Ok, I have a 1970 Skylark with 4 wheel manual drum brakes currently. I have a front disk conversion kit that did not come with a master cylinder or proportioning valve or any hard lines. I want to retain the manual brakes and just convert to disk up front. Found getdiskbrakes.com and talked to them on the phone and they said all I need is the parts below. http://www.getdiscbrakes.com/g0571 http://www.getdiscbrakes.com/ckt68sd http://www.getdiscbrakes.com/indc02 Does this sound right? Do I need anything else? Thanks, Brian Novak
Brian, I appreciate your asking for my input, I'm afraid I'd have to have a lot more info in front of me to see what might happen to pedal effort since I'm not familiar with the specifics. I also wonder why they spec'd a line described as "'64 - '72 Front to Rear Line Ext. for Booster Mounted Valve" if there's no booster? Maybe someone else will jump in that already has some experience with this swap. Devon
Devon and Mike, I am not concerned about pedal pressure as I am used to manual brakes anyway. I know several people that are running manual disk setups and pedal pressure does not seem to be an issue and the stopping power is there. It may not be as strong as with a power booster but it is sure a lot better than the drum brakes. As for the front to rear line ext for booster mounted valve...The valve actually mounts to the side of the master cylinder. They just put booster in the wording since most people run power brakes. My big concern is making sure these are all the parts I should need. I do not want to be in the middle of the install and have to hunt down more parts. Thank you for the replies,
Brian, My conversion was a bit different in that I already had front disc and I swapped out the rear drums for discs. Where I ran into pedal problems was I needed to go with a smaller booster since I also put in a hydraulic clutch with its little master cylinder competing for space with the brake setup. Initially I went with a 7" single booster. It would stop the car, but it was a bit scary at times. I went to an 8" dual booster and it made a big difference. Apparently what drives this is the master cylinder bore size. With disc brakes I believe the bore diameter has to be at least 1" with 1-1/8" preferred. This is so that you get the brake fluid volume to the big bores (big compared to drum cylinders) at the calipers. With the drum brakes, the master cylinder bore was I think 3/4". The bigger m/c bore gives a lot more pedal back pressure to get things moving. Hopefully it won't be too bad since you are already used to manual brakes, but in my case the stopping distance was too much with a 7" booster.
make sure you order the lines for a convert if you have a boxed frame there catalog will aways send unboxed frame lines unless you order for a vert.dont know if it will matter for the front or not but i will say they are a good company to deal with
I just got done with mine. I have a power Booster tho. I made my own lines. I bought a 25' roll of Copper-Nickel line. Man is that stuff great. You can bend it with your hands and it is easy to make a Double flare. It wont rust either. Give it a try if you haven't bought lines yet. I think it was around 50-55 Dollars for a roll. PONCH
Best switch to steel lines ASAP. Copper will work harden and crack from under hood vibration. Also, it isn't rated for the amount of pressure you will give it in a panic stop. That would be a bad time to find out. Steel line has approximately 10X the pressure holding capability over copper.
Every one I know that uses the copper-nickle line (cunifer?) loves it. I wished I had used it on the front lines for my'65. The pre-bent stainless kit fits ok, but I think I could have routed it better myself.
I just got done with the front part of my front disc conversion with a vacuum booster and all new stainless lines. I still have to do the rear running line,flex line ,and axle lines. you really shouldn't need anything else brian.. and on copper lines. on my first g.s., I used straight up refrigeration copper lines.,i never had any issue with work hardening , pressure problems or anything of any sort. it is seamless and can withstand pretty much any pressure( my dad was an appliance repairman and did hvac as well)
Thanks for the input guys, I think I am just gonna go with the master cylinder and proportioning valve and run my own lines since I will be adding line loc also.
I just did this on my 70 skylark using the kit from performance suspension technology, I had power drums already, so I went power again, I dont know if discs will work without power assist? but the problem youre going to run into is the location of the proportioning valve, mine was mounted on the frame below the master cylinder, and even though I was assured the fitting were the same they were not plus the new valve was lager and didnt fit where the old one was, with long tube headers I wish I would have moved that stupid thing before, and to make all the matters worse will my line were rusted into the wheel cylinders so they all broke at the end. So after replacing the fittings and reflareing at each end, then I realized I would have to redo the lines because of the new location of the valve. So unless you absolutely need to go with the new booster and the original location on the PV just jump in and replace the lines, when you move the PV you will have to replace the rear line as well. Not as hard as it sounds, worth the extra work. <o></o>
I am aware of the issues with the frame mounting of the valve especially with headers so mine will be mounted off the master cylinder like in the above kit. I know several people that are running manual disk. they are using factory brakes though and not a conversion and stop without issue so i am not concerned about stopping power its more about getting a master cylinder and valve that will work properly. This will happen when I am swapping the motor so it should be a bit easier.
I quote from Inline Tube's website: Proportioning valves come in various shapes and sizes depending on the car you have and modifications to the braking system. The first year for disc brakes on GM and Chrysler products was 1967, Ford was 1966. All American cars built prior to this had four wheel drum brakes. Disc brakes were introduced as an option from 1967-1972. Starting in the 1973 model year, front disc brakes were primarily standard and front drums were rarely available. The dual master cylinder that separates the front and rear braking systems was introduced and standard on all cars in 1967. Therefore, all 1967 and newer cars came with dual master cylinders from the factory. Disc brakes require over three times the line pressure of drums, so the master was divided to provide pressure to the front and rear separately. This also meant that if a front line blew out the car would still have pressure to the rear brakes and vice versa. All 1967-68 GM factory disc brake cars came with dual piston calipers. If the car is a 1969 or newer car, it came with single piston calipers. All aftermarket conversions come with the single piston calipers, but they are not factory correct for the 1967-68 cars. The single piston conversion will bolt on 1964-72 GM A-Bodies, 1967-69 F-Bodies and 1968-74 X-Bodies and function perfectly. Since disc brakes were new in 1967, the valve was still being worked out for the next few years. The 1967-70 valves could consist of as many as three elements and the valves would not work properly without all the pieces. Both 1967-70 factory drum and factory disc cars have (or had) a distribution block which is identical whether the car was drum or disc. Although very similar in appearance to a proportioning valve, the distribution block does not alter brake line pressure. The distribution block keeps front and rear systems separate, splits the left and right front lines and houses the sending unit for the brake failure warning light. The 1967-1970 factory disc vehicles employed an additional valve, referred to as a hold-off valve, mounted at the master cylinder. The final component in the 1967-70 factory disc brake systems was a correction valve typically located in the front to rear brake line for the rear brakes. This valve was not used in every factory disc brake car, but would make the front to rear line two pieces with the valve usually found mounted near the floor pan of the car. An original 1967-70 disc car can be factory correct without the correction valve, but not without the hold-off valve at the master cylinder. In 1971 for GM and 1972 for Chrysler, the one piece combination valve replaced the multiple piece design. The combination valve keeps front and rear systems separate, splits the left and right front lines, houses the sending unit for the brake failure warning light and provides the proper brake line pressure for the front disc and rear drum systems. This is why it is important to know what is correct for your car and how your car can (or will) be converted from drum to disc. There are three basic disc conversions for 1967-70 cars: 1) Factory original conversion, 2) Combination valve conversion and 3) Adjustable valve conversion. Each conversion has its benefits. Trying to upload pics of the distribution block and proportioning valves but my new laptop is not cooperating.
