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Drive line hydraulic disc brake

Posted: Sat Mar 24, 2018 2:41 pm
by markIV
I have been asked to post some photos concerning my disc brake install on my 1910 Buick model 17.
As I stated on the started thread, I used a rotor from a Nissan Xterra, calipers from mid 70s Chevrolet pickup & Master cylinder from 1966 Mustang GT.
The Xterra rotor had 6 lug holes so I re-drilled between them so that it would bolt up to my u-joint flange.
It was also the same thickness as the GM rotor so the caliper didn't have to be modified.
I used the Mustang master because it was the only single chamber with a port not having a residual pressure valve.
It also has a nice large reservoir.
I mocked up the mounting brackets from wood & then had my machinist friend cut & weld them.
Photos attached.
Mark
IMG_20151128_092914001.jpg
rotor mount
IMG_20151128_092926017.jpg
back of rotor
IMG_20151128_112751798.jpg
wood caliper bracket mockup
IMG_20151214_113206805.jpg
wood master bracket mockup
IMG_20160116_111402114.jpg
steel caliper bracket
IMG_20160116_104706713.jpg
steel master bracket
IMG_20160116_154813751.jpg
all installed

Re: Drive line hydraulic disc brake

Posted: Sun Mar 25, 2018 6:06 am
by Shark
Excellent! Very nice work.

Re: Drive line hydraulic disc brake

Posted: Sun Mar 25, 2018 6:37 pm
by alsfarms
Mark, Did you completely disable your running brake pedal from operating your brakes on the rear axle?
Al

Re: Drive line hydraulic disc brake

Posted: Mon Mar 26, 2018 6:35 am
by markIV
Hi Al,
Buick never used the rear wheel drums as service brakes with the pedal. They used a drum on the drive shaft. That made it very easy to convert to the disc. I didn't have any of the original brake parts which made the decision to covert it easier. You may have noticed the holes in the top of the transmission for the original linkage. I also used the original pedal cross shaft to activate the master cylinder. Also since the master had 2 brake line ports I used one for a hydraulic brake light switch. I couldn't be more pleased with the results.
Mark

Re: Drive line hydraulic disc brake

Posted: Mon Mar 26, 2018 7:00 am
by alsfarms
Hello Mark,
That is an interesting bit of information regarding the technology Buick used on your car. My Locomobile uses both internal expanding and external contracting on the rear brake drums. One for emergency brake and the other for the service brake. I may seriously look at a similar update that you have made when I get to that point. I would want to keep all my original rear service brake linkages hooked up (functional) and devise a way to have a second pull off for the hydraulic disc brake. Some form of a priority system, on the linkages, to allow the disc brake to function just before the rear drum brakes begin the action of stopping the car. I can't tell from the pictures, is your master cylinder mounted lower than the caliper? If it is did you have a challenge when bleeding the system? I guess you could remove the caliper and have it hang lower than the master cylinder for bleeding. You did come up with a very good design for your car.
Al

Re: Drive line hydraulic disc brake

Posted: Mon Mar 26, 2018 12:17 pm
by markIV
Hi Al,
All I did to bleed the brakes was to tilt the caliper so that the bleeder was at its highest point.
The air migrates to the high point so it doesn't matter if the caliper is higher.
Mark

Re: Drive line hydraulic disc brake

Posted: Tue Mar 27, 2018 6:53 am
by alsfarms
Hello Mark,
I am curious, how much pedal pressure do you need to exert to get a comfortable brake. I understand that disc brakes require more pedal pressure than drum brakes to actuate. It should not be anymore than the original brakes?
Al

Re: Drive line hydraulic disc brake

Posted: Tue Mar 27, 2018 7:49 am
by markIV
Hi Al,
I can't speak to how much pressure the original brakes required but with this disc setup it's comparable to my 65 Mustang with drums & no power assist.
Mark

Re: Drive line hydraulic disc brake

Posted: Tue Mar 27, 2018 12:36 pm
by alsfarms
Hello Mark,
That much foot pressure keeps you thinking that you are driving an antique automobile with the plus that you can STOP. You should not have the brake fade that hot drum brakes have and that is scary! We were on tour at Yosemite, a decade ago, in a Buick Model 24 (I think) and going down hill, the brakes got hot and starter to fade.....it scared the devil out of me! At the time I was driving my friends Buick.
Al

Re: Drive line hydraulic disc brake

Posted: Wed Mar 28, 2018 7:57 pm
by alsfarms
Hello Mark, What type of brake fluid did you choose to use for this conversion?
Al

Re: Drive line hydraulic disc brake

Posted: Thu Mar 29, 2018 7:36 am
by markIV
Hi Al,
I decided to just use dot 3 brake fluid in my conversion.
It's been around for a long time with few problems.
Mark

Re: Drive line hydraulic disc brake

Posted: Fri Mar 30, 2018 7:21 pm
by alsfarms
Hello Mark, I would have chosen as you did. The Silicone stuff is good however, it does not trap moisture like DOT 3.
Al