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Prop Valve 4 Whl Disc Brake Avanti/interim update

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  • DEEPNHOCK
    replied
    Just remember....
    The bigger the bore on the master cylinder, the less pressure you will develop in the lines (all other things being the same)..
    You said you were running a 1&1/8" bore...
    Most disc/disc setups (ie: Corvette) run a 1" bore on the master cylinder.
    HTIH
    Jeff[8D]

    Leave a comment:


  • bige
    replied
    I finally got to the point where the brakes were ready to be bled. Bench bled the Master, carefully set the pushrod depth and began to bleed. All lines are free and clear, hoses are new, rear brakes are adjusted.

    I plumbed the adjustable prop valve in the rear lines and opened it up all the way. No more than 600 lbs of pressure to the rear brakes. Air is out and pedal is up, not as high as I would like but it's hard to tell with the car up in the air how much travel I would need to stop the car under normal circumstances. MP Brakes says I need a minimum of 800lbs.

    I'm going to order a gage to pumb into the mastre to check pressure at the outlets. Just because the stream is strong doesn't mean I have enough pressure to the fronts either.

    I'll post once I have it sorted out any guidance is certainly welcome in the meantime.

    ErnieR

    Ever since the initial dual master installation, even before the Turner front brakes, I didn't feel the back brakes were doing anything. When bleeding the drum brakes the fluid just didn't stream out like I'm accustomed to seeing on non-modified systems. Front brakes will shoot a stream two feet from the caliper and the rears maybe 3 inches.

    Right now I'm starting to think that the factory booster either doesn't build enough pressure for a dual master let alone 4 wheel discs or total piston travel is not sufficient.



    This may be the reason no one seems to have any rear brake lock up issues.



    On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

    Leave a comment:


  • sbca96
    replied
    Running a 13" rotor with a two piston PBR caliper up front with an 11"
    rotor with single piston caliper rear. Using a Chrysler dual master
    from the early 70's application (Avanti II). No proportioning valve
    seems to be needed at this point. I'm waiting to see what Karl finds
    out with the same setup on the Twin (he will use the 12" rear, but the
    caliper is the same - marginal effect on stopping according to the Ford
    guys).

    Tom

    '63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: TKO 5-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires

    Leave a comment:


  • bige
    replied
    Makes Sense...

    Thanks Jim

    quote:Originally posted by jlmccuan

    My understanding is the loops allow a greater area for flex and vibration to work itself out to lessen cracking of the hard lines.

    Jim

    ____1966 Avanti II RQA 0088_______________1963 Avanti R2 63R3152____________Rabid Snail Racing

    Leave a comment:


  • jlmccuan
    replied
    My understanding is the loops allow a greater area for flex and vibration to work itself out to lessen cracking of the hard lines.

    Jim

    ____1966 Avanti II RQA 0088_______________1963 Avanti R2 63R3152____________Rabid Snail Racing

    Leave a comment:


  • bige
    replied
    I ordered the 3359.

    Thanks for all the help.

    While I have the attention of some obviously smart guys...

    On many factory brake systems the lines from the master have multiple loops even though a straight line would have worked...

    WHY?


    On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

    Leave a comment:


  • DEEPNHOCK
    replied
    Just an FYI...The VL3350 is for disc/drum, and BigE is running disc/disc, so he'd use a VL3359A..
    Nice plumbing work.
    Nice pic labels.
    Just plain nice!
    Jeff[8D]


    quote:Originally posted by 55Prez


    I use a Master Power Brake VL3350 combo valve on my Hawk
    with Turner Disks
    <http://www.studebaker-info.org/64v24...0407ea.jpg>
    <snip>

    Leave a comment:


  • 64V-K7
    replied

    I use a Master Power Brake VL3350 combo valve on my Hawk

    <http://www.studebaker-info.org/64v24...0407ea.jpg>

    with Turner Disks


    Bob Johnstone
    www.studebaker-info.org

    64 GT Hawk
    55 President State Sedan
    70 Avanti (R3)

    Leave a comment:


  • bige
    replied
    I'm sure it was yours...I haven't seen that combo before or since.

