Master Cylinder conversion for disc brakes on a 55 Buick Special

[Guest 55HDTP]

Does anyone know how to do this? I have the car in a rolling chassis and I've converted over to Wilwood Disc brakes all around. I need a master cylinder

Thanks,

Mark Vaughan

[old-tank]

Mark, that sounds like a neat project and I hope you detail it with pictures and prose. I can't with anything other than a stock brake setup. Hopefully there is a local hotrod fabricator type shop in your area that can help. A friend that had built lots of hotrods with an under floor dual master cylinder had problems with a 54 Buick project similar to yours. He used boosted master cylinder (same one used on other projects) and it would not stop the car! Turned out that the replacement needed a 6:1 pedal advantage vs. the stock 1:1 of the stock setup.

Always remember: "when you change one thing you create 3 more problems"

Willie

[bhambulldog]

here's a guy that converted to disc brakes and dual MC on his '55

http://www.v8buick.com/showthread.php?216402-1955-super-master-cylinder-and-brake-upgrade-questions&highlight=1955

[bhambulldog]

here's another on a '57 buick

http://www.v8buick.com/showthread.php?232991-Master-Cylinder-Booster-options-for-57-buicks

[Guest 54fins]

I'm familiar with a 54 setup and a 56, which then goes on the cowl. I think a 55 is like a 54, under the floor but correct me if I'm wrong, but I'll shoot from the hip a bit.

I assume you went with 4 wheel disk brakes, and want a dual master with a power booster. I had to make an adapter, but you push the brake and a rod pushes the master- simple enough. The power setup uses a long rod to a booster, almost back to the rear seats. But a modern setup is smaller and you get a dual master. I went back on 1 and front on the other, although some cars go dual diagonal. I figure if I loose system pressure then rears or fronts will still give a nice even stop, from a safety standpoint. It was simple, but there was not an adapter I was aware of for a modern master to a 54 buick, so I had to make one, but it was pretty simple. Keep in mind that chevy tri 5 stuff doesn't work with a buick. I did find out that the power booster was set back so the under seat heater would have room. I also ran a fill line up the cowl, undercar masters are hard to service. Last, disk and drum brakes have different pressure requirements but the main issue is balancing the stopping force between the front and rear. You do not want to lock up your rear end too soon, it needs to lag the front brake so you need a balance valve. fronts do most of the work, the rears do more to stabilize the stop and keep the car under control.

As for a brand, I got the master/booster from speedway, a generic hot rod setup and it was simple, with the body off. Body on might get a bit more tricky, but It's not very complex. The only issue was mounting it and getting the right length rod from the brake pedal pivot. If you are not comfortable doing this I would not think it to be too expensive at a shop. I would think they could do it for under $1000 with parts, any more should be questioned. Note, I used the original brake lever and pivot

Edited June 8, 2014 by 54fins (see edit history)

[bhambulldog]

That's a neat trick 54fins.

nice work

[buick5563]

Thanks, Fins

[Eric W]

54fins - can you answer Willie's question - have you driven it yet & is the pedal effort reasonable for the stopping power? Or would it be better to change the ratio?

[bluebetsy]

On 6/6/2014 at 10:45 AM, Guest 55HDTP said:

Does anyone know how to do this? I have the car in a rolling chassis and I've converted over to Wilwood Disc brakes all around. I need a master cylinder

Thanks,

Mark Vaughan

I know this thread is 10 years old, but I'm wondering if you were ever able to make this work?