Back Brake drum locking up! any tips? Page 1 / 2

terry77.ta, Jan 1, 3:24am
Hi, ive got a back drum brake locking up & on the drivers side,no matter what ive tryed it wont change,its all new springs clips shoes drums etc, park brake cables, ive tryed adjusting back, bleeding system, swaping drums side to side, its got me stumped! any input id be greatfull.

tweake, Jan 1, 3:31am
what vehicle !

msigg, Jan 1, 3:55am
You need to champher the edges of the linings, and the leading edges, rough the pads up a bit as well with a rasp or such like, sounds like the trailing pad is locking on.Ive done this with my old jeep and it seems to work.

yz490, Jan 1, 4:09am
maybe i missed it but don't think i saw mention of a new wheel cylinder [brake cylinder]. Probably not very expensive & then you have it all covered. Give a good chamfer on both ends of the shoes. Could something in the brake shoe adjusters click up automaticaly one click too much & lock it up!. Master cylinder foot pedal adjusted adjusted up so far that the m/cylinder can't come back far enough to release the pressure,--run out of ideas sorry.

terry77.ta, Jan 1, 5:07am
its a 1978 Pontiac Firebird, disc fr, 10 bolt Chev drum rear, manual says to bleed from closest to furtherest but i did try both as ive always started at rear far. definatly no air in system. adjusters dont seem to change or move out, when i watch both sides without drums on & they seem to do same movements, i will get new wheel cylinders as well & try that & also try to champher the shoes, cheers

supernova2, Jan 1, 5:07am

stornello, Jan 1, 5:32am
Being a Yank Tank it might have duo servo (floating anchor) , a savage brake if you get it wrong.They have different length shoes for leading and trailing, make sure you've got them the same both sides.

jmma, Jan 1, 5:53am

intrade, Jan 1, 6:06am
oh no i have that on a toyota town ace it just passed a wofi guy calls me its getting hot , thats how it started , i say on the phone throw it away its a goneri toldyou that 4 years ago your car is gona blow up.he refused and wanted me to look at it everything squeekingand ratteling like hell not 1shock is actuarly alive on the thing . but hey passed a wof . right .

now lets hang on dont let me deviate to much of the story here
he goes. its probably theradiator cap like last time huh. i say let medeal with it i needit cold first .
drive him homewith my car in first gear because my toyota has diedalready also.
right so so its cold nowfan is the viscous one its got play like hell waterpump has no play and no water pouring out of pump like i suspected .
so i fill itwith water not coolant as the stuff in there is a rust soupe anyhow.
filled up and i get my 300$ flashlightto look aroundits pissing outdown there somwhere . ah a steel pipe with a puncturedhole in itpissing out like a kid pissing on the side of the road down a bank.
right fond aproblem how to fix that .
scratched myheadgot no hair left anyhownowcome upwith solution
heart surgerya bypass hose for the carslive blood . So a new hosebypasses the puncturerusted coolant pipe now .
filled it with waterstart it up screwd that cap back on thinking that could do withreplacing but so can the whole car sinceyears.
right its fine again it did not overheat i tell him to pick it up as i aintdriving itwith a cembelt overdueever since he got it 8 years ago.

jmma, Jan 1, 6:08am
What you taking!, I want some of that.Lol(o:

intrade, Jan 1, 6:08am
then i hadto fixhis boat enginefor the 3th or4th time now head complete rebuilt drive to opua end of the day he wants to go home at 4 pm i got there 2 pm i sayi am not finishedbut if you drive home i let my van and gear there and you drive me homeand pick me up in moring again.
Rite had i knowen that hisrear brakes lock up when he moovesslowelyi would not have been sitting inside it at all.

intrade, Jan 1, 6:09am
dont interruped me its a true story

intrade, Jan 1, 6:15am
sorear brakes look up he calls it a carwith caracter .
geesus i call it adeath trap.
anyhow we made it as the brakes only lock up when it moves slowly
while i was sitting in the back i saidwe probably going to loose the rear axle and the driveshaft on highway one .
magicallywe did not so in my brake "fixing hisjachtengine"

i crawl under the back of the van to take a look as i have a suspicion what is causing the lock up.
i have no proofbut thats the only logical conclusion its rwd
so the force of the driveshaft will move the wheelswhen it propellsthe car forwardand so will the whole axle and there is a bar atatched to the axle for the brake equalizer ,,,, so you knowwheremy thinking is goingalready now right. what is happening !

neell, Jan 1, 6:17am
Was it sticking on before you replaced those parts or did it start after you "fixed" another problem!

intrade, Jan 1, 6:25am
new plymouth get snoopy to have a look at it either pay him to come from stratford or something

terry77.ta, Jan 1, 6:49am
pretty sure it wasnt sticking b4 renewing parts, done it coz i had to fix park brake (new cables) & decided to renew the rest at same time,im 99% sure i dont have trailing & leading shoes mixed up as i did it 1 side at a time, copyed another car i had also & they seem to only fit 1 way due to the holes & slots in shoes for springs & wheel cylinder arms etc. will have another go over 2moro, just hoping to get it sorted B4 the 5th when garage reopens for my recheck. P/S whos snoopy! dont mind driving to Straty if hes familiar with these brakes!

jmma, Jan 1, 6:57am
Can you post a pic! Do they look like this.

lookoutas, Jan 1, 7:05am
My Mustang used to do that when I first brought it in.
Tried those above remedies, but use seemed to fix it the best.

intrade, Jan 1, 7:14am
i fixed a tractor locking up brakes as soon as you apply them , i cut the leadingedge of the new shoe 45° on each side with the anglegrinder . problem solvedthats for when they lock up when you slight apply the brake.
the abovevan locked them up all on its own
only one thing it can bethe equalizergets actuated when the whole axle mooves and pulls the brakes on as if theback was lifting up under heavy brake load.

terry77.ta, Jan 1, 7:18am
jmma wrote:
Do they look like this.

Hi, yes, dam near identical.great pic!

intrade, Jan 1, 7:21am
is there a number on the drumm! that would be the mesurment maximum diameter . you want to not exeed that mesurment, then you cut the edges of theshoe down , do you know what i mean !

lookoutas, Jan 1, 7:24am
This is a 68 Firebird intrade. No such thing as an equaliser in them.

Just go'n give it shit for a while.

intrade, Jan 1, 7:26am
be the same as tractors i posted what to do.

lookoutas, Jan 1, 7:46am
I replaced cylinders, tapered off leading edges, changed springs from side to side - no bloody difference.
Assume they weren't grabbing before, and the new shoes will be the same, so a couple'a'hundy miles with plenty of braking and you'll be wondering what the fuss was all about.

terry77.ta, Jan 1, 7:57am
now thats a tip i like! just wanna be legal to do it! cops everywhere at mo! tis the season, & with Americarna comin, rather save my $ for gas than fines! will try wearing em down sumhow!

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