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  Topic Review (Newest First)
07-13-2019 05:12 PM
wk2hons The power booster with the master cylinder that I got from Roc auto.com, meant for power drum brakes, the master cylinder looked about the same as the manual master cylinder. I bench bled the master cylinder, and then each wheel cylinder starting from the one farthest away from the master cylinder. and the rod does go to the lower hole in the brake pedal. It stops a whole lot better.
07-12-2019 04:55 PM
justjohn Dave, this is exactly why I'm careful about referrals for brake kits. Over in the pro touring forums there are literally dozens of people pulling their hair out about crappy disk brake conversions that don't stop their cars. A few knowledgeable guys usually step in with the usual questions about MC bore diameter, residual valves, brake pedal leverage, etc. People are actually getting into the weeds about needing larger diameter brake lines because they don't understand simple hydraulic circuits. All of this to save $150 by cobbling together parts. I ordered all of my parts from one guy who only does brakes. Aside from knowing what he is doing, he basically just copies the OE brake circuit over complete and if you don't try to make any changes, it just works. He'll even give away the advice for free and let you go off and fabricate your own stuff. Why people don't plan out something as important as brakes is beyond me.
Yes, getting my parking brake working was a bitch. It was actually the most challenging part of the whole thing. On the flip side, I absolutely hate working on drum brakes because of the added complexity. No disagreement that they work though.
07-12-2019 03:22 PM
Big Dave Difference between drum and disc is the disc requires higher line pressure to work. Drums are self activating and requires a big strong spring to pull the shoes off of the drum as opposed to a disc requiring lots of effort to keep the pad in contact with the rotor to prevent creep at a stop light.

A motor with a big cam and a power booster could have your car creeping up on the bumper in front of you regardless of how hard you stand on the brake pedal. It is rarely a question of stopping the car, but in keeping it held in place. The vacuum level, diameter of the diaphragm, and piston diameter in the bore that allows your car to have power assist.

A Power Assist Disc Brake master cylinder will have a bore of at least an inch, or larger. A Power Assist Drum Brake system rarely exceads 7/8th of an inch; full manual (no Power Assist) has an even smaller diameter closer to 3/4 inch. Master cylinders differ by 1/64 of an inch so "About" has a lot of 64ths of an inch in it: different cars with different engine displacements, and different curb weights all use different sized parts.

Disc brake kits are put together by business men trying to make money, not engineers concerned about your safety or the safety of the car in front of you. The lawyers are not going to sue CPP, MPB, or any other reseller of factory brake parts, when you are the one who installed them.

There are so many variables such as brake rod end, length or location that most don't even think about. Does your new and improved disc brake system still have the residual valve that retained brake pressure to the wheels to prevent sucking in air on drum brake wheel cylinders? Did you install the proper proportioning valve to match the length of brake line from the MC to the rear axle? Have you sized the diameter of the master cylinder to match your caliper piston size? Have to remember a factory correct Power Assist master cylinder for a 1969-'76 full size car is sized for "big" wheel caliper piston bores on the optional disc brake package. The "Metric" G-body brakes frequently sold in aftermarket disc kits or the even smaller bore twin piston calipers 3rd gen F-body calipers are not going to behave with a mismatched master cylinder.

Just ask the man on the phone that you are buying these kits from to see if he even knows what you are talking about, or was he selling shoes the day before? Brakes are not a fashion statement! They are important and thought needs to be put into modifying the system or replacing parts that are mixed and matched by price point.

Big Dave
07-12-2019 01:27 PM
camware
Quote:
Originally Posted by 67SS View Post
Different master cylinder is needed if you are planning on installing a booster. you will need to bench bleed the M/C before installing, and bleed the whole system after installing, starting with the one farthest away corner from the M/C (passenger rear). Upper hole in the pedal without booster and lower hole with the booster.


Gotcha. My car had a dual master cylinder installed when I got it back (sold it and bought it back a few years later). I was reading somewhere on the forum that there is a different dual MC for drum cars and disc cars. I believe the car may have had disc brakes installed while it was owned by whoever had it in between me owning it. That being the case, I知 not sure if the dual MC I have is the same one that was on the car when it had disc brakes. The car has always stopped fine for drums all around so I知 not sure what an incorrect MC would feel like.


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07-12-2019 12:57 PM
67SS
Quote:
Originally Posted by camware View Post
Did that consist of simply installing a power brake booster?


