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  • Brakes: Unbelivable problem

    Well I have a 41 Commander, the only one in Europe, apprently. However i have an on going problem that has bugged me for the last 18 months. My brakes, especially the front ones come on gradually untill they almost seize up. To get going again I have to release the pressure, and wait for everything to cool down.
    What I have done so far.
    Replaced all the metal pipes, fitted brand new hoses, had all wheel cylinders honed and brand new steel pistons* [I replaced the ally ones as the engineer thought that they may be expanding in to the cylinder] engineered for each wheel cylinder. Fitted brand new master cylinder. Fitted brand new return springs. Adjusted the brakes so that they run free. Adjusted the brake pedal rod until I was blue in the face, but none of this has made any difference.
    The brake shoes themselves are not new and dont have high spots on them. I have lubricated all the adjusters so that they all work.
    I have an inoperative hill holder, which has been taken off and cleaned out.
    It seems to affect the fronts worse than the rears. I often think if I have too much fluid in the master cylinder. I have left about a quarter of an inch free at the top of the top.


    I am really at my wits end with this, and I have run out of options. No doubt the answer is really stupid, and in front of my eyes, but I need someone to point it out to me. PLEASE HELP BEFORE I GO INSANE

    If you have any ideas or pictures/ diagrams I would be grateful. I have a shop maual but on the the brakes its as informative as the Beano

  • #2
    I don't know a lot, but maybe enough to help you a little. Someone else more knowledgeable is probably about to pipe in.

    Does your car have 'hill holder'? If it does, there is a little bleeder hole between it and the master cylinder. If it gets clogged, your master cylinder won't release the pressure completely after applying the brakes. So they stay on, heat up and freeze.

    Comment


    • #3
      Bleeding the hill holder is a real bitch. I always recommend that you replace the little panhead 8-32 bleeder screw with either an allen head screw or a hex head screw. Otherwise you may have to try to get an offset screwdriver to open and close the bleeder, and that is not easy.

      Comment


      • #4
        Yes, I'm with Bob here. Never seen a hill holder, let alone worked on one, but if there is any way you can isolate it or disconnect it, that's where I would start. If it's not the hill holder, the next thing I would check is the master cylinder...just because it's new, or nos does not mean it is good. Check for a corrosion-free piston and bore, and that any residual pressure valves, check valves and ports are all clean. You have a better chance of these two things being the culprits, rather than both, or all wheels or cylinders causing you grief at the same time. Living in London, you are indeed in a very damp/cool climate, and remember standard brake fluid loves to absorb water. Good luck, keep us posted as this is interesting problem. Junior.
        sigpic
        1954 C5 Hamilton car.

        Comment


        • #5
          If the brakes are coming on the more you drive, back off the adjustment between the M/C and the pedal, go a turn at a time! I'll bet that will resolve your problem. Be sure there is "about" an 1/8" play between them.

          Jim
          "We can't all be Heroes, Some us just need to stand on the curb and clap as they go by" Will Rogers

          We will provide the curb for you to stand on and clap!


          Indy Honor Flight www.IndyHonorFlight.org

          As of Veterans Day 2017, IHF has flown 2,450 WWII, Korean, and Vietnam Veterans to Washington DC at NO charge! to see
          their Memorials!

          Comment


          • #6
            hill holders work the back brakes not the front ones I was thinking the same as Ragtop, and he piped in first and he more of a brakeman than me.

            Comment


            • #7
              Originally posted by railway View Post
              hill holders work the back brakes not the front ones I was thinking the same as Ragtop, and he piped in first and he more of a brakeman than me.
              If he has adjusted everything properly, as he indicates, I would take another look at that hill holder. Since he states that it is "inoperative," why keep it there? Just remove it and connect the distribution block and lines directly to the master cylinder.

              He states that he has adjusted the shoes so that the wheel spins free, so I doubt that they are adjusted too close to be the culprit. I suspect that if the ball check in the hill holder is in the pressure "check" position, it will cause the pressure to build and not release regardless if he has the linkage connected...functioning or not.(It may be inoperative because the linkage is not adjusted or is missing.) As to whether or not it only holds pressure to the rear brakes...that depends on the lines being properly connected to the correct fittings. I do not have a car that old (my oldest is a '48).

