Overzealous stopping

Brakes for your Classic Mopar

  1. FlDart360

    FlDart360 Well-Known Member

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    Ok this has happened more than once so I think it is time to sort this out. Yesterday on my weekly drive around the block to make sure everything still works my left front wheel locked briefly as I tapped the brakes backing down the driveway and then once more as I approached my first stop sign. The rest of the 4 mile journey was uneventful, stopping was normal with no brake pull or fade. The details: 1971 Swinger with disk brakes from what I believe was another mid 70's A Body. They are single piston.
    The whole setup is manual and I still have drum brakes in the back. On occasion the right front has squealed under light braking but never under heavy. The pads have very little wear on them and other than a visual inspection this is the one part of the car I have not completely disassembled at one time or another. Could this be a caliper piston sticking or a problem with the pins that attach the caliper? Heck I probably should find an exploded
    view picture to verify they were even installed correctly. Thanks for the help.
     
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    • DentalDart

      DentalDart Well-Known Member

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      Air in the lines? The rear drums not adjusted properly or the drums are out of round?

      I have manual brakes and I've never been "ecstatic" with them. I have replaced everything except the proportioning valve and lines from the MC to the prop valve. I also did not replace or resurface the rear drums...

      These are the conclusions I've come to as I've at times felt as if my fronts stick at times after converting to disc brakes.
       
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      • volunteer

        volunteer Well-Known Member

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        Shouldn't have 'pins' since the '73 - '76 A-body calipers were of the sliding type, with a springy plate on each one. Possibly a slight issue with the caliper seal or M/C? Smarter minds than mine will zero-in.
         
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        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

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          Could be a few things. Sticky pistons, worn caliper guides (sliders or pins depending on the style), trash in the brake fluid (rust) or brake lines getting pinched when you steer or the suspension moves.

          The sliders or pins can be inspected pretty easily by removing the calipers, no need to even unhook any lines for that. Any damage, pits or burrs could cause some rough movement that could cause erratic applications. Are your calipers to the front of the car or the rear? Since you have a disk conversion, you may have the wrong length lines or poor routing. Is the sticking related to turning the wheel at all? This can also be inspected, but you may need a helper to turn the wheels back and forth and see if the lines pull tight or get pinched. If they’re getting pinched there may also be damage to the outside of the lines. Also easy do to, for both you’d need to raise the front end and pulls the wheels to see everything. You can flush the brake fluid and look at that. If there’s nothing obvious on the inspection of the sliding surfaces and the lines then do the brake fluid. If that’s nasty then run it for a bit with the new brake fluid and see if it recurs. Brake fluid is supposed to be flushed every few years, BTW. If it does recur then it may be time to rebuild the calipers. It may also be the lines themselves, rubber lines can collapse internally. Although usually when that happens they stay on and drag.

          Since it’s happened on both sides, I would suspect something that hits both sides- like poorly routed lines, or rust in the fluid. The other stuff requires separate problems on both sides. But that is still possible.

          Shouldn’t be single piston calipers is it was stock either. The pin style calipers came on B/E and F/M/J bodies. And since the brakes have been sourced from a later mopar, they could very well be pin types.
           
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          • Dana67Dart

            Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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            "Backing down the driveway"
            Is your driveway sloped?
            What is the driveway made of?
            Was it wet?
            Ase you turning while backing and braking?


            First stop...
            Road conditions?
            Speed?
            Pedal pressure?

            IMHO if a front brake locks up then there is not enough braking happening in the rest of the system.

            The fact that the brakes worked fine after, indicates intermittent or cold (not warmed up) issue.
             
          • volunteer

            volunteer Well-Known Member

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            Here we go again (sigh) - having to reply to and explain my own posting. OP stated his calipers came (he believes) from mid 70's A-body - - so they would not have pins. Thank-you. :p
             
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            • 72bluNblu

              72bluNblu FABO Gold Member FABO Gold Member

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              Whatever bud. The car is 50 years old and assuming it has to have sliders because it’s an A body and ordering parts could easily get the OP the wrong stuff. The OP isn’t sure, and it could absolutely have pin type calipers on it. It doesn’t matter at all what it should have.
               
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              • FlDart360

                FlDart360 Well-Known Member

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                Thanks will pull the wheels this weekend and see what we got. Probably post some pictures
                 
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                • FlDart360

                  FlDart360 Well-Known Member

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                  "Backing down the driveway"
                  Is your driveway sloped? No
                  What is the driveway made of? Concrete
                  Was it wet? No
                  Are you turning while backing and braking? No and No going straight.


