Triumph Repair: TR6 Brakes, fluid restriction, vacuum test

Question
I have a '76 TR6. The brake pedal has become very hard and stiff. The brakes will stop the car but not as they should. It feels like there is a restriction that is not allowing the brake fluid to flow. All fluid levels are as they should be and there are no leaks.
Before I start tearing things apart, do you have any suggestions.

Answer
Hi Eric,

It sounds like the brake booster has failed for some reason. First run a vacuum test on the booster itself to see that it holds a vacuum. If it does and you have vacuum supplied with the engine running then you need to remove the booster to rebuild the booster as it is not activating when you step on the brakes.

It is unlikely that there is a fluid restriction on a dual circuit system in the front and rear at the same time. It is more likely that the booster has failed for what ever reason.

Howard