I removed the proportional valve on the front circuit but as I installed 4-piston calipers at the rear I have an adjustable pressure limiter on the rear circuit.
I received the pressure gauges and took a few quick measurements:
- engine stopped, therefore without brake booster, pressing with all my strength on the pedal there is around 700 PSI on the front brakes.
- engine at idle, pedal feel is the same and there is.........700 PSI
- immediately after giving the accelerator, the pedal sinks further and there is about 1100/PSI
- at the rear, pressure limiter set to the maximum, there is 700 PSI with the engine stopped, 700 PSI with the engine at idle and.....700PSI after an accelerator stroke while there is 1100 PSI at the front .
Conclusions:
- the brake booster works but not at idle, the vacuum is insufficient.
- the pressure limiter seems to work but I still need to check that the pressure decreases when I adjust it
I therefore think that adding an electric vacuum pump is the solution, especially since it is easy to find cheap, second-hand Volvo diesel pumps here in Europe. For this I have questions:
- I suppose it does not work continuously, it is controlled by a pressure switch?
- is this pressure switch incorporated into the pump or is it installed separately?
Thank you for your answers.