back brakes wont bleed

[matty wardle]

hi guys,
i know its an ebody but most of the knowledge is on this site so here goes,i,m trying to bleed the brakes on my 73 cuda,all stock brake system with front discs,in my original service manual it says that the proportioning valve in e bodies is mounted vertically,not horizontally,so in order to bleed the back brakes you have to crack a front bleed nipple so the system thiks the front has had a brake failure,so the proportioning valve will send all the pressure to the back,the master is rebuilt,i,ve cracked a front nipple and tried and tried to bleed up the back i just cant get any fluid thruogh to the back,the peddle is going to the floor but not one bit of fluid is leaving the master cylinder pot for the backs,the front will bleed up beautifull,i,m thinking my prop valve is not working properly its been on since 73,i,ve taken it off and i think i will put a new one on,anyone had this problem with getting the backs to bleed,maybe its just an ebody thing-----any suggestions answers:banghead:

 

[rumblefish360]

I've only had to do my E-bodies Cud's brakes twice...and it's been so long, but I do not ever remember having to do something weird to get it done.

 

[BillGrissom]

I always put a vacuum pump on the bleeds and have my wife pump the pedal as I open the screw. If it still doesn't feel like anything is flowing, try taking the bleed out entirely. Maybe crud is clogging up the bleeds. I would try it first without opening the front bleeds. That sounds strange. Seems like something should flow to the rear, otherwise how would your rears ever work? Hate to argue with a service manual, but sometimes they are too finicky like saying you need this special tool, or must measure the exact torque to turn something as you tighten the nut.

 

[matty wardle]

yeah i,ve tried to bleed with a front nipple cracked and with em both done up,just no fluid to the back,i,ve taken off the prop valve and disassembled it not sure how far that little pin at the top(valve)should move up and down,i swear its a proportioning valve problem,i reckon its seized or something,a company called inline tube sells them new on ebay for $80 i might just buy one

 

[dartman340ta]

hi guys,
i know its an ebody but most of the knowledge is on this site so here goes,i,m trying to bleed the brakes on my 73 cuda,all stock brake system with front discs,in my original service manual it says that the proportioning valve in e bodies is mounted vertically,not horizontally,so in order to bleed the back brakes you have to crack a front bleed nipple so the system thiks the front has had a brake failure,so the proportioning valve will send all the pressure to the back,the master is rebuilt,i,ve cracked a front nipple and tried and tried to bleed up the back i just cant get any fluid thruogh to the back,the peddle is going to the floor but not one bit of fluid is leaving the master cylinder pot for the backs,the front will bleed up beautifull,i,m thinking my prop valve is not working properly its been on since 73,i,ve taken it off and i think i will put a new one on,anyone had this problem with getting the backs to bleed,maybe its just an ebody thing-----any suggestions answers:banghead:

the first thing i would do is get rid of the rebuilt master cyc if you got it from some like advance discount or auto zone there junk ( only new for me ) the master cyc in the brains of your brakes ..... i've put as many as 5 o6 of those junk things on the same car and none of them has worked .... try a napa one i've had much better luck with the rebuild one from them but still prefer new ...bench bleed them first most are supplied with some hoses to do so ... let it gravity bleed for a while .... open the bleeders fluild will drain ... then bleed the system

 

[cudamark]

If the pedal is going to the floor and no fluid is being pumped, you have a bad master cylinder.