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low vacuum, stick with power or switch to manual brakes???

C

chillininnh

Member
Well I bit the bullet today and removed the booster from the car. Removed the drivers seat and for all my procrastinating on this, it didn't come out too bad. It's an original 69 power brake disc/drum system, no power steering. I was sure I had a vacuum leak and after going through everything else it was clear that damn booster was fubar. Some solid advise is what I need at this stage. This engine only produces 8 inches of vacuum at idle. It is a 418W, the engine builder warned me running power brakes may be problematic. The booster had quite a bit of fluid in it. It was one of the only parts during the restore that I chose to reuse, bad decision lol. Should I try a Booster Dewey rebuild and see if the brakes will be right with such low vacuum? I'd hate to go that route, reassemble the thing and not have it work correctly. I know you like pics:

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Under the circumstances it seems I would be wise to convert to a manual brake setup. I know I'll need a manual pedal and that the power pedal support will work with some effort. A 74 maverick master seems to be the popular choice and an adjustable master rod too. What happens with distribution block? What kind of changes to the lines at the block need to happen? Am I missing anything for the swap? Is it possible I'm overthinking this thing and that I should have the booster rebuilt and try it? Good weather is coming and I gotta move forward one way or the other. Thanks in advance.
 
"silverblueBP" said:
Personally, I'm quite happy with manual brakes.
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I'm not opposed to going manual, the booster makes life miserable in that corner of the engine bay. What changes with the plumbing/distribution block? Going this route is where I need some help. :wor
 
Well I sent the booster off to Dewey for rebuild this morning. I'll adjust the timing, bump up the idle and tune for highest vacuum at idle and see what happens. If that doesn't do it I'll try a vacuum canister. If I'm still having trouble I guess there's a vacuum pump in my future. A set of Rhodes lifters, as suggested on another forum, may very well solve my problem but I just don't want to take the top end off the motor.
 
A good manual set-up will make you happy and save you the hassle of trying to get it right with low vacuum. The key is having the correctly sized MC.
 
Pulled the booster off the shipping dock lol. I've decided I'm just going to switch to manual brakes. I may miss the extra stopping power but I won't miss that damn booster, what a pain in the ass it makes working on anything in that corner of the engine bay lol. I would hate to spend money and time rebuilding the booster, reinstalling it with a new master and not having enough vacuum for it to operate correctly. I hate the idea of a vacuum pump. Hell everything else on this car is manual so screw it.
 
I don't think there's a difference in the stopping power. Maybe the amount of force needed to get the same result. Go for a ride in a car setup with the vintage big brakes and manual MC's and I'm bet'n you'll see the light!
 
"silverblueBP" said:
I don't think there's a difference in the stopping power. Maybe the amount of force needed to get the same result. Go for a ride in a car setup with the vintage big brakes and manual MC's and I'm bet'n you'll see the light!
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Lol, I bet. I've seen the light, manual brakes here I come. Now help me with the parts list..... I gotta pretty good idea but I'm sure I'll forget something. :confu
 
Give Shaun a call at Street or Track, he can help you get the right size MC, lines, dist block and bias. You might have to change brake pedals.
 
Although I'm sure Shaun would have been quite helpful I didn't think he'd have a manual pedal. I called Dan at Chockostang and he is sending me everything I need to do the swap. He gave me some good money for my old pedals to save me some cash. The man knows his brakes and knows how to do business. :thu
 
I still think you could've rigged something up to get enough vacuum, and I still you think you should consider Rhoads lifters for the performance benefit:) That said, I also like my manual brakes. They're very linear, compared to a vacuum booster where pedal effort changes with engine vacuum. With the right master/caliper combination and the proper pedal geometry, you won't need a vacuum booster. I certainly don't mind having all that extra space in the back of my engine bay.
 
"Starfury" said:
I still think you could've rigged something up to get enough vacuum, and I still you think you should consider Rhoads lifters for the performance benefit:) That said, I also like my manual brakes. They're very linear, compared to a vacuum booster where pedal effort changes with engine vacuum. With the right master/caliper combination and the proper pedal geometry, you won't need a vacuum booster. I certainly don't mind having all that extra space in the back of my engine bay.
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The problem with going with Rhoads lifters is it may solve some of the vacuum problems but then you are left with the noise they generate. Not a fair trade-of in my book.
 
"Starfury" said:
I still think you could've rigged something up to get enough vacuum, and I still you think you should consider Rhoads lifters for the performance benefit:) That said, I also like my manual brakes. They're very linear, compared to a vacuum booster where pedal effort changes with engine vacuum. With the right master/caliper combination and the proper pedal geometry, you won't need a vacuum booster. I certainly don't mind having all that extra space in the back of my engine bay.
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Good vacuum wih this cam ain't gonna happen I'm afraid.

Comp Cams Part #35-254-4 Grind #XE294H
Lift .554 .558
Duration @ .050 250/256
Lobe Center 110

I'm not crazy about the noise I'm hearing the Rhoads lifters generate. I am encouraged about the feedback I'm getting on the manual brakes however.
 
"silverblueBP" said:
What's the problem then? Solid lifters are COOL!
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Acquired taste that I personally never acquired, I guess. Plus, having run one for a while many, many years ago I do not miss the fun of having to make hot lash adjustments ever again. It's hard enough keeping an engine clean without that mess.
 
"Horseplay" said:
Acquired taste that I personally never acquired, I guess. Plus, having run one for a while many, many years ago I do not miss the fun of having to make hot lash adjustments ever again. It's hard enough keeping an engine clean without that mess.
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I have yet to set a hot lash. Always do it cold and only check it once a year when the engine's blow'd up. Seriously, I've yet to have the rockers go out of adjustment. Everytime I check them, they're the same.
 
wish you had taken a breath or two before buying that stuff. i have everything for a manual brake pedal i would have given you...
 
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