Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Peter on October 31, 2021, 06:20:37 pm

Title: Air brakes at 0 lbs in storage
Post by: Peter on October 31, 2021, 06:20:37 pm
I have stored my coach for winter. I realize I have a leak in air tanks or something which i will deal with in the spring. My question is my brakes and emergency air brake still active? I have all wheels chocked but some reassurance that the brakes are still applied even though the pressure reads zero would be appreciated
Peter
Title: Re: Air brakes at 0 lbs in storage
Post by: FourTravelers on October 31, 2021, 06:24:38 pm
The park brakes are spring activated and released by air pressure

This applies to the rear brakes only.................
Title: Re: Air brakes at 0 lbs in storage
Post by: Chuck & Jeannie on October 31, 2021, 06:27:30 pm
If your air pressure gauges read "0" then your service brakes will not work.  They are applied by air pressure.  However, your parking (emergency) brakes on the rear axel will be set and functioning because they are applied by heavy mechanical springs.  The parking brakes should activate automatically when pressure in the brake tanks gets down around 40 psi.

You will not be able to release the parking brake next spring until you build air pressure in your brake tanks above (about) 60 psi.

Title: Re: Air brakes at 0 lbs in storage
Post by: wolfe10 on October 31, 2021, 07:44:57 pm
CORRECT.
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on November 01, 2021, 01:50:32 am
Thanks for the explanation  I take it the coach will not roll at all throughout the winter. Wheels are chocked and the pad is very very level
Title: Re: Air brakes at 0 lbs in storage
Post by: wolfe10 on November 01, 2021, 08:22:39 am
Thanks for the explanation  I take it the coach will not roll at all throughout the winter. Wheels are chocked and the pad is very very level

No worries.  As already posted, the parking/emergency brake is RELEASED by air pressure.  No air pressure=  no move.
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on November 01, 2021, 08:31:48 am
Perfect!  Again,thanks!
Title: Re: Air brakes at 0 lbs in storage
Post by: Pierce & Gaylie Stewart on November 01, 2021, 12:01:36 pm
You could put blocks in place so the air bags don't compress flat. The bag failures are usually where the bags fold at the bottom. The rubber cracks and leaks right there.

With extended storage, some owners will put short blocks under the front and back, ground to suspension, just enough to take a few thousand pounds off the tires. Most tire manufactures recommend at least the max placarded pressures and even elevate pressures above that when in storage. Check with manufacturer.

Pierce
Title: Re: Air brakes at 0 lbs in storage
Post by: Jerry Whiteaker on November 01, 2021, 12:15:45 pm
Thanks for asking the question.  Probably some other folks on the forum that may need to know more about the air brake system. This link contains some good information. MotorCoach Brake Systems and Saftey Technology (https://wiki.foreforums.com/lib/exe/fetch.php?media=technical:transmission:brake_safety_systems_02-14_508cln.pdf)
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on November 02, 2021, 12:51:41 am
Pierce
I do have 10 inch safety stands (8) in place for that exact purpose. After I raised the coach with the engine on I just installed stands, dumped air and turned everything off  including the salesman. I am plugged into 15 amp so my inverter is keeping the house batteries charged and have a separate charger for my start bank. Going to have to get the air leaks checked out early spring to solve the 0 lbs pressure in the brakes though
Title: Re: Air brakes at 0 lbs in storage
Post by: Big Al on November 02, 2021, 09:02:40 am
Pierce
I do have 10 inch safety stands (8) in place for that exact purpose. After I raised the coach with the engine on I just installed stands, dumped air and turned everything off  including the salesman. I am plugged into 15 amp so my inverter is keeping the house batteries charged and have a separate charger for my start bank. Going to have to get the air leaks checked out early spring to solve the 0 lbs pressure in the brakes though

You might or might not have a issue. How long does it take for your brake tank go to 0 lbs?
Over a period of time mine will eventually go to 0 lbs. Air leak on your park brake side is not as
serious as a air leak on your brake side.
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on November 02, 2021, 09:49:11 am
Big al
Both of my front and rear service brake tanks leak down to 0 in about a week. As was stated I should be ok for the winter because the e brakes lock and will release when I fire up the coach. On the spring and bring the air pressure up above 60psi
Ps.  Going to have someone investigate and repair in the spring
Title: Re: Air brakes at 0 lbs in storage
Post by: Pierce & Gaylie Stewart on November 02, 2021, 10:11:46 am
I think down to zero in a week is going to be hard to beat. (sorry for the rhyme) That's as good as I've ever seen on ours.

