!1.  Well known that costing down hill in neutral saves fuel.

2.  Not too many Thai drives can double de-clutch into  lower gear, so they do not try. 

14 minutes ago, Brick Top said:

Considering I had a fleet of of 5 lorries back in the UK and have had a HGV license since 1979 I  absolutely know what I am talking about.

It is yourself who has just shown your compleate ignorance of how air assisted brakes operate.

Have you ever even driven a heavy goods vehicle ? , I use to drive from Porstmouth in the UK across by ferry into Le Harve in France then through to Bordeaux , into Spain and was often away 3 weeks at time driving through continental Europe.

So I feel highly insulted by your comment.

If you had ever even driven even a small 7.5 ton lorry you would realise if that if you keep depressing the braks an alarm will sound warning you that your air is running low for the air assisted brakes.

There is also an air gauge showing your air pressure , if you keep continuing depressing the brakes while descending a hill the air pressure wont have enough time to repressurise by the compressor.

This is one of the first things we are taught when taking our 3 week HGV course .

If I were you I would delete your comment as your embarrassing yourself with your complete lack of knowledge either that or your one of these trolls who get off on trying to wind people up behind a keyboard.

Driving a vehicle obviously hasn't given you the knowledge of how air brakes work, you lose your air and the brakes will apply automatically, thus @Artisi is 100% correct.

From Wikipedia https://en.wikipedia.org/wiki/Air_brake_(road_vehicle)#

 

"Air brakes are typically used on heavy trucks and buses. Typical operating pressure is approximately 100–120 psi or 690–830 kPa or 6.9–8.3 bar. A compressed-air-brake system is divided into a supply system and a control system.

The supply system compresses, stores and supplies high-pressure air to the control system as well as to additional air operated auxiliary truck systems (gearbox shift control, clutch pedal air assistance servo, etc.). The air compressor draws filtered air from the atmosphere and compresses it, storing the compressed air in high-pressure reservoirs.^[4] Most heavy vehicles have a gauge within the driver's view, indicating the availability of air pressure for safe vehicle operation, often including warning tones or lights. A mechanical "wig wag" that automatically drops down into the driver's field of vision when the pressure drops below a certain point is also common.

The control system consists of service brakes, parking brakes, a control pedal, and an air storage tank. If the vehicle is towing a trailer, it often has a separate trailer-brake system that receives compressed air from the supply system.

The parking brakes use a disc or drum arrangement which is designed to be held in the 'applied' position by spring pressure. Air pressure must be produced to release these "spring brake" parking brakes. Setting the parking/emergency brake releases the pressurized air in the lines between the compressed air storage tank and the brakes, thus allowing the spring actuated parking brake to engage. A sudden loss of air pressure would result in full spring brake pressure immediately.

The service brakes are used while driving for slowing or stopping the vehicle. When the brake pedal is pushed to apply the service brakes, air is routed under pressure from a supply reservoir to the service brake chamber, causing the brake to be engaged. When the pedal is released, a return spring in the brake chamber disengages the brake, and the compressed air is exhausted to the atmosphere.^[4] Most types of truck air brakes are drum brakes, though there is an increasing trend towards the use of disc brakes."

46 minutes ago, Wobblybob said:

Driving a vehicle obviously hasn't given you the knowledge of how air brakes work, you lose your air and the brakes will apply automatically, thus @Artisi is 100% correct.

 

1 hour ago, Brick Top said:

Considering I had a fleet of of 5 lorries back in the UK and have had a HGV license since 1979 I  absolutely know what I am talking about.

It is yourself who has just shown your compleate ignorance of how air assisted brakes operate.

Have you ever even driven a heavy goods vehicle ? , I use to drive from Porstmouth in the UK across by ferry into Le Harve in France then through to Bordeaux , into Spain and was often away 3 weeks at time driving through continental Europe.

So I feel highly insulted by your comment.

If you had ever even driven even a small 7.5 ton lorry you would realise if that if you keep depressing the braks an alarm will sound warning you that your air is running low for the air assisted brakes.

There is also an air gauge showing your air pressure , if you keep continuing depressing the brakes while descending a hill the air pressure wont have enough time to repressurise by the compressor.

