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'68 non-power brakes

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Old 04-23-2018, 11:01 PM
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ST68
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Default '68 non-power brakes

My '68 went to the shop originally right after we bought it. The brakes were trash (pads down to metal, rotors scored, VERY hard to stop the car with hard braking - pedal travel just about to the floor). We told our restoration guy that we just wanted the brakes to work like they did from the factor. He purchases all GM replacement parts where needed (all new rotors, calipers, and master cylinder - not sure what else).

This thing is hard to stop. I don't mean impossible, OMG we're gonna die hard, but I don't think I could lock these brakes up if I tried. It takes a LOT of pressure to slow down fast. I'm glad it's a 4 speed and not an automatic.

My question is, what SHOULD they feel like, and is there anything that I can do to improve things without adding power brakes, which L79 cars did not leave the factory with. Thanks!
Old 04-24-2018, 01:03 AM
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7T1vette
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I'm guessing that he purchased OEM-like brake pads which were not that aggressive. The stopping power of the manual brake vs. power brake C3's IS THE SAME. The difference is in the "pedal effort" it takes to apply them.

Get better quality metallic pads and it will stop just fine.
Old 04-24-2018, 04:03 AM
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terrys6t8roadster
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Their might also be the chance the wrong master cylinder was installed. The power brake master has a 1&1/8" in bore and the manual has a 1" bore, not that I'm trying to bore you, but the larger diameter bore cylinder in a manual application will give you a hard pedal with poor braking. T
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Old 04-24-2018, 08:29 AM
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I had the exact same symptoms in my 68 L79. MUltiple bleeds and flushings. never got better. I went to power brakes just to make it easy on myself and have the ability to stop on a dime when these idiots around here pull out in front of me when they see a 1 car gap.......

I would look at the master cylinder as being for a power brake car and not the manual you are needing. Parts store kids arent too bright now a days

Last edited by Rescue Rogers; 04-24-2018 at 11:41 AM.
Old 04-24-2018, 08:40 AM
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JoeMinnesota
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Agree with the above. My 1970 has manual brakes, and yes takes peddle pressure but stops really well. Something is awry if you have to stand on them and still not confident.

Last edited by JoeMinnesota; 04-24-2018 at 08:40 AM.
Old 04-24-2018, 12:38 PM
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David Mc
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My '67 is a manual brake car and my '72 is a PB car. Anyone that says the baking performance is the same isn't driving their car back to back like I do. Yes, they both stop but I much prefer the power brakes. The non-power brake car requires a LOT of pedal pressure.
Old 04-24-2018, 03:55 PM
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ST68
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Originally Posted by terrys6t8roadster
Their might also be the chance the wrong master cylinder was installed. The power brake master has a 1&1/8" in bore and the manual has a 1" bore, not that I'm trying to bore you, but the larger diameter bore cylinder in a manual application will give you a hard pedal with poor braking. T
Interesting idea, and certainly possible. I wonder if there are identifying markings that would make it obvious? By the way, I saw what you did there.
Old 04-24-2018, 04:13 PM
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69FASTFUN
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My 72 was hard to stop also that is why I am converting to power brakes.
Old 04-25-2018, 08:18 AM
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ST68
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There don't appear to be any markings on this replacement master cylinder. Is there anything external that I could use to determine whether or not this has the correct (1") bore, or do I need to remove it to find out?
Old 04-25-2018, 10:13 AM
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The correct pad material will have a significant affect on your stopping power. In addition, did you burnish the new brakes properly when you got the car back after the rebuild?
Old 04-25-2018, 11:50 PM
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ST68
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Originally Posted by gg521
The correct pad material will have a significant affect on your stopping power. In addition, did you burnish the new brakes properly when you got the car back after the rebuild?
Good question. I have not broken these in at all, actually. I don't know what he put on them to tell you the truth so I'm not sure exactly how to go about it. I would help if I could apply enough pressure to heat them up but right now I'm not sure I can. I'm currently waiting for him to get me the information on the MC (p/n and source) so I can make sure it's for a manual brake car.

Last edited by ST68; 04-25-2018 at 11:52 PM.

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