Pierce
Title: Re: Air brakes at 0 lbs in storage
Post by: craneman on November 02, 2021, 10:15:23 am
Big al
Both of my front and rear service brake tanks leak down to 0 in about a week. As was stated I should be ok for the winter because the e brakes lock and will release when I fire up the coach. On the spring and bring the air pressure up above 60psi
Ps.  Going to have someone investigate and repair in the spring

Protection valves in the spring would be the first thing to replace.
Title: Re: Air brakes at 0 lbs in storage
Post by: Chuck & Jeannie on November 02, 2021, 11:03:16 am
Protection valves in the spring would be the first thing to replace.
Agree...they are one of the most important safety components in the air system.  Plus, replacing the protection valves first can help in chasing air leaks!

Once you know the protection valves are working properly, IF the coach owner has the opportunity to watch the gradual decline in pressure on the dash gauges (like visiting the coach every day to check the gauges), then they can gain a valuable clue to the location of the major system leaks.  Two possible scenarios:

1.  Starting at normal max system pressure, the dash gauges show a continuous decline, with roughly the same psi loss each day until the gauges get to 60 psi (or thereabouts), and then the gauges stop falling.  They should hold at around 60 psi for several days before they start to fall again, at a much slower rate.  In this case, the major air leaks are somewhere downstream of the protection valves.

2.  Starting at normal max system pressure, the dash gauges show a continuous decline, with roughly the same psi loss each day until the gauges hit zero.  In this case, the major air leaks are somewhere upstream of the protection valves.  A study of the air system schematic may help with the search.  Look for any device that is fed directly from the brake tanks (IE upstream of the protection valves).  Also, in this scenario, it is very important to verify that the inlet check valves on the brake tanks are working correctly.  If the inlet check valves leak, then pressure in the brake tanks can flow "backwards" to the wet tank.  Then, if the inlet check valves on the wet tank fail, the pressure from the brake tanks could continue to escape all the way back to the air dryer, and the D2 governor.

Anyway, my point is that the protection valves, when working properly, divide the air system into roughly two "halves".  Knowing which half of the system is leaking can help narrow down the search for leaks.

If you wish to test the inlet check valves on the brake tanks, try the procedure below:

1.  Run engine until air compressor cut-out pressure is achieved.  Shut off engine.  The entire air system is now at the same pressure.

2.  Check (record) the reading on both dash air pressure gauges (or both needles, if single dash gauge).

3.  Open the water drain valve on the WET tank (see air system schematic), and allow pressure to bleed off to zero.
    3a.  What came out of drain valve?  Dry air is good.  Water, or oily grey "mud", or dry white powder is not so good.  Time to service dryer.

4.  Check (record) the reading on both dash air pressure gauges (needles).

5.  If both dash gauges read the same pressure in step #2 and step #4, then the inlet check valves on the respective tanks are good.
    Clarification: With "good" inlet check valves, the "front" and "rear" air tanks should not lose pressure when you drain the wet tank.

6.  If either, or both, of the dash gauges lost pressure between step #2 and step #4, the inlet check valve on the respective tank is bad, and should be rebuilt or replaced.

