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Mushy Brakes - No matter the year - 1957 Golden Hawk

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  • Brakes: Mushy Brakes - No matter the year - 1957 Golden Hawk

    Folks,

    With due respect, not everyone is 100% familiar with (1) what spot to ask a question or (2) how many times in the past a similar topic has been covered.

    In an attempt to either resolve issues I am having, no matter which part of the car it pertains to, I am trying best to reach out to those that have experienced similar problems or might anticipate their own future need to do something and hope to get positive remarks vs negative.

    Not the place to air this? Where else is one supposed to do so pointing out the obvious for some are new....don't have thousands of posts behind them and expressly hope for good return in order to get my car on the road in running condition.

    Mushy brakes on a 1957 Golden Hawk.

    1) I have done brake repair in my past covering over 50 years but until now had never done a conversion to a disc brake system.
    2) I have had for over 30 years a "kit" to do manual bleeding that involves a small bottle to fill, a means to place it on top of the MC and a bag to put bled fluid in to (yes I went to a bottle later on.
    3) I have worked solo and in the past have had success with anything from a 37 Coupe express to a 57 Silverhawk, not to mention newer Chevy products to have a relatively good idea of how to bleed the brakes.
    4) Until now, I had not installed a residual -or- proportional valve after the MC location so if asking it's to get an understanding about flow. Yes, I am 99.9% sure those valves are installed correctly.
    5) I broke down after looking at YouTube video's to research which "pneumatic" type brake bleeder might work best to speed up my bleeding of brakes after the manual bleed didn't work.
    6) I found the proportional valve was NOT opened 100% so did so
    7) In using the larger HF unit selling for $89 I had to increase PSI to 110 in order to get the vacuum to draw fluid IN TO the tank
    8) I have NOT been able to use a fill bottle on top of the 2 bay Raybestos MC36237 due to the clip on top and for NOT having installed the remote reservoir that some say to not use...I have easy access to the top of the MC in its current position to simply reach in and put fluid in "prior to" the level dropping below necessary to prevent air sucking in.
    9) J.T. has been responsive despite my having started this project in February that began with questioning if to stay with the drum brake setup for both front and rear.

    With other things going on (life in general) that included prep work for cleaning/sand-blasting the OEM rims, finding wheel spacers, etc. it wasn't until early June that I began working on the brakes from running for brake lines, looking for fittings, etc.

    10) In using the HF $89 bleeder, I have moderated how the bleeder screw opens but in getting suction and fluid does flow, there is a lot of air.
    11) With what leaked to the floor when I had not tightened banjo bolts to the calipers or to the drivers side junction block and tightened 2 brake lines further, at the present time there appear to be "zero" leaks.
    12) I have adjusted the brake lever push rod to the front of the MC adequately for full pedal stroke.
    13) As of 8/1/2022 after over an hour filling/refilling the rear chamber to the MC I switched to the front brakes that is (to me) a separate chamber and negates the need to do the right rear first then going to the drivers side rear. I

    Independent of one another I wanted to see what would bleed out of the line.

    Same thing...fluid at 110 PSI but air as well.

    14) To those using a pneumatic bleeder no matter if the lesser $ one or the more expensive, HF or Eastwood or anyone else, what PSI level did you find adequate to push the fluid
    15) If using a pneumatic bleeder, did you seal around the bleeder screw to possibly limit air leakage? I have seen grease used but...dislike that thought.

    Granted air or mishap can be a leaking line, a blocked line but I have fluid from all (4) calipers.

    It could be a bad MC or caliper piston? But still, if all 4 wheels are similar and can not build up pressure...

    16) at the end of the day and you have a good, working conversion with disc brakes...whether the front only or both front/rear, what pedal pressure do you have?

    Mine goes to the floor!

    As in my before posts, thank you to all of you who take the time to read thru my lengthy postings. Your help is and has been appreciated.

    It is difficult moving on to the next project when this one has turned in to a literal nightmare and puh-lease....don't add insult to the injury by saying I should "scrap" the rear brake setup and return to drums only...After a $750 investment that bite is a bite!


  • #2
    Bench bled the master first? You can't bleed the rear, and let the front chamber get low enough to suck air. Keep fluid full completely both front and rear chambers of the master cylinder. Make sure all connections are tight. You might be sucking in air even if you tighten the bleeder screw if you have a loose connection somewhere. Make sure your residual valve is not bad. They can stick. Did you eliminate the hydrovac booster? That has to be bled first after the master cylinder before moving on to the wheels. Did you adjust the calipers on the rear? There is a LOT of travel if they are not adjusted, and they have to bottom out the pads against. the rotors to bleed. Otherwise, the air is just moving the pads back and forth.
    Bez Auto Alchemy
    573-318-8948
    http://bezautoalchemy.com


    "Don't believe every internet quote" Abe Lincoln

    Comment


    • hwkmn
      hwkmn commented
      Editing a comment
      Yes, bench bled the MC first!

