I have a small leak from the brake pressure switch which is off a T-coupling on the brake lines going from the ABS pump. Any suggestions on what may be the easiest way to change it? I assume the fluid would need to be drained and system re-flushed?
I've never changed one, but a few points: I would disconnect the battery, and then pump the brake pedal 10 or 20 times to try to drop the pressure in the system. Then put a towel over the switch and slowly unscrew the switch. Hopefully the towel will contain the spraying brake fluid.
No, as long as the power is off, pumping the pedal drains pressure from the accumulator. You can confirm this yourself. When the car has been sitting a while and you turn the key to accessory, you'll hear the brake pressure pump come on for awhile, then stop when full pressure is reached. Turn the key off for a bit, then turn back to accessory... All should be quiet. Now turn the key off, pump the pedal ten times, turn back to accessory, and because you've depressurized the system, the pump will fire up again. Pushing the pedal will increase pressure briefly in the brake lines, but the power for the power brakes comes from the accumulator, so every time you hit the brakes, you drain a little pressure.
Would it be easier to open a bleeder on one caliper and pump brakes with key on till reservoir drains then open it. There should not be much fluid there then?
yes, as long as it involves pressing the brake pedal. I'm not sure about all the hydraulic connections but I suspect that the pressure in the accumulator does not actually connect with the braking system unless the pedal is pushed. If you bled the reservoir just by using a suction device on a bleed nipple without ever pushing the brake pedal, I suspect the accumulator would still be pressurized.
