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74 Disc Brake Conversion

Discussion in 'Intermediate CJ-5/6/7/8' started by shadetreetim, Nov 15, 2019.

  1. Jan 24, 2020
    shadetreetim

    shadetreetim Member 2022 Sponsor

    Riverside, Ca -...
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    If I was doing a full build, I may be tempted to do something like that, BadGoat. But as this is just a weekend upgrade and I have more wheeling coming up in a few weeks, I want an off the shelf solution. If the Accord lines don't work, I'll check out the Blazer lines 4wealn suggest. I wish I could find the specs on these lines before I buy. Everywhere I've found doesn't list the length, so I'm just guessing from the picture. Meanwhile I'll have a growing pile of incorrect parts. Returning parts isn't my strong suit.
     
  2. Jan 24, 2020
    45es

    45es Active Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Naches, WA
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    If you take the time to look up on Rockauto, say mid 1970 Chevy K10 pickup, you will see the front brake hose is 20 inches long.
     
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  3. Jan 24, 2020
    shadetreetim

    shadetreetim Member 2022 Sponsor

    Riverside, Ca -...
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    Thanks. I keep forgetting Rock Auto includes dimensions on many of their SKUs, but not all of them. Looking up the 85 Honda Accord line it’s 18-19/64 long. Hopefully that’s long enough.

    The 1” spacers I ordered yesterday came in this afternoon. Slapped one on and the wheel turns freely. I was hoping I wouldn’t have to go up to 2” spacers.

    just waiting on the brake lines to come in
     
    Last edited: Jan 28, 2020
  4. Jan 24, 2020
    shadetreetim

    shadetreetim Member 2022 Sponsor

    Riverside, Ca -...
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    I liked the stock stance with the tires tucked under the body. So I was glad all I needed was a 1" spacer, although the spacers moved the tires out a little, it doesn't look too bad, and should help with the rear tires rubbing the inner fenderwell.

    I'm pulling the master cylinder tomorrow to install a rebuild kit, and while its apart, remove the drum residual valve for the front brakes.
     
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  5. Jan 29, 2020
    shadetreetim

    shadetreetim Member 2022 Sponsor

    Riverside, Ca -...
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    The Accord brake lines turned out to be the perfect length. While bleeding the brakes I pumped enough through all 4 wheels to flush the old fluid out of the lines. Who knows how old the fluid was. It looked like thin used motor oil coming out, it was so dark. After bleeding the brakes I was excited to take it for a spin yesterday evening. The weather lately has been beautiful and I had the top folded back for the drive. The first thing I noticed is new manual disc brake pedal takes a little more pressure than the old drums did, but it isn't bad at all. Perhaps one of these days I might add a power booster, but it isn't at the top of my current to do list. I tried a few panic stops to see if either axle locked up too soon. Seemed pretty balanced with the stock manual MC and the 74's stock proportioning valve down on the frame.

    After work today I drove the Jeep to my chiro appointment. With the bearings repacked and the smooth brakes, the drive was the best its been to date. This afternoon was a great day for a cruise in the sun, even if it was during rush hour traffic. Arriving back home my neighbor rushed over to ogle the recent upgrades.
    To amuse myself I added this sticker to the dash.
    If you are on the fence on swapping to disc, just know that this conversion was dead simple. Easily bolted on in a few hours. Brennan's Garage website has a complete list of parts, just watch which brake hoses you buy. The ONLY thing I had to modify was the frame end of the Accord brake line. And that was only because it had a d-shape to fit through the frame mount for the clip, and I had to use my grinder to reshape it to round. It is by far the least expensive disc brake conversion I could find. Happily it is also an elegant solution.

    Next project will be to weld up the side mount spare bolt holes, and build some brackets to mount the old school rear spare tire mount I found.
     
    Last edited: Jan 29, 2020
    CraigE, Desertdog48, melvinm and 4 others like this.
  6. Jan 29, 2020
    Lockman

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

    Silver Hill,...
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    I agree ...... I did the Front Disk conversion last season. Best thing I have done so far....The difference in stopping , especially when wet , is priceless.
    Nice job, Sir.
     
  7. Jan 29, 2020
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sheboygan
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    agreed! i did this on my '62, at all four corners, and its by and far, the easiest, and best upgrade i have done. i really like your jeep!
    could you have ground the calipers slightly in the areas that were hitting your wheel?
     
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  8. Jan 29, 2020
    shadetreetim

    shadetreetim Member 2022 Sponsor

    Riverside, Ca -...
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    I didn’t spend much time determining if grinding would help. My 31x10-5 tires rubbed the inner fender wells pretty good while wheeling, or even turning tightly, so I readily accepted the 1” spacers. We’ll be taking it back out to play in the desert weekend after next so we’ll see how it compares.
     
