Frame mounted vacuum booster question.

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Mar 13, 2020 | 12:14 PM

awhtx

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Tuned

Joined: Feb 2006

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From: Lampasas,TX

Frame mounted vacuum booster question.

Normally I wouldn't touch a GM product but a a friend of mine was given a '56 Shivverlay 4400 dump truck that wasn't running. I've got the 265 V8 running now but it has no brakes at all. It has a master cylinder connected to the brake pedal that activates a frame mounted Bendix combination vacuum booster/master cylinder. My '58 F600 has a very similar setup except it has a Midland booster/mc.
This dump truck will only be used on a ranch and will never see a public road. Can I bypass the Bendix booster/mc and go straight from the brake pedal master cylinder to the drum brakes? The bore of the brake pedal mc is 1-1/8" if that matters. I just need enough braking to prevent the truck from rolling away.
Thanks!

Mar 13, 2020 | 01:38 PM

85e150

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If you will never take it on the road, and your place is perfectly flat, and if you are all alone in that world when you drive, you'll be ok.

Otherwise, I would restore it to OEM spec.

Does it have a parking brake on the tail of the transmission with a lever in the cab? That's supposed to be the "roll away" protection.

Serving suggestion.

Mar 13, 2020 | 08:33 PM

awhtx

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Tuned

Joined: Feb 2006

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From: Lampasas,TX

Yep, it has that parking brake.

It will only cost me a short piece of 1/4" brake line to connect it directly to the distribution block so I'll give it a try and see what happens.

Mar 13, 2020 | 11:26 PM

85e150

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You'll know right quick. Good luck, give yourself plenty of room.

Mar 14, 2020 | 10:32 PM

62SY4

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From: Elizabeth

I did a similar thing to a fork truck that I use in my private shop. The 1-1/4" bore master didn't development much pressure/ the pedal effort was extremely hard. I dropped down to a 1" bore, much better. I just can't justify several hundred bucks on a booster rebuild for a machine I use 6 times a year.

Apr 23, 2020 | 09:41 PM

awhtx

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Tuned

Joined: Feb 2006

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From: Lampasas,TX

I bypassed the booster and the truck stops although it requires a lot of pedal pressure and it doesn't stop on a dime. It's good enough for what I need.