1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

DISC BRAKE COVERSION

Discussion in 'Suspension, Steering & Brakes' started by Powerhouse Ranch, Jan 13, 2021.

  1. Powerhouse Ranch

    Powerhouse Ranch 3G Connoisseur Supporting Member

    Posts:
    434
    Likes Received:
    502
    Joined:
    Jan 6, 2021
    Location:
    PA
    First Name:
    Luke
    Truck Year:
    1980 & 1988
    Truck Model:
    C25 & K5
    Engine Size:
    454 & 350
    How do we feel about converting the rear axle drum brakes to disc brakes and what would be the best kit to buy?

    P.S. Is this only limited to 1/2 tons? (LMC only sells for 1/2 ton applications)
     
    Last edited: Jan 13, 2021
    MARIOS DELIVOS likes this.
  2. Bextreme04

    Bextreme04 Full Access Member

    Posts:
    1,070
    Likes Received:
    1,088
    Joined:
    May 13, 2019
    Location:
    Oregon
    First Name:
    Eric
    Truck Year:
    1980
    Truck Model:
    K25
    Engine Size:
    350-4bbl
    I know its popular on the 14 bolts in 3/4 and 1 tons. I honestly feel it is much more appropriate and worthwhile in the 1/2 tons. The 14 bolt drum brakes work awesome, but are pretty heavy. I think the whole axle is something like 800lbs though, so saving a few hundred going to less functional brakes probably doesn't do much for a daily driver. If you are just trail running it then sure.
     
  3. 77 K20

    77 K20 Full Access Member

    Posts:
    2,441
    Likes Received:
    1,578
    Joined:
    Nov 9, 2012
    Location:
    Montana
    First Name:
    Mike
    Truck Year:
    1977
    Truck Model:
    K20 5" lift
    Engine Size:
    HT383 fuel injected
    I did a rear brake conversion on my K20. My rear drums had filled up with mud a few times from water crossings, and since I don't have a good crawl ratio some of the trails I went down I had to ride the brake the whole time. Once drums get hot they won't cool down for a long time.

    Disc brakes fixed those issues- but still aren't perfect for me. Had issues with the rear brakes wanting to lockup before the front ones. Ended up having to add a manual brake proportional valve to the rear.

    I also no longer have a parking brake.
     
    Curt and Frankenchevy like this.
  4. Nonstop

    Nonstop Full Access Member

    Posts:
    452
    Likes Received:
    1,092
    Joined:
    Nov 16, 2014
    Location:
    Ca
    First Name:
    Nick
    Truck Year:
    1985
    Truck Model:
    K2500
    Engine Size:
    454
    I converted to rear discs with Cadillac calipers. I then replaced them with 3/4 ton front calipers and lost my parking brake. I then converted back to drum rear brakes - 13x3.5 and was happy as a clam and got a parking brake back!
     
  5. Bextreme04

    Bextreme04 Full Access Member

    Posts:
    1,070
    Likes Received:
    1,088
    Joined:
    May 13, 2019
    Location:
    Oregon
    First Name:
    Eric
    Truck Year:
    1980
    Truck Model:
    K25
    Engine Size:
    350-4bbl
    ORD does now have the caliper kits with parking brake. They didn’t used to.
     
  6. eskimomann209

    eskimomann209 Supporting Member Supporting Member

    Posts:
    1,587
    Likes Received:
    1,670
    Joined:
    Jan 9, 2019
    Location:
    Modesto
    First Name:
    Marcus
    Truck Year:
    1973
    Truck Model:
    C10
    Engine Size:
    5.3
    I don’t wanna give up my 15” rims. Otherwise I might have considered it.
     
  7. Ricko1966

    Ricko1966 Full Access Member

    Posts:
    1,097
    Likes Received:
    900
    Joined:
    Apr 11, 2017
    Location:
    kansas
    First Name:
    Richard
    Truck Year:
    1975
    Truck Model:
    c20
    Engine Size:
    350
    You can cut holes in the backing plate with a hole saw,to let dirt, mud and water escape the from the drums on off-road rigs.
     
    Last edited: Jan 16, 2021
    Curt likes this.
  8. Curt

    Curt Supporting Member Supporting Member

    Posts:
    372
    Likes Received:
    589
    Joined:
    Sep 11, 2017
    Location:
    Carlsbad
    First Name:
    Curtis
    Truck Year:
    1984
    Truck Model:
    K-30
    Engine Size:
    383
    I like my disk brakes.Brake jobs are much easier,much faster.I like wrench on squarebody trucks,but drum brakes is not one of my favorites.

