Aux brakes??

[MangoMike]

Ray,
Drain main tanks first to avoid surprises.

Mike

[jack14r]

Will there be any air pressure on brake system with emergency brakes on?

[Jon Wehrenberg]

Ray, If you connect to the braking system there is no pressure anywhere on the air supply to the brakes, service or emergency if the bus is parked with the emergency brake on, and no pressure on the brake pedal.

The only time there is pressure to the service brakes is when you are applying pressure to the foot pedal, and the only time there is pressure to the emergency brake system is when they are disengaged.

[jack14r]

Thanks Jon thats what I remembered from my CDL book,but Mangos comment confused me.

[Jon Wehrenberg]

Jack, we need to keep Mango on the straight and narrow. I'll bet he was thinking Ray needs to drain the tanks anyway and as long as he is under there he might as well do it then.

Ray: If you are going to hook up the air brakes for the car here is a picture of where I tapped in. Forgive the crude arrow. It points to the air line for the toad.

The picture is looking up from behind the tag axle, driver's side.

[Ray Davis]

Thanks for the picture Jon, that helps. Does this then go to a fitting on your rear bumper area that you then use quick disconnect fittings?

Is there any danger if this doesn't get "done" properly, that it will affect the braking system? Obviously, I'm not looking for trouble, but have never messed with air brakes in this fashion. I want to "do it right". Hopefully, I can locate a very competent installer? Would Prevost install the extra line to the bumper?

Ray

[hhoppe]

Ray: The air hookups are the easy part. The main adjustments is made during the M&G Air Cylinder installation between the power brake bellows and the master cylinder. There is a threaded rod adjustment critical to the system working properly. It can be adjusted to apply your toads brakes constantly, which is bad, and the other way too little and the brakes on your car will not have a high enough pedal to stop while driving. The screw adjustment is critical and must have loctite applied when it is set correcrtly. My best advice is to find a good tech. that has installed some before. You can do it by reading the instructions, but I will not tell you it's easy to do correctly the first time. M&G lists dealers in your area.

[Jon Wehrenberg]

Ray, yes that small plastic line is mounted next to my electric tow car plug and has a quick connect fitting on the end.

After installing it I checked it for leaks. I routed it away from any heat and sharp spots and tied it in place with nylon ties. Where I though it might chafe I insulated it with a plastic sleeve. I see no reason why it would be any more likely to leak than a conventional brake line.

If there is a leak it will be apparent if you do a pre-trip brake check per the commercial license procedures.

[Joe Cannarozzi]

I had posted a picture of these earlier but for those who did not catch it here it is again.

DSC00695.JPG
These old style compression fittings have been updated to quick fittings like below.

DSC00698.JPG
The first picture is a pipe thread to compression fitting.

Although I have a T fitting pictured they come in all sizes and configurations, including pipe thread to compression. They need to be used with plastic line and you simply push the line in and it's done.

To release there is a collar on the fitting that you press in and simultaneously pull on the line to remove it.

Do any of the folks with newer buses see these on them?

Every time you disassemble a air line with the old style you either have to cut off the end and shorten up the line, if it is long enough, or if not, replace the line with a new one of acceptable length.

With these quick fittings you can reuse the same line and retain its original length over and over and over.

They are fast, you never have to wonder about over or under tightening and don't need to do the double wrench routine in close quarters where it is a pain or to keep from twisting the line.

[MangoMike]

I stand corrected, and should have paid more attention when Jon had AirBoard 2.0 on display rather than throwing spitballs at Trukman.

I guess I was thinking about the air lines to the Norgren valves.

Mike