Driving her home on a long trip recently, red BRAKE light goes steady on, and the next time i hit the pedal it was way too firm and felt stuck at the top of its travel. I had to sort of stand on the brakes to get it to stop, but it stopped. Fluid looks good, pads have been recently serviced.

Brake booster failure?

Jess

 

Agreed as a best guess off the cuff.

Vac supply to the booster system has failed, next on the list.

The brake light is a new one, as when I had booster issues, not a total failure, no lights on at all, just a rock hard pedal, and like you needed 2 feet to stop, but I only got 1 foot, oops.

There is a one valve in that vac supply, and some models had a plastic valve, we did, and I substituted it for a Toyota valve (back in the 90's) which is a steel valve, and that solved odd booster issues 100%. Did all the Series cars, and the XJS's. The valve was sticking, preventing vac build up in the system.

 

89 Should be a Teves system, so either the pressure has leaked out of the accumulator ball (likely if original) and then the electric pressure pump has to work harder than intended. It could have failed leaving you with no power brakes.

If you just turn the ignition on, can you hear the pump start up? It should run for a bit and then the brake light should go out once you have built pressure.

 

OOPS, did not read which car.

 

To the surprise of no one, I got in the car yesterday, turned the key, heard the pump start up, and had full brakes.

I hate intermittent problems.

I took it down to our shop and showed them the system and what was going on so they'd be prepared, but there's nothing to do right now with the system running as intended. Thanks for the help, though, because it has narrowed down the parts we'll need to fix it should it ever fail permanently.

Just to clarify, though: This does not affect the actual braking of the car, just the assist, correct?

Jess