1957 Buick -- Stymied Again w Master Cylinder Removal


Trying to get the Master Cylinder off my '57 and it is NO SIMPLE TASK!!
Some Designer Idiot decided that in addition to the four bolts that hold the unit to the firewall that it will be held with about a 2" nut. This nut is impossible to get to because it is right behind the bracket that holds the steering column in place etc.. I see no way to get this nut off sans removing the entire steering column which seems like huge overkill. They call out using a special Buick tool #6618. I have no idea what it looks like. Thinking I could perhaps get it off with a crowfoot I purchased a $96.00 set because I didn't know exactly what size it was. I am having no luck with that either as it is so tight that I cannot get even the crowfoot on the nut. Are there any old Buick Mechanics on this site that can give me any enlightenment? Sure would be appreciated.
Buicknut Lee
I had a look at my '57 shop manual and I see it doesn't show a picture of the wrench :( .

Soo, all I can give you is sympathy:jeez: . If you buy a large open end wrench could you see some way to bend it that it might work?

Good luck


57 stymied

I looked in my manual as well but no luck. Another good place to post your question is on the Buick Club of America site. Those who know old Buicks are found there!
Good luck....Wayne - 1957 Buick Roadmaster Model 73


New Member
Hi, I know what your going through. I had to remove my 57 master also. I didn't have the "special" tool but found the best way for me to remove it was to use an air chisel with a long offset chisel. One like you would use to remove exhaust but long. Maybe you could use a long chisel with a blunt pointed end also. I think the one I used was about 12 inchs long. You'll need the length to get around the steering column etc. Anyway just work the chisel to gradually loosen the bolt, counter clockwise if I remember correctly. Go gradually if you want to save the nut. I intend to go to a power booster so I wasn't to worried about saving it. Then only the linkage has to be removed and the master should come right out. I have removed the plenum on mine also. I will have a plate made to cover the area the plenum covered and mount a late model power booster to this. I saw this done on another 57 and liked the setup as it is neat and compact compared to other conversions.
Anyway good luck with yours :thumbsup:.

John Zeleznik


Active Member
Did the chisel routine on mine also--seemed when it broke free it just spun off by hand. I used a 1/4 inch plate on the vent cover and mounted my new booster on it--of course you have to make a new rod and put some threads on it for adjusting. I also did some bending on my brake pedal to get the travel I needed---Good Luck:thumbsup::thumbsup::thumbsup:


Talking 1957 Buick -- Stymied Again w Master Cylinder Removal

Well still no further ahead. Tried everything! I was able to find out what the Buick tool looked like to remove the nut. It was a thin-walled socket approx 4" long that had (7) 17/32 holes drilled through the neck of the socket. There was a 1/2" rod that cam with the tool that had a bent 30 degree end. If I could find a thin walled tall socket I could perhaps drill a hole in the top of it and accomplish the same thing. Still searching for an answer.