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    Rear Brake Calipers (need advice)

    Alright, my 88 GTX build is at a stall because it can't stop. The front is getting the Galant upgrade but I still need to worry about the rears. Here's my delima:

    The rear's are in alright condition. I was hoping I could get away with a new set of pads but it's not looking to be that easy. It looks like I need to rebuild the calpiers and refinish the rotors....so should I rebuild everything or just buy new?

    Priced out it looks like the rear set up will run me about $680.

    So the real question is, how hard is it to rebuild the rear calipers and refinish the rotors?
    sigpic
    The Beater and the Race Car....guess which is which!
    Little boys play in the street, real men play in the dirt"

    #2
    rear calipers are a pain to rebuild

    just buy new rotors
    Escort GTR -- 11.87 @ 117.6 mph -- 320 HP / 325 Ft. Lbs. @ 23 PSI
    ... The first FWD BG with a Toyota E153 transmission conversion in the USA!
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      #3
      i did the same but i kept the stock calipers up front and rebuilt all the calipers and really the rear are not fun at all. i failed twice at rebuilding the rear left caliper so i am just buying a newer but used caliper. if you have the money just buy new or have someone else rebuild them.

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        #4
        Looking at the manual they do not look easy, lots of parts in the parking brake system. But with the manual it looks doable.
        88 323 GT - 03 Protege5 - 07 Mazda 5

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          #5
          upgrade the rears too@!!!!! rear rotors from the same galant and 90-93 miata rear calipers.

          1988 White GTX - #1 parts
          1988 Black GTX - #2 reliably broken touge monstar (294,000 miles no rebuilds) - dead
          1988 Blue GTX - #3 in progress (view here)
          1988 Blue GTX - #4 BPT swapped weekend warrior.
          1988 White GTX - #5 Rally car

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            #6
            are the stock brakes that bad? Owned my 323 for 4 years and never have driven it... I am a slacker of highest degree.
            88 323 GT - 03 Protege5 - 07 Mazda 5

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              #7
              No, it's mostly to get rid of the captive rotors for me... That and its a race car.

              1988 White GTX - #1 parts
              1988 Black GTX - #2 reliably broken touge monstar (294,000 miles no rebuilds) - dead
              1988 Blue GTX - #3 in progress (view here)
              1988 Blue GTX - #4 BPT swapped weekend warrior.
              1988 White GTX - #5 Rally car

              Comment


                #8
                Originally posted by 808 View Post
                upgrade the rears too@!!!!! rear rotors from the same galant and 90-93 miata rear calipers.
                you need a bracket made for this upgrade to work
                "See that car, in the 80's that car was deadly." Random man to his son while passing the GTX in a parking lot

                Originally posted by neuspeedescort
                the proper spelling would be "Launchabilitiness" i do believe.
                -88' Mazda 323 GTX, 1.8t, Modified Magazine May 2012
                -88' Mazda 323 GTX, caged and ready for dirt
                -93' Mazda Miata, half caged
                -09' Mercedes C63 AMG
                -87' Toyota Land Cruiser, 33's with slight lift, safari style!

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                  #9
                  Thats what I thought, now that I have a shop press captive rotors are of no concern..
                  88 323 GT - 03 Protege5 - 07 Mazda 5

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                    #10
                    Well it also equalizes the brake bias.. With just the fronts upgraded you'll be biased towards the front.. a lot.

                    1988 White GTX - #1 parts
                    1988 Black GTX - #2 reliably broken touge monstar (294,000 miles no rebuilds) - dead
                    1988 Blue GTX - #3 in progress (view here)
                    1988 Blue GTX - #4 BPT swapped weekend warrior.
                    1988 White GTX - #5 Rally car

                    Comment


                      #11
                      I also did the rear Gallant and Miata rear calipers because I wanted to get rid of the captured rotor.

                      This does help move the brake bias back where it needs to be. I used the front Gallant setup for years and you will lock up the fronts in the wet and dry so much easier. I could actually feel the difference and it makes for a faster GTX because now I can brake deep and not worry about the fronts locking up.