      Raybestos MC36237 has (2) chambers to it. Front chamber services the 2 front calipers. Rear Chamber does the back 2. As far as I can tell, there would be no reason for the front, if low (but not empty) would affect the rear.

      Fluid level has remained well above the port.

      No way of knowing if the residual valve is good or bad. Both (supposedly) are new upon install.

      Hydrovac booster? Where/what is that? 1957 Golden Hawk I own does not have power brakes...is that the hydrovac booster?

      I did adjust the calipers on the rear from videos I looked up. Perhaps not enough but currently without any pressure applied to the rear (or front) but checking the rear, there is slight drag when trying to turn the rotor/hub.

  • #3
    I wonder if the AMC master cylinder, with its 1" bore piston and xx inch stroke, simply does not have hydraulic capacity to operate four calipers, since DB caliper pistons are huge compared to drum braked wheel cylinders. So you might wanna try a MC with a 1.25" bore.

    I ran into the insufficient capacity problem once when helping a friend install a tandem MC on his front (huge) disc brake equipped 56J. The MC was for a Geo Metro, or something similar and IIRC, had a 15/16" piston. He had read an article on the internet that said to use that MC. After hours of frustration, and pedal to the floor, we finally figured it out. You may be blazing a trail with the 4 wheel DB kit. I am not aware of anyone else who has installed one, let alone installed it successfully. I wonder if JT has ever actually installed one, or simply designed and fielded it without testing.
    Last edited by JoeHall; 08-03-2022, 11:48 AM.

    Comment


    • hwkmn
      hwkmn commented
      Editing a comment
      Your last sentence might sum it all up. I do not know anyone that has done an install let alone an install for front/rear brakes and certainly do not know if JT ever installed one or field tested it.

      AMC M/C...I took it for gospel that the system was tried and true for years and that the M/C supplied would be adequate. Regarding 1" bore vs 1-1/4" bore or 15/16" bore, finding a replacement with the same C-C bolt pattern or overall length to fit in the spot where the OEM M/C mounted...arghhhhh more crud to deal with.

  • #4
    Not knowing the size/capacity of your calipers, it is possible your master could not supply enough fluid to properly function, as mentioned above. However, I've never found this to be an issue when using a 1" bore master. I built a four wheel disk system using four, four piston 1965 Ford calipers, and a single reservoir 1" bore Chevy Corvair master. No residual valves, no proportioning valve, or power booster. With all four calipers being exactly the same, the front to rear proportioning was taken care of by different diameter tires. It's been working GREAT for 36 years now with NO issues at all. So the 1" bore master has no problem supplying 16, 1.634" diameter caliper pistons.

    Also did one with a 19mm (3/4") master bore and two 42mm(1.654") calipers and two 33mm(1.3") calipers. Again , no residual, proportioning valves, or power booster. Been working great for 18 years.

    My guess is unless you have puddles of fluid on the ground, your master is not building pressure. But if you have a booster the problem could be with it.

    I have encountered this before. On this car the booster was remote and hidden. After removing the car's interior to find and remove it..., I replaced the 1" master with 15/16" one. The owner said the brakes were better than they had EVER been, even when the the car was first built (presumably when the booster was working). This car also had no residual or proportioning valves. (I did not build this one, only repaired it. And, it didn't come to me because of the brake problem. The engine and trans mounts were improperly designed and under built, so they broke off the frame and it fell out the bottom. The rear axle was about to fall out too; broken spring main leaf the owner didn't know about.)
    Last edited by bensherb; 08-04-2022, 12:27 AM.

    Comment


    • hwkmn
      hwkmn commented
      Editing a comment
      I had never installed a residual or proportioning valve until buying the kit from JT. I "assumed" that this kit, sold for years according to what I was reading and obviously under written from what I'm experiencing, was not going to create the problems I'm experiencing. With zero knowledge about why either would be needed, my understanding is that a residual valve reduces back-sliding of brake fluid...a check valve otherwise??

