2002 Holiday Endeavor Airbrakes question!

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evitagen

Member
Joined
May 28, 2012
Posts
9
Hi everyone,

Purchased this rv a year ago this month, only driven it 2500miles from where i bought it home.
Air pressure would stay in the system for a approx. month  till it leaks down to 60lbs.
Now after it was fully serviced (brakes adjusted, all lube and filters change, air dryer etc..) the air only last about 4-5 days until it leaks out to 60lbs.
I have checked all the bags, (used soapy water for bubble) all connections and can not find any bubbles.  Brakes work fine. Wanted to know if that is the norm and maybe the brakes were plugged up before the servicing. 

Thanks for the info..
Teddy
 
Air pressure gauges read air pressure in primary and secondary tanks only. Do you regulairly drain your air tanks? Do you have taps or valves with cable pulls? The unfortunate thing in the RV world  is people are driving air brake vehicles with no training. There is a fairly extensive Air Brake Course in ONTARIO CANADA and one must complete and pass and get an endorsment on their licence to be allowed to drive an airbrake vehicle. If you knew that information you would know how to check out an air brake system properly and systematicaly.  I am not trying to be smart but you will probably get umpteem different opinions from other people who have motorholmes and don't know the routine themselves. If you go Goggle and punch in MTO ONTARIO you can find a couple of sample questions. If you can't answer the questions you know you have a problem.  You may or may not have a problem but it takes a good twenty minutes to properly check out an air brake system if you know what you are doing and is supposed to be done every 24 hours if you are driving every day. Colorado and some other states are on board with ONTARIO but I'm not sure which ones.
This may sound cynical but I swear our govts. look the other way regarding RVs and air brakes because they allow all ages of people to drive air brake vehicles without the endorsment because the sooner you kill yourself the sooner they quit paying old age security. The information you need is available. It depends what your life is worth to you.
 
Thank you for your response.
I have been a licensed truck driver for the past 30 years. I have been thru all the courses and have all the endorsements.  However the airbrakes that are on this RV, are electronic or pop off valves and therefore do not have cable pulls. Even though i have only had this rv a short time w very little mileage i have put on it, i do bleed the air manually occassionaly. There is an air dryer connected to this system as well, and my problems started after i had it serviced. Before service it would hold for about a month before hitting 60lbs, now about a week.  So my question is more if this is normal or should it hold for a month like it did before?  This is my first Diesel pusher motorhome, but not my first vehicle with airbrakes. 
 
evitigan: My guess would be there isn't a problem.  A good system will sometimes leak out to 0 PSI overnight. other times may hold a long time days or weeks. Air bleed valves  with cables don't always seal 100% after draining tanks . If low pressure indicator is within specs. air build up time, cut in and cut out pressures are correct and air loss test is within specs. then I would suspect everything to be OK . You indicated having in for service and the tech may have drained tanks for you which I would think might be the case. Over here in Ontario at 65 yrs old for a class A we have to do eye test, medical written test forA, written test for AIR BRAKES , circle check, AIR BRAKE practical test and driving test anually. Many older truck drivers give up their truck licence because they can not do the air practical test , others pay $350.00 at a local college so they can take the course and provide a certificate to keep there license. Many are men who have driven for decades.
Like I said not to be smart but last winter I spent the winter in an RV park in California and had lots of time on my hands. I got talking to a salesman at the park who indicated that he sold a 38 foot MH with air brakes to a couple 83 yrs. old who never drove  with air brakes.  My response to him was MY GOD what did you tell them? He said I told them not to drive it until it had 150 PSI. I said you told them the right thing because as you probably know they aren't allowed higher than 135PSI. But I imagine they drove. I met another gentleman who thought he had two compressors because he had two gauges. H e took it in because it cut out at 80PSI and he wanted to be able to air up tires. He didn't have any idea he was illegal as soon as he touched his brakes
 
Teddy, air specs aside you obviously have something different and that would concern me also. If it holds psi for a week it would of course pass all the safety tests but still something is different and my guess would be the air dryer. It could just be a coincidence but probably not and I would have to look closer. My concern would be what ever is a small leak now could get worse in a month or so while on the road.
You could have the Midland air dryer or the Haldex Purest, either of which need the can replaced for a service. One is a spin on and the other held down with bolts, either could have a small leak. Don?t know if they removed the unit to service or did it in place but you could have a small leak on one of the air lines if they removed it.
I would find the dryer, mine is behind the rear axle, and squirt it down to see what I could see. It?s probably not enough of a leak to hear but soapy water should give it away. Let us know what you find. Welcome to the forum also!

