Mack Air Start - Question?

I have always wondered where a air start gets its air from. Is there some sort of tank??

Wow that question stoped you all!

Sorry ByF

me thort everybody took it az granted th@ there B a big air tank th@ is filled up by the engine mounted n driven compressor n wen all the brake n emergency brake tanks R full then it fills the air start tank last

cya

Yer I understand that bit. What happens when the truck sits, all the air leaks out. No starter?

That very seldom happens unless the truck has been sitting for a very long time. In the days when I used to drive R-models, we always carried an air hose long enough to reach from the air-start tank to another R-model's tank alongside in much the same way that you use jumper leads today for a flat battery. R-models and other trucks with air starts were very common then so there would usually be some one around to help. We also carried another hose which could connect the air start tank to the spare wheel; this supposedly would give enough air to start the truck although I never had to use it.

As I said at the beginning though it was not normally a problem. I drove R-models for 8 years and can only remember two occasions when I had to get air from another truck. You would normally get more problems with flat batteries in that time with electric starters.

...i'm not too sure if it's too commonly known, but the Kenny's with the Ingersoll Rand air start had a fail safe set-up whereby if the starter air tank was exhausted, the main (wet and dry) tanks had to be manually depleted to the point where the emergency air supply could kick in, which enabled air to be supplied to the starter.....via the under cab solenoid...and usually activated by a pen or pointy object in the central hole of that solenoid....

...i think the later Macks had the same set-up, but is still an interesting aside as not a lot of people really know about this quirky detail....cheers fellas

Only if you had flat battery no power on key start
No air no biro will start it...

g'day old dog ....it's to do with no start air at all...and no batteries...

...at least for the Kenworths, this mechanical fix still applies...mind that there wasn't a great heap of air in the emergency tank...

Tective M80

Kenworth elect/air relay = NO

Mack elect/air relay = YES

d Old Dog iz jist say n
ifn U got no air
U Got NO AIR
az in all tanks MT
Jist fill the air start tank
or release park n brakes wiff sum air n roll start
Not unusual for air start tanks to hold air fir a month or 3

Twaz easier to get air off sum one than to jump start an elecric beast

cya

I'll take your word for it