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Brake Woes

Discussion in 'Early CJ5 and CJ6 Tech' started by colojeepguy, Jul 7, 2023.

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  1. Jul 11, 2023
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

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    You Guy's are scarring me. Every time I think I know what I need for 11" fronts and 10" rear, something comes up I haven't Thunk Of.
     
    Rick Whitson, Jul 11, 2023
    #21
  2. Jul 11, 2023
    Lockman

    Lockman OK.....Now I Get It . 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Silver Hill,...
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    .........Yep , MC's are very, very, important . Do it right , here. Jeeperman's is your best bet. :)
     
    Lockman, Jul 11, 2023
    #22
  3. Jul 11, 2023
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
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    Don't be scared, it aint rocket science :bananatool:

    IF you are going for 11" front and 10" rear drum brakes I suggest you go with 11" drums all four corners, and use a drum brake dual cylinder MC, of which there are many options available. If you don't want to spend the $ for a dual MC conversion, the 11" drums with the stock MC will be a big improvement in braking.
     
    Oldpappy, Jul 11, 2023
    #23
  4. Jul 11, 2023
    colojeepguy

    colojeepguy Colorado Springs

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    Looking at it again, the replacement I got for the CJ looks exactly like the one on my Commando. Same braking system, factory 10" drums all around, but the Commando is firewall mounted. I wonder if there's a reason for the bolt on cap on the low mount Master cylinder vs the bail hold down on the firewall mounted one....
     
    colojeepguy, Jul 11, 2023
    #24
  5. Jul 11, 2023
    vtxtasy

    vtxtasy oldbee 2024 Sponsor 2023 Sponsor

    Tucson, AZ
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    Bolted being a better fastening system?
     
    vtxtasy, Jul 11, 2023
    #25
  6. Jul 12, 2023
    jeepdaddy2000

    jeepdaddy2000 Active Member

    Eagle Point oregon
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    My factory MC had a straight bore. The braking balance was done by the more traditional way, larger wheel cylinders in the front, smaller in back.
     
    jeepdaddy2000, Jul 12, 2023
    #26
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  7. Jul 12, 2023
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
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    Yours may not have had the original master cylinder. The factory under floor dual master cylinder has a stepped bore with 7/8" bore for the front brakes, and a 1" bore for the rear brakes. It also has a residual valve in each exit port.

    In addition to the stepped master cylinder bore, they also had 1" front wheel cylinders and 13/16" rear wheel cylinders.

    You can see the different sized pistons in this disassembled one from my '68. 7/8" front piston to the left and 1" rear piston to the right:
    [​IMG]

    That said, you shouldn't need a stepped master cylinder to make it all work. As long as you have the needed residual valves and properly sized wheels cylinders (and possibly an adjustable proportioning valve in the rear brakes) a non-stepped master cylinder will work fine.

    The math works out to needing a 1.39 front wheel cylinder to keep the same front to rear proportioning with a non-stepped 1" master cylinder, so a 1 1/8" would get you pretty close. All that's assuming the factory proportioning is what you want.
     
    Fireball, Jul 12, 2023
    #27
  8. Jul 12, 2023
    CJ51973

    CJ51973 Member

    Versailles, KY
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    The one I showed fits under my floor, no issues. It is a bail type.
     
    CJ51973, Jul 12, 2023
    #28
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  9. Jul 12, 2023
    jeepdaddy2000

    jeepdaddy2000 Active Member

    Eagle Point oregon
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    I may stand corrected on this.

    I disassembled it but it was pretty crunchy inside, so I went with a new one. I was sure all the cups were the same size, but that was thirty years ago. I was working as a mechanic at the time and would have thought a stepped bore would catch my eye:susp:.

    It was stock. The bolt on lid is a pretty good give away.

    As it stands, it's a non issue. I Adapted a 72-75 MC in conjunction with an 11" Waggy upgrade. The combo seems to have the proper front/rear bias.
     
    jeepdaddy2000, Jul 12, 2023
    #29
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  10. Jul 16, 2023
    colojeepguy

    colojeepguy Colorado Springs

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    Aaaand, the replacement MC won't fit. Hose fitting sizes are wrong. I don't want to try adapters because the lines are already very close to the bellhousing. I guess I'm gonna have to order the Crown replacement :steamed:
     
    colojeepguy, Jul 16, 2023
    #30
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  11. Jul 17, 2023
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

    Chico CA
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    Wildwood?
     
    Danefraz, Jul 17, 2023
    #31
  12. Jul 17, 2023
    colojeepguy

    colojeepguy Colorado Springs

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    I have (or rather, had) a perfectly functioning OEM dual master cylinder.
    I just want to replace it with the same, and not mess with plumbing and mounting and what not.
    If it comes to that, and it may, I'll switch to hanging pedals & power brakes but that's a whole nother can of worms that I don't want to open.
    The Crown replacement, which seems to be the only option for V6 CJ's, has mixed reviews. Hopefully it'll work out OK!
     
    colojeepguy, Jul 17, 2023
    #32
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  13. Jul 17, 2023
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
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    I've had the Crown replacement in my '69 for four years now with no issues.
     
