OT: Towing a bin lorry

They just connect it to the compressor of the tow truck with a long hose.

Towing backwards is the best way to tow them, as the gearboxes can be damaged due to lack of lubrication if the engine is not running and the alternative to lifting the rear wheels off the ground is removing the half-shafts or prop-shaft, which is far more work ... especially at the side of the road.

Scott pretended :

They lock the steering wheel and plug a hose from the tow vehicle into the air line of the towed vehicle, so brakes operate from the tug.

Thanks both. Mystery solved.

Is that standard with vehicles that use airbrakes: that they have a port through which a towing vehicle can operate the brakes on the towed vehicle? Is there a way of balancing the braking force between the towing and towed vehicle, to prevent the wheels on the towed vehicle locking up?

I've always wondered with air brakes: how responsive are they - can you apply / release / re-apply / re-release as quickly as with hydraulic brakes, and do you get the fine control of the exact amount of braking force that you want? Does a vehicle with air brakes have to be driven differently to one with hydraulic brakes, or would you still brake progressively: gentle at high speed, gradually increasing as the speed drops, then reduce the braking a bit as the vehicle is about to stop?

It happens that NY formulated :

That I don't know, but they are equipped with ABS.

Having driven with air brakes, they work just like hydraulic, just as responsive but lighter to use. Even easier, is the handbrake, which is just a small lever to operate. Safer, as in any leak and the brakes come on - hence the skid marks you sometimes see on the road.

I don?t think they operate the towed vehicles brakes, they just hold them off. Could be wrong though?

Tim

That's always been my assumption. While (in theory) they could reduce the air pressure fed to the towed vehicle when they are braking, that's not necessarily a recipe for stability!

Tim+ submitted this idea :

Common sense suggests you would have to be wrong. Imagine a towed vehicle of up to 40 tons, being towed with no brakes at all. Legally, only a very light weight trailer can be towed with no brakes at all. Towing a broken down vehicle is even riskier, more risk of becoming detached, imagine the mess if a 40 ton vehicle broke loose, with no brakes.

If it broke lose, the air hose would get detached and the brakes would come on automatically.

On the truck recovery programmes that I have seen on TV, they only seem to connect a single airline, to release the brakes and no additional ones to operate them.

In some cases, where they have been unable to find the connection point for the line, they have gone under the wagon and manually wound each brake off (there is a hex-head screw on each brake for that).

no.

no

Yes

Air brakes are used for one reason only. If you lose the air, the brakes come on. Hard.

There is I believe almost no pedal feedback. The pedal operates to let air pressure out.

It is a totally different way of using brakes.

It's a good while since I was allowed to move an HGV (& that not in a public place) but FTAOD you don't have to press *harder* to get more braking but you do have to press the pedal down *further*. It's not, as I've known some people think, a binary on/off system.

And AIUI another reason for using air brakes is that they cope better with small leaks. The compressor may keep on running but the braking performance doesn't drop off like it would in a hydraulic system.

I've never had to move an HGV, but there are occasions where I need to start them, you can be damned sure I have my foot jammed very hard on the brake pedal while turning the key ... just in case.

On Mon, 28 Mar 2022 12:20:06 +0100, Robin snipped-for-privacy@outlook.com wrote: [snip]

It is one of my ambitions to drive an HGV. I see there are various truck driving experiences. Would anyone recommend one in particular? I drove a Routemaster bus once.

I never fulfilled my childhood ambition to drive a Routemaster on the skid pan they used for training drivers.

and I see there is a firm advertising driving experiences with them. Is this where you drove one?

I recall a trip on a local service bus when it kept stopping sharply. As the journey went past the depot, it pulled in and we transferred to another vehicle. In this case the leak was obviously more than the compressor could cope with.

Chris

No, I drove mine at Chiswick. It was round the perimeter track not on the skidpan. I did go on the skid bus though.

I've only driven a 7.5 tonner, but after the first couple of presses, I found the air-brakes not too dissimilar to a car that I had to think about it much, other than a slight feeling of a lag.