D.Pearring Posted March 20 Report Posted March 20 1937 D5 when I start the day the brake pedal is pretty loose with very no bounce back, I kind of have to pull it back with my foot. As the day goes on the pedal gets harder and harder to press and barely moves but still brakes.. Next day the same thing. Figuring The master cylinder needs to be replaced or rebuilt since it is the original one leaning more towards replacement, But thought I'd ask a you knowledgeable people if they had any thoughts or ideas. Quote
Ivan_B Posted March 20 Report Posted March 20 (edited) 1) check for leaks below each wheel cylinder and master 2) bleed the brakes (unless you are already set on changing things) Also, while you are at it, drive the car for a couple of miles and verify whether or not all of the wheels (disks) are approximately the same temperature. And please stop driving with improperly operating brakes Edited March 20 by Ivan_B More info. 1 Quote
Dave72dt Posted March 20 Report Posted March 20 There's a small port in the master that let's fluid return to the reservoir. I suspect it's plugged or restricted at the least. Binding at the pedal pivot may also be part of it. 1 1 Quote
kencombs Posted March 21 Report Posted March 21 20 hours ago, Dave72dt said: There's a small port in the master that let's fluid return to the reservoir. I suspect it's plugged or restricted at the least. Binding at the pedal pivot may also be part of it. My guess also. Pedal must fully return after each application. Springs, binding or push rod adjusment are likely causes. Quote
desoto1939 Posted March 21 Report Posted March 21 I have the same master cylinder in your car as in my 39 Desoto. Had a very similar issue. One day the brakes would work then the next day not and then could pump up the brake. then went to the floor. Decided to remove the floor pans, pulled the MC. Already had a spare rebuild kit and rebuilt the entire MC. Cleaned the two holes inthe resevoir. Bleed the MC on my bench and installed the MC back in the car and had good brakes. Next day working at my bench I looed at the pressure release valve that sits at the very front on the MC and then noticed a vey small slit in the rubber part of the valve. Also do not play with the piston push rod or turning it in or out. So this value permits the fluid to move out of the MC and also return but when there is a slit inthe rubber you get a very low pedal. Suggest that you rebuild the MC. i know it is a pain to get it out of the car but if all else fails then this is your only option. Rich hartung Desoto1939@aol.com 1 Quote
Bob Ritter Posted March 21 Report Posted March 21 If the master cylinder is working and no leaks why not add a return spring. I would mount it at the push rod pin. Take a look at the clutch return spring and see how it is mounted... 1 Quote
desoto1939 Posted March 22 Report Posted March 22 4 hours ago, Bob Ritter said: If the master cylinder is working and no leaks why not add a return spring. I would mount it at the push rod pin. Take a look at the clutch return spring and see how it is mounted... Bob: according to my 1936-42 Dodge Master parts book there already is a brake pedal return spring. Below is the page from the catalog showing the part and part Number. Rich Hartung Desoto1939@aol.com 1 Quote
D.Pearring Posted March 24 Author Report Posted March 24 Thanks everybody, I will be rebuilding pretty much everything with the brakes. Appreciate all the help! Quote
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