    Fireball, Jul 17, 2023
    #33
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  14. Jul 17, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    Just another anecdotal comment, but I have run the Crown replacement in my CJ for 10+ years now without an issue. It was one of the first things I had to fix on my jeep to make it driveable. I think Jerry Panek at Predator ordered it for me as I didn't know anything about how to find or get parts at the time and he had helped me with my CJ7 from many years before (college days).
     
    FinoCJ, Jul 17, 2023
    #34
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  15. Jul 17, 2023
    colojeepguy

    colojeepguy Colorado Springs

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    They're just a mile or so from my house, but I haven't been in there for a loooong time. Like most 4x4 shops they cater to the JK crowd which is understandable, not a lot of us guys still flogging the old iron!
     
    colojeepguy, Jul 17, 2023
    #35
  16. Jul 17, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    I haven't worked with them in a lot of years as well.....but Jerry was always an old iron CJ guy if he's still around - maybe he sold it. Its hard to make money doing CJ parts and work, so I get the need to do modern stuff. At least for a while, Jerry tried to keep some connection and willingness to help out CJ owners. He never had in stock CJ parts, but he'd be willing to work on them (for shop rate of course) and for a few years I'd buy through them just to get a bit of knowledgeable help. They had also really helped me out with my CJ7 when i was in college and i never forgot that. I almost paid them to do a saggy swap that first year or so I owned the CJ5 - probably should have considering I am still running Ross. In Denver, there wasn't much help of any kind for CJs....the guy at Republic Park was difficult (to say the least) to deal with and HC4x4 completely went the direction of JK style build kits long before Predator did and there was no one left with CJ interest or knowledge etc. New stuff starting popping up in Denver metro over the years like Edgewater and Timbuktu and some other stuff - I think early on they had the idea to work on old CJ and whatnot, but the business side pushes them towards bolt on kits for new stuff.
     
    FinoCJ, Jul 17, 2023
    #36
  17. Jul 17, 2023
    colojeepguy

    colojeepguy Colorado Springs

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    You never dealt with Mile High Jeep on Federal? Most of my CJ parts came from there, pre-internet, but I think they were gone by the early 2000's.
     
    colojeepguy, Jul 17, 2023
    #37
  18. Jul 17, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    nope... IIRC I got the CJ5 in 2012, and MHJ was already gone. I think I drove by soon after I got the jeep and there was still some indication of the business (I think the brick had some painted sign or something), but it looked like it had been left as an empty shop for a quite a bit already. In the late 90s, early 2000s, I dealt mostly with Predator (lived in the springs), but I recall buying my first lift kit from Tanner and picked up a few items from FN jeep. I think FN was very new - started like 1998 or something? - and I am sure it was located sorta back behind the SE corner of Nevada and Fillmore. In those days, Predator was located out in a grocery store or Walmart style shopping center on north Academy just east of I-25 (I think). Predator has moved a few times over the years....looks like they are still in their N Nevada location, although i seem to recall them being in a slightly different N nevada location at one point. Oh well....now we all just share information and buy parts online and whatnot....I sorta miss the days of being able to walk into a shop and get knowledgeable help and good recommendations. Guess that may still be possible with more modern stuff.....honestly, minus the snorkel (and probably the wheels), I'd drive this (sorry - can't go 4 door)....and then everytime I saw an old jeep, I could go talk to the owner say "i had some old jeeps back when, they were the best ever"....then get in my air conditioned/heated, sound proofed, dry jeep, sit in the comfy bucket seat, take a sip from my mug in the drink holder, turn on the music, buckle my 3pt seat belt, and then take a nap while Jen drove it with an automatic:
    [​IMG]
     
    Last edited: Jul 17, 2023
    FinoCJ, Jul 17, 2023
    #38
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  19. Jul 17, 2023
    neohic

    neohic Gentleman Jeepist

    Woodland Park, CO
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    Jerry is still running Predator. They rebuilt my Dana 44 and added the TrueTrac a couple months back. Seems like a good crew there.
     
    neohic, Jul 17, 2023
    #39
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  20. Jul 21, 2023
    colojeepguy

    colojeepguy Colorado Springs

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    Dang Crown junk. First I had to file out the mounting holes for the bolts to fit. Then I had to remove the plug in the bottom of the master cylinder and re seal it because fluid was dripping out. Now with it installed and the pedal hooked up, the pedal goes about halfway down and just stops. No pressure in the system, it just stops. I'm really frustrated, I was able to bench bleed it ok but now I can't get it to work. About ready to push it out of the garage and light it on fire.
     
    colojeepguy, Jul 21, 2023
    #40
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