This is one of the first things we are taught when taking our 3 week HGV course .

If I were you I would delete your comment as your embarrassing yourself with your complete lack of knowledge either that or your one of these trolls who get off on trying to wind people up behind a keyboard.

Do you know the difference between air brakes and air over hydraulics, your original comment was air brakes NOT air over hydraulics - different system, different problems, different discussion. 

 

23 minutes ago, Brick Top said:

 

That's for air over hydraulic system, you need to differentiate  between air operated and air over, that should have been covered in your 3 week HGV course. 

34 minutes ago, Brick Top said:

 

Can I just say I have spent 25 years as a HGV mechanic, have City and Guilds and went on to own a fleet of trucks with my own operators licence and CPC. I have fit more brake chambers than I care to remember. 

Each wheel station has a brake chamber fitted and incorporated into the chamber is a massive spring that keeps the shoes pressing on the drum and only air can release the shoes. So should you lose air when travelling the brakes will engage the vehicle, but where the system fails to operate as it should is when the brakes are not adjusted when they should be ie, operator neglect. In normal conditions the cam that the shoes are located on has reached its very maximum and when using the vehicle on hills etc the brake drums expand through friction and the shoes will lose contact with the drum and cause the vehicle to run out of control. 

On 6/20/2023 at 4:23 PM, Brick Top said:

Why on earth are they allowed to drive these big lorries and busses without the simple knowledge of engine breaking. 

It's Thailand's answer to population control.

When u have people like my Thai  Mrs...   who kept of  falling off her Honda Wave  until i found out that  she, ( and many others) did'nt  realise that  these bikes have rear brakes,  she, / they thought that pedal  down  by your foot was a footrest !!, & by applying  the front brake only,  especailly in the rain will cause  the bike to lock up, and u to fall off ... But being Thai they already  knew that !!

On 6/19/2023 at 4:41 PM, stevenl said:

Unfortunately a regular occurrence there normally caused by overheating brakes due to poor brake usage 

Yeah. There could be almost nothing wrong with the truck if he was using just his brakes and no engine braking. 

On 6/20/2023 at 6:13 AM, ezzra said:

such accidents are happening due to poor regular maintenance of heavy vehicles, where many of those vehicles don't see preventative maintenance until the trucks brake down.

Where do you get that "information" from?   You make it up?

3 hours ago, Harsh Jones said:

Yeah. There could be almost nothing wrong with the truck if he was using just his brakes and no engine braking. 

Your post doesn't make sense.

5 hours ago, stevenl said:

Your post doesn't make sense.

With a big enough hill and a big enough load and an incompetent driver riding the brakes, the drums can expand to the point where the brakes fade into failure 

On 6/22/2023 at 2:23 PM, Robin said:

!1.  Well known that costing down hill in neutral saves fuel.

2.  Not too many Thai drives can double de-clutch into  lower gear, so they do not try. 

I think If the engine is revving too high you can't do that anyway once it's too late. I'd say almost all experienced truck drivers would know how to do that.

 

There should be a mandatory truck stop at the top of the hill to check brakes and signage requiring low gear with a huge fine.

6 hours ago, Harsh Jones said:

With a big enough hill and a big enough load and an incompetent driver riding the brakes, the drums can expand to the point where the brakes fade into failure 

Quoting me to repeat my point. Got it 

5 hours ago, ozimoron said:

I think If the engine is revving too high you can't do that anyway once it's too late. I'd say almost all experienced truck drivers would know how to do that.

 

There should be a mandatory truck stop at the top of the hill to check brakes and signage requiring low gear with a huge fine.

Mandatory truck stop, ha ha ha, you can't get then to stop for stop signs etc.... 

29 minutes ago, stevenl said:

Quoting me to repeat my point. Got it 

but you or someone said it was basically impossible unless something was wrong with the system. Or you questioned my claim that it could have happened with nothing wrong with the truck

2 hours ago, Harsh Jones said:

but you or someone said it was basically impossible unless something was wrong with the system. Or you questioned my claim that it could have happened with nothing wrong with the truck

I didn't say that.