    Thanks BTW.

    quote:Originally posted by wcarroll@outrageous.net

    Hey Bige-

    You may have bought that setup from me.

    I sold one with a Wilwood/Strange master attached some while back on Ebay -it was kind of an olive drab green color.

    Anyhow, Master Power has a lot of good info on their site and the Wilwood guys were pretty helpful with me on the phone during the design of my new dual disc system which is comprised of independent masters for front and rear and no booster.

    I'll definitely be running a valve so I can dial the brakes in exactly the way I want them -I just hope I did all my math right [:0]

    Just got the car back from the muffler shop, and it's ashame that the job they did will rarely be seen. That's one of the problems with lowered cars -people don't wanna crawl around on the ground to see the party underneath!!



    http://community.webshots.com/user/s...host=community

    On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

    Leave a comment:


  • DEEPNHOCK
    replied
    Great description of how the caliper should adjust.
    Basically, you rotate the pbrake lever as far as you can until it stops.
    If you can get it to the next hex...go for it.
    (like swinging a box end wrench in a confined space).
    It won't retract, because you don't have the spring and cable hooked up.
    After you are done, pop the spring back on and feed the cable through and hook the ball end up.

    As far as the master cylinder goes?
    Bore diameter on the master cylinder depends on the piston diameter and piston travel of the calipers.
    The smaller the piston in the master cylinder, the higher the psi load on the caliper 'per pound of pedal effort'.
    You can get a real high psi load, but you might not have the volume needed to move the calipers far enough.
    A larger bore master cylinder will get more fluid into the caliper, but the pedal effort goes up with each bore increase at the master.
    I tried a 1&5/16" bore master once, but the pedal effort went way up.
    Settled on a manual disc/disc Corvette master cylinder at a 1" bore and it worked well without too much pedal stroke.
    Sounds like you are right in the ballpark with your size..

    As far as the valve goes?
    Here's what I am running...

    This is basically the same valve from MP Brakes:
    http://www.mpbrakes.com/products/pro...product_id=613

    It is a non adjustable valve.
    An adjustable valve in the back line can still be added for adjustability...With or without this valve.
    If you do install an adjustable after this valve the adjustable part won't start until after the non adjustable valve has done it's part.
    I got my valve when I got the calipers for their brackets.
    I figured I could add an adjustable valve later, after testing to see if I needed it.
    My method of testing was crude and somewhat violent.
    Go fast...Stop fast...Repeat.
    (Testing continues to this day)
    Jeff[8D]



    quote:Originally posted by bige

    <snip>
    Just so I understand, once I'm bled I set the parking brake. If I have good squeeze before the lever moves its full travel I'm good but if it doesn't I remove the lever and position it such that I get enough travel to set the brake without bottoming the lever.

    So to alter my original question...would you, with your experience, install a non-adjustable prop valve?
    I think I'm good with the bore size it's 1.125.
    Thanks for the help Jeff.

    Leave a comment:


  • wcarroll@outrageous.net
    replied
    Hey Bige-

    You may have bought that setup from me.

    I sold one with a Wilwood/Strange master attached some while back on Ebay -it was kind of an olive drab green color.

    Anyhow, Master Power has a lot of good info on their site and the Wilwood guys were pretty helpful with me on the phone during the design of my new dual disc system which is comprised of independent masters for front and rear and no booster.

    I'll definitely be running a valve so I can dial the brakes in exactly the way I want them -I just hope I did all my math right [:0]

    Just got the car back from the muffler shop, and it's ashame that the job they did will rarely be seen. That's one of the problems with lowered cars -people don't wanna crawl around on the ground to see the party underneath!!



    http://community.webshots.com/user/s...host=community

    Leave a comment:


  • bige
    replied
    Great info on the caliper adjustment, thanks. This is Jim Turner's kit but I didn't see anything about the initial adjustments in the instructions. I think I'll be OK with the bleeder it sits up high enough that I think it will bleed ok.

