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  1. #1
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    A-60 Master Cylinder

    Is there any way to 'bench test' the master cylinder for an A-60 actuator ?

    I have blown air through all of the brake lines to ensure they were not blocked.
    I tried to bleed the brakes using the vacuum pump method but it would not draw any fluid.
    I tried to bleed the brakes using the manual pump with a screwdriver but it would not push any fluid.
    With the brake line disconnected at the master cylinder while still on the trailer - Did the manual process
    to see if it would spray a thin stream ( I understand they have an orifice with tiny opening). But it would gush out when using the screwdriver pudh method.
    But would not pump any fluid into the lines when connected.

    I installed this actuator new last year and worked great. I had to replace the break away cable and now it no worky.
    I am guessing it is something I did but for the life of me, I can't figure it out.

    I guess double check the actuator but I don't know what else to test.
    1999 TR-21
    Optimax 225 Serial Number 0G842489

  2. Member
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    #2
    Hmmm. After you replaced the break away cable did the brakes work?

  3. Member
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    #3
    Quote Originally Posted by billnorman1 View Post
    Hmmm. After you replaced the break away cable did the brakes work?
    No. After replacing the break away cable......the next step was to bleed the brakes.
    1999 TR-21
    Optimax 225 Serial Number 0G842489

  4. Member
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    #4
    I'm not 100% sure on how the break away system works, but I think it removes a block that allows a spring to activate the master cylinder. Unless that system is properly reinstalled the master cylinder may not work correctly.
    You may need another new actuator unless that work is done.

  5. Member
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    #5
    I took pictures before I disassembled and it looked like I got it back together correctly. But I might have missed something.
    The break away cable is pulled on trailer separation (or when you pull way after parking the trailer with unhooking it ) forcing and locking the
    piston to apply the brakes.
    I was wondering if maybe that could damage the master cylinder leading me to the question of testing it before I buy a new one.
    There is the possibility that I missed something when I reassembled......but it is not a complicated set up.

    Thank you.
    1999 TR-21
    Optimax 225 Serial Number 0G842489

  6. Member
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    #6
    The guy at e-trailer said he did not think that pulling a way from parked trailer and breaking the cable would damage the master cylinder.

    So, I guess I will re-assemble the actuator this evening and then attempt to bleed the brakes again tomorrow - I ordered a vacuum bleeder. I hope that will get it done.

    Thank you for your help.
    1999 TR-21
    Optimax 225 Serial Number 0G842489

  7. Member
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    #7
    I would disconnect the main line from the master cylinder and it’s connection at the first caliper, and see if you can blow air through the main line.
    If you are using one of those little hand squeeze vacuum pump bleeders, they take for ever to pull fluid through the system, especially when the entire system has a bunch of air in it. If you have an air compressor, Harbor Freight make a pneumatic bleeder that is like $31.99 that works way better. You just hook it up to the open bleeder screw and hold the trigger down on the canister until you get a good bit of fluid into the canister.
    It takes about 5 or 10 minutes to pull all the air out.
    https://www.harborfreight.com/brake-...der-92924.html

  8. Member
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    #8
    Quote Originally Posted by Blair B View Post
    I would disconnect the main line from the master cylinder and it’s connection at the first caliper, and see if you can blow air through the main line.
    If you are using one of those little hand squeeze vacuum pump bleeders, they take for ever to pull fluid through the system, especially when the entire system has a bunch of air in it. If you have an air compressor, Harbor Freight make a pneumatic bleeder that is like $31.99 that works way better. You just hook it up to the open bleeder screw and hold the trigger down on the canister until you get a good bit of fluid into the canister.
    It takes about 5 or 10 minutes to pull all the air out.
    https://www.harborfreight.com/brake-...der-92924.html
    I did the blow air thing.
    I bought one of the bigger pneumatic tools.
    worked just like a charm.

    Thank you.
    1999 TR-21
    Optimax 225 Serial Number 0G842489

  9. Member
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    #9
    Air in brake lines and power steering lines is a demon, takes forever to get that demon out. Sounds like you were on the right track the first time, but needed more time.

    Glad you got that demon out and can go fishing!

    PS If you take short 1/2 inch strokes with the screwdriver method, you will see little air bubbles inside the reservoir and then streams of brake fluid. That is how to bleed the master cylinder on surge brakes. Don't get to close with your eye when doing this.

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    #10
    Do you have a tube type trailer? If yes, I had a 1998 TR20 with a tube trailer and the brake line chaffed against something inside the tube and caused a leak, It was a nightmare and alot of swearing to figure it out, I lowered the tongue as low as it would go, to try and bleed the system and my buddy seen brake fluid slowing dripping out of the front part of the tube.
    Last edited by Team Mud; 10-18-2022 at 03:15 AM.
    1998 Triton TR-20, 2017 Evinrude 150HO

  11. Member
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    #11
    Did you get it figured out? I was going to suggest pushing in the tab on the underside of the actuator to see if that helps. It resets the break away feature. I've torn my a60 apart more than once. Bleeding can be a pain initially.
    1995 Champion 190 dcx Elite

  12. Member
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    #12
    Oh geez, surge brake problems, sorry for your struggle. You might consider pressure bleeding to determine if brake fluid will exit the master cylinder. If pressurizing the mater cylinder does not allow break fluid to flow I would replace the entire assembly. Good luck sir.
    Carte's Custom