Title: Re: Air brakes at 0 lbs in storage
Post by: wayne m on November 02, 2021, 11:22:19 am
dicksop
truck driving schools offer air brake courses. in b.c they are
mandatory for driving a vehicle with air brakes. they are
not expensive, usually five weeknights for a couple of hours.
the course won't eliminate all the mysteries of the foretravel
air system, but will certainly give you a clear understanding
of your air brakes.
Title: Re: Air brakes at 0 lbs in storage
Post by: John Haygarth on November 02, 2021, 11:57:52 am
Airbrake course and driver licence endorsement is needed in all of Canada if you are to drive a vehicle over 26,001 gvwr. It is commonly called a Z endorsement but in BC it shows as a class 15. You may never get stopped to check but if you have an accident and police look at your licence and do not see it you insurance could be void.
JohnH
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on November 02, 2021, 01:55:23 pm
The air brakes course is called a Q rating in Alberta. I took the course last year
Peter
Title: Re: Air brakes at 0 lbs in storage
Post by: TGordon on November 02, 2021, 07:15:12 pm
How do the Canadian air brake rules affect US coach drivers in Canada?
Title: Re: Air brakes at 0 lbs in storage
Post by: oldguy on November 02, 2021, 07:56:57 pm
Whatever the regs in your State is allowed in other States and Providences.
Title: Re: Air brakes at 0 lbs in storage
Post by: TGordon on November 02, 2021, 11:18:32 pm
Whatever the regs in your State is allowed in other States and Providences.
Thank You
Title: Re: Air brakes at 0 lbs in storage
Post by: tmehrkam on November 06, 2021, 09:41:17 am
All air brakes leak down. In the US it is no problem. They are allowed to leak down in less than a hour and still be ok.

Parking brakes do not need air to hold. Always chock the wheels when parked. Parking brakes might not hold on steep grades.
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on August 21, 2022, 01:05:44 am
I am visiting this topic of air brake and emergency park brakes again
I am currently at a site backed in where my back of the coach is sorta level and the front of the coach and wheels are sloped down. When I auto leveled it leveled out with the rear is the coach resting on the wheels and the front of the coach air bags raised to the max. Four red lights hitch many it is level. It never indicated excessive slope.  I have chocks  on each wheel ( heavy rubber). Now I am asking if  my air brake (pulled out and activated of course) will hold the coach. ??  My air brakes will lower frozen 120/130 to just under 60 lbs in couple of days. Will they hold and will the spring brake come on to hold it as well. Do I have any worries...I would hate to wake up with the coach rolling right in to another coach...lol
X
Title: Re: Air brakes at 0 lbs in storage
Post by: Jan & Richard on August 21, 2022, 02:41:38 am
Peter,

My understanding is that when you pull the parking brake knob, the air pressure in the brake lines is immediately released and only the springs on the rear brake cans are applying the braking power.  It does not matter at that point whether the air pressure gauges go down even to zero.  It is the parking brake springs that are holding the coach. 

