Drum to Disc conversion

[Hankrebel]

Just received my full kit from Scarebird and about to start.
Looking at the MC and it is already a dual reservoir. I havent looked at the line sizes but everything else is pretty much stock.
Anyone else seen a dual MC on a 71 Swinger?

 

[prorac1]

IIRC, it was mandated that around 1967, all new cars had dual masters. Even on drum brake cars. But I don't believe it would have the correct piston size for the disc set up. Im planning on using a 1973ish manual disk master cylinder. Hope this helps, Eric L

 

[Pete in NH]

Hi,

I'm in the middle of putting Scarebird front disc's on my 69 Barracuda. I have a Raybestos MC36406 master cylinder to go on it that has a 15/16" bore.

Dual reservoir master cylinders came in, in 1967 as was mentioned. Disc brake masters have larger rear reservoirs and feed the front disc brakes. Disc brake calipers need more fluid to actuate than drum wheel cylinders.

 

[charger426]

I don't really understand your Q. 71 swingers will have dual reservoir master cylinder. I did a Scarebird front drum to disk conversation on my dart last fall and never changed the MC. With that said I know i need a proportioning valve for the rears since they lock up under hard braking. There was a long thread a few months ago about whether or not you need to change your MC when changing from drum to disk with the main point being factory disk MCs have a larger reservoirs. Disk brakes themselves don't need more fluid than drums to work. HOWEVER, if you the typical car owner that might never look at your brake fluid then changing the MC to a factory disk style will give you a higher amount of fluid that will fill the space that comes from pad wear.

 

[BillGrissom]

What charger426 said.
If you find it takes too much pedal force w/ disks, you can change to an MC w/ a smaller bore, in which case buy one meant for disks (see rockauto), i.e. a larger rear (front system) reservoir. Could also consider a vacuum booster.

 

[OUTLAW]

I did the Scarebird conversion on my 68 cuda several years ago (love it by the way) and I put a reman master for a manual disc/ drum setup and never replaced the proportioning valve and it stops great and straight from any speed

 

[Hankrebel]

Thanks guys for the info.
I will leave the dual MC on it now and see how it stops after the conversion.
I also forgot to ask about the wheel studs. The scarebid kit mentions getting longer studs but didnt say how much longer. Looking at rock auto, I see some that are for the front disc, rear drum setup but want to make sure they are correct before I order.

 

[Inertia]

There was a long thread a few months ago about whether or not you need to change your MC when changing from drum to disk with the main point being factory disk MCs have a larger reservoirs. Disk brakes themselves don't need more fluid than drums to work. HOWEVER, if you the typical car owner that might never look at your brake fluid then changing the MC to a factory disk style will give you a higher amount of fluid that will fill the space that comes from pad wear.

Well done..

cheers

 

[salinasjoel]

Switching to LBP and front disc on one car but on the other I was thinking of going the scarebird route as it is a more "finished" vehicle and I don't really care to swap axles and get new wheels and such. Can anyone in the process or who has done this tell me in all honesty what the biggest pain has been. I've heard its a lot more grinding and trimming then you are lead to believe. It would be going on a 69 barracuda with front 10".