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INSTALLING DISC BRAKES on a 61 Cadillac

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  • ja70cad
    Info found on www.caddydaddy.com website. A good parts source. By Carl McAbee Upgrading to disc brakes generally is not difficult for anyone with reasonable
    Message 1 of 1 , Jul 27 1:00 AM
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      Info found on www.caddydaddy.com website. A good parts source.

      By Carl McAbee

      Upgrading to disc brakes generally is not difficult for anyone with
      reasonable mechanical ability and can be very rewarding for those of
      us who prefer to actually drive cars that preceded the availability
      of disc brakes by a few years, ie, generally cars of the early
      1960's. I have made the swap on four different vehicles and can say
      I'm glad I did. One of them, a 1964 Chevelle, has gone over 300,000
      miles since the discs were installed with nothing more than one
      replacement booster, a few pads and an occasional bleeding.

      A word or two or more of caution: virtually all swaps require
      fabricating new steel lines to the front disc brakes as they need to
      be smaller diameter than the original drum brake lines, and they are
      now a separate system (front & rear). The outlet to the brake hose
      might need to be relocated to ahead of the suspension on the frame,
      as was required on the 1961. The line to the rear brakes can be
      lengthened and adapted to the equalizer which should be obtained,
      with lines, along with the master cylinder - booster unit. A tubing
      bender is a must, a flaring tool will allow you to do a neater job by
      creating custom tubing lengths. This part of the job requires endless
      patience, and by the time the job is complete you'll have started to
      get the hang of it. A wheel alignment will be required as a final
      step.

      So where to begin? First, determine if your vehicle's front
      suspension is similar if not nearly identical to the suspension used
      a few years later in the first model (or later model still) offered
      with disc brakes. If it is, your car could be a candidate for disc
      brakes! When in doubt, measure, measure and compare, measure and
      compare. If you can't find a disc brake car with suspension just like
      yours, ask at the wreckers - often they know what works and what
      doesn't - but not always. It's well known that early GM intermediates
      can get disc brake set ups' from later models as a virtual bolt on.
      In my case I found that the ball joints listed for the disc brakes
      are the same ball joints as the earlier drum brakes. My 1961 Cadillac
      got a disc brake set up from the 1969 DeVille model. The 1961
      Cadillac was the first year for the front suspension design that was
      used up until 1976, so presumably a 1962 - 1966 could also benefit
      from the use of discs from a 1967 - 1969. 1 recommend the '69 because
      all '69 Cadillacs had disc brakes and therefore parts are more
      readily available. 1967, '68 and '69 each use a different rotor and
      pads. 1970 through 1976 use a larger lower ball joint and the lower
      arm mounts differently inboard so they won't easily adapt to the
      1961. An auto parts dealer can be a wealth of information, if you
      call or visit when they are not busy. Tie rod ends and ball joints
      don't necessarily have to have the same part number to be the same
      size tapered end. When in doubt, a visit to the wrecking yard is in
      order. Bring a tie rod end or ball joint if possible but at least
      bring calipers and measuring tape. A good look at the donor car is a
      good idea also. Pay attention to where the equalizer is mounted and
      the steel lines run. Get as much of the brake system from the donor
      car as possible, including small brackets and the bolts, nuts and
      clips! You may not use it all, but it beats having to run back after
      something missed.

      I spent a lot of time researching and measuring for this job before I
      bought part one. The tie rod ends were a different part # so that
      necessitated my first visit to the wrecking yard. It was quickly
      apparent what the differences were, but the '61 tie rod ends were the
      same size and taper as the '69 steering arms and would work fine. So
      the steering and rotor assemblies are a bolt on - ball joint to ball
      joint & steering arm. But in 1961 the booster mounting studs were
      slightly farther apart than the '69's and so the holes in the
      firewall had to be altered slightly. There is plenty of support
      material so overall strength is not compromised. But the two lower
      studs on the 1969 booster are also much shorter. Solving this dilemma
      involved enlarging the holes in the firewall and the inside pedal
      support bracket. I used extra long 'coupling' nuts together with
      studs epoxyed into one end to

      ' Disc brake set up means: steering knuckle & arm, hub, rotor,
      caliper, etc. for each side, plus a master cylinder/booster

      unit, equalizer and the steel lines from the master cylinder to the
      equalizer; all from the same car if possible



      lengthen the too short lower studs on the booster. But this made the
      studs too long so I used a piece of tubing and a large flat washer to
      make it all work. I avoided modifying the booster itself, as it is a
      service part and might be needed as a core. The actuating rod fits
      the stud on the brake pedal perfectly, but is longer than the
      original 1961 by 1/4" and left the pedal way too high in the car. I
      solved this by spacing the booster out from the firewall 1/4". This
      puts the pedal at stock height; I would have liked to have spaced it
      out even a bit further to lower the pedal even more but the booster
      would then be too close to the engine's rocker arm cover. The brake
      light switch was still in perfect adjustment. An alternate way of
      resolving the pedal height might have been to relocate the pivot
      point of the pedal, which could be done.

      The original master cylinder fed the fluid straight down, the new one
      feeds horizontally to the left, directly into the inner fender, which
      must be modified for clearance. I cut a pair of slots less than one
      inch apart, and with the center strip bent out of the way, cut long
      enough (=4") to clear the forward fluid line from the master
      cylinder. The rear line cleared without modification.

      Wheels from a disc brake model are required to clear the calipers,
      and they also happen to increase the total track width by 3/4" (3/8"
      each side), This will also necessitate late model wheel covers, as I
      seriously doubt the 1961 covers will fit. Don't forget the spare
      wheel!

      While upgrading to disc brakes, take the time to inspect the rest of
      your suspension as now would be an excellent time to replace worn out
      bushings and ball joints. I always rebuild the master cylinder but
      have never needed to rebuild the calipers. I always use new rubber
      hoses to the calipers too. This is a good time to check and rebuild
      if necessary the rear wheel cylinders too. Check the rear hose(s)
      too! A through bleeding is in order after any brake work that opens
      the fluid system, and be sure to check for leaks, including seepage,
      for several days after! The 1969 DeVille used a junction block as
      well, to divide the fluid to the front wheels. This junction block
      also has a button on it which must be held out while bleeding the
      brakes.

      Upgrading to disc brakes is a fair bit of work but for the sake of
      driveability and safety, it's well worth the effort! This car is much
      more fun to drive, as now I can stop with the best of them
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