                  First stop...
                  Road conditions? Dry
                  Speed? 25MPH residential area
                  Pedal pressure? Light to very moderate
                   
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                  • FlDart360

                    FlDart360 Well-Known Member

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                    Your good no explanation needed I will hopefully have time this weekend to pull the wheels and upload some pictures. Not going to order anything yet until I understand more about what I have.
                     
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                    • volunteer

                      volunteer Well-Known Member

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                      Thank-you for your nice replies - so much better than the 'boots on ribs' response I always get from one particular responder. I suppose he has more than my 50 years of experience so I'll just stay out of it. Main topic was for you to get the brake problem solved and it will likely (hopefully) happen, as lots of other members on this site. Good luck and stay safe. :)
                      Oh - - and, I love your 'avatar'!
                       
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                      • dirty white boy

                        dirty white boy 50 yr old Juvenal delinquent

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                        rubber hose coming apart inside and temporally blocking fluid flow back to M/C! did have brake shoes stick to drums that was getting wet from a automatic transmission leak, was alotta fun!!
                         
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                        • Phreakish

                          Phreakish Well-Known Member

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                          I've had this happen too. If your lines are old, they're not worth ignoring even if they don't fix the issue.

                          Binding of the caliper (regardless of slider/pin type), sticking of the piston, or even worn wheel bearings can all cause more drag on one wheel which can make it lock early. Dig into it and replace anything that is old/unknown/worn with quality replacements and it should go away.
                           
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                          • 72bluNblu

                            72bluNblu FABO Gold Member FABO Gold Member

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                            “boots on ribs” ? :drama:

                            Good grief man. I simply said that the car was clearly not factory, so narrowly considering what it should or shouldn’t have from factory in this case isn’t really relevant. The car in question could easily have either type of caliper.

                            I never said anything negative about you, and what I wrote was not pointed or mean. You’re the one that’s taking a simple correction personally. It’s not my fault that assuming which kind of caliper the car has is a bad idea, since neither type is original to the car and both are available in abundance.

                            As for experience, I’ll say this as a general observation. I have met people with 50 years of experience that have gotten by doing things the wrong way the entire time. I have also met people with 5 years of experience in a field that I would consider experts. Making the same mistakes for a long time without learning from them isn’t useful, but you can still call it experience. Some people can learn in a year what takes others 10, it’s not a level playing field.

                            I have also found that the people that are the most vocal about their years of experience are usually not the ones that have gotten the most out of it. Which is why they demand respect for their years instead of letting their knowledge speak for itself.
                             
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                            • RustyRatRod

                              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                              To the OP, please post some good pictures of which brakes you have to stop all of the quibbling. This will help us help you. I would look for things described above in addition to a possible leaking caliper or hose getting fluid on the rotor, a possible leaking grease seal getting grease on the rotor. Grease or fluid will make brakes grab and lock up. But again, pictures would help the situation. You're obviously going to have to remove the wheels to inspect and fix the problem anyway, so get us some pictures up. Thanks.
                               
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                              • FlDart360

                                FlDart360 Well-Known Member

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                                That was my intention all along I probably should have waited until I had the pictures before starting this post. Monday thru Friday my mind is pondering what I can hopefully work on on the weekend.
                                 
                              • SGBARRACUDA

                                SGBARRACUDA ROY FABO Gold Member

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                                Check the opposite side front brake. It may be that the left is working to good and is getting no help from the right side. Check for Piston in caliper stuck, brake hose collapsed, That it is bleed out properly.
                                 
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                                • FlDart360

                                  FlDart360 Well-Known Member

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                                  Sometimes it seams that half an upgrade gives you about half the satisfaction. The previous owner of my car got frustrated and that is why he sold it. Very seldom is their a one part solution, but I still enjoy it.
                                   
                                • FlDart360

                                  FlDart360 Well-Known Member

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                                  Ok as promised here are some pictures of what i have. This is before taking anything apart. I know everyone is probably working on their own stuff today so let me say thank you to anyone who has time to respond. I would like to know if anything is wrong with how it might be assembled. This is the drivers side left front.

                                  IMG_0776.jpg IMG_0777.jpg IMG_0780.jpg IMG_0781.jpg
                                   
                                • Dana67Dart

                                  Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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                                  is the first photo rotated or is the caliper really mounted with the bleeder screw pointing down?
                                   
                                • FlDart360

                                  FlDart360 Well-Known Member

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                                  The bleeder is up the photo rotated
                                   
                                • FlDart360

                                  FlDart360 Well-Known Member

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                                  Are there supposed to be rubber bands where the caliper is seated? I can’t imagine they would last very long.
                                   
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