Page 3 of 3 FirstFirst 123
Results 21 to 26 of 26

Thread: Brake master cylinder upgrade ?

  1. #21
    Need to win Power Ball. Senior member AV8TER's Avatar
    Join Date
    Jun 2013
    Location
    Eugene, Oregon
    Posts
    3,226
    Nice article but you will gain nothing from that master cylinder. It has a 1.125 inch bore just like the one you have now. I take it you have an all stock 77 brake system. The nice thing about the Vette cylinder is it is made for four wheel disc so it has large reservoirs on both ends not just one. Disc brakes need large capacity of fluid compared to drum.

    Don't confuse line size with pressure. Pressure will be the same at the end of a 1/16 line as a 1/2 inch line as long as the flow rate of the 1/16 line isn't exceeded. Think of it as electricity. The wire for the tail light is small and the wire for the starter is big but they both have 12 volts right? Hydraulics is much the same. Voltage is pressure and amps is flow rate. Disc brakes have very little flow as the piston in the caliper is already all the way out against the rotor (with pads in there of course) so it doesn't need to move much to start clamping. Just add some pressure mainly which results in very little fluid flow. Drum brakes require some fluid flow to move the wheel cylinder enough to get the shoes out and against the drums and start working. They (the rear drums) need bigger lines because of the amount of fluid flow to work drum brakes. Once the shoes are engaged to the drums and flow has stopped line size isn't a factor as any increase in pressure on one end of the line (master cylinder) will be the same at the other end of the line (drum brake).

    Your best bet for a cylinder is a 3/4 ton or one ton master as they have a larger bore (3/4 is bigger and 1 ton is biggest) which will give a firmer pedal feel. Just remember, as you increase bore size for a firmer feel you will have to push the pedal harder to get the same braking result. Personally, if I were you, I would do the brake swap and try it with the factory master cylinder for awhile. Mine felt 'soft' when I first did it but after a couple days I was used to it and it was fine. It just felt different than I'd been used to for 20 years.
    Last edited by AV8TER; 01-13-2018 at 05:46 PM.
    I don't always drive a 4x4, but when I do, it's a Chevy.

    1984. HO 454, EFI, 4L60, 208, D60, shaved 14FF, both locked.
    4 in lift. 35 inch Toyo MTs.
    AKA The Trail Master 3000
    October 2014 TOTM. December 2017 TOTM

    The only thing funner than a big engine is a bigger engine!!!

  2. #22
    Shadetree Mechanic
    Join Date
    Oct 2017
    Location
    Denton, TX
    Posts
    58
    I already picked up that Vette master cylinder for the added capacity as well as the Summit Racing proportioning valve made for the disk brake swap. Between the two I should be ok for brakes once I get it all back together.

  3. #23
    Need to win Power Ball. Senior member AV8TER's Avatar
    Join Date
    Jun 2013
    Location
    Eugene, Oregon
    Posts
    3,226
    Quote Originally Posted by Blindaviator View Post
    I already picked up that Vette master cylinder for the added capacity as well as the Summit Racing proportioning valve made for the disk brake swap. Between the two I should be ok for brakes once I get it all back together.
    Did you get just a proportioning valve or the combination valve with the failure light switch? Either way good deal there. With that master from the Vette your pedal will feel different. It will be a little 'soggy'. Just tell yourself it is just different not something bad. I bet you will get used to it and it will be fine.
    I don't always drive a 4x4, but when I do, it's a Chevy.

    1984. HO 454, EFI, 4L60, 208, D60, shaved 14FF, both locked.
    4 in lift. 35 inch Toyo MTs.
    AKA The Trail Master 3000
    October 2014 TOTM. December 2017 TOTM

    The only thing funner than a big engine is a bigger engine!!!

  4. #24
    Shadetree Mechanic
    Join Date
    Oct 2017
    Location
    Denton, TX
    Posts
    58
    Quote Originally Posted by AV8TER View Post
    Did you get just a proportioning valve or the combination valve with the failure light switch? Either way good deal there. With that master from the Vette your pedal will feel different. It will be a little 'soggy'. Just tell yourself it is just different not something bad. I bet you will get used to it and it will be fine.

    It was just the valve. Don't remember offhand if it had the switch in it or not. Someone on here directed me to it for a replacement and I picked it up (I seem to remember an electrical connection on it.)
    It was this one:
    https://www.summitracing.com/tx/part...0185/overview/

    I never drove the vehicle since I purchased it so it will all be new to me anyway.

  5. #25
    Senior member jjvh5150's Avatar
    Join Date
    Jul 2011
    Location
    Grove City,OH
    Posts
    1,386
    Youl'll be fine with that prop valve.
    That is what i put in when i did the disc swap.

    Sent from my LG-H910 using Tapatalk
    JUNE 2017 Truck Of The Month

  6. #26
    Need to win Power Ball. Senior member AV8TER's Avatar
    Join Date
    Jun 2013
    Location
    Eugene, Oregon
    Posts
    3,226
    Quote Originally Posted by Blindaviator View Post
    It was just the valve. Don't remember offhand if it had the switch in it or not. Someone on here directed me to it for a replacement and I picked it up (I seem to remember an electrical connection on it.)
    It was this one:
    https://www.summitracing.com/tx/part...0185/overview/

    I never drove the vehicle since I purchased it so it will all be new to me anyway.
    That's the one. The nice thing about it is it will be a direct bolt in with no mods to the lines. I see they call it a proportioning valve but I call it a combination valve since it has more to it than just a proportioning valve. Doesn't matter, it is the one you want.
    I don't always drive a 4x4, but when I do, it's a Chevy.

    1984. HO 454, EFI, 4L60, 208, D60, shaved 14FF, both locked.
    4 in lift. 35 inch Toyo MTs.
    AKA The Trail Master 3000
    October 2014 TOTM. December 2017 TOTM

    The only thing funner than a big engine is a bigger engine!!!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •