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Discussion Starter #1
About 6 months ago, I was drivng my 68, power brakes and life was good....
Power brakes, felt like power brakes, everything was fine, all the sudden, when I hit the brakes, I felt a weird feeling in the pedal, and now the brakes are harder to push, Still seems to have some power assist, stops fine, Booster retains vaccum, but it doesnt quite feel like power brakes anymore, no fluid loss, no pulling, stops from 100 plus MPH ok, but you really gotta step on the pedal, has anyone ever seen a booster go half bad? If it was the MC, it would bleed to the floor, at 139 for a rebuilt unit for a booster, I wanna be sure, OR does anyone know where to buy a new diaphram for the booster? I have 5 gallons of alodine, and the resources of a complete shop so if I put a new diaphram in, and plastic media blasted it, then soaked it in alodine, it would look factory new. If anyone can tell me where to get a diaphram, Ill build and alodine yours for free, thats a promise. The ones with the factory stamp even go for more, thats half the reason I dont wanna xchange mine


any help would be appreciated

Steve
 

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Try pulling the hose from the check valve on the booster with the engine running to make sure you're getting good vacuum. May have a collapsed or split hose. If the vacuum is good then make sure the check valve is unobstructed and functioning. If you have good vaccuum you are probably looking at repairing or replacing the booster
 

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Dang i just noticed my brakes doing the same thing this week, i checked my pads and they look good, it does feel like it went half bad and i have good vaccum. Ive been wondering for 2 days now. thanks for posting.
 

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Had a split vacuum hose at the manifold on a 78 Monte a few years back, that was the culprit cutting the boost to the power brakes.
 

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A simple test of the booster is to depress the brake pedal several times with the engine off. hold the pedal down and start the engine, the pedal should drop 1-2 inches, if it does the problem isn't in the booster. When you inspect the pads look for anything on the surface, dirt, grease, oil, pitting as a sign of over heating. You can scuff the pads and drive it again, not for a fix, but for a change, this will give you a direction. another option is to clamp one rubber line at a time, see if the pedal improves, this will give you a starting place. good luck.
 

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Discussion Starter #7
Vaccum

Plenty of vaccum at the hose, pedal does not sink when engine started, or any other time for that matter LOL


Looks like booster time
Man that sucks, its always somethig LOL


thanx guys
Steve
 

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There is a vent on the firewall side of the booster. In order for the booster to work the vent needs to be unblocked so air is free to move in and out on the atmospheric side. If it can not then you basicly have a vacuum on both sides. One created by the engine, the other due to the blocked vent. This will cause a hard pedal.
 

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Discussion Starter #9
Dude

There is a vent on the firewall side of the booster. In order for the booster to work the vent needs to be unblocked so air is free to move in and out on the atmospheric side. If it can not then you basicly have a vacuum on both sides. One created by the engine, the other due to the blocked vent. This will cause a hard pedal.
Thats such an awesome idea, Im gonna go look right now maybe it rusted shut or something lol, IM sure once you rotate that housing its simply a bellows to hold the vaccum, boy if I could just order the parts.....
lol

Ill report right back with the results of the hole search

Steve
 

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I've never heard of anyone repairing a booster. If you go that route, please post pics! But for that matter, I've never heard of a repair kit either. You'll probably have to scrap a new booster for the diaphram. Post pics of that too!
 

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Discussion Starter #11 (Edited)
Actually its your lucky day

I've never heard of anyone repairing a booster. If you go that route, please post pics! But for that matter, I've never heard of a repair kit either. You'll probably have to scrap a new booster for the diaphram. Post pics of that too!
VERY repairable, 29 Buck rebuild kit, im gonna order one this week, prob buy a old used to get me to the track friday

Pics below
Have already blasted cover, has the delco moraine stamp, so at least its not a chiwian POS













 

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I did mine 2 years ago, but I could hear it hissing, it took awhile before it stopped working, I was quite surprised how long it worked considering it was so loud.
 

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Discussion Starter #13
Not that this will solve all my troubles

but engine should run better without a 1/4 inch vaccum leak LOL


Steve
 

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Discussion Starter #14
Incredibly easy`

on a complexity scale, maybe a 1 or 2 out of 10. a trans build being a 10

Got a used booster from a 70-72 didnt fit, rod was too short, took it apart, diaphram was fine, cleaned, and reassembled, then had to dissassemble again to put the proper booster to MC pushrod in, once you have it down, takes about 10 minutes to do once its on the bench

I would recommend a short gear wrench for the booster to firewall nuts, what a pita

Ill never buy another booster again


Steve
 
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