Great thread! Thanks to all.
One question:
I could not bleed my driver's side rear globe because of rust. The 10 m wrench could not grip the bleeder so i just left it alone. All of the other globes/ accumulator were able to be bled fully.
How necessary is bleeding each globe if they are connected side to side? Wouldn't bleeding the pass rear clean out most of the lines that lead to the rear globes?
It is worth doing the 16-step test just to be sure that nothing strange is happening at each individual corner. It is also worth being confident that the Front and Rear Levelling Valves are operating properly – you can do the “Active Test” for this but good evidence also is that the vehicle ‘shuffles’ upwards normally, alternately at Front and Rear, when rising from “LO” to “N”. You can also use Techstream to watch the signals sent by the ECU to the levelling valve solenoids during the rise – watch ‘SLRL’ (for Solenoid Rear Levelling) and ‘SLFL’ (for Solenoid Front Levelling) on the Techstream read-out during the rise. This operation also can be heard/felt at the Control Valve Assembly. Checking that the Gate Valves actually are working correctly is more tricky because the ECU uses speed, steering and other inputs. Watching ‘SLRG’ and ‘SLFG’ on Techstream while someone else is driving and turning sharply at speed may give an indication.
Anyway, assume that all relevant valves are working correctly. If so, then the Gate Valves remain open when the vehicle is travelling in a straight line,
OR, when the vehicle is at rest. The hydraulic connections then are as shown below, except that when the "LO" or "HI" button is pressed on the console switch, the Levelling Valves open and the vehicle falls, or rises with pump operation, as required.
Ideally, the bleed is done at “LO” so that as much as possible of the old fluid in the ‘shock absorbers’ is returned to the AHC tank for removal. At “LO”, more weight is supported by the front torsion bars and rear springs (because of their greater deflection) and less weight is carried by the AHC system. If the ‘globes’ are in good condition (meaning that most of the nitrogen is still in place behind the diaphragm), then more fluid will be pushed by the nitrogen pressure behind the diaphragm out of the ‘globe’ and back to the AHC tank for removal. Fresh fluid is then added while vehicle is raised by AHC Pump, to refill the components. This is not a perfect process – which is why the process is repeated until clear new light red fluid can be bled from system.
If one ‘globe’ cannot be bled, then it is hard to be sure what fluid movement from it actually has taken place -- especially if the ‘globe’ is only in moderate to poor condition and the nitrogen pressure behind the diaphragm in the ‘globe’ is weak.
However, even with this limitation, possibly imperfect bleeding of the system is far, far better than not doing it all.
It does make sense to go through the usual AHC check-and-adjust sequence in the correct order:
- Check the static front ‘cross-levelling’ of the vehicle and adjust if necessary with Torsion Bars adjusters, and then,
- Check the operating front and rear hub-to-fender distances and adjust if necessary with Height Control Sensor adjusters, and then,
- Check the Front and Rear AHC neutral pressures and adjust at Front with Torsion Bar adjusters and deal with over-pressure at Rear with new springs or spacers, or at least recognise and make allowances for the situation, and then,
- Check overall condition of globes using difference in graduations observed at AHC Tank between “LO” and “HI” height settings (~14 = as new; ~7 = time to change ‘globes’). NOTE 1: If this check is done with AHC pressures too high because the AHC system is carrying excess share of vehicle weight, then the nitrogen pressure behind the ‘globe’ diaphragm will return less than expected AHC fluid to the tank and the observation will be erroneous. This test has to be done at correct AHC neutral pressures to be comparable with FSM specifications. NOTE 2: Low graduations in a correctly done test indicate that nitrogen pressures behind the diaphragms in the ‘globes’ are weak and unable to push the expected amount of fluid back to the tank. NOTE 3: This test does not identify any single faulty ‘globe’, only indicates overall deterioration, but the 16-step test may reveal differences between each corner of the vehicle.
AHC Circuit for Straight Line Driving or Vehicle at Rest:
Source:
https://lc100e.github.io/manual/
then follow the index tabs starting right at the top:
New Car Features > CHASSIS > Suspension > Active Height Control Suspension.