Carryfast:
Juddian:
on the Volvos you had the extra aitr operated switch you could pull out labelled Broms Brake, which once pressurised stayed out, this applied the trailer brakes, and wouldn’t release till you pushed it manually back in again.
That was an eye opening moment for me, for some reason since we’d lost the blue auxilliary brake line (operated by the secondary or dead man’s brake) i’d assumed the park brake on two line systems applied all, wrong.
Broms is Swedish for …brake.Can’t remember in the case of F10/FL10 but on the Scania 112 and 93 can only remember it being usable when moving and couldn’t be locked in the on position for when stationary only the park brake valve as usual ?.
Park brake is here at 6.27 and trailer brake valve is 6.41 as shown it’s spring loaded and can’t be locked in the on position and 6.45 is the hand ‘throttle’ control.Strange how I can remember the apparently rare Scania 10 speed splitter type box ordered by Ryder and the other controls of the 112 like it was yesterday.
youtube.com/watch?v=AU4Vd7T9BBA
I guess not enough space to label it correctly trailer brake in English let alone Swedish.
The blue secondary brake line’s valve actuation had long been fitted into the foot brake valve on all recent trucks when I started.The old hand operated secondary valve had long gone.
I guess the detachable gooseneck front end loading or removable rear axle loader types might have been a sort of solution to weight transfer or any movement caused by loading a semi trailer with ramps and across its rear overhang/beavertail on its wheels.It’s easy to see how a unit only being braked could cause disaster in that case.Surely using wheel chocks on the trailer wheels should be a routine precaution ?.
Scanias (i think right up to the 113, might have been 112 the trailer brake was meant to be used by the drive as such, it was operated by a large lever similarly to how a dead man on UK built wagons was, the difference being the Scania trailer brake only applied the trailer brakes, a typical UK dead man applied the trailer brakes and the tractor steer axle at the same time but not the tractor drive axle, meant to help a driver overcome a jack nife if normal footbraking had caused one to start and the drive had caught it in time, or if a jack knife was likely…for new drivers a jack knife is usually when the tractor drive axle locks up prematurely and the trailer pushes the the tractor around…remember no such thing as anti lock systems on typical lorries in those days, many didn’t even have load sensing with proportional braking so lock ups were frequent when empty or lightly loaded.
My first artic didn’t have a normal as we know it park brake at all, on old Fodens it comprised (similar in operation to series Land Rovers) of a manually operated brake drum and shoes fitted to the back of the diff, applied and the vehicle would rock back and forth till it settled just like an old Land Rover, so not something you’d use as a secondary brake, even if it was effective enough being an open diff one wheel could lock up leading to ain immediate jack knife spin out.
You could use the dead mans handle (secondary brake lever which utilised the blue air line) which was a lever about 8" long pivoting on the lump of cast iron just under the huge (no power) steering wheel, this cast lump was amusingly referred to as the dashboard, this you could vary the pressure applied to tractor front and trailer axles simultaneouly, you could also use it to subsidise the park brake when loading or similar and in normal driving you’d use it for hill starts etc (not a hope in hell the manual drum park brake holding the vehicle on a decent hill), but no spring brakes in those days so when the vehicle lost air pressure the brakes operated by air would release, so for safety’s sake you’d apply the dead man and leave it pressurised then nip out and ratchet the cable trailer park brake up…assuming it wasn’t seized snapped or wound over its spool in a bloody great messy tangle when you came to use it.
There, the good old days of braking.
Volvos Broms brake was a pull out switch on the dash, it wasn’t meant to be used as secondary or alternative brake nor really to be used when driving because when you pulled the button it took several seconds to pressurise the trailer brakes, when pressure achieved the switch would stay out till you physically pushed it back in, it would be a brave soul who tried to use it as Scania drivers could as an auxilliary braking control because release like pressurising up wasn’t instant or variable, so was only meant in my opinion to apply the trailer brakes when required by the driver in such circs as the possible situation in the OP picture, ie loading or parked up on an incline.
Can’t remember what brakes were applied if you used the normal secondary brake on older european wagons, i’m talking about applying the park brake steadily before you flipped over the indent when standard park brake.
Most Brit wagons of the time that had air operated park brakes but no dead man or secondary brake lever, the secondary brake could with varying pressure be applied using the initial travel of the park brake, this is of course still the case mostly with manual air park brakes, some of the old brakes the park brake operated in a small h pattern, the secondary brake operation was the upright of the h, pull the lever straight back, to apply the parking brake you pulled it back then moved the lever over into the n section where it would stay, these brakes were often situated to the right of the driver’s seat (late Fodens) and you didn’t need to look when operating because they was often a loud rush of air with different sounds accompanying each operation.
you have a good point here 