      No fluid underground. No way of knowing if fittings are tight or need further over-tightening as all are quite tight currently. Removing the 2 residual valves and proportioning valve will mean running for more brake line, additional expense and time and further dislike for the choice I made to invest in the system. I could have had the brake drums, shoes, wheel cylinders, springs, etc replaced 3 months ago. Irked is not the real word to use.

      Thanks for the suggestions.

  • #5
    The smaller the master cylinder bore you use , The higher pressure to the wheel cylinders or calipers you will have , You are not alone on these brake issues as other people on other forums are having some of the same issues , Ed

    Comment


    • hwkmn
      hwkmn commented
      Editing a comment
      It's a crap shoot at this point in time. Certainly can see others for other forums having issues as well. Thing is trying to get straight, reliable info is like pulling teeth. If something has worked across the board, why not tell the world and what parts or where to get them. Issue is the space under the floor where Studebaker installed the M/C. That negates, along with the brake pedal where it's located and the length what different M/C might be used??? All above my paygrade...rather I'm just fed up with trying to get what should have been a relatively simple modification done on the car. I'm capable of doing repairs...something like the brakes working solo is a bit more complicated due to applying pressure on the brakes as you know. Thx

  • #6
    FWIW, I've never had good results with the pneumatic bleeders. They always seem to make some brake fluid/air emulsion to me. Moreover, high pressure can damage the MC's seals. I have had always great success with brake bleeder check valves, though.

    I don't think the capacity of the MC is the issue there. Sure, they take a lot more fluid to be filled, but once the pads are touching the disc brake, the movement is minimal.
    Did you check if your brake lights are working? If they don't, there is no pressure in the circuit.
    At this stage, I would make two short lines to act as plugs on the MC and try to build pressure with the MC alone. If you can't, you've found the culprit!
    I hope this helps.
    Nice day to all.
    sigpic

    Comment


    • christophe
      christophe commented
      Editing a comment
      Re: bench bleeding the MC.
      It takes far less pressure to bench bleed the MC than it takes to have the brakes performing properly. Bottom line: bench bleeding is not the proof that the MC is building enough pressure.

    • hwkmn
      hwkmn commented
      Editing a comment
      Certainly I agree...basic principle...sorta like a fulcrum. Pivot point, length of travel all add up to more pressure in the car when applying with your foot than using a screwdriver in the end of the MC on the bench. I just got off the phone with JT who sent a modified M/C set up for the remote reservoir and will try a gravity bleed before attempting with the vacuum pump again. Thanks!

    • christophe
      christophe commented
      Editing a comment
      In tough cases, I fill the circuit by the rear using a large syringe without its piston, to act as a perfusion. Usually, the gravity does the trick. Never tried it with a residual pressure valve in the circuit, though.

  • #7
    I'm going to guess air in Bendix Hydrovac. They are and absolute bugger to bleed. I figured I'd solve brake bleeding woes with a vacuum bleeder. I wasted $50 as I could not make the thing work. I leaked regardless of what I did. I think Speed Bleeders might just help a lot. Remember water (and brake fluid ) seeks its own level so with a master cylinder the lowest point in the system, you are trying to defy nature when you bleed Studebaker brakes!

    Comment


    • hwkmn
      hwkmn commented
      Editing a comment
      It might appear as a dumb response, but on the 57 GH that I haven't started in at least 4 years, I know it had power steering but it does not have power brakes. The parts manual, page 361 shows a typical set-up that I do not have. Page 359 does show similar to what the car had. Speed bleeders...looked online...didn't see anything locally. Yet another thing to buy and lose time over but a good suggestion. As it is, I lowered the rear end so that the calipers would be below the MC to try gravity. But too impatient to let it just sit for 2 days and went back to the vac bleeder. Will march on. Thx

  • #8
    When you push the pedal, lines swell, and brake components shift as they begin to clamp down. All that movement requires more fluid coming from the MC. If the piston displacement capacity (measured by bore & stroke) runs short before the brakes are fully applied, you get a must pedal, or pedal to the floor, and little if any brake application at the wheels. That's what I was talking about by hydraulic capacity. The rear calipers are likely 2" diameter or more, and replacing 7/8" diameter wheel cylinder pistons. Again, it may be as simple as the MC you are using does not have the hydraulic capacity to operate the system. I'd be curious to hear what JT has to say on this, and if he's actually placed a 4 wheel disc setup in operation on a Stude, with AMC master cylinder.

    Comment


    • #9
      Thanks again...you know, I would "think" that the source of the parts would come straight out and say whether a 4 brake system would work with the AMC M/C or not. If it did in the past and Raybestos modified the AMC M/C I would not know. JT probably wouldn't know.