Richard

Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on August 21, 2022, 03:46:13 am
Thanks for the reassurance. I hope the rear brake cans can hold the weight at a slight angle. At 32000 lbs it all makes me nervous...
Title: Re: Air brakes at 0 lbs in storage
Post by: Rudy on August 21, 2022, 07:33:25 am
Peter, block your wheels on the downhill side to be sure.
Title: Re: Air brakes at 0 lbs in storage
Post by: John44 on August 21, 2022, 07:50:15 am
Think I would find a level spot,make some wooden ramps for the front,the back very low and the front super hi is not the best circumstane.Anyone nearby with a front end loader,have leveled around our house with mine.
Title: Re: Air brakes at 0 lbs in storage
Post by: dsd on August 21, 2022, 09:32:15 am
Thanks for the reassurance. I hope the rear brake cans can hold the weight at a slight angle. At 32000 lbs it all makes me nervous...
So if you have concerns I would reccomend seeking a steeper slope and park there and set the parking brake (releasing air and setting spring brakes) could also park the opposite direction and check it also. You get 100% of your spring brake effectiveness the moment the air is released (parking brake set). Regardless of what your service brake pressure is at. Also understand that you only have spring brakes on your rear brake cans. By parking on the steeper slope with you in the drivers seat you can apply service brakes if it starts to creep. Can also put into drive then back to neutral to actually cause it to creep then see that it stops. Reverse can also be used to then back to neutral
Scott
Title: Re: Air brakes at 0 lbs in storage
Post by: John44 on August 21, 2022, 10:08:16 am
If he is somewhat level now with one end fully extended and one end depressed a steeper slope
Will make a not too good situation worse.Will not take much to get the windshield out of whack.
Title: Re: Air brakes at 0 lbs in storage
Post by: oldguy on August 21, 2022, 10:23:11 am
I have a sloping driveway near the street and in gear the the park brake won't hold and as soon
as I take it out of gear the park brake stops the coach. It never hurts to put the chocks behind the
wheels, you can never be to safe.
Title: Re: Air brakes at 0 lbs in storage
Post by: Elliott on August 21, 2022, 10:31:33 am
Two is one and one is none.
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on August 21, 2022, 10:38:59 am
Unfortunately I do not have the option of moving to another site. I have all 4 wheels chocked in front to prevent moving forward. I will post some pics in a bit. Another thing, would not the fact the rear tires of the coach are resting on the wheel wells help prevent it from moving?
Title: Re: Air brakes at 0 lbs in storage
Post by: NevadaBornRvR on August 21, 2022, 10:52:03 am
Next time you are at a light sitting and waiting... put the Parking brake on with it in drive... It should not move and when it doesnt ..walla you know its good when you leak down. ^.^d

With the motor pushing on the brake it will hold very well.. if now a little service might be warranted.
Title: Re: Air brakes at 0 lbs in storage
Post by: craneman on August 21, 2022, 11:02:07 am
Unfortunately I do not have the option of moving to another site. I have all 4 wheels chocked in front to prevent moving forward. I will post some pics in a bit. Another thing, would not the fact the rear tires of the coach are resting on the wheel wells help prevent it from moving?


You are safe at this point don't worry. I have parked on much steeper slopes and the brakes held fine.
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on August 21, 2022, 11:45:03 am
Maybe I am abit paranoid!
Title: Re: Air brakes at 0 lbs in storage
Post by: Jeff & Sandy on August 21, 2022, 12:05:33 pm
Looks fine/safe.
Title: Re: Air brakes at 0 lbs in storage
Post by: Pierce & Gaylie Stewart on August 21, 2022, 12:05:54 pm
In most jobs requiring driving a large vehicle, you would be disciplined if you don't chock the tires.

The engine has a lot to do with whether the parking brake will keep the vehicle stationary if in gear. I have to shift to neutral going down our driveway as the high torque at idle of the Detroit overpowers the service brakes when they are cold.

Drive 30 mph and apply the parking brake. This tells you how effective it is. Never trust it on any kind of incline. The parking brake is much less effective if the disks are cold.

Easy storage of the chocks is in the entry step on a GV. Lots of room to store two large rubber chocks with a rope between them. Good to put one chock in front of the wheel and one behind. Impossible to leave the chock behind that way.

Pierce
Title: Re: Air brakes at 0 lbs in storage
Post by: Joe Phebus on August 21, 2022, 12:59:25 pm
Thanks for the reassurance. I hope the rear brake cans can hold the weight at a slight angle. At 32000 lbs it all makes me nervous...

We always chock the wheels on both sides with a couple of these:  https://www.harborfreight.com/rubber-wheel-chock-with-eyebolt-69828.html

