'66 Belvedere brake problem...FRUSTRATING!
 

Old 4dr. 318 auto, manual drum brakes, single master cyl.----pretty simple stuff, BUT it's whippin' me. I have very little front brakes------good solid pedal, but low and if I stand on 'em the rears only lock up. Pretty much new everything-- shoes, wheel cyls. rubber hoses, master cyl. no leaks that I can see and I've bled 'em REPEATEDLY............I've had all the wheels off and adjusted the shoes out 'till they dragged and backed 'em off a little. I opened the bleeders individually and let them run--------all have good delivery. The brakes were fine untill I drove the car about 40mi. up to the paint shop---on the way up I started smelling brakes and by the time I got there the brakes were dragging badly. All 4 seemed to be dragging and hot. The painter had it for a couple of weeks and I trailered it home 'cause it had no brakes. The master cyl. was empty, so I looked to see where the fluid went. The back of the master cyl. was wet lookin' so I replaced it. I'm about out of ideas.....somebody else replaced the wheel cyls., shoes, and stuff, so I'm not absolutely sure that the all parts are the right ones. Sorry 'bout the marathon post----first post too-----surely could use a fresh idea or two. Thanks in advance

did you check the adjusters to see if they are right and in working order sounds like they are allowing the shoes to go out,.......maybe

start over again.

adjust the brakes (slight drag, then back them off a few clicks until only slight drag is felt)

bleed the brakes (do you know which wheel gets bled first?).

you should at this point have a solid pedal.

at this point you need to spin a wheel and see if it continues to drag when the pedal is released.

we'll continue after that.

How are the brake lines? Did you say you have rubber lines?

I am thinking it may be a pressure issue in the lines.

Thanks for the prompt responses...I bled the farthest from the master cyl. first---pass. side rear to dr. side front last. I'd adjusted the shoes out 'till I couldn't get the drums on and adj. back in 'till I could-----slight drag on the fronts, I can hear the shoes rubbing when I spin it. Haven't had my assistant(daughter) stab the brakes to check the release. There are NO self adjusters on the rear---is there supposed to be? I can't seem to find a picture of these brakes online-----my old books are still buried from moving 3yrs ago. The "rubber" brake lines are the lines between the steel lines on the chassis and the wheel cyls. and they look fresh, the plating on the fittings is still bright and shiny. I didn't mess with it yesterday, cooked a big pork butt on the grill and watched both NASCAR races. THanks again

Right, I couldn't get it out of mind that all your hoses were rubber. Now that I am thinking clearly are there any kinks or pinches in your brake lines?

do you mean that there are no adjusters or that they are manual adjusters. for this to be a line problem it would have to be before any splits for it to hold all 4 brakes applied.

Rich, unless there are the same problem on both lines. But what are the odds.

All 4 wheels have the knurled adjuster between the bottoms of the shoes. The fronts have the littlle cable that actuates the self adjusters----the rear brakes do not have the little cable or the self adjuster------I don't know if they're supposed to or not. By self adjusters I mean the adjusters that are supposed to work when you back up and jam on the brakes.
I've looked as closely as I can following the steel brake lines from the master cyl. looking for squashed places or dents in the lines and don't see any suspicious places on 'em.
I'm going to get after it again tomorrow------just go over ALL of it again very carefully, wish me luck.
ps: are there reproduction arm rest pads for this car? the rest of the interior (blue) is very good, but the pads are busted open.
Thanks again

being that thinks were ok before, i'd assume pretty slim odds but you know what they say about assume, lol.

it sounds like the rear self adjusters were replaced with manual adjusters. that's ok, just a bit more maintenance. btw, you don't have to "jam' on the brakes, normal stopping will do if things are lubed properly and the cables aren't stretched.

with the brakes bled, you should have a hard pedal, if you don't, you may have air in the system of the brakes need adjustment. be careful you don't adjust the brakes too tight as the will expand when they get hot and drag. a normal pedal as a bit of deflection before the braking action starts. if the pedal dips a lot on the first application and comes up hard and high, on a rapid second application, i'd check the brake adjustment.

when the brake pedal is released the brakes should release immediately and turn by hand without dragging.

one other thing to try is driving for a while then spinning the wheels to see if they're binding.

your proportioning valve could also be hanging up. that happened to me.

drove it some today, jacked it up, the front wheels spin with a little drag and stop when you apply the brakes. front brakes were warm but not hot like the rears. good solid pedal but low, still doesn't stop like the fronts are working. guess I'm going to have to take it apart even though everything looks pretty fresh and new.

74fldart, Thanks, this thing is so old I don't think it's got a proportioning valve............. which side of Orlando are you on? I'm over near Titusville.

it might have a proportioning valve, i think it would be the

block where it spits off the front and rear lines. it won't have a pressure differential valve.

if ytou pump the pedal a few times, does the pedal get higher? if it does, two things come to mind, adjustment, which i think you covered and incorrectly sized linings.

i once got a set of mislabeled linings. if you take one shoe (removing the one towards the front of the car is easiest, and place it in the drum and look to see if that arc matches the drum. i think in those years they used different sized drums based on the engine it came with. look at the wear pattern on the shoes. are the scuffed over the whole shoe or just part of it?

one other possibility is that the wheel cylinders are the incorrect bore size.

did these brakes ever work correctly? if so, what was done just before it went south?