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Is a 1-Ton Master Cyclinder better?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by zakk, Apr 23, 2002.

  1. zakk

    zakk 1/2 ton status

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    I am having (among others) problems with the brakes. A buddy of mone floated the idea that I still have the 1/2 ton master cyclinder and should upgrade to a 1-ton M. C.

    Is thebore different? would it really make the breaking better?

    thanks for any input!
     
  2. m j

    m j 1/2 ton status

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    bore size changes required pedal pressure and length of stroke.
    assuming you are not bottoming out the master it will not really effect braking performance.
     
  3. SAVAGE1

    SAVAGE1 1/2 ton status

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    A lot of people have swapped the 1/2 ton master cylinder in favor of the 1 ton, after doing an axle swap. I plan on changing mine soon, my brakes don't feel up to par after going 3/4 ton.
     
  4. bigblue

    bigblue 1/2 ton status

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    I didn't swap out any master cylinder and my brakes are the one thing on my truck that works flawlessly
     
  5. Boss

    Boss 1/2 ton status Author

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    I'm pretty sure if you swap out the 1/2 MC to a 1ton MC, then you'll need to swap the Booster as well. Not 100% on that though. But I kept the 1/2 ton brake stuff and even have the rear disk setup and the brakes works really well. Had it for about a year now...
    Boss
     
  6. MTPockets

    MTPockets 1/2 ton status

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    I went with the rear discs and needed to change to 1 ton master because calipers require more fluid volume than the wheel cylinders did. Some people just change out the proportioning valve, but I found the most cost effective way to handle it was to swap out masters. Went to autozone, 25 bucks, lifetime warranty, and bolted right up to my booster. Good luck!
     
  7. BurbinOR

    BurbinOR 3/4 ton status

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    You would need a booster too.

    1/2 ton stuff stops my D60/14BFF fine. Must be something else wrong. Did you powerbleed the system?
     
  8. outlaw612

    outlaw612 1/2 ton status

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    I would recoomend changing to the 1 ton MC.

    Boss and Blazzin OR... just to let you know, I used a 1 ton Mc on my 82 and didnt have to change the booster. Thats not to say that holds true on all of the years, there was a major improvement in braking.
     
  9. HarryH3

    HarryH3 1 ton status Author

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    I'm running the master cylinder from a 1980 Trans Am with 4-wheel disc brakes. It has resevoir capacity to feed the rear calipers on my 14-bolt. /forums/images/icons/cool.gif
     
  10. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Cool that it works, but the reservoir size has little to do with whether or not the MC pushes enough fluid to cover the movement of all wheel cylinders and caliper pistons. The bore/stroke determines how much fluid is pumped not the reservoir. A big reservoir is good so that you make sure there is enough fluid that the MC doesn't run short, but it won't add any volume to the MC itself. Unless I'm missing something.
     
  11. HarryH3

    HarryH3 1 ton status Author

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    The resevoir size becomes important when you run rear disc brakes. Take a look at the tiny resevoir for the rear brakes on a vehicle with drums out back. If you don't keep up with the fluid level as the pads wear, the resevoir can get quickly sucked dry. As the pads wear, the pistons move further out in their bores. Since the bores are so much larger than the bores of a wheel cylinder, they need a lot of fluid volume to keep the space behind them filled. /forums/images/icons/frown.gif

    As for the master cylinder bore size, the Trans Am master cylinder has no trouble locking up all 4 of my 35-inch BFG muds. /forums/images/icons/cool.gif
     
  12. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    With the dual piston front calipers on the 60, and the late '70 3/4 ton calipers out back, and NEVER touching the MC, my truck can lock all 4 36 TSLs. Granted it drinks more fluid (as Harry stated above), but it sure does stop my rig in a big rush. /forums/images/icons/cool.gif

    Anyone tried power bleeding their brakes before replacing the MC? I too was having problems at first, but then one day I got mad, and ran something like 5 gallons of fluid /forums/images/icons/crazy.gif thru the system to be SURE the air was out. Since then, I have had ZERO problems with my brakes.

    -Dan
     
  13. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    The reservoirs on the MC are designed to provide more than enough fluid to keep the bore/stroke filled (in most cases you don't use all of the volume of the piston and if you did you would be flurting with disaster as there is a built in buffer which is why most can use their stock MC for discs but MAY not be a good idea as the pads wear and more fluid is needed IF they don't keep the fluid topped off and don't have a good enough buffer). Each time you hit the brakes the stroke should be roughly the same but as the pads/shoes wear more fluid is needed to take up the "extra" space so that is why topping off is sometimes necessary. The only problem is when you go to put new pads/shoes on, you may have to remove some as to not make a mess as the fluid that was making up for the wear is pushed back into the MC. If you run out of fluid (assuming you keep it topped off), you have bigger problems than needing a bigger reservoir. If you do, you don't need a bigger reservoir, you need a bigger MC or at least one with a bigger chamber for that circuit. Sorry if I was a little vague at first. Bigger reservoirs are necessary for bigger MC's and help so that you don't have to keep topping off, but if the stock reservoir is not enough, then you need to get a bigger bore/stroke to match your needs. It more a question of safety.
     
  14. BurbinOR

    BurbinOR 3/4 ton status

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    <blockquote><font class="small">In reply to:</font><hr>

    Anyone tried power bleeding their brakes before replacing the MC?

    <hr></blockquote>

    Good point...........I had to do that after the one ton axle conversion and almost went through the windshield after I got the truck back...............huge difference.
     
  15. 91gmcjimmyCH_IL

    91gmcjimmyCH_IL 1/2 ton status

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    I just took my truck for a test drive after the rear one ton swap and it doesn't stop for crap. A buddy said I need a new proportioning valve and a MC. The thing is I never listen to my buddies, especially on the trial! "go for it" Anyway, I think I will try a powerbleed and see if that does the trick. What did it cost to do the power bleed?
     
  16. BurbinOR

    BurbinOR 3/4 ton status

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    About $50ish. Make sure your rear drum brakes are adjusted out too.
     
  17. 91gmcjimmyCH_IL

    91gmcjimmyCH_IL 1/2 ton status

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    Is there any way to see if a prop valve or an MC is bad? if there are no visible leaks.
     
  18. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Adjust them tighter and get the rest of the air out. Let them gravity bleed a while if necessary.
     
  19. Blue85

    Blue85 Troll Premium Member

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    Anyone ever try use one of those reverse fluid injection kits as an alternative to powerbleeding? The kit is about $50, which pays for itself the first time if it works. You have a small tank of fluid on the tool and it connects to the bleeder screw and forces fluid back up through the system into the MC. The idea is that air tends to rise in the fluid, so it is better to move the fluid up through the system instead of down. Only problem is that you need a good way to get the excess fluid out of the MC while you do it.
     
  20. POWERMAD

    POWERMAD 1/2 ton status

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    That is all I did after the 3/4 ton swap.
    At work we have a gallon jug with a pump and a hose that fits over the bleeder screw, after bleeding the master almost dry on both front and rear I just back bled the system, I had adjusted the bakes prior to that and after I back bled the system I had a solid pedal and it it will lock em up with no problem.
    I had to relearn to brake they were stopping so well, I kept hitting them to hard and would lock it up.
    Before I had to realy lay into it to get it to slow and the first time I did that I was glad the seat belt was on.
     

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