Too much brake pressure

JasonNC
JasonNC Expert Adviser
in HUDSON
I installed a brake reservoir to the firewall and for some reason the brake pedal keeps rising to the point that the brake lights come on by themselves.  I've adjusted the rear brake drums to alleviate some of the brake pressure, but when the car is car cranked and the tires engaged, the brake lights flicker.  I'm thinking I need to make an adjustment where the brake pedal rod enters the master cylinder so that the brake pedal has some travel before the brakes engage.  I don't see how that is done in the repair manual.  Right now the brake engages immediately when the brake pedal is barely touched.  

Comments

  • Glowplug
    Glowplug Expert Adviser
    Are you running disc brakes on front? If so are you running a brake pressure balancing valve?
  • bob ward
    bob ward Senior Contributor
    The master cylinder push rod is a simple threaded rod with a lock nut, just back the rod off until you feel minimal clearance to the back of the piston.
  • RichardD
    RichardD Member
    edited March 2017

    All I have read is that you don't need the 2 psi proportioning valve for the front if the reservoir is higher than the disk calipers. I removed the 2 psi PV when I installed the remote reservoir on the firewall. I kept the 10 psi PV for the rear.
    Just installed a Power Brake unit, PBR VH40; but am having a problem bleeding the system so I am certainly not an expert.


  • JasonNC
    JasonNC Expert Adviser
    I have drum brakes all around on this car. I'm going to try what Bob said.  
  • Geoff
    Geoff Senior Contributor
    It is essential to  have that clearance between the  rod and the cylinder, otherwise the bleed hole is covered, leading to what you have experienced. 
  • JasonNC
    JasonNC Expert Adviser
    Ok, so I adjust the rod that goes to the master cylinder and notice afterwards that brake fluid is accumulating in the boot that covers the rod.  What is causing that?
  • bob ward
    bob ward Senior Contributor
    You have a leaky piston seal, time for a new master cylinder kit and maybe a hone.
  • RichardD
    RichardD Member
    edited March 2017
    Jason, I ordered a repair kit from NAPA last week. They found one in Memphis warehouse. Read on site that the number is 138 for my '53. If that isn't right, guess what I am having for lunch?
     Came in today but I haven't picked up yet.
  • Frankvintagefullflowcom
    Frankvintagefullflowcom Senior Contributor
    edited March 2017

    Jason, Richard,

    Just my opinion, but by the time you get it back together after trying to hone out the pits or having it sleeved, you'll wish you had just replaced it with a new one. The NAPA # for a new cyl. is NMC M3081 and they seem to be fairly common. Our local Po Dunk town has one and I see that there are several at the nearby distribution centers. They fit a ton of Hudsons, a few Hyster forklifts and many mid-fifties Packards.

    The rebuilt version (P3081) is shown as being much cheaper but availability is zero according to my info. Shop that number at your favorite AP Store if you don't want NAPA.

    Good luck.

    F 

  • RichardD
    RichardD Member
    Correct, Frank. Mine is not leaking but might not be pressurizing enough. $20. vs $100. so I am taking the chance.
  • cardoclassics
    cardoclassics Expert Adviser
    bleed the brakes???
  • JasonNC
    JasonNC Expert Adviser
    I went to NAPA and according to the salesman, the 138 is for the 48-50 Hudson.  The kit is in Columbus, OH and not available until next week. They can have a new MC there in the morning.  I elected to purchase a new MC as opposed to rebuilding a part that may be over 67 years old.  
  • Frankvintagefullflowcom
    Frankvintagefullflowcom Senior Contributor
    edited March 2017

    Bingo! We have a winner!

    You won't regret going that route, especially if you don't have much/any experience with such repairs.

    I think they're off base with the '48-'50 kit application but it doesn't matter. My info says they're all the same '48 thru '54 and even the '55-'57 Hornets (except Jet and Italia, of course).

    Good luck.

    F

  • RichardD
    RichardD Member
    edited March 2017
    Jason, if you are using the same remote reservoir as I showed you on mine {Wilwood}, you can use a 3/8" bolt shoulder (not threads) to slip in the tubing at the MC QUICKLY then tighten the clamps quickly to save most all of the fluid in the remote resv. WHEN YOU TAKE YOUR MC OFF.

    I just did it !!
  • JasonNC
    JasonNC Expert Adviser
    Richard I took the Wilwood reservoir off because I couldn't get it to stop leaking.  The car came with a Toyota forklift fluid reservoir that I relocated from the fender to the firewall and it works great.  I'm going to flush out the DOT 3 fluid per Ken U's suggestion, so I'm not going to try to salvage the fluid in the reservoir.  Are you going to Sanford Saturday?  If I can get bugs worked out on the car that I bought from Lance, I may see you guys there.  Even if I can't get the '49 Super Six to cooperate, I'll probably drive the Kaiser as it running pretty decent right now.  
  • RichardD
    RichardD Member
    edited March 2017

    Remember that the wire-type clamp that they furnished with the kit would not stop it from leaking. I had to change to a SS wormgear type of clamp for the hose on the plastic reservoir.

     
    We have too much going on to go to Sanford--I hate it since I didn't make the Christmas party.  Give condolences. Thanks.


    My car is dead due to the brake problem now anyway. Put on Power Brakes but can't get the system to bleed out !! Took MC off this afternoon to redo it then go again.
     Guess I will have to look forward to getting to Lance's now.

    3/24>> just installed rebuild kit; found out that the 'rubber' check valve (#18) was torn all the way around, no way to check. I am NOT sure that was the problem- doesn't make sense to me, but sometimes nothing does !!!!



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