Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Master Cylinder 4 wheel disk

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by proyouring71nova, Dec 3, 2003.

  1. proyouring71nova

    proyouring71nova Registered Member

    Joined:
    Jul 17, 2002
    Posts:
    39
    Likes Received:
    0
    Location:
    CA San Rafael
    So im replacing all brake parts threw out the truck with 4 wheel disk it origanally came with 4 wheel dddddddddrums ha ha..... so I was wondering if anyone out there know of a Master Cylinder that will bolt up to a 1972 3/4 boster mabe a 69-72 Corvette Master Cylinder with 4 wheel disks or somthing along thos lines, I know that some people use there two wheel disk brake MC and have no problem but I thought while I was replacing the MC I should consider a MC ment for 4 wheel disk. thanks max
     
  2. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

    Joined:
    Mar 5, 2001
    Posts:
    15,683
    Likes Received:
    1,392
    Location:
    642 Days to BB2018
    Max,


    I APPLAUD YOU!!! /forums/images/graemlins/thumb.gif


    First post on the site....already a paying member....already have your profile COMPLETELY filled out....AND you are a "local" enthusiast (Bay Area)

    Excellent Work. /forums/images/graemlins/cool.gif



    As for your question, it seems there is no clear agreement on the necessity of swapping out the master cylinder/ brake booster setup when going to larger axles (1-Ton) or doing a rear-disc brake conversion.

    You'll see people have done all kinds of different things...3/4 Ton boosters, aftermarket prop valves, etc. I personally still have the stock 1/2-Ton setup on 1-Ton axles and it's "adequate" but I've been pondering a swap to the larger booster setup....it just doesn't HOLD on steep downhill grades when wheeling /forums/images/graemlins/shocked.gif

    Anyway, take a look around.....you can probably find quite a bit of info by using the "search" feature at the bottom of this page, and the one in the '73-'91 area might also yield some good info. The search function is only good within the specific forum that you're in..... so you have to re-run the same keywords in a few places sometimes.



    /forums/images/graemlins/usaflag.gif
     
  3. Beast388

    Beast388 1/2 ton status

    Joined:
    Nov 6, 2001
    Posts:
    3,039
    Likes Received:
    0
    Location:
    Clinton, IA USA
    Welcome to CK5, Max!!

    I am still running the stock 1/2 ton brake stuff with my 3/4 ton axles and rear disks. I have been researching the possibility of swapping the master cylinder out for one from an OEM 4 wheel disk vehicle. The best candidate so far is the MC for a '78 Vette. The front & rear fittings and bore are the same as my '71. I just need to verify that the mountings identical. /forums/images/graemlins/thinking.gif

    Right now my brakes are much improved over the stock set-up, but I want to get all the available stopping power I can. /forums/images/graemlins/thumb.gif
     
  4. 69K5

    69K5 1/2 ton status

    Joined:
    Nov 10, 2001
    Posts:
    1,544
    Likes Received:
    0
    Location:
    Monroe, LA
    first off welcome!

    second

    you gotta love 4 wheel drums. i now have disc. hydroboost as soon as i figure out how to hook it all up.

    i think the 1/2 ton would be fine for now. since you are only on 33's i would think that you would be fine. Greg72's truck is huge and needs more stopping power. someone i think it was boregok5 was explaining over in the garage about if you upgrade the master you need to upgrade the booster or something like that. just a bigger master is not necessarily going to make the breaks stronger i guess is what im trying to say. i would just leave it and wait till necessary to change it. they are easy enough to change and readily accesible. bonnevilles also had 4 wheel disc breaks as well as the caddies as im sure you already know. some camaros (new) also.

