help with MGB BRAKE MASTER PEDAL BOX

I replaced my brake master pedal box!i blooded the brakes!they will not get hard unless u pump them!but Is their adjustments some where i need to do or is my master box bad?

Bleed them some more... Sometimes it takes a few rounds...

You still have air in the line.

i mean they want stay hard!

just want stay harD!

Add some Viagra that should do it.

Dwight

REZKID2261 Wrote:

u think it maybe a bad master box?

Can you provide some more details on where you started, what you replaced, etc. Having to pump the pedal is a classic symptom of air in the lines.

Typically when folks say pedal box, I think of the frame and the cover. By pedal box, do you mean the brake master cylinder?

I doubt it, but did you bench bleed it first?



Also when you install it and then bleed each wheel, start with the driver's side rear wheel, then the pass. side rear, then the pass front, then the drivers front.

Keep an eye on the level of fluid in the MC and keep it topped up. If it gets empty you have to start over.

i was told i had to use a different kid of brakes oil?is that true?

I use DOT 3 brake fluid.

What kind of brake fluid did you use? Did you replace the flexible hoses, wheel cylinders or calipers. Bleeding brakes takes a few times on each wheel.
What procedure of bleeding are you using.
1 Pump pedal hold pedal pressure crack bleeder screw let air our close bleeder screw Repeat til all ail is out of each line.

2. Get bleeder hose with valve on end to only let fluid go out and not let air back in

3. Get pressure bleeder

4 Get vacumm bleeder.

Follow the advice above... plus I'll add one more thought:

I understand that sometimes it's helpful to temporarily defeat the warning-light switch (i.e. unthread the switch from the distribution manifold and replace it with a bolt so that the piston can't move.) With the piston sliding back and forth, you get less fluid (and fewer air bubbles) in each spurt through the bleeder.

Did he say what year it was.

LET ME MAKE IT CLEAR I HAVE BLOODED ALOT OF BRAKES BEFORE ARE THEIR ADJUSTMENT ANYWHERE FROM BRAKES ON THIS CARS?Paul McLaren
YOUR HOOD PICS LOOKS DAM GOOD

On a completely rebuilt system, where all the lines and cylinders are dry, I start at the farthest wheel cylinder and pump fluid through it until it reaches the master cylinder and then go on to the next, farthest to the shortest, until all lines and cylinders are full. Have someone watch the master cylinder reservoir so it doesn't overflow and pump out excess fluid. I get no air in the system with this procedure. I do the clutch system the same way.

Hey, Adam!

First, can you take your CAP LOCKS off? :)

There are brake adjusters for the rear brakes. Square peg coming out of the backing plate. I think it's a 1/4" square.

That's not going to help much with a soft pedal unless your rear brakes are WAY out of adjustment.

These cars can be tempermental...just take your time and make certain you have all of the air out of the system. (Wait til' you have to bleed the clutch!)

Have you bled the master cylinder? That should be done before instalation. Once you install the bench-bled master cylinder, attach the lines and add fluid as the level goes down. Start at the right rear, then add fluiod. Then the left rear, then add fluid. Then the right front, then add fluid. And finally the left front, then add fluid.. Then bleed the master cylinder again. Then add fluid. Then bleed the wheels in the order given again and you should be fine unless you have a bad hose or a bad fitting. It's a pain but bench bleeding the master where you can get long strokes on it is imperative.

REZKID2261 Wrote:

Adam,

Do you have a repair manual?
Did you bench bleed the master cylinder?
Where did you get the master cylinder from? Is it new, used, or rebuilt?
What kind of brake fluid are you using?
Do you have a brake booster or servo?
Have you pulled the drums off the rear and inspected the wheel cylinders for leaks?
Are the rear brakes adjusted properly?
Have you checked all the pivot points for wear?
While bleeding, are you getting a good flow of fluid to each wheel?
What is your primary language?
You should let us know the model year of your car when asking for assistance. Different years may have different procedures for repairs.

I use a Mityvac to help pull the air from the lines startingwith the back right wheel. Nothing out of the ordinary from your '67 GTO you worked on.