Help! Need Quick Help!! 65 Cuda manual drums

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1965cudav8

1965cudav8

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Hey guys, I have a 65 cuda that I just did a bunch of brake work on. I replaced all the hard lines (3/16), cleaned and rebuilt the brake assemblies, and replaced the original single bowl master cylinder with a dual bowl master. I ran the primary port line down to a brass T which then diverted to the two front brakes. The rear I ran straight back to the junction on the rear axle. I bench bled the master, installed it, then started to bleed the system. After fixing two leaks, I was able to bleed the system.

HOWEVER, the problem is that the brake pedal will not return off the floor by itself. We put the car in neutral and rolled it and the brakes worked when the pedal was depressed, but would not come back off the floor. I can use my toe and pull it off, so its not stuck there. There are no leaks apparent in the system.

I am supposed to drive this car 3.5 hours on Monday to get it home, im currently working on it a few states away where I bought it so that I can drive it back.

Anybody know whats up with this? Im scratching my head.

Thanks

D
 
Hmm, its brand new though and when I bled it the piston was returning fine. Could it have been damaged just from the bleeding process?
 
WELL "FAULTY" kinda means that there does not need to be much use to initiate catastrophic failure........ if the spring that was installed from the re-builder is a substandard spring.....just like a tootsie pop you get ONLY so many licks.......so to answer your question YES simply pushing the pedal down can initiate a complete failure, so can bleeding so can stopping......I have heard MORE & MORE & MORE people bitching about re-builds failing right out of the box!!!! ALL you can do is return it and replace it and re-bleed it then re-bleed the system......THAT should solve your problem
 
haha ok. are there any other issues that can explain my problem of the pedal not returning? getting a new master and re-bleeding everything is a pain, so i want to cover all my bases before i go through with that.
 
If the pedals going all the way to the floor, you either haven't got all the air out, or the brakes need adjusting up till they scrape the drum.. to check for either of these, with the master cyl top on, have the brakes pumped 2 or 3 times and held down,, take the cap off the M/C and watch as the brakes are let go,, if you have any form of a "geyser" shooting back out of the master,either front or rear, indicates that system has compressed air pushing back, or the return springs shooting fluid back, if so, resolve these issues, by bleeding more, or adjustment, then question M/C..

Because you changed the type of master cylinder, it may be nec to adjust the pushrod length, some rods are adjustable, and it kinda sounds like yours may be a bit short, not sure, just one possibility..
 
The pedal didnt go to the floor, i misspoke in my first post. It went about halfway then got real tight. I adjusted all the drums to the proper spot when I rebuilt them (I read that the wheel should spin 1 time around when properly adjusted...). However, when I was bleeding and had a valve open the pedal did, obviously, go to the floor. Otherwise it got real hard around halfway down, just wouldnt return
 
do you have the pushrod on the proper side of the pedal?? sounds more like it's binding on something?
 
Yeah, do check for binding at the pushrod-to-pedal bolt/pivot. Now that you mention it, I recall running into some brake pedal binding years ago on my '65 that was fixed by loosening the pivot bolt slightly. It is an interference thread; it won't self-loosen further and if you were worried about it you could use low-grade Loctite to make extra-sure.

That'd be an easy, fast fix if that's the problem. Also, come to think of it, did you transfer the assist spring, plate, and boot from the back of your original 1-pot master?
 
I believe the main thing you forgot to mention in your install was the use of a proportioning valve. You cannot use a dual master cyl. by runining lines to t's. Also the front connection of the master cyl. operates the rear brakes and the rear line operates the front. Get a proportioning valve on there or you'll have problems forever.
 
Alright so it was the push rod being too tight to the pedal. So thats all fixed. Thanks everyone!!!

And yes oldmanmopar I did do the front and rear correctly on the primary and secondary ports but i did not use a prop valve. I will look into it, thank you. I thought it would be fine but I geuss not.

D
 
Prop valve is used only with front disc/rear drum systems, not with 4-wheel drum systems which use only a splitter block (equipped with brake system failure warning light switch on '68-up models).
 
^^^^ Perfect, thats what I had understood from researching around the forum. I will keep my Ts haha. I appreciate all your guys' help! I will be driving it for an inaugural 3.5 hour cruise to its new home tomorrow! Im going to make a resto thread soon and ill post pics
 
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