In the words of Homer Simpson: DOH!!!

I just put in a remanufactured master cylinder.

After I got it installed, I bled the brakes in the order that Chiltons said. To bleed the brakes, I unscrewed the bleeder valves and had my brother stomp on the brakes until fresh fluid was coming out. I figured that was enough to get any air out if the new fluid had made its way all the way from the master cylinder.

I did each one like that, and started it up and the brakes are almost nonexistant. I can stop the car if I hold the brakes to the floor, but barely.

There are no fluid leaks on my driveway, so I dont think its leaking fluid.

The reservoir if topped off, should I take some fluid out and maybe make it half full?

Also, I know that the booster is working because when I pull the vacuum hose out of it, the brakes are very hard to press.

Any ideas? Take it to Meineke first thing Tuesday maybe?

Thanks,
Rob

 

My first thought on this was: Did you "bench-bleed" the master cylinder before you installed it? I'm pretty sure you must do this, otherwise you will have air in your system.
Anyone else?

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'88 Formula 350
Bright (VERY bright) red. Mods? yep, but never enough!
Check out the newest f-body site: http://www.lastgen.com/

 

Nope, I didnt prime the master cylinder when I installed it. I just bolted it in and filled up the reservoir. Thats all the manual said to do, but maybe that is the problem?

 

yep that's the problem you sucks a lot of air into the system. od a gravity bleed and then preasure bleed it again. i usually do each screw 4 times or untill i get a really strong blast of brake fluid.

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ICON Motorsports
1st & 3rd

 

Ede, how do I do a gravity bleed?

Pressure bleed is when I stomp on the pedal and force it out at the brake bleed nipples, right?

Do I need to unscrew the brake lines at the master cylinder?

 

Another thing...don't STOMP the pedal. Press slow and even to relaese the fluid.

Between bleeding, pump the pedal to achieve the best feel, then open the bleeder. Repeat as nec.

If you slam the pedal down too fast you can lock the proportioning valve to one side or the other, then only the front brakes or the rear brakes will work.

I would bleed the master on the car first, then move to the RR tire, LR, RF and finally the LF.

This is what works for me.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

 

just open a bleeder screw and let gravity pull the fluid through the line. make sure the MC doesn't run dry when you do this.

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ICON Motorsports
1st & 3rd

 

Anybody ever check out speedbleeders? I read about them somewhere but have never tried them.

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89 Iroc-Z LB9 TPI auto 2.73 posi:
3" Dynomax muffler, K&N filters, TB bypass, 3" pipe in place of cat, cleaned and flow-matched injectors, accel 300+ wires, cap&rotor, synthetic oil, flexlite transmission cooler, afpr, !air pump&diverter valve, kicker sound system, soon to attempt engine swap...

 

I have the speed bleeders and they work all right.
One thing I'm not sure if you're doing right.
You should push down on the brake pedal and hold it. Then open the bleeder screw to allow air bubbles out and shut it BEFORE you let up on the brake pedal. If you don't, you will suck air right back in.
Not trying to insult you but the way your post was written, it didn't seem like you did it that way.
Randy

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Randy
84 Trans AM LG4, 700R4 T-tops
1984 Z28 L69, 5 Spd, T-tops
"Don't sweat the petty things...Just pet the sweaty things"

 

I second Wolfcoast's suggestion. That's the exact same thing I was pondering after reading you original post. If you don't pump them up good and hold the pedal before you loosen the bleeder screw, then tighten it back up before your helper lets up on the pedal, you'll never get all the air out of the system.

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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

 

this was mentioned, but i dont konw if you fixed it... take the mast. cylinder back off, put fluid in it(not too much, easy to spill)... this is the best way i found to do it. get a metal vice and put the mast. cylinder in it, get a large screw driver(or other metal rod), and push the plunger in.. this will fill the bottom of the mast. cylinder with fluid, which previously had air --- a note to remember, its not as easy as you think to push the plunger in.. so dont give up to quick

 

Thanks for the help guys. No, I didnt realize that I had to screw and unscrew the bleeder screw with every step of the pedal. Ill try that.

 

Rob,
No, not with EVERY STEP, do it like this:

Leaving bleeder valve closed, have buddy climb into car and pump pedal 4 or 5 times - until pedal holds pressure and is up.

THEN, have buddy keep foot on pedal while you SLOWLY open the bleeder valve...and just open it a little. Bubbles will come out followed by fluid, and your buddy will feel the pedal go to the floor.

When the pedal hits the floor, STOP. Have him leave the pedal on the floor while you snug the bleeder valve closed. THEN have him release the pedal, pump, and repeat.

Do it 3 or 4 times per wheel and you're finished. You will know a wheel is done because no more air will come out when your buddy releases the valve - only fluid will come out. Check the fluid resevoir after each brake is done, because you will be losing some fluid, right ?

Go forth and make stops. Good luck.

BOR

 

ITS ALIVE!!! My brakes work!!! I actually ended up buying a $7 1 person bleeder kit that came with the clear tube that goes on the bleeder screw. Im so glad it works, thanks for the help guys!