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Brake Pedal Rod Too Short?

Discussion in 'Early CJ5 and CJ6 Tech' started by EFranzen, Aug 5, 2023.

  1. Aug 5, 2023
    EFranzen

    EFranzen Member

    Queen Creek AZ
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    Nov 5, 2020
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    My brake pedal seems to be too low at rest. Any one happen to have the measurement for a dual master cylinder from a 69 CJ5?

    This photo is with the pedal at what seems to be the correct height and the rod is about 3/4" short

    upload_2023-8-5_17-16-22.png
     
  2. Aug 5, 2023
    alpina72

    alpina72 Member

    Georgia
    Joined:
    Mar 1, 2015
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    180
    I just put in a new Crown master cylinder a couple weeks ago, it was the same.
    Everything was identical with the one I took off except the original had "made in USA" on the casting.
    There is adjustment in the pedal height if you are handy with a grinder.
    Can add notches on the shaft between the pedal and the arm to shorten the throw.

    Was trying to post a picture but I can't seem to shrink the file size down enough.
     
    Ol Fogie likes this.
  3. Aug 6, 2023
    EFranzen

    EFranzen Member

    Queen Creek AZ
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    Nov 5, 2020
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    The problem is that the arm is too far back and very close to the master cylinder mounting bracket. I did think about adding to that rod you mentioned and still might.
     
    Ol Fogie likes this.
  4. Aug 6, 2023
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Southern...
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    Nov 24, 2019
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    If I changed the rod length, I would take close measurements of the original length of it first just for future reference in case you found the correct master cyl later. I would be tempted to try and find another factory rod to tinker with and save your factory rod. Also helm joints are available in multiple sizes and configuration's and size threaded bases. Might be you could fabricate an adjustable length rod too.
     
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  5. Aug 6, 2023
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Southern...
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    Just thinking :shrug:, with your new master cyl looking so closely like your old one. Is the cyl bore the same diameter in both of them? You might disassemble the old one and examine your old piston, (it must have a much shallower rod hole than the new one) and see if it's possible to swap them. you would need to just swap the rubber parts of the new cyl piston over to your old piston. Again, so long as the pistons are identical externally.
     
    vtxtasy likes this.
  6. Aug 6, 2023
    EFranzen

    EFranzen Member

    Queen Creek AZ
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    Nov 5, 2020
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    This is the same master cylinder that was on the Jeep when I got it and looking at old photos, I can see the arm in the same forward position. This was a 2 step master cylinder. My plan is to cut the rod, thread and then use a long coupling nut to make it adjustable.

    upload_2023-8-6_19-25-27.png
     
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  7. Aug 7, 2023
    Jw60

    Jw60 Cool school 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sedalia MO.
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    That's what I did but the coupling nut hit the spring retainer. I had to drill out a washer to clear.
     
  8. Aug 8, 2023
    duffer

    duffer Rodent Power

    Bozeman, MT
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    The sanitary way to fix this is to obtain a length of 3/8" steel rod (at least cold rolled quality), thread one end for a heim joint, and cut it to a length that will give some adjustment leeway with that heim joint. That is the way all my clutch slave cylinder rods have been made for the last 50 years.
     
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  9. Aug 8, 2023
    Jw60

    Jw60 Cool school 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sedalia MO.
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    Here is the rod on mine before it got cut:
    [​IMG]20230529_110847 by Joe with a jeep, on Flickr

    I used a threaded union but it hit the c shaped plate behind the spring clip here:
    [​IMG]20230529_073458 by Joe with a jeep, on Flickr

    [​IMG]20230529_125346 by Joe with a jeep, on Flickr

    If I were to do it again I think starting with a female thread heim like duffer suggests and cutting the head off a bolt would be easier. Chuck the threads of the bolt in a drill and cut it with an angle grinder. Then you can make a decent dome on the cut bolt. Use mild thread locker once you are happy with the length.
     
  10. Aug 9, 2023
    EFranzen

    EFranzen Member

    Queen Creek AZ
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    Thanks for the tip. I have some 3/8 rod and a heim joint left over from another project. Better than destroying the original this way.
    Interesting that you had to shorten yours and I need to lengthen mine.
     
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  11. Aug 22, 2023
    EFranzen

    EFranzen Member

    Queen Creek AZ
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    I ended up buying a cheap adjustable rod for a Ford for mine. I had to weld a washer to the tip and cut it down, but it's in and the pedal looks correct now.
    upload_2023-8-22_18-24-58.png upload_2023-8-22_18-25-8.png
     
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  12. Aug 22, 2023
    Jw60

    Jw60 Cool school 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sedalia MO.
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    Do you have a link? It looks better than mine.
     
  13. Aug 23, 2023
    EFranzen

    EFranzen Member

    Queen Creek AZ
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    Ol Fogie, jeepstar and Jw60 like this.
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