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Thread: Rubber brake hoses

  1. #1
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    Rubber brake hoses

    Today I went to bleed the rear brakes. This is a job I should have done when I installed the new master. I didn't because I was short on time. I bench bled the master and it seemed to work, but I always intended to go back and do the job right. For one thing, I wanted to run clean fluid through the whole system.

    So I removed the wheels and loosened the bleeder. Hooked up a clear hose into a cup and began pumping the brakes. Nothing! I couldn't believe it. No fluid would come out. I removed the bleeder completely and tried again. I could push the brakes as hard as I wanted and nothing would come out of the caliper. I tried the other side and the same result.

    So I began tracing the system. The fluid would pump out at the master and at the tee in back. But not a drop out of the rubber hose on the trailing arm. I was able to blow compressed air through the short tube from the caliper to the hose, but even a 120 psi wouldn't go through the hose. I removed the hoses on both sides. (That turned out to be a major pain in the arss.)

    I put one end of the hose in a vise and pulled it straight. Tried the compressed air again. (No joy) I stuck a piece of safety wire in about 3" and tried the air again. This time it went through. I washed it out with some brake clean and more compressed air. I repeated this on the other hose, but it required a lot more wire in both ends to clean out.

    Installed everything back and finished the bleeding job.

    So, why just the hoses clogged? They looked good on the outside. Should I assume they are shot on the inside and replace them? Anybody else have this happen or am I just lucky?

  2. #2
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    It's common for brake hoses to fail internally and the failure can act as a check valve.


    It was one of the first things to come up when I googled brake hose failure.
    Dave B.

  3. #3
    Administrator Ron's Avatar
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    Brake hoses usually act like a check valve in the other direction when they act like a check valve, i.e., you put the brakes on and they stay on. The "valve" usually forms where a mounting bracket is squeezed around the line. The master has enough strength to push fluid through the restricted area, but the caliper can't push it back through... Either way, change the lines.

  4. #4
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    Quote Originally Posted by Ron View Post
    Brake hoses usually act like a check valve in the other direction when they act like a check valve, i.e., you put the brakes on and they stay on. The "valve" usually forms where a mounting bracket is squeezed around the line. The master has enough strength to push fluid through the restricted area, but the caliper can't push it back through... Either way, change the lines.
    These were act as a check vale both ways. Lol. I'm going to order some braided stainless lines.

  5. #5
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    So I got a set of the braided stainless hoses from DMC. I can't say I'm very happy.

    The frame has brackets that have a hex socket that fits the stock nut that is crimped on the hoses. So it makes it easy to undue the lock nut that holds the hose to the frame. The new braided hoses have a smaller nut crimped on them. So it can spin in the frame socket. Because the crimped nut is sunk in to the socket, you can't grab it with anything. So you just hold the hose and try to snug the lock nut as best as you can. I don't suppose it needs to be real tight except for one problem. After you have it mounted, you have to tighten the coupling nut on the ends. If you try to make that tight, the whole mess can turn and wind up your hose.

    I guess the answer is to grind/cut the socket off the stock mount. Then you could get a wrench on the hose nut to hold it. Of course, all this could be avoided if they would have just made the ends the same as stock. Also, there's no instructions to let you know you are in for this issue.

    I got it on there and maybe the coupling nuts are tight enough. If they leak, I'll be doing it again.

  6. #6
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    Quote Originally Posted by Helirich View Post
    So I got a set of the braided stainless hoses from DMC. I can't say I'm very happy.

    The frame has brackets that have a hex socket that fits the stock nut that is crimped on the hoses. So it makes it easy to undue the lock nut that holds the hose to the frame. The new braided hoses have a smaller nut crimped on them. So it can spin in the frame socket. Because the crimped nut is sunk in to the socket, you can't grab it with anything. So you just hold the hose and try to snug the lock nut as best as you can. I don't suppose it needs to be real tight except for one problem. After you have it mounted, you have to tighten the coupling nut on the ends. If you try to make that tight, the whole mess can turn and wind up your hose.

    I guess the answer is to grind/cut the socket off the stock mount. Then you could get a wrench on the hose nut to hold it. Of course, all this could be avoided if they would have just made the ends the same as stock. Also, there's no instructions to let you know you are in for this issue.

    I got it on there and maybe the coupling nuts are tight enough. If they leak, I'll be doing it again.
    The only vendor that I know of that has the brake lines made with the correct size hex end is PJ Grady. Otherwise, it's not difficult to just wedge a flat screw driver between the hex head of the brake line and the well it's in to hold it and then tighten it, this is what we've all been doing for years. No need to cut the well off and create more work.

  7. #7
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    Quote Originally Posted by dmcman73 View Post
    The only vendor that I know of that has the brake lines made with the correct size hex end is PJ Grady. Otherwise, it's not difficult to just wedge a flat screw driver between the hex head of the brake line and the well it's in to hold it and then tighten it, this is what we've all been doing for years. No need to cut the well off and create more work.
    How did you get that info? I guess you ordered one set and then started asking? Is PJ's NOS or is he making them? It's funny, the hex socket is a great idea because you can easily set the double bend in the hose so it creates the least stress. Delorean is the first car that I've seen it on. Great idea from the manufacturer and the aftermarket messes it up. Usually, it's the other way round.

    I'll have to try the screwdriver thing the next time I'm under there. Thanks.

  8. #8
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    Quote Originally Posted by Helirich View Post
    How did you get that info? I guess you ordered one set and then started asking? Is PJ's NOS or is he making them? It's funny, the hex socket is a great idea because you can easily set the double bend in the hose so it creates the least stress. Delorean is the first car that I've seen it on. Great idea from the manufacturer and the aftermarket messes it up. Usually, it's the other way round.

    I'll have to try the screwdriver thing the next time I'm under there. Thanks.
    Post #7, directly from Rob: http://dmctalk.org/showthread.php?14...ts-what-to-buy

  9. #9
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    Quote Originally Posted by dmcman73 View Post
    Wish I had seen that. Don't suppose these will ware out in my lifetime.

  10. #10
    Senior Member Chris 16409's Avatar
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    The UK DeLorean Club is selling the Goodridge stainless brake lines:

    https://www.ebay.com/itm/264272824522

    I donít know if Rob has them any longer.
    Chris Miles

    For Better or Worse I own a DeLorean!
    1983 Grey Manual, VIN #16409, Fresno, California

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