90 240 Bad Booster?

Whats a good way of diagnosing a bad booster on these cars?

I have already replaced the check valve. Master cylinder isn't leaking. As well as, the junction on the front driver frame rail was leaking and replaced a while back. You can hit the brakes sometime and have great pedal feel. But... most of the time you hit them and it will slowly go to the floor, eventually stopping the car.

Need some help! What should I look at next.

Test the master cylinder: it could be bad even if it isn't leaking fluid.

Apply pressure to the brake pedal until it comes to a stop and then hold the pedal there, sustaining the pressure. If moments after the brake pedal has come to its initial stop it begins to drop down again slowly, then the master cylinder is not functioning properly and will most likely need to be replaced.

You described the exact action that is occurring. I?ll get one here in near future and see if it fixes it! Thanks

Mr. V said:

Test the master cylinder: it could be bad even if it isn't leaking fluid.

Apply pressure to the brake pedal until it comes to a stop and then hold the pedal there, sustaining the pressure. If moments after the brake pedal has come to its initial stop it begins to drop down again slowly, then the master cylinder is not functioning properly and will most likely need to be replaced.

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