Thread: Help me choose a Rangie

I agree. It's the reason I bought JA613937.

Originally Posted by DieselLSE

>My only real issue with the 93 is the abs


The Hydroboost system looks a more appropriate replacement for earlier vacuum assisted Rangies. The LSE WABCO ABS with ETC is a far superior system with the electric pump pressurisng the system to 2700psi and the accumulator providing up to seven brake applications in the event of an engine failure at speed.

Hydroboost Back-Up all done with zero electronics.

Similar to the vacuum booster, the hydro-boost is equipped with a backup or reserve in case the source of pressurized fluid is lost. A failure in the power steering system, such as a broken hose, broken power steering pump drive belt, or failed pump, would result in a loss of pressure to both the hydro-boost and steering gear. The hydro-boost uses a high-pressure accumulator to store power steering fluid under pressure in the event of a failure. There are two types of accumulators used, some hydro-boost units use an external accumulator, while others incorporate the accumulator in the power piston. The accumulator could be either of the spring-loaded variety or nitrogen-gas type.

In the event of a loss of pressurized fluid, the accumulator will provide two to three power assisted stops. Upon the first application of the brakes after an engine stall or loss of power steering, you would find approximately 60 to 75% of the normal assist available. If you were to release and apply the brakes again, you would find approximately 30% to 40% assist, then again approximately 10% to 20%, until you have depleted all stored reserve assist. Once you have depleted all of the stored pressure, the brakes will no longer have power assist and will be manual in their operations.

During normal operation, the accumulator is charged by pump pressure though a check valve assembly. The check valve allows fluid into the accumulator, but prevents it from escaping. When the pressure in the power chamber is lost due to a failure, the input rod linkage will override the power piston linkage and cause the check valve to be opened. The open check valve will release the stored fluid in the accumulator into the power chamber which will provide the power assist.

Originally Posted by blackrangie

Hydroboost Back-Up all done with zero electronics.

Similar to the vacuum booster, the hydro-boost is equipped with a backup or reserve in case the source of pressurized fluid is lost. A failure in the power steering system, such as a broken hose, broken power steering pump drive belt, or failed pump, would result in a loss of pressure to both the hydro-boost and steering gear. The hydro-boost uses a high-pressure accumulator to store power steering fluid under pressure in the event of a failure. There are two types of accumulators used, some hydro-boost units use an external accumulator, while others incorporate the accumulator in the power piston. The accumulator could be either of the spring-loaded variety or nitrogen-gas type.

In the event of a loss of pressurized fluid, the accumulator will provide two to three power assisted stops. Upon the first application of the brakes after an engine stall or loss of power steering, you would find approximately 60 to 75% of the normal assist available. If you were to release and apply the brakes again, you would find approximately 30% to 40% assist, then again approximately 10% to 20%, until you have depleted all stored reserve assist. Once you have depleted all of the stored pressure, the brakes will no longer have power assist and will be manual in their operations.

During normal operation, the accumulator is charged by pump pressure though a check valve assembly. The check valve allows fluid into the accumulator, but prevents it from escaping. When the pressure in the power chamber is lost due to a failure, the input rod linkage will override the power piston linkage and cause the check valve to be opened. The open check valve will release the stored fluid in the accumulator into the power chamber which will provide the power assist.

It would need to be a MASSIVE accumulator. accumulators work for brakes, but aren't any good for steering (trust me I know this, I have owned and driven fully hydraulic cars since I was 16years old). They also need contant upkeep. I consider an old accumulator quite unsafe. You see if the start leaking with age they will slowly fill your brakes with air (nitrogen from the other side of the accumulator diaphragm). If they suddenly rupture (which can happen as when they get low on gas, the diaphragm can hit against the sharp edges on the back of the filler plug). If it ruptures it will instantly fill your braking system with massive amounts of nitrogen. Meaning you have no brakes.

Originally Posted by DoubleChevron

It would need to be a MASSIVE accumulator. accumulators work for brakes, but aren't any good for steering (trust me I know this, I have owned and driven fully hydraulic cars since I was 16years old). They also need contant upkeep. I consider an old accumulator quite unsafe. You see if the start leaking with age they will slowly fill your brakes with air (nitrogen from the other side of the accumulator diaphragm). If they suddenly rupture (which can happen as when they get low on gas, the diaphragm can hit against the sharp edges on the back of the filler plug). If it ruptures it will instantly fill your braking system with massive amounts of nitrogen. Meaning you have no brakes.

The accumulator is part of the hydroboost unit, its quite small and it is part of the brakes, the power steering system provides the pressure boost.

There are 3 different types of accumulators below, the silver one uses spring pressure not nitrogen.

So you have a backup using accumulator via spring activation, then when that is used you still have manual not assisted brakes, if that fails you have a 4 wheel handbrake

Originally Posted by blackrangie

The accumulator is part of the hydroboost unit, its quite small and it is part of the brakes, the power steering system provides the pressure boost.

There are 3 different types of accumulators below, the silver one uses spring pressure not nitrogen.

So you have a backup using accumulator via spring activation, then when that is used you still have manual not assisted brakes, if that fails you have a 4 wheel handbrake

even if the enigne dies, so long as it's in gear and turning, your pump should still work either way. The accumulator will work if a seperate sytem from the steering (steering will exhaust an accumulator in the blink of an eye as it's low pressure high flow, accumulators work well for high pressure low flow ... ie: brakes).

The hydraulic cars usually have a main system accumulator, a brake accumulator. However the rear suspension circuit is the supply for the rear brakes (if that makes sense, nothing in the boot, next to no rear suspenion pressure, so hardly any pressure for the rear brakes ... .no brake lockup. Throw a loaded car trailer on the back ... massive pressure in the suspension circuit to lift it upto height, so huge pressure to the rear brakes). This also gives you your final emergency brakes. If the pump fails, and the accumulators are exhausted..... if you still have rear suspension height, you will have rear only brakes until the back suspension sinks to it's bumpstops. If you continue driving at that point, your in for a world of hurt

In the range rover it really shouldn't matter, even if everything fails, you should still have full braking capacity, pedal pressure will just be very high!

seeya,
Shane L.

Originally Posted by DoubleChevron

even if the enigne dies, so long as it's in gear and turning, your pump should still work either way. The accumulator will work if a seperate sytem from the steering (steering will exhaust an accumulator in the blink of an eye as it's low pressure high flow, accumulators work well for high pressure low flow ... ie: brakes).

The hydraulic cars usually have a main system accumulator, a brake accumulator. However the rear suspension circuit is the supply for the rear brakes (if that makes sense, nothing in the boot, next to no rear suspenion pressure, so hardly any pressure for the rear brakes ... .no brake lockup. Throw a loaded car trailer on the back ... massive pressure in the suspension circuit to lift it upto height, so huge pressure to the rear brakes). This also gives you your final emergency brakes. If the pump fails, and the accumulators are exhausted..... if you still have rear suspension height, you will have rear only brakes until the back suspension sinks to it's bumpstops. If you continue driving at that point, your in for a world of hurt

In the range rover it really shouldn't matter, even if everything fails, you should still have full braking capacity, pedal pressure will just be very high!

seeya,
Shane L.

I quess your talking about trucks, im just talkin about gm hydroboost with willwood dual channel master cylinder, seperated res for front/rear circuits allowing front to still work if rear fails and visa vera..would be extremely unlikely to loose fluid to both circuits