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Disc Brake Conversion

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  • Disc Brake Conversion

    First off, I had a blast at the White Elephant party, it was my first one and it didn't disappoint! My boys also had a lot of fun and I can't say thank you enough for those invoved for putting it all together!

    As I made the trip down to Tacoma in the rain, I realized that I really need to get some new brakes, yikes!! I'm inching closer to finally converting my scary front drum brakes set-up to the Original Cooper "S" 7.5 Disc brakes. I have a few questions as I start looking into the purchase, all and any input is greatly appreciated! Which kit(s), where to buy, etc.

    My initial thougts are just going with the original 7.5" Cooper S Brake kit that includes the "Genuine Calipers" (part # C-AJJ4028). Has anyone used the kit that offers the "non Genuine" Calipers? That kit is a little cheaper, but if I'm doing this, would you recomend I just go with Genunine Calipers for the few extra $$?

    Best place to order from (as far as price goes).... is I'm waiting to hear back from mini Spares with a shipping quote.

    Thanks again for any input!


  • #2
    I was going through the same issues as you are. I had gone back and forth on replacing the front brakes to discs but kept putting it off as I was concerned about the tires sticking to for outside of the tire well. At that time I had 165/10 on Cosmic II wheels. I really did not want to put spats on the car. In addition, I rebuilt the drums last winter and although the car stops great I just did not feel safe with all of the other drivers cutting in front of my Mini since they do not realize how small our cars look in their mirrors.

    Since then I have changed to 145/10 which has helped in the amount the tire sticks out, they may still stick out but not as far as 165 did. I went ahead and ordered a set of 7.5 Cooper S disc brake kit. I ordered the kit assembled so as not to have to deal with assembling the various parts.
    I did a lot of looking around and talking with Chuck and decided on the kit with the aftermarket calipers. They appear the same (without the AP on the side) are well made and require the same pads and rebuild kits as the AP branded calipers. What also helped in this decision is the overall cost savings which depending on who you order the kit from can be as much $300 (Se7en).

    I ordered my kit from GB car parts which received them from Mini Spares. Ultimately saving on the cost from shipping overseas. All total shipping etc. came to less than $1k.

    I have not installed them yet as I’m waiting to receive additional parts such as the smaller rear wheel brake cylinders GWC1101 (5/8 vs. ¾). Once I receive the additional parts I will be taking the Mini to Chuck’s for his assistance to install them. I figure if something does not go as planned, such as the drive shafts not separating as planned, Chuck will be there to save me and the Mini.

    Hope this helps


    • #3
      What they don't sell with the kits:
      New front brake hoses. Time to change them most likely.
      Smaller diameter rear wheel cylinders.
      Spacered rear drums (or spacers, studs and screws). The discs are making the front track wider. Time to do the same at the rear.
      The more I know about Minis, the more I know I don't know about Minis.


      • #4
        Sounds like we are in the same boat there Steve, it might just come down to the cost for me. I see that GB Car Parts has a pretty tempting sale on that kit w/aftermarket calipers right now, but the kit doesn't show in stock as of now, so I'm not sure they still honor the sale price or not.

        Chuck- I'll take a look at the front brake hoses, I suspect they were most likely replaced already by the previous owner, he was not shy on replacing just about every rubber part on the car during the restoration. As far as the rear drums go, I've recently replaced the rear drums with the built in spacer so I should be set there.


        • #5
          On the brake hoses on the front. The hoses are different on the disc setup. The drum hoses will not work on the disc setup.
          Chris Miller


          • #6
            Originally posted by cmiller View Post
            On the brake hoses on the front. The hoses are different on the disc setup. The drum hoses will not work on the disc setup.
            Chris Miller
            Duly noted Chris, thanks!


            • #7
              The drum hoses are slightly longer. The disc ones were made shorter so they wouldn't rub on the tie rods. I'd hazard a guess that the longer hoses life span wouldn't make it past 50 years based on where they hit and how often!
              Another option is to change to the braided type.
              This is a good time to change hoses because they almost always have to be refitted anyway to keep them from twisting badly when used with the new calipers. It's one of those, "as long as I am there" things.
              The more I know about Minis, the more I know I don't know about Minis.


              • #8
                Do I need to change the brake master Cylinder?


                • #9
                  The longer hoses with disc brakes are required to have a U-shaped bend in them that seems to wear out the hoses quickly. I had a set that looked to be in very good shape but when I put on the discs neither would pass fluid. They had completely broken down internally.

                  Fender flairs can be avoided by choosing the right wheels. If you like aluminun wheelse the Mini Spares 4 1/2" Minilife wheels are good. If you like steel wheels there are 4 1/2" Cooper 'S' wheels and 4 1/2" regular Mini steel wheels (I need to check the offset of these).

                  If you can afford the car, you can afford the manual...


                  • #10
                    Kelley, I currently have the sport pack flares, and have the 13x7 Minilites so the fitment shouldn't be an issue.
                    Last edited by Old No.7; 02-10-2015, 01:36 PM.


                    • #11
                      I have the "yellow tag" master and it works fine with my disc setup. As Stated above, you will need smaller rear wheel cylinders, 5/8 I believe. Also, you will need 1" rear wheel spacers as the 7.5 cooper s discs are wider (I think I have a set if you go that route).
                      I would definitely get the full (front/rear) braided hose kit as well.


                      • #12
                        Now you've opened up an entirely new subject. If you are going to stay with 13" wheels (or go down to 12" wheels) you'll want to go to the later 8.4" discs fitted to all Minis starting in late 1984.
                        The more I know about Minis, the more I know I don't know about Minis.


                        • #13
                          I was kind of wondering about that Chuck, I do plan on staying on staying with the 13" wheels so I guess I need to re-evaluate my search.


                          • #14
                            Originally posted by 80_estate View Post
                            ... As Stated above, you will need smaller rear wheel cylinders, 5/8 I believe. ...
                            Out of curiosity, are the 5/8" wheel cylinders needed because the extra volume of the 3/4" ones makes the pedal travel too far?



                            • #15
                              You are correct.

                              Chris Miller