Removing Master Cylinder 57 Special

Discussion in 'Classic Buicks' started by Dznuggets, Oct 22, 2016.

  1. Dznuggets

    Dznuggets Active Member

    I'm trying to remove my master cylinder and the manual calls for tool #6618 to remove the large nut from the cowl. I've tried channel locks and vice grips but can't seem to get a good grip. Any advice out there? Does anyone have tool #6618 or is this a long lost item? Any suggestions as to the size of the nut? Maybe I can buy a wrench and bend it to fit.

    Thanks as always
     
  2. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    Flat blade screwdriver and a hammer to spin the nut.

    Wait, does it have power brakes? If so, you can spin the entire booster and MC off from the outside if you have someone inside who can hold the nut in place.
     
  3. Dznuggets

    Dznuggets Active Member

    Yes power brakes. So find some vice grips that I can get to fit up there and have someone spin it? Excellent. Thank you
     
  4. BUICK 57

    BUICK 57 Well-Known Member

    . Here's what you do. Here are the steps I used to get mine off as follows:

    What you are going to do is remove the entire M.B. assembly out in one complete piece via the engine bay not from under the dash.

    So with that said:

    Get a pair of round wide mouth vis-grips. The kind when fully closed allow for approx. a 2" diameter ABS pipe to slip through.

    Get a pair of needle nose pliers as you will be removing a cotter pin. Also have a small diameter punch like a nail punch. Including a med sized standard screw driver as well. You also will need an adjustable rubber strap type oil filter remover tool. You know the kind you can adjust around various size diameters. What you will be doing with this is strapping it around the large diameter M.C. plunder chamber that attaches to the firewall housing. It is held on by the 4 bolts as mentioned below.

    So Open hood of car and located the 4 hex head bolts that hold the power brake canister to the firewall enclosure. Remove these bolts.

    Disconnect your brake line from the front of the M.C. and remove the brake light harness cable connector from the sensor pod.

    Gathering your tools and wide mouth vis-grip , get inside the car from the passenger after moving the front seat back fully and slide up under the dash so your head pointing toward the driver's side and you are on your left side facing the engine.

    Now look up into the bracket area where the push rod goes into and through the firewall. Remove the cotter pin and remove free the push rod from it's clevis by removing the set pin.

    See attached photo of removal strap and wide mouth vis-grip:

    Take the 2 screws out that hold the transmission white shift rod positioning assembly and move it over to the side out of your way. Put the screws back so you do not lose them. Master Brake Removed: Rbld 1.jpg
    Do not worry about attempting to remove anything else from under the dash.

    Now take your wide round mouth vis-grip and approaching the bracket that encases the push rod and the large 11/16" nut from the passenger side, you should be able to grip this large nut with the wide mouth vis-grip. This is how I have done it. If you wiggle yourself just right you can access the nut and grip it with the wide round mouth vis.

    Now get out of the car and install the rubber strap tool around the canister. Now you will be able to grip the canister assembly with the M.C. attached to it and be able to turn it.

    Remember since you have the nut on the inside of the firewall secured with your vis-grip it will hold the nut from turning . Since is is almost impossible to get a wrench or socket up into this area, we hare securing and holding the large nut with the vis-grip. So you will be turning/spinning the canister from the engine bay counter clockwise. It will give you some initial resistance but be firm and take your time attempting to turn/spin the canister. When free from the initial resistance, keep turning/spinning until the nut falls off onto the floor board inside.



    Now simply remove the entire assembly out of the engine.

    Gather up the set pin, cotter pin and large Hex Nut and reattach to the pushrod and clevis.
     
  5. Dznuggets

    Dznuggets Active Member

    Thanks for the replies fellas! I had someone to finally help and using a channel locks I got the nut loose. Good to know that there is help out there. Thanks again.

    Now for the fun of removing the the exhaust manifold on the driver's side. This may require another post. Hahaha.
     

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