I met another gentleman who thought he had two compressors because he had two gauges.
Thats kind of scary! :eek:
 
Teddy, there is a purge valve located on the dryer that sometimes leak. They should not but mine got so bad it was down to 70lbs when we pulled into a campground. Called Freightliner and they sent a tech out. The purge valve had just been replaced at Miami Freightliner. I now have a whole new dryer. My coach normally does not leak any air when it is functioning properly. Some leakage may be normal and I have owned some trucks that would leak down overnight but I don't consider that normal.
 
My favorite air brake story - several years ago I delivered a truck to Billings, MT and was riding Greyhound back to Quartzsite.  The bus left Billings at O'dark:30 on a foggy 0 degree morning, by noon it had warmed up to 19 degrees F when we stopped for a break in Dillon.  Everyone piled out of the bus to run and get something at the local Quikee Mart. 

When we got back to the bus the driver told us we wouldn't be going anywhere for a while.  He said it had been too cold to drain the air reservoirs when he started the trip, so he decided to do it on this stop.  The drain valves were now frozen open and the bus had no air pressure.

The company had to dispatch a mechanic from Billings, with luck he'd be there before sundown.  I wanted to crawl under there with all of the cigarette lighters I could scrounge up, but my offer was politely declined.

When the mechanic arrived, he had a few choice words about the kind of person who would try to drain a tank in sub-freezing temperatures.  Then he grabbed his propane torch and had us going in a matter of minutes.
 
Thanks you all for the responses.

I figured it was the air dryer since it was serviced and replaced and they only adjusted the brakes.  I have checked it wit soapy water and no bubbles.  I even checked the airbags and nothing.  The brakes function well, and the air stays up for about a week.  I guess compared to the old trucks i used to drive, which would be down quite a bit the next morning!  Funny, how they would still pass me at the scale house.  I miss driving trucks since i retired in 1991, one day i will full timing in my RV.

I got a deal one this one, and if it works out we are a okay, if not we will get a new one. (or new to us) 

My daughter has an rv as well ( 1991 holiday rambler aluma lite class A)  she hasnt gotten much use out of it yet but i am trying to get our schedules together so we can camp at medina lake thousand trails. 
 
I mentioned you might get many theories. The main fact remaining still is the pressure on the gauges only reads what is happening on the primary and secondary tanks.  To the gentleman who pulled into a campground with 70PSI your spring brakes could have allready began to apply. That is one reason you are never supposed to drive below 80 PSI. I feel like I might be treading into unwelcome territory. One more interesting point is that  when airing up depending whether a spring brake priority or service brake priority you could be driving without enough air to stop the coach or driving away with spring brakes partially still applied. I'm not aware where your location is but up north you will loose the air much quicker on a cold night sitting not running. If your unit will hold 3PSI or less "drop" in one minute @ 100PSI full brake application and coach turned off your leak is legally acceptable. If it leaks more than 3 PSI you should take out of service and bring out a moble mechanic. This test will test all of these other components other people talking about from the drivers seat. All air brake systems leak while sitting to a degree and the less they run the more leaks you will develop. I'm trying to help you sir not pick on you. Good luck and now I think it is time to back away from this one unless requested.
 
My (Freightliner) coach chassis always seems to have tiny air leaks - I consider it to be working well if the air pressure stays up for a week! If it gets down to loosing pressure overnight, I get it fixed. Not always easy to find, though. I recently replaced a valve on an auxiliary air line that pneumatically latches the entry door when we are underway. The valve wasn't closing tightly and leaked air once we stopped and opened the entry door, allowing pressure in the front tank to go to zero overnight.  Only way I found it was that  I was looking for a fuse near it and heard a slight hiss.

As I am sure you realize, this sort of tiny leak has no measurable effect on brake operation - the compressor easily keeps tank pressure in the safe zone when the engine is running. I've had some fairly major leaks and the entire system pressure still stayed at 125 psi with the engine running.
 
