bleeding a new brake system
 

Ok so i have a brand new brake system. everything is brand new on my brake system. So i did the bench bleed on the master cylinder and that went great. I went to bleed one caliper just to check for leaks and i found one leak at the proportion valve. Fixed that. went to the rear passenger side with my mini vac plugged it all in and cracked open the valve and i must of sat there for about 10 mins and nothing was coming out. i tried the reverse bleed and got in about 45cc of fluid and locked it but then i noticed that no fluid filled up in my master cylinder. what am i doing wrong? i am going to have my wife pump the brakes for me today to see if that helps but figured the mini vac for the brake system would work just fine.


for those who don't know what reverse bleeding or back feeding is here is a link for it fast forward to 2:45 and he shows you what i mean
http://www.youtube.com/watch?v=lBk00597EyE

Shaun, I have never used the power bleeder but I agree it should work, I'm interested in what happens with you manual bleed.

yeah i am going to go out there in about an hour to see what happens

Raise the front end of the car and gravity bleed the complete system. Open all 4 bleeders and keep on eye out for fluid to appear. Close that bleeder when it does.
Works for me every time.

i guess what bill says is next on my list. I had my wife help me bleed the brakes and the fronts came out perfect the rear nothing came out. I opened up the line from the rear brakes to the distribution block and had my wife pump and i saw little air pockets coming out of it. is it normal or should a stream of fluid come out?

A stream of fluid should come out given there is no, or shouldn't be any resistance to the flow of brake fluid.

i think i figured out my issue. I think i need to adjust my rod on the pedal. because i dont think its pushing all the way to the front of the master cylinder which is its not pumping to the rear. I do have a question. on the brake pedal i noticed it had two wholes. which whole should it be in? the top or the bottom?

1) There are 2 holes on the brake pedal where you can put the pushrod: The upper one is for manual brake, the lower one is for power brake. If you use the lower hole with manual brake, your pedal will require more effort

2) You may also need to adjust the length of the master cylinder push rod to get sufficient depth like you mentioned.

ok that might be my problem right there. i have it on the top one where my manual brake setup was. I will move it to the lower one and see what happens thanks a lot!!

With the pedal at rest, you want no pressure being applied to the MC. Any pressure will not allow the MC piston to fully retract and it will be unable to recharge the rear brake port with fluid.

so i put it on the second hole and said ok let me see what happens. had my wife pump and nothing. i was like no way this cant be right. so i went to the master cylinder took the line off that goes to the proportioning valve.
http://www.ss396.com/mm5/graphics/00000009/FPV-89.jpg
had her pump and a big amount of fluid shot out so i know now that the master is getting fully pressed. so i put the line back and took the line off behind the proportioning valve and nothing came out. So i think that is my issue. at least i didnt have to go to everything to see what else was clogged. but that is upsetting because NO ONE around me has this thing

Isn't there a button on the proportioning valve that req's holding in during bleeding??

a button? that rubber cover on the back?

Yeah...that's the way I recall doing it.

You are correct there is a button that needs to be depressed while bleeding the brakes, so says the GM service manuals. The button is really a rod that goes into the combo valve with a black rubber cap on it. GM makes a tool to depress that button in a one man operation, but if you find the button, have someone push it while you bleed the rear.

ok i tried pressing that button and it doesnt move. i put it on a clamp and the clamp bent. so that mean s its no good right?

Nah! 3 lb hammer, a little MAPP gas heat and it'll be fine, or maybe it's no good. :D

ok so i looked at some of my friends chevelles and i found this
http://i114.photobucket.com/albums/n...ps11af1831.jpg

i went to 5 different chevelles from these chevelles 71 ss 72 ss 69 wagon 67 ss and a 70 malibu. none of them had this valve. i asked all of them why they dont have that valve in place. they told me they removed it because it was something they will not need anymore remove it and put the line in place and bleed your brakes and go. so is this valve really need? they all told me you dont need it remove it. and the picture is from my friends with a 69 wagon. he also told me that he is using all of the original hardware as in the distribution valve on the frame. any truth to this?

so after weeks of working on my brakes and not figuring out what it was, i finally took the time to day and go over line by line to figure out what is wrong with my brakes. Took the lines apart and pushed some fluid down the pipes and it was coming out hooked everything back up and instead of putting it on the master i put the syringe in the lines and pushed fluid and it came out. we took the master off and did a bench bleed and we noticed that when we did the rear for some reason the fluid was coming out milky. it was full of air pockets little tiny ones. let it sit for a few and all the bubble went away. pumped again and the bubbles came back.

So my buddy said it seems like a seal on the inside of your master must be going bad and is getting air in every time you pump it. so i called summit and explained everything to them and they said yes you need a new unit. So they are sending me a new unit should be here by tuesday. so once we knew i was getting a new unit my friend said lets open it up and check it.
So we opened it and all of the seals are in good shape. everything seems fine. so then he started measuring everything and then we found the problem. the seal that sits in front of the rear res was about .020 to small for the bore of the master. he put in a make shift seal and we stuffed it back in and it started to pump fine no more milky fluid. we put it back on and fluid was coming out the rear like it should. so now i have it sitting on the shelf waiting to be returned. o and we took the seal back out didn't want to have an issue...lol lets see what happens now

Sounds like you have solved your problem. Good luck.

yeah well i will find out tomorrow when my parts come from summit..lol

So did you get everything working?

i got the parts but i have not touched it. I was very frustrated with the car so i stopped working on it for a while

I had to do that with mine. You just need to walk away sometimes.

so i finally took the time to work on my brakes on weds put the new master in after the bench bleed. put all the lines on. went to the rear passenger side. had my wife do a few pumps cracked it open and bah bam! fluid came out...lol so it was the master cylinder after all that!

Took awhile, glad you got sorted out. Some problems can be really frustrating and you have to walk away for awhile.

yeah i am kind of scared now because 3 things in a row has gone my way now...lol

Glad to here you got it figured out.