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Different master cylinder is needed if you are planning on installing a booster. you will need to bench bleed the M/C before installing, and bleed the whole system after installing, starting with the one farthest away corner from the M/C (passenger rear). Upper hole in the pedal without booster and lower hole with the booster.
07-11-2019 01:51 PM
wk2hons Yes it was a power brake booster with a master cylinder, meant for 67 power drum brakes. it had studs that went thru the firewall, and the rod went to a lower hole in the brake pedal.
07-10-2019 06:40 PM
camware
Quote:
Originally Posted by wk2hons View Post
I ended up just putting a power assist for my drum brakes on my 67. It made a big difference in the amount of foot pressure. Just didn't want to hassle with what parts were wrong with the disc conversion. Car stops a lot better and cost less.


Did that consist of simply installing a power brake booster?


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07-10-2019 05:02 PM
wk2hons I ended up just putting a power assist for my drum brakes on my 67. It made a big difference in the amount of foot pressure. Just didn't want to hassle with what parts were wrong with the disc conversion. Car stops a lot better and cost less.
07-10-2019 03:05 PM
67SS
Quote:
Originally Posted by justjohn View Post
I have fronts and rears but was specifically talking about the rears. CPP had to machine a send me a new bridge on their kit to get one caliper centered, one of the caliper parking brake arms bent over time, and I had to do some manual fitting to the the rear bracket bolted on. Point was it worked but....

The KORE3 kit had zero issues and bolted right up. It would have worked fine with the original foot parking brake and some extended rear cables as well but I have since put in a new Camaro console and hand parking brake lever.

I also wasn't worried about wheel spacing. I have adapters with C6 wheels. I respect keeping the 14's but it's not where I went.
I'm not trying to defend CPP, I had my share of issues with them. They are definitely not my 1st choice when it comes to parts for my cars.

I kept 14's cause I really like the classic look with hubcaps, at the time, I think CPP was the only option. Another reason that I went with CPP is that my car is bagged so I didn't want it to rub when it's laid out with bigger wheels.
Also I can mount wheels from my other cars and they won't rub.
I change wheels on my cars like I change shoes .
07-10-2019 10:51 AM
justjohn
Quote:
Originally Posted by 67SS View Post
You are talking about rear disc kit. You will not feel much difference by installing rear disc brakes on these old cars, I don't care where the kit is from. On classic cars about 90% of braking is on the front, rear drums do more than good enough job for the remaining 10%.
I do agree that KORE3 has quality kits, I have their kit on my Cutlass and I'm very happy with it. Also customer service and tech support that Tobin provided is outstanding.

The reason I went with CPP kit is cause it doesn't push the wheel out like most kits on the market and I am able to run my 14's with hubcaps with minor modification.
I have fronts and rears but was specifically talking about the rears. CPP had to machine a send me a new bridge on their kit to get one caliper centered, one of the caliper parking brake arms bent over time, and I had to do some manual fitting to the the rear bracket bolted on. Point was it worked but....

The KORE3 kit had zero issues and bolted right up. It would have worked fine with the original foot parking brake and some extended rear cables as well but I have since put in a new Camaro console and hand parking brake lever.

I also wasn't worried about wheel spacing. I have adapters with C6 wheels. I respect keeping the 14's but it's not where I went.
07-09-2019 03:15 PM
BA.
Quote:
Originally Posted by justjohn View Post
I've previously installed a CPP rear disk kit. Initially it did not fit and there were some issues that CPP worked to resolve fairly quickly. I got everything installed and working but it was marginally satisfying.

The KORE3 kits kits are a giant step up in quality and function.

I'm not really a big fan of CPP but I try not to ever mention that.....or them.

BIG FAN of KORE3 though - really good reputation there.

I'm sure they can hook the OP up with front brakes similar to a C3 Vette, assuming the rotor is sized to the OP's rims.
07-09-2019 11:49 AM
67SS
Quote:
Originally Posted by camware View Post
Is there a KORE3 kit that covers a 66? I looked at their site and only saw one for 71-76.


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Call them and ask for Tobin, he can answer all your questions and I'm sure he can put a kit together if they don't have one.
07-09-2019 11:48 AM
67SS
Quote:
Originally Posted by justjohn View Post
I've previously installed a CPP rear disk kit. Initially it did not fit and there were some issues that CPP worked to resolve fairly quickly. I got everything installed and working but it was marginally satisfying.

The KORE3 kits kits are a giant step up in quality and function.
You are talking about rear disc kit. You will not feel much difference by installing rear disc brakes on these old cars, I don't care where the kit is from. On classic cars about 90% of braking is on the front, rear drums do more than good enough job for the remaining 10%.
I do agree that KORE3 has quality kits, I have their kit on my Cutlass and I'm very happy with it. Also customer service and tech support that Tobin provided is outstanding.

