Damn, brakes suck.

[HT413]

My brakes have always sucked, firm pedal, just never quite stopped very well. Manual disc/drum 69 belvedere. Well I finally bought the SSBC brake pressure gauge kit and looks like I have 500 psi at the MC. Brutal.

I guess my mc is bad, correct? Any recommendations on which brand to use?

Also, nows the time for new lines, any preference on the best kit?

Gracias.

 

[GITEX]

Inline Tube in Michigan for the lines, might ask them about the mc also
I went with Wilwood myself. Your going to need the ratio for the brake pedal for a correct mc. I believe it should be at 1000lbs for disc brakes.

 

[Cranky]

Yup, disc brakes take a lot more PSI plus more volume and the master has to be matched for them. If you 'stand' on the brake, does it stop any better? If not, then I'd say you need to go back with a different MC for sure....

 

[Longroof]

What bore size is the MC?

 

[lewtot184]

master cylinder bore size is critical. i use a 15/16" bore and it works great. if you have an 1 1/8" then you'll have issues. on my car just going from a 1 1/32" to the 15/16" was night and day difference.

 

[Yatzee]

Depends on weather you want the OE look or you want to stop on demand. Wilwood 15/16 bore MC is about as good as they come and you may not even need a brake booster if the pedal ratio is correct. I myself do not have have any interest in vacuum boosters and went with SSB's disk retrofit ( they use Corvette calipers with four pistons and you can by pads anywhere of any material ) a 1 1/16 bore master ( no shortage of fluid volume ) and a hydro boost power unit instead of a vacuum booster. Braking is absolutely, unbelievably, positively spot on with no drifting or wheel lockup. This system uses very little pedal travel and gives three positive stops even if you blow a line. That's technology I guess and like throttle body it's becoming one of the most popular mods to resolve issues of the past. Like I said, it all depends if you want the OE look or not.

 

[69 GTX]

I'm putting manual disks all the way around on mine. I asked about what size bore mc and they said 15/16.

 

[bm02tj]

The smaller the bore on MC and the larger the calliper pistons and wheel cyl the better you stop
with a small bore you must keep your brakes adjusted and wheel bearings tight

 

[khryslerkid]

Also make sure you're useing the right lenth pushrod. Too long and the piston is already past the first port.

 

[lewtot184]

on my car a small master cylinder, small caliper pistons and small rear wheel cylinders work the best.

 

[HT413]

What bore size is the MC?

I guess I left out some details. Manual disc/drum, 1-1/32" bore MC and I just measured the pedal ratio to be 6:1. With me standing on it in panic brake mode, the most I can produce is about 550 psi. That's half of what I calculated I should produce. Incidentally, if I pump it up I can get it to about 700 but it leaks back down to 500 while I'm still standing on it. Something tells me this is not a good thing.

Also, I attached the gauge directly to the m/c, just so I can eliminate the possibility of a blocked break line, etc.

I 'should' be able to produce almost 1100 psi with this mc:

Force X ratio / mc bore area
150lbs X 6 / 0.836 = 1080 psi

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Depends on weather you want the OE look or you want to stop on demand. Wilwood 15/16 bore MC is about as good as they come and you may not even need a brake booster if the pedal ratio is correct. I myself do not have have any interest in vacuum boosters and went with SSB's disk retrofit ( they use Corvette calipers with four pistons and you can by pads anywhere of any material ) a 1 1/16 bore master ( no shortage of fluid volume ) and a hydro boost power unit instead of a vacuum booster. Braking is absolutely, unbelievably, positively spot on with no drifting or wheel lockup. This system uses very little pedal travel and gives three positive stops even if you blow a line. That's technology I guess and like throttle body it's becoming one of the most popular mods to resolve issues of the past. Like I said, it all depends if you want the OE look or not.

That's interesting. Yeah I'm not looking for factory correct at all, just a quality mc that will solve this issue. I'll look into the wilwood and SSBC masters.

 

[Longroof]

I got my 15/16 bore master from Dr. Diff. Works great.

 

[Cranky]

Generally, a small bore MC will give you more braking power but at the cost of more travel....especially with drum brakes but like bm02tj says, keep things adjusted and it works very well. I've had the argument with several over the years that a larger MC creates more PSI vs a smaller bore using the same pedal ratio. It does not but if you you need more capacity, changing the PR will do the trick but if you have Incredible Hulk legs, go with the big bore MC :grin: Also, your MC shouldn't leak down and your psi should be at 1000 psi. or more. http://www.markwilliams.com/braketech.aspx

 

[Durandal25]

........I use my feet to stop my 69' Bee......11' drums all around. Love that rush from the " 200 foot" braking distance.....

 

[747mopar]

Never tried them but Just Suspension offered an MC called Red Bore that's supposed to significantly lower the amount of pressure reqired to stop the car??

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[furyus]

I had the 73 up A body disc brake setup. Worked well with a 15 / 16 bore. Went to the larger rotor, and larger 76 up calipers to get more stopping power. Ended up with a 1 1/32 bore MC the smaller MC wouldn't move enough volume. Also went with smaller rear wheel cylinders. It took some time to get sorted, but it was worth it. Point is, it's all got to match.

 

[HT413]

Yup, disc brakes take a lot more PSI plus more volume and the master has to be matched for them. If you 'stand' on the brake, does it stop any better? If not, then I'd say you need to go back with a different MC for sure....

The car never really stopped very well, I always figured it was just how manual brakes were BITD. Looking forward to some decent braking, gotta add some Whoa to all that new Go the 451's gonna add.

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Never tried them but Just Suspension offered an MC called Red Bore that's supposed to significantly lower the amount of pressure reqired to stop the car??

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View attachment 303863

Doesn't seem like they make it anymore - I see mention of it online, but their website doesn't mention it at all.

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I got my 15/16 bore master from Dr. Diff. Works great.

I talked to cass a while back and he recommended the 1-1/32 for me. I ended up going with a oem type disc / drum cast iron mc, but I think I might go with cass's mc this time around.

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........I use my feet to stop my 69' Bee......11' drums all around. Love that rush from the " 200 foot" braking distance.....

Lol, I know that feeling! Plan waaay ahead!

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Generally, a small bore MC will give you more braking power but at the cost of more travel....especially with drum brakes but like bm02tj says, keep things adjusted and it works very well. I've had the argument with several over the years that a larger MC creates more PSI vs a smaller bore using the same pedal ratio. It does not but if you you need more capacity, changing the PR will do the trick but if you have Incredible Hulk legs, go with the big bore MC :grin: Also, your MC shouldn't leak down and your psi should be at 1000 psi. or more. http://www.markwilliams.com/braketech.aspx

Thanks for the link, I have some reading to do!!

Yeah that leak down has me convinced it's the mc. Somehow I'm losing 1/2 my psi and with that leak down its time to try a new mc. Glad I bought that gauge.

 

[HT413]

Well, I just installed a fancy new MC from Dr. Diff. After bench bleeding the MC, bleeding the system of the old fluid, I now have a rock solid pedal and over 1500 PSI. The brakes have never felt so good. Excited to get the car back up and running so I can test these babies out!

Thanks to all !!

 

[Homstead]

Right on! Looking forward to the test results!

 

[HT413]

And here's the victory shot! Looks to be a hair over 1700 psi. Oh yeah.



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Right on! Looking forward to the test results!

Yessir, me too. My 451 is almost done so I hope in a couple of months she will be ready to run! (And stop!)