    A44B20EB-B6BF-4FF6-9C9F-F3036CA53310.jpeg
     
    Mr Clean and 77 K20 like this.
  9. Powerhouse Ranch

    Powerhouse Ranch 3G Connoisseur Supporting Member

    Posts:
    434
    Likes Received:
    502
    Joined:
    Jan 6, 2021
    Location:
    PA
    First Name:
    Luke
    Truck Year:
    1980 & 1988
    Truck Model:
    C25 & K5
    Engine Size:
    454 & 350
    not a bad idea and not a bad rig (your driveshaft is missing haha)
     
    eskimomann209 likes this.
  10. Bennyt

    Bennyt Full Access Member

    Posts:
    253
    Likes Received:
    254
    Joined:
    May 17, 2019
    Location:
    Surprise
    First Name:
    Ben
    Truck Year:
    1977
    Truck Model:
    C10
    Engine Size:
    350
    All this is my opinion and you can tell me to suck it if you like. Half of the cars/trucks I build I do rear conversions, but only if it adds up.

    Other than wet environment there is almost no benefit on the rear.

    Pros:
    Easier to change pads then drums

    Possible braking improvement but since your rears do about 30-40% of the braking and unless you are upgrading to a 14" rotor and 4-6 piston $3k rear set-up, you'll only get a maybe a 10-20% over a drum, the net return will be maybe, maybe 3-5% better. Only in the right environment. If you tow, you'll overheat a small pad much quicker than a large shoe.

    Cons:
    Ineffective parking brake on most set-ups.

    Rear disc suffers from knock back issues unless it's a full float. Have to drag or pump brakes to keep pad to disc if road racing.

    Reduced gas mileage. Disc brakes usually outweigh drums when you add up bracket, calliper, rotor. Increased unsprung weight and more rolling resistance as pads frequently in contact.

    Increased lining changes. How often you change shoes vs. Pads? I would bet 2-3x as much.



    Racing-yes
    Off-road only-yes
    Rain every day and you don't know how to pump-yes

    Daily driver-no

    If it's a 1/2 ton. Better return is the larger 1/2 ton drum set-up. Increased performance without all the hassle. Cost $50-100 at junkyard and another $100 for all new parts for it.
     
    DoubleDingo and Ricko1966 like this.
  11. Curt

    Curt Supporting Member Supporting Member

    Posts:
    372
    Likes Received:
    589
    Joined:
    Sep 11, 2017
    Location:
    Carlsbad
    First Name:
    Curtis
    Truck Year:
    1984
    Truck Model:
    K-30
    Engine Size:
    383
    it was,not no more,and thanks!

    DC7080BD-2A3A-477A-8C29-CB8AB4000272.jpeg
     
    Mr Clean and Snoots like this.
  12. Curt

    Curt Supporting Member Supporting Member

    Posts:
    372
    Likes Received:
    589
    Joined:
    Sep 11, 2017
    Location:
    Carlsbad
    First Name:
    Curtis
    Truck Year:
    1984
    Truck Model:
    K-30
    Engine Size:
    383
    Maybe disks weigh more on a 1/2 ton axle,not sure,but I know I’m about 75 lbs lighter on the full float 14 bolt with out drums...
     
    Mr Clean, 84 M1008 and Bennyt like this.
  13. Powerhouse Ranch

    Powerhouse Ranch 3G Connoisseur Supporting Member

    Posts:
    434
    Likes Received:
    502
    Joined:
    Jan 6, 2021
    Location:
    PA
    First Name:
    Luke
    Truck Year:
    1980 & 1988
    Truck Model:
    C25 & K5
    Engine Size:
    454 & 350
    that's a heavy duty looking driveshaft dude
     
    Mr Clean and Curt like this.
  14. Bennyt

    Bennyt Full Access Member

    Posts:
    253
    Likes Received:
    254
    Joined:
    May 17, 2019
    Location:
    Surprise
    First Name:
    Ben
    Truck Year:
    1977
    Truck Model:
    C10
    Engine Size:
    350
    I agree and with 14b FF every part is heavy so switching to discs makes sense. Also, the rotor that is swapped is larger than what is used on the 1/2 ton. But I haven't seen a caddy caliper set-up that I trust with the parking brake. The stock pedal simply does not take up enough movement in the cable. Adding a ratcheting handle or an e-stopp makes it safer.
     
    Curt likes this.
  15. bucket

    bucket Super Moderator Staff Member

    Age:
    39
    Posts:
    23,076
    Likes Received:
    9,464
    Joined:
    Aug 3, 2010
    Location:
    Usually not in Ohio
    First Name:
    Andy
    Truck Year:
    '77, '78, '79, '84, '88
    Truck Model:
    K5 thru K30
    Engine Size:
    350-454
    All good points, but one thing worth mentioning is modulation. On bigger 4x4 trucks with large tires it's not so much of an issue, but with smaller tires it tends to be easier to modulate the rear brakes in a panic stop with discs.
     
    Mr Clean and Curt like this.

Share This Page