Kenny Ganz Posted April 25, 2020 Share Posted April 25, 2020 Hi, I have a 1941Plymouth Special Deluxe. My brakes work fine, however, my brake pedal doesn't return all the way. I have to pull it back using my toes. The Master cylinder is topped off and I detect no leaks at any of the wheels. I pulled out the brake pedal return spring and inspected it and it seems fine. Any ideas to get the pedal to return to it normal position with me having to bring it back manually? Thank Kenny Link to comment Share on other sites More sharing options...
PFitz Posted April 25, 2020 Share Posted April 25, 2020 The brake pedal linkage pivots may need cleaning, and/or, oil ? And, there is another spring in the system. It's inside the master cylinder and it may be broken ? If the brake hoses are swollen shut inside - which often happens with older and NOS hoses - the fluid may not be retuning quickly enough from the wheel cylinders and causing suction drag of the master cylinder piston if the reservoir doesn't feed fluid through the small reservoir feed hole fast enough to allow the piston to retract by just spring tension. Does the pedal eventually come back up if you don't lift it with your foot ? Sounds like time to start checking inside the system. Paul 1 Link to comment Share on other sites More sharing options...
Kenny Ganz Posted April 26, 2020 Author Share Posted April 26, 2020 Hi Paul, Thanks for the quick reply. I went over the whole brake system last year with new hoses and a new Master Cylinder. The pedal stays down on it's own and doesn't seem to retract over time. I'll work on the pivot linkages tomorrow. Again, thanks for the info. Kenny Link to comment Share on other sites More sharing options...
Frank DuVal Posted April 26, 2020 Share Posted April 26, 2020 Disconnect the master from the linkage and see if it returns. I usually find a sluggish brake pedal is from a bad master, but you just changed it last year. Maybe new defective part? Also flush the system again, especially if you are using DOT 3, 4. Maybe the master sucked some trash back into itself from the steel lines. Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted April 26, 2020 Share Posted April 26, 2020 My 50 Chrysler was stopping fine day before yesterday. This morning it started doing the same as yours. Sounds contagious ha. I am not following you though on where the return is. Cap off, look in fill hole. Press pedal slowly and release. The return should squirt from the back of the cylinder. Are these what the series of holes are around it? Or am I way off? Link to comment Share on other sites More sharing options...
hwellens Posted April 26, 2020 Share Posted April 26, 2020 See if this helps. The master cylinder cup has to be aft of transfer hole. This considers that you brake shoe springs and hoses are in good shape. 1 Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted April 26, 2020 Share Posted April 26, 2020 OK, cap off, Push down on pedal no movement of fluid at all on release. Pull back. Peddle is very firm, plenty of fluid. Take a straightened paper clip and find the hole straight down and get paper clip to go in easily and wiggle it around. Went in pretty far. repeat process and get a little blurble now on release but pedal still won't fully return. It is better for sure. But remember in my case the brakes went to the floor first and would not return. I didn't have brakes on the first push till I returned it manually and then the pedal got firm again. Now I have a good peddle but still wants to stay 1/4 depressed. Will take for a ride after dinner and see if the brakes are disengaging when I release the peddle. Before they weren't unless I manually pulled the pedal back. This all happened of course with no warning. Rebuilding it I am sure would not hurt in anyway and give me a good reason to change the fluid. Link to comment Share on other sites More sharing options...
hwellens Posted April 26, 2020 Share Posted April 26, 2020 (edited) That spring in the master cylinder does not apply the pressure to return the cup; only keeps the cup in place. The springs on the brake shoes pull the shoes in and forces the fluid back into the master cylinder That is the force that pushes back. I have had cars that the wheel cylinder metal cylinders were corroded and not allowing the springs to push the fluid back. Also, the hoses can collapse internally and look good on the outside. Also, that valve in the picture (number14) could be bad. Rebuild it and that will eliminate the master cylinder. Edited April 26, 2020 by hwellens added data (see edit history) Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted April 26, 2020 Share Posted April 26, 2020 I am figuring that would included in the rebuild kit? Like I said I was having zero issues and then it went to the floor like I blew a cylinder or a line. Investigation showed neither. I pulled it back manually and has not done it again (down to the floor) so I was assuming it was something in the master. When it was to the floor the brakes stayed engaged. When I pulled it back they disengaged. Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted April 26, 2020 Share Posted April 26, 2020 Well out for a ride and a great firm pedal that is still not releasing 100%. But much better for sure. Just a little toe grab up. On a hill it will roll backwards though after a stop. So my guess is the valve is not allowing full return flow without a little help. Have a kit coming from Arizona Vintage Parts. But poking around in there did a lot of good. Thanks for the tip. 1 Link to comment Share on other sites More sharing options...
