Air Brakes

[antzy]

Not sure if this is the right place for this - admin please move etc). So I recently had starter motor problems on my ex army MB 609D. This has air brakes which meant that I couldn't move the thing - what I really wanted to do was jump start it - this would have saved me a lot of money.
Instead I got a recovery truck to pick me up - this had an on-board compressor hose which connected to the brake reservoir on my truck - hey presto mine charged up and I couold release the brakes.
It occurred to me that I could get a small(ish) electric compressor myslef in case of future emergency - at least enough to chrage up brakes and get moving...

Am I way off track/too dangerous etc here?

I see a lot of big expedition vechiles who must have a way of dealing with this in the middle of nowehere

TIA

 

[rossvtaylor]

Our Freightliner ambulance has a separate DC electric compressor, for use when the engine isn't running or for backup. Works great. Just has a check valve and is plumbed into the primary system.

 

[LocoCoyote]

The brake chambers should have caging bolts. They insert into the back of the chamber and pull the diaphragm back to unlock the brakes...

 

[RedF]

If this is anything like a hiway tractor, be careful caging brake pots, or using an air source to directly release the maxi brakes without the air system charged - it will leave you without any wheel brakes whatsoever.

You would be safest to air up the resivoir to release the maxi brakes, as you will still have service brakes until the resivoir is depleted - at which pint the maxi brakes typically apply automatically.

 

[antzy]

Thats great

Thanks, all i need to find now is the hose to connect - I reckon they will be universal. I now have a new starter motor but the expense (particularly roadside rescue) was ludicrous, I think a small compressor would be handy anyway.

 

[Bikersmurf]

The air lines use a standard fitting. you should be able to tie in to the tank. I'd be surprised if there wasn't a spare plug you could remove to the tank. As a percaution Id install a 1 way check valve.

 

[peneumbra]

CAUTION: Air Braking Systems can be very dangerous to untrained people due to the high pressures encountered.

Please at least TALK to an expert before loosening any fittings, etc on an air brake system.

 

[IdaSHO]

In addition to the issues already mentioned, air brakes also constantly fight moisture issues.

Moisture within the lines is always a problem.

I drove truck for more than a decade, and the amount of times I had to deal with frozen lines was absurd.

Even with the best air dryer, and antifreeze/oil within the lines, tank spitters, etc, freeze up is always a possibility in the winter.


I'm currently in the market for a HD/2-ton 4x4 of some sort, and with my experience with air brakes, for now I'm refusing to even look at rigs with air brakes.

 

[red EOD veteran]

Main thing with air brakes regarding water is to drain your tanks after every day of driving. Worked as a mobile mechanic on class 8 trucks and construction equipment and most people don't drain the tanks.

An easy way to supply air to your truck is to connect an airline to your emergency (red) glad hand and open the valve. You can also use this same hose as an air supply for tools. Or remove the air line coming from the air compressor and make a fitting that will thread into the hose there (usually a JIC 8/10/12 fitting). This is the better way to run the air supply because the air must go through the air dryer before reaching the tanks.

 

[IdaSHO]

Main thing with air brakes regarding water is to drain your tanks after every day of driving. Worked as a mobile mechanic on class 8 trucks and construction equipment and most people don't drain the tanks.

I've already mentioned tank spitters.

Tank spitters and/or manually draining never gets it all.

 

[cali9x]

Our Freightliner ambulance has a separate DC electric compressor