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  9. Jan 29, 2020
    DrDanteIII

    DrDanteIII Master Procrastinator

    Milford NJ 08848
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    I put front brakes from an 83 cj on mine. I'm still running the same non-power master cylinder. I've had no problems with pedal effort or braking power. It was a nice upgrade. I think your plan to rebuild the existing master is the right way to go.
    Note that even disks can benefit from a residual pressure valve. They prefer 2-3 psi to drums 8-10 psi. Inline residual valves can be purchased from summit racing or other such places. I'd recommend it to maintain more instantaneous performance. https://www.summitracing.com/search/part-type/residual-pressure-valves

    I bought wilwood 2-psi valves when I did the disk conversion. One day I might even install them, but for years I've run with the original valves without issue. However, I'm never driving at high speeds for long times.
     
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  10. Nov 10, 2022
    nsargeant

    nsargeant New Member

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    Not intending to hijack this thread but I am interested in doing this disc brake upgrade as a winter time project to my 74CJ5. I haven't found many post using this setup on intermediate jeeps. Mostly older ones. My questions are do you still have to take all of the old brake stuff off as well as the hubs down to just the axle to get the caliper mounting brackets on? What makes this kit easier than like the chevy brake conversion? I have done a lot of things to my cj during my 15 year ownership but I have never been super confident with brake systems. Thanks for you guys help

    Nathan
     
  11. Nov 10, 2022
    Jw60

    Jw60 Sitting up n buckled down. 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    All the drum dana 25, 27, 30 are the same spindle and hub the only functional difference would be the studs on a dana 30 vs the bolts through the caliper bracket into a knuckle. This kit does not require new studs and machining of the the back side of the hub for the other style rotor.
     
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  12. Nov 10, 2022
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    The 30 spindle is different on the backside due to the open knuckle design, bearing and seal differences where the axle shaft passes through and how thrust is controlled. Correct on the hub/bearing side dimensions being the same.
     
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  13. Nov 10, 2022
    jeepermc

    jeepermc Active Member

    Western WA
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    This allows slip on rotors, which the chevy conversion does not. You'll still have to pull the hub down to the spindle to install the caliper brackets, but everything is easier after that.
     
  14. Nov 18, 2022
    Noneyah

    Noneyah New Member

    Caneyville KY
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    Shadetreetim. Great thread. I got a lot out of it. 2 questions off topic. What is the lift on your Jeep. I’m looking at making a spring swap and like how yours sits in your pics. And were did you get that air bag warning sticker? I need it!
     
  15. Nov 30, 2022
    nsargeant

    nsargeant New Member

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    Shadetreetim. might be out of it for as old as this thread is but maybe I can help a little bit. The body pucks on mine are 3" tall but without any bushings so probably closer to 2". I installed a 2-2.5 in skyjacker softride lift just to replace the flat soft springs that my jeep had. I went round and round with doing the rocky mount yj conversion and just ended up with skyjacker. I am happy with my choice. to each their own. My jeep rides alot better than it has in the 15 years that I have owned it. Here is a before and after. The previous owner did the body lift I feel due to the fiberglass tub and the flat springs. I just replaced the springs. The tires on mine are 31x10.5x15. Mind you the after the springs haven't settled yet.
     

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  16. Dec 1, 2022
    Noneyah

    Noneyah New Member

    Caneyville KY
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    Thank you. Mines a little taller but I like how yours sits and am considering going to the 2-1/2”. Thank you for the picks. They are very helpful.
     
  17. Feb 22, 2023
    Lucas

    Lucas New Member

    Utah
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    I did Brennan s conversion up front drums in rear no need for power brakes just another thing to fail. The bias as is is perfect l. I have single res under floor.
     
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  18. Feb 22, 2023
    Lockman

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

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    Hey there Lucas.......Yep , but not on the Jeep in your Avatar , Right ? . I'm think'n that you did this on your ' 67 ?
    Please PM me sometime , regarding concrete floor leveling / overpour type repair , OK ?
     
  19. Feb 23, 2023
    shadetreetim

    shadetreetim Member 2022 Sponsor

    Riverside, Ca -...
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    Sorry I never replied Noneyah. I have been doing house projects and haven’t been on here much. The Jeep has been on the back burner the past year. For lift this Jeep currently has 1” lift shackles and 1” body lift. So with the saggy springs, maybe 1-1/2 to 1-3/4” over stock? I like the stance with the 31x10.5s. I have all the parts gathered to install YJ OME springs and hope to stray in the next week or so. The sticker came off eBay if I remember correctly.
     
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