My air problem started in San Antonio where they replaced the relief valve, woke up in Cheyenne, WY and couldn't move, no air pressure and couldn't build pressure, Freightliner sent road service and bypassed the air dryer. Got back to Miami and had Freightliner Miami reconnect the dryer, replaced a valve and everything was supposed to be fine. Pulled into Eustis, Fl campground with air pressure dropping at 70lbs PSI when I backed into my site. Freightliner  Orlando replaced the dryer and all seems to be fine now. The dryer filter is supposed to be serviced every 3 years as per manual. Freightliner covered the whole thing under warranty including service calls.

So far sitting now for 2 weeks it is still at 125PSI and normally operates at 140PSI. This is my first experience with a dryer. All my trucks that had air brakes you had to manually drain the lines.

And yes, the spring brakes were starting to apply when I backed into my site and the temp between the ears was rising.
 
gw cowgill: Electronic gauges on MH read funny compared to old mechanical gauges. With that in mind I would check very closely to make sure your not reading incorectly from angle you may be looking at it. If indeed it is 140 PSI I would take another ride to Freightliner and have reduced to 135PSI. Cut out pressure is supposed to be between 120 PSI and 135 PSI. There is a pressure relief valve if you reached 150PSI. I would be checking as you are a bit over Maximum.
Back to OP when you retired all trucks had manual slacks. Any vehicle after 1995 came equiped with automatic slacks. If the slacks are working properly you shouldn't need to go in for brake adjustments. They must be kept greased  and monitored though. The truck shop I deal with recomends doing six full brake applications before heading out because rarely would you ever do a full brake application and may not reach the next cog in the slack. Now with that in mind I would do this while still up on your hydraulic legs so you can release your spring brakes without coach moving. newer coaches will be equiped with an anti compounding valve but I would still release spring brakes. I notice everyone mentioning there personal air leak experience but still waiting for someone to say according to DOT or MTO no one worries whether a week or month or overnight to lose air pressure when not running. I guess in a perfect world it would hold air pressure indefinely but good luck on that one. Guess I can't stay uninvolved after all. Fun chatting. Good Luck.
 
I'm like evitagen, I bought a Holiday Rambler from an individual and have never had any experience with air brakes.  He told me to push that knob in to release the brakes for driving and to pull it when I stopped.  However, he did tell me to wait for the pressure to build up to 90 before driving.  I drove the motor home about 400 miles home with all ease.  I won't be going to Canada for a course, but I would like to know a lot more about the air system.
I can tell Bib knows air systems. 

I know this is an old topic.
 
Bo,
You CAN'T drive an air brake equipped vehicle until the system builds adequate pressure.  I mean "can't" in the sense that it is impossible. The reason is that the park/emergency brakes are operated by static spring pressure and always try to apply automatically. The air system overrides the springs and keeps the park/emergency brake off.  If there isn't enough air pressure in the system, the brake stays on. Obviously there is a middle ground where the air pressure is barely enough to partially release the park/emergency brake, but you get the picture.  That happens at about 60 psi, so by 90 psi the brake system is fully functional. At that point, air brakes work as expected - the harder you push the pedal, the more braking pressure is applied at the wheels.  The onboard, engine driven, air compressor automatically runs to keep air pressure between about 90 and 125 psi.

Be aware that if the air pressure ever falls below the minimum, the park/emergency brakes apply automatically. You can manually trigger that by pulling the Yellow handle out.  That dumps air pressure in the lines, allowing the springs to apply the park/emergency brakes. The park/emergency brake also function as the rear axle service brakes. Same physical brake shoes, applied by either spring or air.


However, air pressure also provides the suspension in your coach and it needs 90+ psi to inflate the air bags to the required height.  90 psi may be enough to get the suspension lifting the body somewhat, but pressure really needs to be closer to 125 to do its job well. Unless there is good reason, I'd suggest waiting for the gauges to hit 125.  If parked, you should hear an air discharge as well, signalling that the air system has stabilized at working pressure.
 
In addition to what Gary said, some motorhomes (like ours) don't have adequate tire/fender clearance until just before the air system is fully pressurized. In our coach, the front two air bags are the last things to inflate when our air system is pressurizing. If I were to turn the steering wheel sharply in either direction, before the front air bags inflated, the tires would hit the fiberglass fenders, and I'm quite sure they'd be damaged. Because of that, I also have to make sure that the steering wheel is centered (or close to it) before I level the coach, or dump air pressure. I've heard that some other coaches are the same.

Kev
 

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