Cheap insurance and peace of mind.
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on August 21, 2022, 01:25:30 pm
Joe
Exactly the chocks I have. I have four, one on the downhill side of the each steer tires and one on the downhill side of the each outside drive tires. I also put two paving bricks in front of the inside drive tires
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on August 22, 2022, 01:52:17 am
So more questions and advice!
My HWH did it's thing and checked the system every  30 minutes or so. It would start dumping air and did this about 3 times in the last day. Then it dumped air and the compressor came on and ran about 10 minutes and shut off. Looking at the panel I discovered the air button and the excess slope buttons were on.  ( and no yellow lights) After reading my manual it stated that if I wanted to get into sleep mode I would have to shut it off and then back on, which I did.  The air light is now on and the excess slope light is off. Is my air system still checking the system?????  Or am I going to loose air (which my system does over time) until I am completely out of level?? ON THe SLOPE I DESCRIBED AT the BEGINNING OF THIS POST???  Too late at night to start the big engine and disturb my neighbours...
Advice would be great.....
Title: Re: Air brakes at 0 lbs in storage
Post by: Jeff & Sandy on August 22, 2022, 07:07:20 am
Do you have a residential fridge? If you do, I think you are overthinking this. I'd just shut the HWH off and not worry about it.
Title: Re: Air brakes at 0 lbs in storage
Post by: John S on August 22, 2022, 07:46:54 am
So more questions and advice!
My HWH did it's thing and checked the system every  30 minutes or so. It would start dumping air and did this about 3 times in the last day. Then it dumped air and the compressor came on and ran about 10 minutes and shut off. Looking at the panel I discovered the air button and the excess slope buttons were on.  ( and no yellow lights) After reading my manual it stated that if I wanted to get into sleep mode I would have to shut it off and then back on, which I did.  The air light is now on and the excess slope light is off. Is my air system still checking the system?????  Or am I going to loose air (which my system does over time) until I am completely out of level?? ON THe SLOPE I DESCRIBED AT the BEGINNING OF THIS POST???  Too late at night to start the big engine and disturb my neighbours...
Advice would be great.....
When mine did that I needed a new brain or silver box
Title: Re: Air brakes at 0 lbs in storage
Post by: Chuck & Jeannie on August 22, 2022, 09:08:13 am
1.  My HWH did it's thing and checked the system every  30 minutes or so.
2.  It would start dumping air and did this about 3 times in the last day.
3.  Then it dumped air and the compressor came on and ran about 10 minutes and shut off.
4.  Looking at the panel I discovered the air button and the excess slope buttons were on.
Advice would be great.
Here's my armchair analysis FWIW...

In Reply #22 you said you were able to achieve level in your steeply sloped parking spot (no yellow lights showing) with the rear end of the coach lowered all the way down, and the front raised to the max height.  Then after a couple days your auto level system went through the steps listed above.

The auto level program operates in two modes.  First, it tries to lower the high end (or side) to put out any yellow lights.  If that doesn't work, then it tries to raise the low end (or side) to put out the yellow lights.  It runs the HWH aux compressor to supply the pressure required to inflate the bags to raise the low end.

Your front air bags must be slowly losing air pressure, probably leaking back through the front 6-pack manifold valves.  This allows the front of your coach to slowly drop down from the fully extended position.

It sounds (to me) like your system operated normally until it reached the 3rd step listed above.  It must have woke up and saw a yellow light at the front end (because it had started to drop).  It tried to release air from the rear bags to get back to level.  Perhaps this worked for a while, until the rear bags were totally empty.  At that point, it switched to trying to raise the front of the coach by running the aux compressor.  When this did not work, it gave up and turned on the excess slope light.  If the aux compressor cannot (for whatever reason) generate enough pressure to raise the front of the coach back up to max extension, then there is nothing more the system can do.  Turning it off and back on won't accomplish anything - it will simply repeat the same program steps and end up back where the excess slope light is on.

I think your aux air compressor is the problem.  Until it is restored to proper operation, the only simple way to get your coach back to level will be to start the engine, let system air pressure build back up, then level the coach manually and leave the auto level function turned off.  You may need to do this every few days at some regular interval as required.

Or, as a temporary solution, you could use your "safety stands" to hold the front suspension up in the fully extended position.  You DO have safety stands, right?

