1970 Brake Confusion

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by freakpower, Oct 20, 2003.

  1. freakpower

    freakpower Registered Member

    Sep 26, 2001
    Likes Received:
    Chattanooga, TN
    First of all, a long overdue thanks is in order. Several months ago, I posted "To Sell or Not To Sell" and received a lot of thoughtful responses. I ended up selling, and just couldn't bring myself to revisit the board. I recently bought another 1st gen (1970 K5), this one with way fewer body issues. Thanks to all who contributed their advice.

    Anyway, back on topic. I have brake issues, want to upgrade to the 3/4 ton booster, but am a bit confused with what's on the truck right now.

    1. I have front discs. I was under the impression (perhaps wrongly?) that 70's came with drums in front. Could these be stock, or how can I tell what later year they came from?

    2. The master cylinder has different sized resevoirs. All the MC's I see for 70's have same sized reservoirs. Do I replace it with what's supposed to be on it, or with what's currently on it? Does it make a difference?

    3. In the thread about upgrading to the 3/4 ton booster, I think I read that it works only on 71's and 72's. Can I pull off the upgrade on my truck too? Do my above questions have any bearing on the issue?

    Feels good to be back. Feels even better driving around topless in the beautiful Tennessee fall. Thanks for all the help.

  2. Beast388

    Beast388 1/2 ton status

    Nov 6, 2001
    Likes Received:
    Clinton, IA USA
    1. Yes. 1970 trucks would have stock drum brakes up front. Your axle must have been swapped in. You can look for the BOM number on the front of the drivers side axle tube, but it may not be easily visible.

    2. My '1971 has different sized resevoirs on the MC. It works just fine.

    3. It should work on your truck. My 1/2 ton brake booster came off a '68 pickup. It bolted up just fine to my '71 Burb.

    Welcome back to CK5!! /forums/images/graemlins/thumb.gif

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