                      Bob Martin in the 323GTX@yahoo groups had the adapter plates made, but his original reason was to use OEM GTX fronts in the back, and use Ford Contour rear calipers. I found that the Miata ones also bolted right up with minor shimming and grabs a larger rear Gallant rotor.









                      Greg Downing
                      Beautiful Downtown Spanaway
                      Washington State USA
                      gpd323@earthlink.net

                      Comment


                        #12
                        That is awesome work man! I bet that thing stops on a dime. Any plans to use a larger bore master cylinder?

                        Though that would only make the length of push shorter, perhaps you could lengthen the brake pedal arm to give more leverage, more force.
                        Last edited by sethro_GT; 12-06-2009, 12:14 PM.
                        88 323 GT - 03 Protege5 - 07 Mazda 5

                        Comment


                          #13
                          Originally posted by sethro_GT View Post
                          That is awesome work man! I bet that thing stops on a dime. Any plans to use a larger bore master cylinder?
                          I have had the Protege vacuum canister and the 929 master cylinder on my GTX for a very long time ago (July 2006). This combo creates a very firm pedal and braking can be done very precisely.

                          With the Gallant rotors all around and the Porterfield R4 race pads I can do lapping track events lap after lap with never any fade or a soft pedal.

                          I use the R4S pads on the street. I feel this brake upgrade is all the GTX will ever need. It now has the ability to lock up the wheels if needed and has plenty of brake reserve for any applications. These are my opinions.

                          You can get bigger brakes on the GTX, but using the Gallant non captured rotors and the increased size makes this upgrade very doable and relatively easy.

                          Greg Downing
                          Beautiful Downtown Spanaway
                          Washington State USA
                          gpd323@earthlink.net

                          Comment


                            #14
                            Originally posted by gpd323 View Post
                            I have had the Protege vacuum canister and the 929 master cylinder on my GTX for a very long time ago (July 2006). This combo creates a very firm pedal and braking can be done very precisely.
                            good to see your on cp now, what year pro booster and what year 929 mc are you running?
                            5 boosted bp cars,why...

                            Comment


                              #15
                              Originally posted by toronto323gtx View Post
                              Alright, my 88 GTX build is at a stall because it can't stop. The front is getting the Galant upgrade but I still need to worry about the rears. Here's my delima:

                              The rear's are in alright condition. I was hoping I could get away with a new set of pads but it's not looking to be that easy. It looks like I need to rebuild the calpiers and refinish the rotors....so should I rebuild everything or just buy new?

                              Priced out it looks like the rear set up will run me about $680.

                              So the real question is, how hard is it to rebuild the rear calipers and refinish the rotors?
                              If you want to stop better just upgrading to the Galants up front only will make it stop worse. It will just make the overly forward brake bias worse than it already is. Youre better off just getting more aggressive pads custom made.

                              The upgraded Escort GT caliper for the larger Gallant front rotor has a bigger pistion bore than stock 2.13” versus stock 2.01” so it shifts the bias further forward. Sure it won’t overheat on the track as easy because of the larger rotor mass but it due to the messing up of the bias ratio with the rear it won’t stop as quickly.

                              The Galant rear upgrade uses a Miata rear caliper. That has a bore of 1.35” versus the stock rear bore of 1.19”

                              Rotor diameters
                              Stock f/r are 259.7mm/246.9mm
                              4 wheel Gallant upgrade are 266mm/265mm

                              Bias works out 75% to the front with the stock configuration.
                              If you just upgrade just the fronts you end up with 77.7% to the front.
                              If you upgrade all 4 with the Miata rear caliper the bias comes out 71.4% to the front.

                              With the 4 wheel upgrade you can lock all 4 wheels at roughly the same time and the rear actually is doing allot more. Upgrading the front only just makes it so you can lock the front tires up easy without stopping very fast.

                              The larger bore master cylinder just makes the pedal feel better but doesn’t actually make it stop better.

                              Bob

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