1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

D27 Disc brake swap on my 71'

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

  1. Dec 29, 2006
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,322
    I really need to quit aksing dumb questions. The bolt supplied is the right diameter and fits, it was too long but right size.
     
  2. Dec 29, 2006
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
    Joined:
    Nov 6, 2002
    Messages:
    4,275
    The only dumb question is one that you don't ask... and spend hours/days trying to figure it out on your own!
     
  3. Jan 7, 2007
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,322
    OK, Quick update.
    I rebuilt the brake/clutch shaft with a new shaft from Krage's. Installed the AA clutch linkage, ran the brake lines as outlined (front to rear, rear to front) Spent countless hours maiking new brake lines and remaking brake lines. I think I am finally rid of all leaks. Mind you these were less than 12 inches long from the M/C to the res. valve.
    Good news, I now have almost full pedal when I push the brakes. I think the biggest help on this one was the tip to switch the brake lines. I hope to get it on the ground and try it out tonight.

    More updates to follow.
     
  4. Jan 9, 2007
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,322
    Well I finally drove it with the disc swap. All I can say is WOW. I had 11" brakes prior to the swap. They did the job but I had some pretty scary trips after a few water crossings. I have not had these in water yet but I tired it out on the street and it stopped extremely straight. I used to have all kinds of problems getting the 11" adjusted right. I also could lock up the front brakes, something I could never do before. All in all after many, many, many hours and much great advice from this forum I am happy with the results. The 2 most important steps in my opinion to remember are:
    1. Make sure you have the correct routing on the brakes lines (front outlet - rear brakes, rear outlet - front brakes)
    2. Use organic brake pads.

    Thanks again to everyone here that helped with advice and encouragement.
     
  5. Jan 10, 2007
    1960willyscj5

    1960willyscj5 Well-Known Member

    Mesa, Arizona
    Joined:
    Nov 27, 2006
    Messages:
    2,793
    :) Herm the overdrive guy, also handles a dual-master cylinder. Should come with all the plumbing instructions. Or you could ask him.:coffee:
     
  6. Jan 10, 2007
    barucker

    barucker Member

    St. Louis area
    Joined:
    Nov 10, 2006
    Messages:
    87
    I don't know how many times I have read this thread, but I learn every time! Thanks guys. My '66 CJ-6A is sitting on three wheels awaiting the disc upgrade after the linings fell off of the shoes and I lost all brakes. I have a '74 scout donor vehicle that appears to have the 11/8" rotors and the right calipers/brackets. I am just waiting on the things all Jeepers lack... time and money. I have emailed with Herm, and plan on using his dual chamber reservoir disc and drum M/C and bracket. It is my understanding this M/C is for discs and 11" drum rear. Has anyone tried it with 10" rear, or should I go ahead and swap those (to 11" drum)also?
     
  7. Jan 10, 2007
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    12,529
    You can swap the rear to 11". Makes a big difference. The Scout donor brackets will work but may need to be re-drilled. Most Scout 2 brackets were 8 bolt and Jeep is 6 bolt. There were some very early Scout disc brake set ups that used a 6 bolt bracket though like Jeep. You can re-drill these by using the Jeep spindles as a guide. Done it many times and works good. Two of the holes line up already but can't remember if they clock the bracket correctly. Make sure the bracket is "clocked" in the position you want before drilling the holes in relation to the knuckle for caliper clearance. The Scout donor will allow you to use the brackets (after redrilling), the calipers, bearing hubs, rotors, and IIRC the hoses, although unless in real good shape I'd replace 'em for safety sake. Nickmil
     
  8. Jan 11, 2007
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,322
    Side note, somewhere along the line I had to change the M/C, early Nov. 06. I used one that is intended for a disc swap from a local parts house. This unit looked stock to me, mounted on the frame. Not sure how to tell the difference.
     
  9. Apr 4, 2007
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,322
    Finally got to try out the brakes. What a difference. I am extremly happy with this conversion. I drove to Hoillister 2 weeks ago (about 50 miles one way) for a day of fun. The brakes stopped straight everytime. I really put them to the test on some steep descents and they worked great. I did not have a chance to try them out in the water yet but I think I will be just as happy. I have attached a picture of the pass side for you to see.
     
    Last edited: Apr 4, 2007
  10. Apr 4, 2007
    zed

    zed Iowa- Gateway to Nebraska

    central iowa
    Joined:
    Aug 4, 2004
    Messages:
    745
    nice lookin!
    i am slowly collecting parts. actually found the 1/2 ton chevy mounting plates. what was the brand and part number of the rotors and calipers you used. were they the same ones listed in the tech section?
     
  11. Apr 4, 2007
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,322
    I went to the bone yard and pulled the calipers off a 82' Chevy Blazer along with the mounting brackets. A friend that works at a repair shop got me the rotors. I don't have a part number but NAPA has them.
     
  12. Apr 4, 2007
    zed

    zed Iowa- Gateway to Nebraska

    central iowa
    Joined:
    Aug 4, 2004
    Messages:
    745
    thanks
     
  13. Jun 12, 2008
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,322
    I have seen a number of folks doings this conversion and thought I would list some part numbers:
    Dual Master Cylinder for 1971 - Raybestos MC36365, Brake Pads (organic) Raybestos RRD52
     
    eldoradojim likes this.
  14. Jun 12, 2008
    Smokie

    Smokie Member

    Rolla MO
    Joined:
    May 27, 2008
    Messages:
    53
    Hey guys, one thing I found out on my front disc swap is, any of the calipers that we are using for this conversion that are I think '83 and older have standard size hose ports. '84 and newer have metric size hose ports, so make sure you get the right hoses and banjo bolts. Ask me how I know this....:D
     
  15. Oct 23, 2022
    eldoradojim

    eldoradojim Member

    El Dorado, Ca
    Joined:
    Aug 11, 2022
    Messages:
    101
    Hi, I know this is an old thread but i just put dana 44 axles in my 69 cj5 , front disc brakes on the front, I have the original dual reservoir master cylinder..I removed the residual valve from the rear port, installed a 2 lb residual inline valve , that now goes to the front brakes....hooked the line that goes to the rear brakes to the front port....I bled the brakes and now the rear brakes arent releasing....everything is new on the rear brakes....any ideas of what could cause this?????
     
  16. Oct 23, 2022
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    12,529
    When they don’t release loosen a bleeder fitting and see if fluid squirts out. If it does it is hydraulic pressure being held in the system. If not it is mechanical within the drum brakes. Wheel cylinder pistons stuck, incorrect assembly, something came loose, etc.
     
    eldoradojim likes this.
  17. Oct 24, 2022
    eldoradojim

    eldoradojim Member

    El Dorado, Ca
    Joined:
    Aug 11, 2022
    Messages:
    101
    thanks, I checked today and they are working completely normal,very weird but im glad....
     
New Posts