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Disc Brake Conversion

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Roostr84, Mar 5, 2001.

  1. Roostr84

    Roostr84 1/2 ton status

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    I have a 69 Blazer that has the original drums all around. I want to swap to discs in the front b/c the brakes suck and i am going to 33s soon on a 4 in lift. I know how they brake now and this will definetley be a problem. i want to keep my 6 lugs though. Any ideas?
     
  2. pcorssmit

    pcorssmit 1/2 ton status

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    Either find a new front end with the right gears, or swap the disk brake parts onto your axle. We did option B on my brother's '70, it helped a lot. You will need: hubs, disks, calipers, caliper brakets, spindles, knuckles, axleshafts, and assorted seals. I don't remember if the bearings are different or not. The knuckles have the same 6-bolt spindle pattern, but it is clocked differently and it won't bolt together. The later front ends (disk) have bigger steering (u) joints between the inner and outer shafts, which is another plus to this swap.

    Additionally, you need a disk brake master cylinder and a new proportioning valve. I would use a Wilwood adjustable valve, around $40 from Summit, instead of the factory ones. Plumb your front brakes straight off the master, and put the adjustable valve in the rear line. This will also accomodate a future rear disk swap if you want (thats why my '83 has one).

    You should be able to pick up a 1/2 ton front end for $150-$200 at the most. I've got a disk brake 10 bolt for sale w/3.73s if you're interested. I think my brother has a 44 w/ 3.08s. (Colorado)

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  3. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>I have the original 71 disk-braked 44 from my truck and I live in NJ. Its needs to much to sell whole (ball joints, axle u-joints) so if you want I can sell you just the brake parts. The rotors definetly need machining or mabye replacing but the calipers are good. Where in NJ are you?</font color=blue>

    [​IMG]
     
  4. Triaged

    Triaged 1/2 ton status

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    If you do swap in disc brakes use the perportioning valve off of a disc brake truck (actually a combination valve because it has a hold off valve in it as well). The hold off valve delays application of the front brakes untill line preasure is around 40psi (not sure on exact number). This allows the preasure to overcome the rear drum return springs (also why you have to press that little button to bleed your brakes). If you don't use the combination valve, only the front brakes will be used on light peddal aplication, causing the front brakes to wear faster than they should, even with the adj. perportioning valve. You can then get rid of the combination valve if you do go to 4 wheel disc.
     
  5. pcorssmit

    pcorssmit 1/2 ton status

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    If this is a concern you can also purchase an inexpensive residual valve to plumb into the rear brake line.

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  6. Steve_Chin

    Steve_Chin 1/2 ton status

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    Hey Roostr84, why not go whole hog and put rear discs in too??? Then you won't have to worry about an RPV (although for best braking performance, you will need a different proportioning valve and master).
     

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