Hydraulic System - Pressure Test Revised
90jaguar05TEVES BRAKE TEST SECTION: 70
No: 12
Model: ALL Date: JUNE, 1990
KEYPOINTS: POWER HYDRAULIC TEST KIT
When checking the operating pressures of the brake system using the Power Hydraulic Test Kit, refer to the following pressure information.
NOTE: This information supersedes the pressure information provided in both the XJ-S and XJ6 Service Manuals.
PRESSURE SWITCH (all pressures are quoted in bar):
WARNING SWITCHES:
NOTE: The following pressures are measured by reducing pressure from a fully charged system. To perform this, operate the brake pedal several times with the pump motor power supply disconnected.
NOTE: Only one set of pressures exist for the pre-1990 MY switch assembly; the low pressure warning (LPW) and ABS warning acting simultaneously. The slight delay of ABS warning behind the LPW is caused by the ABS electronic control unit (ECU).
Pressures not identified on the charts are for the warning lights to extinguish during system charge-up. These pressures should not be greater than their warning illumination pressure (shown on chart) plus 30 bar. For example, if W.S. 1 operates at 105 bar as pressure is reduced, the same switch may not operate until 135 bar is reached as the system charges up.
If any measured pressures are not consistent with the figures included in this bulletin, or if the warning sequence is incorrect, change the pressure switch assembly and return the faulty part to Jaguar Cars Inc., attention Product Investigation (include a Product Quality Report with the part).
A new accumulator has a gas charge of 84 bar, and must not fall below 30 bar. To check this, fully deplete boost pressure, switch ignition on, and record the pressure indicated on the gauge. If the pressure is below 30 bar, replace the accumulator.
NOTE: Maximum charge-up time of the system from a fully discharged system is 60 seconds. If this time is exceeded (even with the pressures complying to the figures previously given) the pump may be at fault.
Battery voltage should be between 10.0 and 14.5 V, measured with the pump running.