Alert !!!!/ Toad Air Brake Tn rally

[Ray Davis]

Sounds like a really important thing to remember when having these installed, i.e. run it through a full range of motion by letting all air out, and pumping up again?

[lloyd&pamela]

I had one installed. They sent me replacement LED's since ours did not work when we left the RV park.

As a newbie I do not understand everything that Bruce described. What should I do and look for? Thanks.

[Jon Wehrenberg]

Lloyd,

The system should not use air except when applying the service brakes if I understood the explaination.

What Bruce is saying I think is that when his coach was sitting low it sheared off a fitting on the device that separates the toad air system from the coach air system.

What I do not understand is why Bruce heard air at times other than when he was applying brakes.

For your peace of mind you should do a pre trip inspection to verify everything is OK. After you hook up the Jeep, with the system completely aired up shut off the engine. Release the parking brake. The brakes should release, there should be a slight drop in the air pressure and then it should stop. The air pressure should hold where it is and there should be no sound of escaping air.

Then apply the service brakes and hold them. Again there will be a small drop in pressure as they are applied, but the drop should again stop almost immediately. Like before there should be no sound of air escaping. If you want to really be sure have Pam walk around the outside while you are doing this to listen carefully for the sound of air escaping. If she hears any you have a problem.

What Bruce said about not being able to raise the coach would strongly suggest the component in question was attached to the aux air circuit. Bruce, we need a more detailed description because the only air escaping should occur when the service brakes are applied.

[lloyd&pamela]

Thanks Jon. We are her in Gatlinburg until Sunday AM. We will check them first thing in the morning. Thank you,
Lloyd

[Jim Skiff]

I have contacted Peter at SMI Brake and expressed my concerns.
He has been given codes and will be available to address member issues.

Jim

[Joe Cannarozzi]

"After you hook up the Jeep, with the system completely aired up shut off the engine. Release the parking brake. The brakes should release, there should be a slight drop in the air pressure and then it should stop. The air pressure should hold where it is and there should be no sound of escaping air.

Then apply the service brakes and hold them. Again there will be a small drop in pressure as they are applied, but the drop should again stop almost immediately. Like before there should be no sound of air escaping."

What Jon has described here is critical and is worth repeating even if only 1 more member soaks it in.

This is a standard pre-trip inspection that should happen EVERY time you head out. It only takes 2 minutes. This is also the way we isolate a problem and helps pinpoint what.

Adding to this would be to air up and shut the bus off before you release the brakes, if there is a evident air leak at this point it would/could probably be in a suspension component. An air bag or a line to them or a ride height valve or norgren valve or possibly less common, a tank or tank fitting.

If all good, next, when the parking brake is released but before service brakes applied you shut the bus off and you encounter a leak that would be "emergency air" leaking, either a maxi chamber or an air line leading to them or possibly a valve.

If again all good then with the emergency brake off and the brake pedal applied and you shut the bus off and you hear a leak that would be "service air", possibly a brake diaphragm, (also incorporated into the maxi) or a line leading to that.

The maxi (brake chamber) has 2 air lines going to them. 1 is emergency air that airs up (by pushing the parking brake button) the side of the diaphragm opposite the large spring, just neutralizing (not overwhelming), the large parking brake spring thus releasing the parking brake.

For all you scuba divers think of it as when you release the parking brake your creating neutral buoyancy within the chamber by putting emergency air to the opposite side of the diaphram as the spring.

The other air line is service air and it is introduced (by stepping on the brake pedal) to the side of the diaphragm WITH the spring and that service air combined with the force of that spring DOES OVERWHELM that emergency air on the other side of the diaphragm thus engaging the brakes and with as little as or as much air as is introduced depending on how hard you apply pressure on the brake pedal.

[phorner]

This is bad news, as I think that you have to assume that ALL installations performed at the rally were done in the same manner. What would be the rationale to doing it differently on individual busses?

It seems to me that everyone that had the Air Force One installed at the rally should have their installation inspected as soon as possible to determine what needs to be rectified.

[lloyd&pamela]

Bruce did you have the Aif Force One tank relocated at Prevost? What was your fix?

[lloyd&pamela]

We did the tests this morning that Jon and Joe mentioned and do not hear any air leaking.

I contacted Pete at SMI and we are going to have John Bleakely in Atlanta (one of there Tier 1 dealers) look at the bus while they are doing some other work next week.

I feel better now, but will feel even more secure after they lift it up and check underneath.

Thank you Bruce for the heads up and then you Jon and Joe for the trouble shooting. We now have a new addition to the checklist.