how to remove residual valve for disk brakes or . . .

Discussion in '40- & 55-Series Tech' started by slickrock, Feb 11, 2009.

  1. slickrock

    slickrock

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    This has been discussed but I am not sure if I can or should do this. I am installing a 60 series axle into my 73FJ 40 so I will now have disk brakes. I spent many months getting my FJ40 brake master to work with a 60 series booster for my old drum brakes ( and lots of money so I would hate to see it go right now) I also have a mini truck master (disk brake) that I could install in place of my 40 master that is on a shelf in the garage..

    I need to get this project completed ASAP and I can install the mini master after a club trip in April. For now . . .

    Question: Can I keep the 40 master and remove the residual valve from the front line so the front disk brakes will work? If so, how do I do this and what else will I need to buy or figure out to match up to my stock brake lines.
     
  2. 71-CRUISER

    71-CRUISER

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    Yes you can. First remove 10mm fitting for the hard line and bend the hard line out of the way a little. Next remove the large fitting that is still in the master where the hard line used to go (24mm ?). Now take the little spring and piston type tting and throw them across the shop. Now just reinstall and bleed and you should be good to go.
    You may have to put a proportioning valve in the rear system to get the balance correct but other than that you should be fine.
     
  3. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Yes.





    TECH LINKS! <---- this is a link

    Your brake master cylinder will look similar, but not identical, unless you do not have the correct master cylinder for a drum brake 1974 40 series. Remove the brake line adapter fitting from the master cylinder that the front brake line attaches to, and remove the residual valve. Re-install the brake line adapter fitting and bleed the brakes.

    It really is that simple.



    Will need to make sure your flex hose from the frame to the axle will work, and may need to fabricate a brake line or two.


    No big deal.
     
  4. slickrock

    slickrock

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    THanks for the responses. Can't believe I missed the FAQ.

    One more, my back is still drum and the FAQ link said to remove both valves. I should leave the rear brake valve correct for drums?
     
  5. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    It is not the Frequently Asked Questions list, it is the Tech Links....




    Yes.
     
  6. slickrock

    slickrock

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    Poser,
    I pulled the front brake line fitting (large screw type that the hose attaches into) and I was surprised to see that there was no residual valve inside it. All there was was a spring and a mushroom like silver cup that went on the end of the spring and had a mating surface for the brake line to make a good connection (with a round black seal ring) . This silver item was only a bucket with a few holes in it and no way close to a residual valve.

    I find this very strange as this was a napa brake master replacemet for a 73 FJ40. I know residual valves are plastic and only allow fluid to go one way. This was not a residual valve.

    This may have been the casue for eariler brake problems as there was no residual valve and probably once I came to a stop, my back brakes were holding me in place and I never noticed that the front brakes probably lost pressure since there is no residual valve for the brake lines.

    Do you know anything about what I ran into . . . a brake master that has a spring and a silver bucket that has a nipple on it to make good contact with the brake hose?

    Here is a picture from SOR of my brake master. Circled in grey is the silver bucket I am talking about. Definitely not a residual valve (which is white and back with holes and and little springs)
    [​IMG]
    So I bolted eveything up and bled the lines. Before I take a test drive, I wanted to run this by the board.

     
  7. antFJ

    antFJ

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    if you connected it all back up and bled the lines properly what can be the harm in taking it slowly and seeing if they work... this forum is very useful but it can't answer situations out of sight... give it a shot! (go slow :p)
     
  8. slickrock

    slickrock

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    This isn't really out of sight. I believe we were all expecting to see a residual valve inside my front brake output on the brake master. Instead, there was a large spring and a connection to seat the hard brake line. Since my 73 should have had a residual valve to control the brake drums from releasing pressure, it is strange for there not to be one.
     
  9. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Post up pictures of what you have going on.
     
  10. slickrock

    slickrock

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    It is what is circled in the above picture and it is not a residual valve, they are white and black. What I have is silver and has nothing in it to stop the flow of fluid either way. If I pull it out now, I'll have to re-bleed. I was hoping someone would know why an August 8/73 brake master would not have a residual valve in it. Before I test drive it and find out I don’t have brakes, I hoped that someone knew what was with this master.

    Guess I will have to drive it. IF it doesn't have front brakes, I guess I will know pretty quickly.

    I do have a mini truck master that I could try, but I really don't want to have to readjust the booster/master push rod.
     
  11. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    If you want help with this, post up a picture of WHAT YOU HAVE IN YOUR MASTER CYLINDER, not some abstract drawing.




    :wrench:
     
  12. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    What makes you SO CERTIAN of this?


    Based on what?
     
  13. slickrock

    slickrock

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    Poser, if it does not work, I will take apart and post a pic. A residual valve is usually like 2 pancakes on top of each other with little holes in each and little springs in between. The piece I have in mine is a thimble type thing with a good surface for the hard brak line to but up against. No "moving" parts in it like a residual valve.

    As I said, will try and driveing tonight and go from there. Thanks for the help.
     
  14. pbgbottle

    pbgbottle Forum Lifer

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  15. 71-CRUISER

    71-CRUISER

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    Like Poser said What makes you so certin? That IS the residual valve from a pre disk brake master.
     
  16. slickrock

    slickrock

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    Thank you for the link!!! I have this valve and from what I can tell from that post, my MC is not a US MC and came with a different type of valve than the US ones (they are 10# and white plastic)
    [​IMG]

    From what I read (and I admit quickly as I am trying to work), this grey bucket allows fluid to flow both ways but the reverse flow is more restricted than the out flow (like 2#). This type of valve is used for a disck brake and a drum brake non US cruiser.

    I did drive it up and down the street last night and it seemed to stop fine. I did not go too fast as it was in my neighbor hood and my son was with me, but it stopped better than just rear brakes working. I also did not feel any additional drag from the front brakes as if they were holding pressure.

    So from the link above and the picture, I should keep this valve in there. THis sound about right?
     
  17. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Do you have a Land Cruiser drum brake master cylinder in the truck right now?
     
  18. 71-CRUISER

    71-CRUISER

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    I have a 71 Drum Brake Master and Booster in my 40 w/ LC disks. I removed the valve that you have circled in post #6 years ago when i did my swap with zero problems to date.
     
  19. slickrock

    slickrock

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    I have the Napa MC replacement for a 73 FJ40. It looks like this and Item#: TS 111722 :
    [​IMG]
    As for it being a MC for only drum brake, I thought that when I bought it. But, after reading that link, it appears there are different types that work for 4 wheel drum and disk/drum combos and depends on where manufactured. It was running fine with 4 wheel drum. But with the type of valve I have (not the white/black one) I am not sure when it comes down to it.
     
  20. slickrock

    slickrock

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    From this page: https://forum.ih8mud.com/40-55-series...nder-mods.html

    There is a very good discussion about the type of valve I have (as you had). Some say that I should leave this valve becasue it is 2#s and can be run for both disk and drum and others say it should be removed. Oh the fun of modifications.
     
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