Power Brake Booster
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Power Brake Booster
Have a 74 f100 with 360 auto. Power brakes and steering. All stock. Recently the truck doesn't seem to want to stop. No odd sounds from the brakes, but I have noticed a buzzing sound I thought was the power steering pump developing bad bearings. When I hit the brakes occasionally it seems I slow but if I apply more pressure it doesn't seem to slow faster. I bought the truck 3 years ago and the booster body was very rusty. I painted it to make it look better. What symptoms might I expect if it was beginning to leak? Thanks
Post Fiend
Joined: Dec 2006
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From: Lexington Mo
Have a 74 f100 with 360 auto. Power brakes and steering. All stock. Recently the truck doesn't seem to want to stop. No odd sounds from the brakes, but I have noticed a buzzing sound I thought was the power steering pump developing bad bearings. When I hit the brakes occasionally it seems I slow but if I apply more pressure it doesn't seem to slow faster. I bought the truck 3 years ago and the booster body was very rusty. I painted it to make it look better. What symptoms might I expect if it was beginning to leak? Thanks
When that booster for your power brakes fail, the brake pedal will be hard as a rock. Almost like you can't push it down, and brakes will be vary week.
If that's happening, check the vacuum line that is going to the booster and going to either the intake manifold, or to a spacer under the carb.
Another way to test the booster, is to pump the brake pedal with the engine OFF, several times. This will take the vacuum out of the booster.
Then take your foot off of the brake pedal, then push back down on the brake pedal, and start the engine with your foot still on the brake pedal.
If the brake pedal goes down, then your booster is most likely working. If it does not go down, you eith have a bad booster, or vacuum issue.
Unk Bob
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Thanks for leads. The buzzing sound I hear changes when I hit the brakes and the brake pedal is very hard about half way down. Vacuum lines goes to back of intake. Will check further with your leads. Thanks....
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By the looks of things the booster looks original. I will probably go ahead and replace the booster and master cylinder as well as the rubber brake hoses under the truck. 42 years is enough to expect. The truck came stock with disc brakes up front. Can anyone help me with the bleeding procedures? Other vehicles with drum brakes all around have a sequence to follow. Since these brakes are 2 different systems I understand each system bleeds independently.
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