Brake problems

6

69 Mach 393

New Member

Jan 28, 2004

76

0

0

SW Missouri

Jun 25, 2007

#1

• Jun 25, 2007

• #1

I Finaly got my car running but the brake lines keep getting air in them.All new calipers new master cylinder and booster new brake lines and no visible leaks. It has four wheel disk brakes but the master cylinder is off of a 69 with power brakes. A porportining valve at the back and a residual valve. Where can the air keep coming from. This car looks awsome can someone tell me how to post pictures.

 

65 fastback

Founding Member

Mar 17, 2002

1,347

0

37

Northern VA

Jun 25, 2007

#2

• Jun 25, 2007

• #2

When you say air is getting in, is the pedal getting softer over time? Maybe there is air in there that you just haven't bleed out yet?

Did you bench bleed the Master Cylinder?

What calipers are you running, front and rear?

The best way to post pictures is to open a free account at PhotoBucket.com. Load your pictures there and link them to here.

Tim

 

6

69 Mach 393

New Member

Jan 28, 2004

76

0

0

SW Missouri

Jun 25, 2007

#3

• Jun 25, 2007

• #3

I can bleed them and come back 30 minutes later and have air again. I have to pump them but I can get some brake. The front calipers are stock the back I think were off a 98 Mustang. Yes I did bench bleed the master and even took it off and blead it again tonight.

 

65 fastback

Founding Member

Mar 17, 2002

1,347

0

37

Northern VA

Jun 25, 2007

#4

• Jun 25, 2007

• #4

69 Mach 393 said:

I can bleed them and come back 30 minutes later and have air again.

Click to expand...

OK, so you definately have a leak somewhere. First, I would put it up on jackstands and take off the wheels. Then try to determine where the air is in the brake line, try to isolate your problem to left/rear, right/rear, left/front or right/front.

Add some clear tubing to each bleeder valve and watch for bubbles in the fluid as you open the valve under pressure.
Once you have determined which section of the brake line is leaking, trace it inch by inch back to the MC. Look for any signs of leakage. Also, check the bleeder valve - it's my guess this could be the problem.

Tim

 

2nd Mustang

Founding Member

Feb 24, 2002

2,488

0

46

Southern California

Jun 25, 2007

#5

• Jun 25, 2007

• #5

How are you bleeding the lines?

 

6

69 Mach 393

New Member

Jan 28, 2004

76

0

0

SW Missouri

Jun 26, 2007

#6

• Jun 26, 2007

• #6

Just pumping them up and then releasing them.And the air will be in all lines. Master cylinder maby.

 

2nd Mustang

Founding Member

Feb 24, 2002

2,488

0

46

Southern California

Jun 26, 2007

#7

• Jun 26, 2007

• #7

69 Mach 393 said:

Just pumping them up and then releasing them.And the air will be in all lines. Master cylinder maby.

Click to expand...

Do a search on bleeding techniques.

Basically when you pump the brake pedal, hold it down, open the bleeder screw and do not let the brake pedal up until you've closed the screw. Letting the brake pedal up while the screw is open will suck air back in if you're not careful.

If you have two people, it's a lot easier. A "one man" bleeding kit also works, but make sure the bottle is higher than the bleeder screw which will help keep air out if doing it with only one person.

 

NasaGT

Founding Member

Sep 19, 2002

1,993

2

49

Virginia

Jun 26, 2007

#8

• Jun 26, 2007

• #8

2nd Mustang said:

A "one man" bleeding kit also works, but make sure the bottle is higher than the bleeder screw which will help keep air out if doing it with only one person.

Click to expand...

Thats good advise, took me awhile to figure out why I had always has a soft pedal using a one-man kit. I was putting the bottle on the ground.

 

65 fastback

Founding Member

Mar 17, 2002

1,347

0

37

Northern VA

Jun 29, 2007

#9

• Jun 29, 2007

• #9

Did you get your brake issue resolved, yet?

Tim

 

6

69 Mach 393

New Member

Jan 28, 2004

76

0

0

SW Missouri

Jul 6, 2007

#10

• Jul 6, 2007

• #10

We are still looking for the brake problem. The air is in all 4 brakes and I do know how to blead the brakes. Has anyone done this conversion and did you use a stock master cylinder. Could the master cylinder be the problem.

 

Rusty67

20+ Year Stangneter

Dec 3, 2002

3,749

37

109

LA, CA

Jul 7, 2007

#11

• Jul 7, 2007

• #11

69 Mach 393 said:

and I do know how to blead the brakes.

Click to expand...

That is most likely your problem. Get a friend that knows how to do this to help you and see whats going on. Another option is to buy some speed bleeders from the parts store. Also, go read up on proper brake bleeding techniques.