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R&P GM 1/4 Ton Disc Conversion

Discussion in 'Builds and Fabricators Forum' started by FinoCJ, Aug 5, 2023.

  1. Sep 2, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,810
    according to Willwood, its no RPV for disc with firewall mounted MC (MC higher than caliper), and 2lbs only if the MC is frame mounted (MC equal or below caliper)....
     
    Dwins1 and vtxtasy like this.
  2. Sep 3, 2023
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
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    That's how I understand it too. You for sure want a 10lb RPV in the rear circuit to keep the lip seals in the slave cylinders sealed up.
     
  3. Sep 3, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,810
    Found the duckbill....going to go without for now, and then give Wildwood a call this coming week to see if they make a 2lbs duckbill to go in it's place ....or if I may need to put an external (to the MC) one inline just downstream of the outlet fitting.....
    [​IMG]

    As a side note, with the outlet fitting on the bottom of the MC, and my marginal hard line bending skills, the line hangs a bit low and is exposed below the frame rail.... I'd love to find some 90 degree flare fittings to keep the line up tighter and more protected ...would also be helpful if I have to run an external 2lbs rpv...
     
    Last edited: Sep 3, 2023
    Jw60 and vtxtasy like this.
  4. Sep 3, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,810
    FWIW...i only took it out for a very short test drive (before getting into the CJ frame project), but my initial take is the brakes are AWESOME. Certainly, not power, but the pedal feel is great....nice and firm, no significant travel before getting brake resistance, and it feels like the harder you push, the more it stops without bottoming out. Actually, it feels a lot like my old CJ7 with manual discs up front. I never could get this MC and the old OEM Wagner 11" drums to get good pedal feel. It always felt a bit soft without much stopping power, and the pedal would travel essentially to the floor. Of course, I haven't slammed them on from above 30mph yet, but very confident in them so far. Eventually I'll get to the rear brakes - they will get 11" bendix with internal parking brake from and FSJ.....After a bit more use, I'll go back and put the list of useful ancillary items I found/used.
     
  5. Sep 6, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,810
    I actually drove the 58 around a bit more with these brakes - imagine that, driving a jeep and not working on the damn thing! stopped by duffers and checked out the new CJ from Roy - had a cup of coffee with Les (bubblehead from OWF who was traveling through town), and picked up supplies for the next house project (anyone want to restain a bunch of decks?).....that including some backroad cruising, highway driving and around town stop and go - still loving the new brakes - I might need to get 3pt seat belts to keep from hitting head on the windhshield! And also greatly appreciate the lack of 'pull' one way or the other - they stop straight. Need to maybe adjust the pedal/piston engagement or freeplay - think I might want just a smidge more freeplay in the pedal, and a side note is I think I need to adjust the alignment just a bit more toe-in after I replaced all the TRE and drag link....but hopefully I have at least one jeep that can drive around!
    So, here are the final parts and pieces I found useful to complete this project - and I guess I should copy this up to the first post as well:

    R&P 1/4 ton disc brake kit (although I ordered this from Rich at his new venture called R&P Early Jeeps, I assume its the same as the original R&P 4wd set-up)....probably depending on what you order from Rich, it seems people get more or less parts, depending on how 'complete' of a kit they want. But the basic idea is that the custom caliper brackets are the key part to get from R&P, and the rest you can get from FLAPS:
    1) caliper brackets - custom from R&P
    2) rotors - I got mine along with the caliper brackets from Rich, so not sure exactly what they come from. I think they are from something like a 1990 Suzuki Samarai - the typical GM s-10 rotors don't have large enough center bore to fit over Jeep hubs)
    https://www.rockauto.com/en/catalog/suzuki,1990,samurai,1.3l+l4,1271179,brake+&+wheel+hub,rotor,1896
    3) Calipers - I used Carquest 18-4129 (left) and 18-4128 (right)
    4) Brake Pads - D154 (organic - only found these through O-riellys)
    5) Brake Lines - Summit Racing 230910 - these worked out really well as they work with 7/16 in. banjo bolt at the caliper end and female 3/8 in -24 inverted flare on the other (to connect to my traditional hard line). 15.75 in. length seems really good and is a bit shorter than many of the other options, so less excess hose to deal with.
    6) Wheel studs - Dorman 610-260....I still had the OEM style wheel studs and Wagner brake drums pressed on the back of the hub....I needed a longer wheel stud to work going through the rotor and using a thicker modern mag wheel with acorn nut. If still using a thin steel wheel or shanked lug nuts, maybe not necessary....These Dormans have a very short section of knurl as I initially concerned the knurl could protrude through the hub and engage into the outboard rotor, but the rotor was counterbored so this wasn't as big of an issue as I was thinking.
    7) Knuckle Studs...3/8" - 24 x 1.5" I did the buttonhead knuckle studs conversion at the same time, and as the caliper bracket is 1/4' thick, I went with a 1/4" longer buttonhead to 1.5" length bolt to ensure it would go through the caliper bracket and leave enough thread to nut off properly. I used metal lock nuts on mine, but there was enough thread you could use a standard lock washer if preferred.....

    So far, I am liking this set up so much, and given that I don't know how long Rich might keep doing this stuff, I am debating trying to buy a second set of caliper brackets to eventually use on the CJ....
     
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  6. Sep 6, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,810
    Guess I never posted this pic - the 15" aftermarket wheels clear the caliper. I really like that this set-up has no knuckle/caliper interference grinding needed, and the access to the outboard, slip on/off over the hub rotors makes brake service easy. My biggest concern was stopping power of the 1/4 vs 1/2 ton, but so far (and with manual brakes, no power/vacuum assist), its more than enough.
    [​IMG]
     
    Danefraz, jeepstar, wheelie and 5 others like this.
  7. May 26, 2024
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
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    Thanks for the nice write ups and honest reviews. Richard is still currently doing this stuff but is a one man shop since I retired and he is pushing 70 years old so no idea how much longer he will keep doing it. I have lunch with him on Wednesdays and he is quitting working on vehicles, just finishing up existing projects, but being the crotchety old fart he is no telling when he will shut down the business I suspect he will be building parts like this for a while but will not guarantee anything.
     
  8. May 26, 2024
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,810
    A small update - some of this was covered in my build thread when I added in the 11" rear Bendix with parking - also from Richard.....
    The combination of the front disks and rear drums hasn't felt right - the pedal has a sort of two step engagement. I think with the OEM Wagner brakes in the rear, they were not doing anything, but the new Bendix ones you can actually feel them engage at a slightly different time/pedal position than the discs etc. Been fighting the self adjusters as well....anyway that doesn't really apply to the front discs, but led me to adding in a 2lbs RPV for the front brakes after initially removing the 10lbs and going without. I am hoping some of the odd pedal feel will go away and blend in a bit as the rear shoes wear into the drums a bit.....of course it's got other problems not brake related so not getting any usage. Here is the new Wildwood 2lbs rpv.....
    upload_2024-5-26_8-13-4.png
     
    Jw60, Danefraz, Stakebed and 3 others like this.
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