              I had a fellow SDC member to bring a '51 to me with binding brakes. His hill holder linkage was missing. The actuator had been accidentally moved in the "check" (hold pressure) position. Simply moving the little lever to the correct position eliminated his problem.
              John Clary
              Greer, SC

              SDC member since 1975

              Comment


              • #8
                Check the vent in the M/C.I once had one to plug,when being driven heat would expand the brake fluid.with the vent pluged it had no where to go so it applied the brakes.

                Comment


                • #9
                  Brizzle,
                  When you "release the pressure" what are you doing? I too would look at the hill holder first. If it is causing you problems you can always remove it and replace with the fitting used on cars without this option. No hills to speak of in London anyway...

                  If it were my car I would reinstall the factory pistons. Moisture WILL get in this system and eventually you will leave it parked long enough that the piston will rust to the cylinder leaving you with a very expensive paperweight.

                  Nathan
                  _______________
                  http://stude.vonadatech.com
                  https://jeepster.vonadatech.com

                  Comment


                  • #10
                    I am a firm believer in DOT 5 (Silicone brake fluid) no more moisture absobtion, no rust, and doesn't eat your paint off when bleeding or leaking or filling.
                    Good Roads
                    Brian
                    Brian Woods
                    woodysrods@shaw.ca
                    1946 M Series (Shop Truck)

                    Comment


                    • #11
                      I had a mechanic with a lift adjust my clutch linkage. He and I were not aware that the release rod to
                      the Hill Holder had to be adjusted as well. On the way home , up a hill, the Holder worked so well
                      it locked up my brakes and the rod would not release the Cage/check ball when the clutch was
                      released.. If you have the release rod installed, and it has not been adjusted in length, to hold
                      the check ball in an open position, it can hold pressure in the lines. How to adjust ? Trial and error.
                      Cheers,
                      Dick Curtis
                      The 1950 Champion Starlight
                      Santa Barbara
                      CA

                      Comment


                      • #12
                        Originally posted by woodysrods View Post
                        I am a firm believer in DOT 5 (Silicone brake fluid) no more moisture absobtion, no rust, and doesn't eat your paint off when bleeding or leaking or filling.
                        Good Roads
                        Brian
                        Brian,
                        I've thinking of converting my older cars over to Dot 5, any tips ? Can I just flush out the old Dot 4 fluid and replace with the Dot 5, or will I need to replace the piston seals etc ?
                        Matt
                        Brisbane
                        Australia
                        sigpic

                        Visit my Blog: http://www.mattsoilyrag.blogspot.com.au/

                        Comment


                        • #13
                          If you convert to DOT 5, make sure you flush the system out a couple times, then flush it again! DOT 5 is also prone to leaking more. I run DOT 5 in my 52 Commander, and DOT 3 in my Avanti.

                          Jim
                          "We can't all be Heroes, Some us just need to stand on the curb and clap as they go by" Will Rogers

                          We will provide the curb for you to stand on and clap!


                          Indy Honor Flight www.IndyHonorFlight.org

                          As of Veterans Day 2017, IHF has flown 2,450 WWII, Korean, and Vietnam Veterans to Washington DC at NO charge! to see
                          their Memorials!

                          Comment


                          • #14
                            We usually start with all new componants. But yes you can do a thourogh flush. As for the seals? I would disassamble everything to clean and check it out anyway. Then relube with silicone fluid and re assemble. Brake parts are so cheap in comparison to the rest of most projects, that we usually use "all " new stuff.
                            Good Roads
                            Brian
                            Brian Woods
                            woodysrods@shaw.ca
                            1946 M Series (Shop Truck)

                            Comment


                            • #15
                              Hi all,

                              I've had the same trouble on a Peugeot DMAH. If opening a bleeding screw releases the brakes, then the problem is the master cylinder. This indicates that when the piston comes to its rest position, it doesn't fully allow the fluid to return to the tank. It may not be the right piston. There is also a large washer behind it. It's thickness can cause the same problem. Check also that the vent in the filler plug isn't clogged.

                              Best of luck.
                              sigpic

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