Title: Re: Air brakes at 0 lbs in storage
Post by: John44 on August 22, 2022, 09:18:14 am
Make some ramps out of 4 by material,compute how many inches you have to raise the front and
Make that your height..
Title: Re: Air brakes at 0 lbs in storage
Post by: nitehawk on August 22, 2022, 09:32:24 am
Here is how I determined how high my ramps had to be for my sloped driveway.
I hooked a string around the rear on the rear dual (on the ground) and pulled it tight up to the vertical midpoint of the front wheel, with a string level on the string. Raise or lower the string until the level bubble is centrally located.
The string height from the ground, when below the vertical line of the center of the front wheel, is the height you would need to get perfectly level with ramps.
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on August 22, 2022, 12:05:21 pm
I unfortunately do not have my many safety stands with me for this trip. (Dumb..) I was going to go out and buy two 2x10 or 2x12 boards and re Center the front tires on them...just enough height so the air bags would not max out for leveling
My mind is over thinking stuff but if I put 2 of these boards on top of each other,screwed together (double thickness) made one shorter than the other (sort of a ramp) would that do?  Or is one enough?  What about laying these in the angled driveway?  They will not slip right?  And can I just put the chick on the front of the board(not pavement) that I will make long enough to put the chock on?
Title: Re: Air brakes at 0 lbs in storage
Post by: John44 on August 22, 2022, 12:37:54 pm
Nitehawk said the same thing I said in above posts,we cannot tell you how much the slope is,YOU
Have to measure.Get a level that clips on a string.They do make treated 4x12 wood.Tie the string
At ground level at the back of the coach,run the string to the front and have someone hold it,put
The level on the string and move the string up and down until level,measure the gap from the front
String to the ground and build the ramps that hi.
Title: Re: Air brakes at 0 lbs in storage
Post by: nitehawk on August 22, 2022, 12:59:49 pm
Dave, my way I am using the tires for determining ramp height, altho both methods will work.
Title: Re: Air brakes at 0 lbs in storage
Post by: Pierce & Gaylie Stewart on August 22, 2022, 02:16:06 pm
Even better to check the slope is Johnson Level & Tool 750 Pitch & Slope Locator, Orange, 1 Level - Constructio... (https://www.amazon.com/Johnson-Level-Tool-Pitch-Locator/dp/B00002N7UH/ref=sxin_14_ac_d_rm?ac_md=3-3-c2xvcGUgbWV0ZXI%3D-ac_d_rm_rm_rm&content-id=amzn1.sym.568df61d-e115-4cb1-a96a-ba070b8f0935%3Aamzn1.sym.568df61d-e115-4cb1-a96a-ba070b8f0935&crid=2RYW48EZ0QTPD&cv_ct_cx=inclinometer&keywords=inclinometer&pd_rd_i=B00002N7UH&pd_rd_r=cf5a24c8-acf3-471d-a250-e7cfd8b97378&pd_rd_w=StqRD&pd_rd_wg=31iYs&pf_rd_p=568df61d-e115-4cb1-a96a-ba070b8f0935&pf_rd_r=3Z3S27WH0JFV3D0HM0NY&psc=1&qid=1661191838&sprefix=inclinometer%2Caps%2C254&sr=1-4-7d9bfb42-6e38-4445-b604-42cab39e191b)

The best are the free apps for iOS or Droids: 11 Best Inclinometer Apps for Android & iOS | Free apps for Android and iOS (https://freeappsforme.com/inclinometer-apps/)

Pierce
Title: Re: Air brakes at 0 lbs in storage
Post by: tmehrkam on October 02, 2022, 06:22:54 pm
I carry four wheel chocks and if I am not on level ground I chock the wheels just to be sure.

Does not hurt.

In Texas the law says you have to have chocks on board. I purchased mine at northern tools.  They are common and not hard to find. Amazon even has them.  I paid about $9 each.

Title: Re: Air brakes at 0 lbs in storage
Post by: Dakota Slim on October 02, 2022, 09:35:52 pm
Do you have an absorption refrigerator?
Title: Re: Air brakes at 0 lbs in storage
Post by: Peter on October 03, 2022, 06:38:25 pm
Yes I do. I check it often to make sure things are normal, not over heating and that there is no "yellow" oozing etc
I plan to change things out next year to a Samsung rf18 residential