seems like the system is leaking a bit more than it was before.  A question on the shuttle valve on the front tank.  Am I correct in thinking that if the shuttle is leaking the air is not leaking out of the air system but it is leaking from the front to the back tank or the other way around.  An indication of that leak would be that the pressures go down about equally in the front a rear tanks. Is that correct?

[Ivan K]

35 minutes ago, c210pa18 said:

I’m am chasing air leaks as well.   I fixed two on the front tank, they are not leaking now.  But seems like the system is leaking a bit more than it was before.  A question on the shuttle valve on the front tank.  Am I correct in thinking that if the shuttle is leaking the air is not leaking out of the air system but it is leaking from the front to the back tank or the other way around.  An indication of that leak would be that the pressures go down about equally in the front a rear tanks. Is that correct?

Exactly right. A small leak will not be enough to close the shuttle valve and makes it hard to figure where that leak is, front vs rear. Since I couldn't detect any last obvious leaks with bubbles anymore anywhere, I isolated the two tanks.  It was a very small leak but i wanted to finish it off. Unplugged the 1/2" line to rear tank right at the shuttle valve an capped it. Put a short piece of line with a cap into the open valve port. Filled the tanks and watched the front tank lose pressure over time while rear was good. That let me focus on the front accessories that I kept similarly isolating until the culprit was found in a place I couldn't have accessed with sprayer previously. Good luck!

[jacwjames]

In 2021 prior to going on a long trip I did a leak down test on my rig, it held air for over a week.  Good enough.

Later that year I left on another trip and stopped at a campground overnight, next morning ready to leave I turned the key on and the low air alarm came on.  So I started monitoring and my rig started to loose air at a faster rate but it had decent pressure while driving.  Made to Big Bend National Park and had time to try and find the problem.  Took a spray bottle of soapy water and started spraying, every one of the four Pressure Protection Valves were leaking.  But since it seemed to be at an acceptable rate I continued onto my trip.  While I was visiting the Petrified Forest NP in AZ I stopped at the visitor center, 45 minutes later the air had dropped to almost 40 psi.  Decided to head  home to investigate. 

I replaced all the PPV's plus any other fitting that had the potential for failure.  Decided to replace most of the push to connect fittings.  I had one piece of tubing that had a sharp bend in it going into the PTC fitting, ended up replacing that fitting with a compression fitting and that fixed that small leak. 

My rig will now stay up for weeks, like Ivan I chased all the leaks until there were NONE.

 

 

Edited 22 hours ago by jacwjames

[bmulvenna@hotmail.com]

1 hour ago, Ivan K said:

Exactly right. A small leak will not be enough to close the shuttle valve and makes it hard to figure where that leak is, front vs rear. Since I couldn't detect any last obvious leaks with bubbles anymore anywhere, I isolated the two tanks.  It was a very small leak but i wanted to finish it off. Unplugged the 1/2" line to rear tank right at the shuttle valve an capped it. Put a short piece of line with a cap into the open valve port. Filled the tanks and watched the front tank lose pressure over time while rear was good. That let me focus on the front accessories that I kept similarly isolating until the culprit was found in a place I couldn't have accessed with sprayer previously. Good luck!

Ivan, I have capped the shuttle valve as you suggested and as you found, my leaks are in the front tank. At this point the soap bubble test is not identifying any leaks.

If I may ask what was the culprit you found?

Thanks

Mike

 

[Ivan K]

14 minutes ago, bmulvenna@hotmail.com said:

Ivan, I have capped the shuttle valve as you suggested and as you found, my leaks are in the front tank. At this point the soap bubble test is not identifying any leaks.

If I may ask what was the culprit you found?

Thanks

Mike

 

Mike, my leak is from the air operated step cover cylinder when retracted. Sometimes I can hear the leak and if I close it again it goes quiet. Very slow leak but one day I will pull the cylinder out and fix it.

[bmulvenna@hotmail.com]

13 minutes ago, Ivan K said:

Mike, my leak is from the air operated step cover cylinder when retracted. Sometimes I can hear the leak and if I close it again it goes quiet. Very slow leak but one day I will pull the cylinder out and fix it.

Thank you

[jacwjames]

On my front fire wall there is a black plastic cover over the brake treadle valve.  There are several air connections there.  You might pull the cover and check.  I think @Vanwill52 had a leak at the treadle valve, the hoses going into the were coming in at an angle and the PTC fitting was leaking.

[Ivan K]

Mike, I should have mentioned that my leak stops at 60 psi so I knew it is one of the accessories past PPV, like the horns, vacuum generator, step cover, door seal and whatever else you might have there, I think even the tire inflation hookup might be on PPV.

[Frank McElroy]

4 hours ago, Ivan K said:

Exactly right. A small leak will not be enough to close the shuttle valve and makes it hard to figure where that leak is, front vs rear. Since I couldn't detect any last obvious leaks with bubbles anymore anywhere, I isolated the two tanks.  It was a very small leak but i wanted to finish it off. Unplugged the 1/2" line to rear tank right at the shuttle valve an capped it. Put a short piece of line with a cap into the open valve port. Filled the tanks and watched the front tank lose pressure over time while rear was good. That let me focus on the front accessories that I kept similarly isolating until the culprit was found in a place I couldn't have accessed with sprayer previously. Good luck!

One other option would be to dump the air in the front wet tank and the rear dry tank.  That should set the internal shuttle check valve and isolate the front tank without a need to cap the line.  Naturally, that assumes the shuttle internal check valves are working.

[bmulvenna@hotmail.com]

14 hours ago, Ivan K said:

Mike, I should have mentioned that my leak stops at 60 psi so I knew it is one of the accessories past PPV, like the horns, vacuum generator, step cover, door seal and whatever else you might have there, I think even the tire inflation hookup might be on PPV.

Good point. Thanks