The reason I went with CPP kit is cause it doesn't push the wheel out like most kits on the market and I am able to run my 14's with hubcaps with minor modification.
07-09-2019 10:49 AM
camware
Quote:
Originally Posted by justjohn View Post
I've previously installed a CPP rear disk kit. Initially it did not fit and there were some issues that CPP worked to resolve fairly quickly. I got everything installed and working but it was marginally satisfying.



The KORE3 kits kits are a giant step up in quality and function.


Is there a KORE3 kit that covers a 66? I looked at their site and only saw one for 71-76.


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07-09-2019 08:23 AM
justjohn
Quote:
Originally Posted by BA. View Post
If Summit indeed sold you a kit entirely from "The Right Stuff", that companies' kits have worked well for many members on this forum.

Either the wrong kit was sent, or maybe it got packaged wrong. Either way, both companies are solid and work to make us DIY'ers satisfied.
I've previously installed a CPP rear disk kit. Initially it did not fit and there were some issues that CPP worked to resolve fairly quickly. I got everything installed and working but it was marginally satisfying.

The KORE3 kits kits are a giant step up in quality and function.
07-08-2019 06:31 PM
BA. If Summit indeed sold you a kit entirely from "The Right Stuff", that companies' kits have worked well for many members on this forum.

Either the wrong kit was sent, or maybe it got packaged wrong. Either way, both companies are solid and work to make us DIY'ers satisfied.
07-08-2019 02:23 PM
67SS
Quote:
Originally Posted by camware View Post
Ok thanks for the info. What kit did you use?


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I've used CPP 0 offset kit. Part number 6568WBK-S0
07-08-2019 01:59 PM
camware
Quote:
Originally Posted by 67SS View Post
I don't know about OP, but converting to disc brakes was a best upgrade I've done to my Impala. It proved to be a right upgrade when a car jumped in front of me without signal light and I had to slam on the brakes, there is no way in hell my drum brakes would've stopped that fast from 65mph. With drum brakes my stopping distance was a lot longer and in traffic they would get hot and start slipping. With disc brakes I'm driving the behemoth like a normal car, I don't need a mile gap between my car and the car in front of me, and I'm not scared to drive up and down the hills of San Francisco anymore.


Ok thanks for the info. What kit did you use?


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07-08-2019 01:33 PM
67SS
Quote:
Originally Posted by camware View Post
What made you want to keep your drums if Summit can sent you the right parts? Mainly asking because I知 trying to decide if I want to convert my drums to disk also and I知 curious to see what your take is. Just don稚 want to deal with the hassle of it all?


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I don't know about OP, but converting to disc brakes was a best upgrade I've done to my Impala. It proved to be a right upgrade when a car jumped in front of me without signal light and I had to slam on the brakes, there is no way in hell my drum brakes would've stopped that fast from 65mph. With drum brakes my stopping distance was a lot longer and in traffic they would get hot and start slipping. With disc brakes I'm driving the behemoth like a normal car, I don't need a mile gap between my car and the car in front of me, and I'm not scared to drive up and down the hills of San Francisco anymore.
07-07-2019 05:16 PM
camware
+power disk brake conversion

Quote:
Originally Posted by wk2hons View Post
I have decided to keep the drum brakes. I will look at Rock Auto for a power assist unit for drum brakes.


What made you want to keep your drums if Summit can sent you the right parts? Mainly asking because I知 trying to decide if I want to convert my drums to disk also and I知 curious to see what your take is. Just don稚 want to deal with the hassle of it all?


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06-28-2019 11:39 AM
wk2hons I have decided to keep the drum brakes. I will look at Rock Auto for a power assist unit for drum brakes.
06-28-2019 11:35 AM
wk2hons I think maybe the wrong parts were sent, because I have bought other things from Summit without any problems.
06-25-2019 02:42 PM
67SS Not trying to be a d1#k but are you sure you are doing this right? Or maybe wrong parts were sent, which Summit will fix.

I've used Right Stuff conversion on multiple cars and never had an issue.

I've done many 61-70 Impalas and many different A-body cars, front and back, without any major problems.
06-25-2019 07:37 AM
justjohn I didn't see the model year of your car...

Try giving Tobin at KORE3 a call. He mostly makes big GM brake kits for older cars and often covers applications not listed on his web site.

I have his C6 Z51 kit on my fronts and rears. The kit is not listed on his web catalog and I had to wait about 6 weeks for him to make the front hubs. Well worth it. Fit was perfect and he was always available to answer questions.
06-25-2019 07:01 AM
wk2hons The Right stuff is what Summit sold me.
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