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D27 Disc brake swap on my 71'

Discussion in 'Early CJ5 and CJ6 Tech' started by jzeber, Mar 18, 2006.

  1. Nov 2, 2006
    mortten

    mortten I can’t put my finger on it 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Peninsula, Ohio
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    Pull out the diaphram and the spring and you're done.
     
  2. Nov 2, 2006
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    One thing I'd like to add to this thread is if you are not using a power booster, make sure you use organic pads on the disc brakes. Semi-metallic pads were designed to be with used with a booster and can actually require more pedal effort than drums if used with manual brakes. Organic pads are softer and will offer better braking with manual brakes. While they do fade faster than semi-metallics, really not an issue on a light weight Jeep. Plus organics don't have the tendency of chewing up rotors like semi-metallics do. Nickmil
     
  3. Nov 2, 2006
    Vhunter

    Vhunter Member

    Redding, California
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    Can somone clarify this, seems to me that the only thing on my MC that has a big nut is the bottom hole for the brake light switch to be screwed into. So, how do you remove the brass flare insert that is in the hole for the brake line and is the residual valve under it, and what comes out. Can you please discribe in detail so I don't screw up my MC. Thanks,
     
  4. Nov 2, 2006
    mortten

    mortten I can’t put my finger on it 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Vhunter-Are you talking about the old style single master cylinder?
     
  5. Nov 2, 2006
    Vhunter

    Vhunter Member

    Redding, California
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    I am using a MC from a 1971 Jeepster with manual brakes, dual reservoirs and a 1 inch bore (good for disc brakes). It has the inlets for the brake lines on the passenger side so it won't interfere with my clutch MC (using hanging pedals) and it has a bottom hole to mount the brake light switch (so it is nice and easy to get to for wiring). But, I need to remove the residual valve for the line to the front disc brakes and put in the summit residual valve for disc brakes. So, I need to know how to do it and what am I taking out and where is it, I am assuming it is under the brass flare insert in the outlet port. Thanks in advance for any advice,
     
  6. Nov 2, 2006
    mortten

    mortten I can’t put my finger on it 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Peninsula, Ohio
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    The original Jeep dual MC had threaded inserts on them. You simply remove the insert and then the check valve. Some of the aftermarket ones I've seen have the typical pressed in inserts. If this is the case with yours the Haynes manual says to thread a sheetmetal screw into the hole in the insert and pry them out with 2 screwdrivers. They go on to say to replace the inserts with new although I have never been able to find any of these at any local FLAPS. Therefore I have never removed them. Mine had the treaded inserts.
     
  7. Nov 2, 2006
    Vhunter

    Vhunter Member

    Redding, California
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    Oh, and I am sorry for hi-jacking this thread. I just thought since we where on disc brakes I would ask some questions and help others that are going to do this with understanding what needs to be done, including me!
     
  8. Nov 2, 2006
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    I have a replacement dual MC. I unscrewed the front brake line and that is where the large nut is located. It is actually a fitting that screws into the MC. I removed it and felt a diaphram. Tonight I am going to remove the diaphram and spring as noted above. I found the Wilwood 2# residual pressure valve at a speed shop near my house. I plan on plumbing that into the brake line like in the write up in the tech section.

    Thanks again for the great feedback and tips.
     
  9. Nov 2, 2006
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Finished pic. I have others in another thread
     
  10. Nov 2, 2006
    nyejos11

    nyejos11 Member

    Emmaus, PA
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    I am interested in doing this swap also. Please give us a review of the non-power disk brakes over the drum brakes when you are finished and have tested them out. I dont know if it is worth the $ and trouble.

    Thanks,
    Josh
     
  11. Nov 2, 2006
    mortten

    mortten I can’t put my finger on it 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Peninsula, Ohio
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    I did all four wheels after having both 9" cams and 10" self adjusting. Stops straight and true. I would never go back. Power is in the near future.
     
  12. Nov 6, 2006
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    OK,
    I have the diaphram and spring out. I am using a power bleeder and I can't find any leaks in the new lines but I still have no pedal. Any guesses? Was I supposed to leave the rubber diphram and spring out?

    Thanks as always!
     
  13. Nov 6, 2006
    Posimoto

    Posimoto Hopeless JEEP Addict

    Minden, Nevada
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    Did you install the calipers so the bleeders are on top?
    Did you bench bleed the MC as per the directions?
    Did you bleed the wheel farthest from the MC first, then work your way back to the one closest to the MC?
     
  14. Nov 7, 2006
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    X2. I bled and bled and bled some more until I realized I had the calipers on the wrong sides. If the bleeders are on the bottom when the calipers are installed, they'll never bleed all the air out. :rofl:
     
  15. Nov 7, 2006
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Yes, yes, and yes. I am going to bench bleed the MC again tomorrow night and see what happens. I think I will ditch the power bleeder and get my son out there to help me the old fashioned way also.

    Thanks for the input.
     
  16. Nov 7, 2006
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    Speed bleeders are the cat's a**. ;)
     
  17. Nov 7, 2006
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Pasenger side!
     
  18. Nov 8, 2006
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Bench bled the MC again last night, re-bled each wheel. The pedal came back up but when I drove it I could hardly stop and the pedal when straight down to the floor. I am going to remove the MC and see if I can find a rebuikd kit.
    This past summer during a weekend 4 wheeling trip my MC was acting up. After a long day of trails we left the next morning and the pedal went to the floor so I think there must be a gremlin somewhere.
     
  19. Nov 8, 2006
    Posimoto

    Posimoto Hopeless JEEP Addict

    Minden, Nevada
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    Could be an internal leak in the MC. I had that happen with my clutch MC.
     
  20. Nov 8, 2006
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Supposed to leave for Pismo Beach Ca on Friday at 9:00 am.
    I just ordered a new MC that should be here by 11:00 am tomorrow. Now I just need to bench bleed it, install it and bleed all 4 corners before leaving!
     
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