    Just so I understand, once I'm bled I set the parking brake. If I have good squeeze before the lever moves its full travel I'm good but if it doesn't I remove the lever and position it such that I get enough travel to set the brake without bottoming the lever.

    So to alter my original question...would you, with your experience, install a non-adjustable prop valve?

    I think I'm good with the bore size it's 1.125.

    Thanks for the help Jeff.


    On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

    Leave a comment:


  • DEEPNHOCK
    replied
    The reason a disc/drum master won't work on disc/disc is because the master cylinder bore sizes are different 'within' a disc/drum master.
    A disc/disc master has the same bore size for both the front and the rear.
    Pay attention to the bore size on the master, as it will affect your foot pressure required.
    Eldo/Toronado/Riviera rear calipers work well, but watch how they mount on your caliper brackets.
    A lot of them get mounted to get a good parking brake cable alignment, but thet gets you a real bad bleeder screw position.
    That usually means you have you have to remove and clamp the caliper piston to bleed the brakes (initially)
    Their comment about parking brake adjustment affecting normal brake application is true.
    That style caliper had a six sided hex bolt type caliper piston adjusting screw on it.
    You load up your caliper/rotor setup and bleed your brakes.
    Then you crank the parking brake lever as far as it will go (until the pads hit the rotor)
    (I did this by hand before installing the parking brake cable(s).
    If you are far enough along in rotation before the pads contact the rotor, you remove the parking brake lever and put it on the next hex (60 degree's).
    If you don't do this, then in normal use the caliper piston retracts quite a bit. This means that you lose pedal stroke just getting the pad pushed to the piston.
    It really isn't a big deal, and it shouldn't chase you off that style caliper.
    Once you adjust it the first time, you only adjust it for pad wear...
    And it takes a LOT of pad wear to get the parking brake lever to move 60 degree's.
    I am running this basic setup on the yellow truck, and it works great.
    (Except I am running a hydroboost power brake setup)
    Hang in there... You'll get it sorted out.
    BTW... I am not running an adjustable proportioning valve, but am running a stock GM proportioning/distribution block (off an Eldo/Riviera/Toronado.
    HTIH
    Jeff[8D]

    PS: Strange Engineering makes great stuff. I've bought a lot of Bob Stange's stuff through the years. Good drag race supplier..


    Leave a comment:


  • bige
    replied
    The gage will tell me if i have enough pressure to the back wheels. 800-1000 is recommended for disc brakes. Living in heavily populated NJ my opportunities for brake testing are limited. It's possible that things may feel right because the rears don't lock but it may be because they are barely working.

    I have a Summit prop valve and gage without the brake switch, I converted to mechanical. The prop valve should be installed after the junction block in the single line going to the rear brakes according to instructions with the valve. Which means somewhere under the car or bringing lines up into the passenger or engine compartment if I wanted to adjust while testing.

    I always questioned whether my drum brakes were getting enough pressure with the dual master conversion. They never seemed to do much. With the Turner brakes up front the car stops deceptively well, meaning it feels like it should but I want to be sure the backs are doing something.

    I may plumb the gage inline first, I have a spot under the hood where the hydraulic switch was before I converted to mechanical. If the pressure looks good I'll forgo the prop valve.

    We'll see.


    On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

    Leave a comment:


  • DEEPNHOCK
    replied
    Question.
    What is a gauge going to tell you?
    Most people use a pressure gauge to 'set' the brakes on the starting line consistently.
    Summit sells a nice one that incorporates the distribution block and even has a brake light switch...
    http://www.summitracing.com/parts/SUM-G3910/

    Makes for a cleaner install.
    Summit sells a bunch of brake pressure gauges...
    Here's a search.
    http://www.summitracing.com/search/?...%20gauge&dds=1

    That R3 (Clone) Avanti I worked on had an adjustable proportioning valve installed. The plumbing was less than appealing.


    Leave a comment:

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