    69k5 /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  5. proyouring71nova

    proyouring71nova Registered Member

    Joined:
    Jul 17, 2002
    Posts:
    39
    Likes Received:
    0
    Location:
    CA San Rafael
    Thanks for the welcoms, ya I'm a local but I'm right out side san fran. The hole deal about getting the new stuff is that I have to replace it anyways so I would rather get the best now because I/m thinking about bobing the truck and putting 37" pluse a little more of a lift on it mabe somthing like gred72 and putting some flexy springs in the back and front down the way. So I would rather just spend the money now then later and have more usless parts sitting around. For the boster and the MC I had the origanal MC and there was no boster so Igot the linkage for the boster so I need to buy one anyways. I thought about getting the 3/4 for sure, the MC I got a friend working at a parts store that will take his time with me. Do you know the size of the front and rear brake lines going into the MC? Greg I'm going to put some more pics up thursday, I will have the 14 bolted up and take some pics of the new d44 up front. Pluse im only 20 and have beed reading the posts scenc I was 18 and Most of the help full stuffs and insperations been from your blaze, so Thanks. thanks for all the help from all ya to
     
  6. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    The main reason for swapping master cylinders with 4 wheel disc is so that the resaviors will be the same size. If you notice GM got cheep and kept the same casting for the 4 wheel drum's when they went to front disc. Almost all full size master cylinders (including vetts) are 1.125" bore so that won't do you much good either. I would say go with 3/4-ton booster (wish I knew to do that when I replaced mine /forums/images/graemlins/frown.gif ) and stock master with a 4 wheel disc prop valve.

    Also if you are looking for more breaking effort you want a smaller bore master cylinder. Most people get that mixed up and think you want bigger (which will just make the peddle firm and you have to push harder).
     
  7. jasonkh2tg

    jasonkh2tg 1/2 ton status

    Joined:
    Mar 27, 2003
    Posts:
    139
    Likes Received:
    0
    Location:
    MPLS MN
    Ok Ive heard the posts and I agree....Im just saying I run a 3/4 ton booster with a 3/4 ton MC...I like the feel of a firm pedal that stop on a dime...Some people like little effort, but they have to push more to get the same result...I have 4 wheel disk with a prop valve, work fine...You asked about size I belive you have 3/16 on the front and 1/4 on the rear, but the rear on a 3/4 MC is plumbed from the front of the MC........ /forums/images/graemlins/k5.gif
     
  8. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    [ QUOTE ]
    but the rear on a 3/4 MC is plumbed from the front of the MC........ /forums/images/graemlins/k5.gif

    [/ QUOTE ]

    This is why I sugested the stock 1/2-ton master cylinder. They both have the same bore...the only difference is in the brake lines.

    This is from www.napaonline.com and is a 71 K20 MC

    Item#: TSM101534

    Price: $ 21.49
    tax and shipping not included
    Core Price: $ 25.00
    What is a Core?

    Usually ships in 24 hours.


    Attributes:
    Attributes: Brake Master Cylinder - Remfd
    # of Line Ports: 2
    Bore Size: 1.12500''
    Line Thread Size: 1/2-20, 9/16-18

    It does apear that they also make a 1.25" bore MC. If your peddle is too soft and requires to little effort this might be a good solution.
     
  9. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

    Joined:
    Jul 18, 2001
    Posts:
    5,693
    Likes Received:
    0
    Location:
    CA
    Welcome dude! Pro Touring '71 BBC nova huh? Sweet. /forums/images/graemlins/thumb.gif /forums/images/graemlins/pimp1.gif

    I'll throw in my .02 here... I swapped from the 1/2 ton to 3/4 ton '72 Power Brake booster and it made a hell of a difference! /forums/images/graemlins/blush.gif
    Then i swapped in my 1 ton axles with rear disk brakes.. still using the 1/2 ton master cylinder.. A few guys on this board told me it would work fine...
    Well upon testing out my new setup, It stops on a dime with the D60 front brakes and the disks on the 14ff, but the rears lock up just a bit before the fronts do, which would tell me that i need to install a proportioning valve for the rear..
    Its not so bad that i need to do it right away, Its alright for my daily driver, but it is something that i would like to get around to installing so that i can adjust my brake bias. /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/pimp1.gif
     

Share This Page