keithb7 Posted April 27, 2020 Share Posted April 27, 2020 (edited) Original Chrysler shop manual image (pic 1) compared to the Motors manual image. See the little rubber gasket at the far left end only on the Motors manual illustration (pic 2) . It's not shown in the original Chrysler illustration. I see that rubber seal in your parts image above. Where did you place it inside the master? Edited April 27, 2020 by keithb7 (see edit history) Link to comment Share on other sites More sharing options...
keithb7 Posted April 27, 2020 Share Posted April 27, 2020 Other odd things I have seen, parts kit shows up and parts are not the same as expected. Be sure the piston assembly is the exact length needed. Seen here, the new longer piston was supposed to be for my 38 Plymouth. What came out of my 38 however was the shorter one. 1 Link to comment Share on other sites More sharing options...
hwellens Posted April 27, 2020 Share Posted April 27, 2020 The original Chrysler valve came with the rubber gasket as part of the valve. See picture below of the original box and valve (part number 645930): Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted April 27, 2020 Share Posted April 27, 2020 17 hours ago, keithb7 said: Original Chrysler shop manual image (pic 1) compared to the Motors manual image. See the little rubber gasket at the far left end only on the Motors manual illustration (pic 2) . It's not shown in the original Chrysler illustration. I see that rubber seal in your parts image above. Where did you place it inside the master? I have to replace mine Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted April 27, 2020 Share Posted April 27, 2020 So when the master fails what is the most common part that takes a dump ? Link to comment Share on other sites More sharing options...
TerryB Posted April 27, 2020 Share Posted April 27, 2020 56 minutes ago, Brooklyn Beer said: So when the master fails what is the most common part that takes a dump ? The driver if he has to try and stop the beast before hitting something! 1 1 Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted April 27, 2020 Share Posted April 27, 2020 A good service brake and switching off the ignition in a split second. Can't soil the original wool interior ! 1 Link to comment Share on other sites More sharing options...
61polara Posted April 28, 2020 Share Posted April 28, 2020 1 hour ago, TerryB said: The driver if he has to try and stop the beast before hitting something! Always keep your emergency /parking brake in top order and adjustment. If your MC fails, shift down to low and use the emergency brake. Remember this is actually a two wheel mechanical braking system and will stop the car. Link to comment Share on other sites More sharing options...
FLYER15015 Posted April 28, 2020 Share Posted April 28, 2020 3 hours ago, 61polara said: Always keep your emergency /parking brake in top order and adjustment. If your MC fails, shift down to low and use the emergency brake. Remember this is actually a two wheel mechanical braking system and will stop the car. If it does not, something else will. 2 Link to comment Share on other sites More sharing options...
Frank DuVal Posted April 30, 2020 Share Posted April 30, 2020 On 4/26/2020 at 6:08 PM, Brooklyn Beer said: Like I said I was having zero issues and then it went to the floor like I blew a cylinder or a line. Investigation showed neither. I pulled it back manually and has not done it again (down to the floor) so I was assuming it was something in the master. This is a common failure of a master cylinder. Usually notice it first when you are lightly pressing on the brake pedal and then suddenly you notice your foot is on the floor. Releasing the pedal and pressing again (of course this time you are usually pressing harder) makes the brakes work fine. And then it keeps working fine, until you gently press the pedal. Trust me, replace or rebuild the master NOW. 😧 Happens on single and dual masters. 1 Link to comment Share on other sites More sharing options...
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