Bad booster??
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Joined: Nov 2004
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From: Turlock CA
Bad booster??
Ok so my son and I performed a disc brake upgrade on his 67 f100. We gathered a brake booster and proportional valve from a 77 and the spindle and brake assembly from a 74. I have done the same conversion on my 65 with no problem.
When we hook his booster up to the manifold vacuum the pedal stays down after being pushed and brakes stay locked. If you lift on the pedal they release. We disconnect the vacuum and the brakes work but you have to press hard that is to be expected but they release when you let up.
Brake booster or what??
Help please.
When we hook his booster up to the manifold vacuum the pedal stays down after being pushed and brakes stay locked. If you lift on the pedal they release. We disconnect the vacuum and the brakes work but you have to press hard that is to be expected but they release when you let up.
Brake booster or what??
Help please.
Hotshot
Joined: Oct 2002
Posts: 18,488
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From: The Big, Oregon
Sounds like it. A vacuum brake booster normally has vacuum on both sides. As you press the pedal, it vents vacuum on the firewall side, increasing your force. When you release the pedal, it closes the vent valve and allows vacuum back into the firewall side of the chamber. If this does not happen, then the brake pedal stays down with whatever force the booster was adding.
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Posting Guru
Joined: Nov 2004
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From: Turlock CA
Thanks.
Sounds like it. A vacuum brake booster normally has vacuum on both sides. As you press the pedal, it vents vacuum on the firewall side, increasing your force. When you release the pedal, it closes the vent valve and allows vacuum back into the firewall side of the chamber. If this does not happen, then the brake pedal stays down with whatever force the booster was adding.
Hotshot
Joined: Oct 2002
Posts: 18,488
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From: The Big, Oregon
Disks are better than drums in enough ways that having to add boost doesn't matter:
More fade resistance
more even application (less pulling)
Brakes recover from being wet sooner
Less weight
Overall disks are better, but without boost they can be a bit harder to apply.
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I guess I could have clarified. It's actually my truck that was having the issues, and my drums were in horrible shape before the swap. Major leaking, and it took at least one pump just to pressurize the system before I could get pressure to the drums.
I was just saying that having the discs on their with the bad booster was a hell of a lot better than the ****ty leaking drums I had before
But all in all, there is an insane difference between discs with and without the booster! And I would not recommend disks without the booster unless your drums are completely shot and you have the disc brake parts ready to go.
I was just saying that having the discs on their with the bad booster was a hell of a lot better than the ****ty leaking drums I had before
But all in all, there is an insane difference between discs with and without the booster! And I would not recommend disks without the booster unless your drums are completely shot and you have the disc brake parts ready to go.
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