I asked that question of Master Power Brakes Salesman and got a non-answer. He skirted the issue. I asked because they state in their literature that if you use DOT 5, it will void their product warranty on the Power Brake Booster system that they sell.I invite everyones's comments    Dick Palmer

My 55 T-Bird restoration was completed in 1985 with new stainless system using DOT 5. Zero problems.

1955 312 T-Bird Warwick, NY

I asked that question of Master Power Brakes Salesman and got a non-answer. He skirted the issue. I asked because they state in their literature that if you use DOT 5, it will void their product warranty on the Power Brake Booster system that they sell

I failed to notice "system" on the first read. I thought that they were not warranting the booster only purchase/install on a DOT 5 system (but I now realize why they wouldn't warranty that scenario also).

The reason(s) for a major brake vendor such as MPB (and they are a class act IMO) limiting their component(s) warranty as to use of DOT 5 is explained in the terms aerobic and compressibility, along with water (vapor - humidity). DOT 3, 4 and 5.1 will absorb and carry the water whereas 5 won't.

One should also consider if a MC leaks fluid into the booster and is drawn into the engine.

If a DOT upgrade is not performed correctly and the system fails (or the system fails due to the fluid), the first thing that will happen is that the vendor will be blamed as to quality of components supplied. Makes perfect sense to me as law suits are very costly.

I just want all sides of the equation to be heard. If you have done the conversion and have had no problems, good. But maybe you also live in a low humidity area and/or have not maxed the brakes out.

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