Most of those who know me understand I am not happy about removing the ABS or the load valve.
This just to make a few points and not about how someone messing with their brakes caused an accident and/or killed someone, that's up to them and their conscience.
Let's lay out a few scenarios, remember this is not a quick reaction to an up and coming situation where you brake hard and KNOW you are going to stop if you think and handle the situation quickly enough. Then there is the 'moment of inattention' kind of off emergency where either you or someone else was not paying attention and the true FACT that you are almost certainly going to have a crash, and I mean the FACT. That is your thinking time, the speed you are doing, the road surface and other factors means you are pretty much going to have a collision. Feel free to offer your comments, but don't bother with 'I am the best driver in the world and will never crash' or 'I always pay attention so will never be put in an emergency situation', if that's how you think then you should not even own a car let alone drive it and perhaps you should stop stop reading the following as well? Nor being a hard arse but I have been under a car for 50+ years and have heard and read so much absolute bo**ocks from putting on a pancake air filter on the carburetor because it makes the car faster......oh and it makes a great sound, the first reason is bull****, and the second is subjective, to my car goes faster as I use a laptop to tune my car whilst in the middle of a street race, or perhaps watching 'The Fast and the Furious' at the same time.
The following assumes your brakes/tyres are all good with tread/pressure and so forth, and the load valve has been adjusted with pressure gauges attached, I don't ever recall someone saying 'after doing my suspension lift I had the load valve adjusted with the correct equipment' or even after fitting a new load valve saying the same thing.
Scenario 1, You are driving you 80 with just a single passenger, you are driving on a dry surface with good traction and an emergency braking situation is called for, but I mean a REAL braking situation, you will NOT, evaluate the surface condition, you will NOT try to gauge your stopping distance, what you WILL do is slam on the brake pedal as hard as you can, it could be someone pulling out in front of you, a kiddy running out in the road or perhaps even a dog, the very fact that you suddenly see something that is pretty much unavoidable you will react by braking as hard as you can, again the suddenness of the situation you may not have a chance to steer away but this is also another normal reaction.
So what does your 80 do in reaction to your panic braking?
The front and rear brakes come on, both the front and rears make the attempt to lock and the ABS comes in to prevent this, the front brakes having the weight of the engine over them increases the traction and more stopping power pulling the front of the car down, hence front brakes are designed to take advantage of this by being larger in size. At the rear of the car two things will be happening with the brakes, the relative light weight of the rear of the car versus the front means the rear wheels will attempt to lock, to prevent this the ABS will be activated but in conjunction with the load valve. That is the ABS is fluctuating the brake pressure to the rear brakes, and the load valve will be reducing the pressure but only for the period of time until the vehicle comes to a stop, that is the vehicle has returned to it's pre accident level.
Scenario 2, So what happens if the road is wet/greasy or even icy? Everything is pretty much the same as scenario 1, same passenger, same weight and same emergency condition except, the load valve will NOT reduce the pressure to the same degree. The front traction being reduce by the poor surface means that the front does not dip and of course the rear does not lift so the load valve barely moves if at all so the reduction in pressure is not so pronounced as in scenario 1, you are pretty much relying on the ABS to stop the rear wheels locking.
Scenario 3, This time the the vehicle is fully loaded, passengers with luggage and so forth, so now what happens? Exactly the same as in scenario 1, and 2, this is why the ABS is so important, it's function is null but not like the ABS which responds to all conditions (which is more important), because as we know the load valve will vary the pressure to the rear brakes depending on load but is unable to do this on an icy road, as again there is very little movement of the valve due to lack of change in the vehicles attitude.
I would point out that no ABS on any vehicle on a loose surface will bring it to a stop quicker, a pair of locked wheels off road would see tyres dig into the loose surface, this builds up a 'wedge' of soil/gravel in front of the wheel helping to stop the vehicle.
I would say if the 80 brakes had a design issue it is the size of the brake disc/caliper combination which I would say this can lead to early overheating when off road in mountainous areas. This would be worse in an automatic due to the lack of engine braking of an automatic behind a petrol engine. add in the bigger wheel/tyre and suspension lift combination. This is not an issue of just driving around town keeping in mind the all up train weight of an 80 with a trailer is around 7 tons, so the brakes are adequate. I have yet to see someone off roading fully loaded and towing a 4 ton trailer, but assuming no trailer but full of camping gear etc, I know the fitting of the bigger wheels forces the driver to press the brake pedal harder for the same amount of retardation than when the smaller wheel/tyre combo was fitted, this creates more heat, and then the suspension lift without resetting the load valve (with gauges) moving the load valve into a position of less pressure to the rear wheels means the rear brakes are contributing less to the overall braking effort, this again forcing the driver to press even harder on the brake pedal to bring the vehicle to a stop adding even more heat to the front brakes, so this incidentally may explain why the wear rate of the 80 front brake pads is excessive due to the excessive work they have to do.
These are thoughts and opinions drawn from my own experiences with off road competitions (competitions in a Land Rover and never in an 80) my experiences off road in my fully loaded (3 tons) 80 and of course added to my aforementioned years as a mechanic and still running my own business (presently closed due to a long term health issue), if I was to ever make modifications to the braking system other than the dimpled (never fit cross drilled discs) and slotted brake discs I fitted all round to my own 80 a few years back, I would fit larger front brake discs/pads/calipers and a matching master cylinder, this along with a correctly set load valve then I think this would be a better option than removing the ABS and load valve, I see no benefits in doing this whatsoever, recounting what I have said, if you have poor brakes without bigger wheels/tyres or suspension lift then a fault exists.....period.
Regards
Dave