      Without feedback from those attempting the conversion or if someone does that they might post their results, others just stumble in the dark...as I am doing.

      Just arrived Thursday afternoon was a replacement MC36327 by JT. I didn't open the box but supposedly he was sending me a MC set up for the remote reservoir that I bought from him months ago and was going to give up on. I am ok with just filling the MC as it is vs making a bracket for the remote for unsure just where to mount it under the hood.

      I will consult with him prior to tearing it apart but prior to doing so will be rechecking the position of the emergency brake bracket/lever on the Cadillac caliper/s. Believe it was 1/8 that is well within what I saw others posting to YouTube.

      Speed bleeders? Yet another thing or...to try using silicon based grease on the fittings. I have left over dielectric grease or grease from doing other brake caliper replacement (recently was on my Avalanche) to try.

      But if it doesn't have the capacity to push it, then what would fit using the same 2 holes but also position of the MC under the floor. As it is I cut out a huge rectangular hole to gain access to the M/C lid/top. But it is the overall length as I also had to drill a 2 1/2 dia hole thru the frame as the rear of the longer M/C hit. Then too the plunger and position of the brake pedal. I'm not that adept nor have a decent welder to make a different brake pedal to accept a different type of MC.

      Bottom line? I know few owners of 1957 or other Golden Hawk (or other) that have done the actual work themselves. I know no one that has done both the front and rear using the Raybestos MC and what issues they encountered...to include within 100 miles of my home.

      Most state they did the front brakes without an issue. Do I simply remove the residual and proportional valves? I am getting fluid flow...just a ton of air and by adjusting the clearance at the brake calipers on the rear isn't going to change that .

      Sigh!

      Comment


      • #10
        I have used Jims 4 wheel disc brake setups before, and also have made my own. You have to adjust the rear parking brakes first in order to get the pads close enough to the rotor. Also, the emergency brake will not work if you don't do that.
        Bez Auto Alchemy
        573-318-8948
        http://bezautoalchemy.com


        "Don't believe every internet quote" Abe Lincoln

        Comment


        • #11
          Originally posted by bezhawk View Post
          I have used Jims 4 wheel disc brake setups before, and also have made my own. You have to adjust the rear parking brakes first in order to get the pads close enough to the rotor. Also, the emergency brake will not work if you don't do that.
          Bez, which MC did you use with JT's four wheel DB setup? Also, with the tapered rear axles running at .002" to .006" clearance (IICR), it may not be advisable to have the rear pad clearance just shy of 'kissing' the rotors, as modern cars do. Though the 2 PSI residual pressure valve oughta allow pad 'float' as needed.

          Hwkmn, As for MC, I have NEVER had to cut a rectangular hole in a Stude Hawk floor for clearance, and have installed them in several 56Js and GT Hawks. All Hawks are the same, regarding MC clearances; the GTs may have an additional .100"to maybe .250" floorboard clearance due to slightly thicker rubber spacer-cushions, but again I never had a problem with clearance in 56J either. If you had to drill a hole in the frame outrigger to accommodate the rear end of the MC, it is the wrong MC, and ditto for clearance of the bail wire that holds the cover in place. I have seen two styles of MCs, one has a taller top cover and is slightly longer, which causes clearances problems as you describe. But, since you have already cut the floorboard, you should be able to run other MCs more easily, including one with larger diameter piston, if needed.

          NAPA has a new numbering system, for at least 5 years, with new numbers to match their parts that now come from China. At least that's been my experience with u'joints for the 56J, and with a two MCs for the wife's 63GT. The new numbered, offshore MC is M1843, and replaces MC36327; it is identical to the old MC I replaced it with last October (2021). It fits as it should, no floor mod needed, and is OEM for 1976 AMC Hornet, with front & rear drums. Per my maintenance log, the prior MC that I installed on the wife's GT was Sept 2017, when I first converted it to JT's dual system in September 2017, and that MC was also M1843, so the new numbers have been in NAPA's system at least since 2017.

          To check / top off fluid, I first drilled the holes in the floorboard, as JT says, but later learned to do it from under the car, even easier, especially with Hawks that have the carpet anchored under the door sill plates. The wife's 63GT is the only Hawk I've ever had with a reservoir, but it is handier than a pocket on a shirt.

          Hope all this rambling helps.

          Comment


          • #12
            Joe, I used a Wilwood 1" bore master cylinder.
            Bez Auto Alchemy
            573-318-8948
            http://bezautoalchemy.com


            "Don't believe every internet quote" Abe Lincoln

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