Air Brakes - Principles of Operation

24 minutes of U Tube

Air Brakes - Principles of Operation

Clikn here will getcha there

Cya

[ch9787]

Hey Swish, go run thru that movie again and stop it at the 23:31 mark.

OK, it's yankee land and they don't like a stirring stick, so a slushy is fitted, so that means just two pedals on the floor, right. Now take note of this clown, who's meant to be hittin' the picks with his size 9, now if he did it this way for real, then 'the sarge' would be scraping up and identifying bits after the big bang.
Have a good look at the two pedals, air brake pedals just dont have any linkages fitted to the bottom of them, now do they, or am I just seeing things.

You would have thought that with making a safety type of movie, they would of at least got it right, now wouldn't you

regards greenie [smiley=vrolijk_1.gif]

GuddayM8

Well wot can eye say
tiz a 1967 movie with a truck of X amount of years old @ th@ time

the 1st KW to cum to Australia had the pedals hang n down from firewall n it had linkage to the stoppers valve



Eye Rest my caee U're Honor

LOL
Cya

[ch9787]

Greenie, after looking at that movie quite a few times, I can't really see your problem I'm afraid. :-[ :-[ :-[ I'm only a newcomer to the forum and a Kiwi at that so I don't like to argue too much with the experts, but I'm quite old and I have driven most makes of American trucks for a living.................

There will be 3 pedals there, as with most American trucks the accelerator and brake are on the right of the steering column and the clutch will be a huge great thing hanging from under the dash somewhere on the left of the steering column, you just can't see it in this movie. In this truck, as in many American trucks of the time, the foot brake is on the right and the accelerator is in the centre, I think BigCam will know all about this arrangement and it was very common in many makes of trucks, and older cars for that matter.

There has to be some way of connecting the pedal to the air valve and it was quite common for the air valve to be underneath the floor with a rod through the floor connecting it to the pedal.

Yep, some vehicles did have the accelerator in the middle, but that was in the 30's, not the 60's. The centre go pedal was very confusing and it went the way of the dinosaurs.

Go back and check that movie again, just before the size 9 is meant to hit the stop pedal, the commentator is showing how the air system works on that truck, compressor, then the tanks in the chassis, a shot of him hitting the wrong pedal, then the camera pans down to the underneath of the cab, with the detail of the stop pedal showing, which has the air leads coming out of it, and shock/horror

---

it IS the CLOSEST fitting to the steering column. Check again at the 23:30-35 mark and have a good look at the design of the pedals too, the closest one to the steering column looks identical to todays floor mounted stop pedal, big foot up top and all workings under the floor. Now the one he hits with his size nine, has the linkages fitted, as per lots of go pedals. Now if it was a middle go pedal, then the air brake fittings would be away from the steering column and you would see the linkages for the go pedal, not the air leads.

No clutch is shown, 'cause I'd say its fitted with a slushy, you know how awkward "grunts" are, fork holes in their cheeks and all that stuff, don't think their brain could handle a stick.

Now most trucks I've driven, that have had air brakes fitted and the 'go' pedal was either a cable, or direct linkages fitted under the 'go' pedal, or some form of linkage attached to the end of the 'go' pedal. I've yet to come across an air system with" linkages " under the air brake pedal, they normally have the big foot upstairs and the body with the workings, under the floor, just the same as what's shown in that movie. Or, as swishy said, the stoppers fitted up to the firewall, with the workings fitted directly to the back of the pedal at the fire wall. Some older vehicles I've driven had even been manufactured during the last war, all pedals were still in the same place as todays vehicles, yep, I'm about as old as you Vic.

So, you still want to say that truck had centre 'go' pedal fitted, or the idiot put his size 9 on the wrong pedal. :

I got some old reading glasses if you need them, I could post them over to you, freebies if you want.

regards greenie [smiley=vrolijk_1.gif]

I haven't checked out the movie yet, but Greenie is right. Us geriatric old farts, know damn well, that accelerator pedals mounted in the middle between the brake and clutch were gone by the mid 1930's.
I have a '32 Chev (unrestored) and it has that setup .. but restorers always convert them to the standard (reverse A-B-C) setup.
The centre-positioned accelerator is a PIA, a classic poor piece of designing .. and it was deemed unsafe by about 1935, thus resulting in the standard layout we all know.

Maybe VicHung has been reading this following book?? .. where the author is debating the advantages of placing the driver on the left or on the right? (and vehicles were still being produced in BOTH versions, for driving on the right hand side of the road!!) .. and whether handbrake and gear lever controls should be on the right or left of the steering column?? (1919, by the way) .. :

books.google.com/books?id=Hor32UipsUIC&p...v=onepage&q=&f=false

Sorry VicHung - but I just viewed the movie (which really threw me, because the blurb said 1994, but the movie looked more like Greenies and my era - then I found out at the end, it said "1967"!) .. and the grunt is stomping on the loud pedal, no shred of doubt about it.

The Vietnam-era rig has a standard Bendix-Westinghouse floor mount brake treadle, mounted alongside the steering column, as standard practice since Bendix-Westinghouse air brakes became de riguer in the 1930's ..
Bendix-Westinghouse was established in 1930, went world-wide in 1934, with licensing agreements in the U.K., France, Germany and Italy .. and heavy duty trucks started to be fitted with air brakes from just before WW2. In 1949, all heavy duty, trucks, buses, fire trucks and off-highway vehicles were fitted with air brakes as standard fitment ..

The right pedal is the Go pedal, a la everything built since circa 1935 .. the pedal next to the steering column is the air brake treadle .. the truck is a slushbox, because Grunts can't handle pedals and levers together in one dextrous movement .. and the movie makers obviously never picked up the glaring error .. probably because, not one of them had ever driven a truck ..

Hi Greenie and onetrack , Know bugger all but do know diamondTs of the 60s had the go pedal in the middle .Melon reo should been able to confirm that .ian.

Hi Greenie, well, that got things going, didn't it! I did as you suggested and brought my reading glasses home from work today (Work today, just as a matter of interest was a 900km drive in an American truck and will be the same again tomorrow).

However, now that I've seen the movie with my reading glasses on, I must agree with you that on the truck in the movie the brake pedal is to the left of the go pedal, so apologies. :-[ :-[ :-[

I cannot agree, however, with you guys who insist that the central accelerator was gone by the 30s. I'm a geriatric old fart too (70) but I do remember a few things. It may have been nearly gone, and may have been used by only a small minority of trucks, but gone it wasn't! You will have seen IanOz's post about Diamond T's and I drove a late 50's Federal (not sure of the exact year) with a central accelerator. A stupid idea, but they were still around.

Guys
tiz very informative
thru out the movie
U do see the colonel pont n @ stuff th@ shouldn't B there
jist after the gas n brake debarkle
he B on the driver side n point n @ the quik realease dump valve to front axle
as far az I dunno this valve should B in centre of vehicle with equal lengths of brake pipe btween the front boosters to the dump valve
th@ way they should release @ the same time

IfnUGetMyDrift

LOL
Cya

[ch9787]