Brake Problem after replacing front caliper..

M

Morgstang

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Aug 9, 2003

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Dec 11, 2009

#1

• Dec 11, 2009

• #1

Ive got an 02 GT. The drivers front caliper locked up on me so i replaced the caliper, rotor, and pads on that side. When i took the brake line off of the caliper the master cylinder completely drained. When i tried to bleed the brakes i had no pedal at all. Had my son pump the brakes while i bled them. Whats weird is i had clean fluid with NO air coming out of each bleeder. I bleed the front and back lines. After bleeding the entire system i still had NO pedal at all. It goes completely to the floor. I am absolutely stumped as to what the problem can be. Anyone have any ideas? Thanks for your help.

 

wmburns

SN Certified Technician

Aug 14, 2009

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Houston Texas

Dec 11, 2009

#2

• Dec 11, 2009

• #2

Did you let the master cylinder run dry? If so, the master cylinder will need to be bleed.

How are you bleeding the brakes? I have been taught to start at the wheel farthest from the master cylinder. Have the helper apply pressure on the brake pedal. Open the bleeder screw. When the pedal goes to the floor, close the bleeder screw. Return pedal to normal position. Repeat until fluid is clear.

Do not let the master cylinder run dry. No more than 10-15 pumps before its time to refill.

The manual will say that a master cylinder can not be bleed on the car (needs to be level).

I suspect that you forgot to block the brake pedal half way down when the system was open. This allowed the brake fluid to drain out during the repair.

 

M

Morgstang

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Dec 11, 2009

#3

• Dec 11, 2009

• #3

brakes

i just edited my post because i forgot to add that i had let the master cylinder run dry. What is the procedure for bleeding the master cylinder?

 

hotrodredneck

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Jul 28, 2004

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Dec 11, 2009

#4

• Dec 11, 2009

• #4

you have to get two brake lines that you can cut and bend into the master cyl. with fittings to screw into where the brake lines normally. fill the MS, and pump slowly till all the bubbles stop. then hook your brake lines back up and bleed normally

 

M

Morgstang

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Aug 9, 2003

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Dec 11, 2009

#5

• Dec 11, 2009

• #5

brakes

just went and bled the mc with a mityvac and now ive got a good peddle....thx for your help...being that i had already bled the brake lines...will bleeding the mc last have any effect on my previous line bleeding?...do i need to go back and rebleed the brake lines now?

 

hotrodredneck

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Jul 28, 2004

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Dec 11, 2009

#6

• Dec 11, 2009

• #6

if you took the lines off the MS to bleed it, yes. I would recommend it anyway, since you had air in the MS while bleeding them before

 

M

Morgstang

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Dec 11, 2009

#7

• Dec 11, 2009

• #7

brakes

i didnt take the mc lines off.....i used the mityvac to bleed them.

 

wmburns

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Dec 12, 2009

#8

• Dec 12, 2009

• #8

One school of thought is "the proof is in the pudding". IE it works.

If we assume that the vacuum pump was used to pull the fluid through the MC into the wheel cylinder, then then the combination is bleed.

If on the other hand, you used the pump to pull a vacuum on the MC (without disconnecting the lines), well IDK since I have never done it that way (However, see above).

For the future, when doing brake repairs where the system will be open for an extended period of time, take a 2x4 and jam it between the seat and the pedal. Move the seat forward so that the pedal is blocked halfway down. This will block off the refill port in the MC preventing the fluid from running out.

Obviously with the brake pedal blocked the brake lights will be on all the time. It may be a good idea to disconnect the battery neg.

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

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Dec 12, 2009

#9

• Dec 12, 2009

• #9

Make sure you bleed the two bleed screws on the side of the MC as well.

 

SVT32VDOHC

waiting for the next hack atta

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Nov 22, 2001

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Motor City

Dec 14, 2009

#10

• Dec 14, 2009

• #10

Glad you found your problem, but yeah, the master cylinder has two bleeder nuts you need to bleed. When I put the 4.6L drivetrain in my notch I had no pedal. After bleeding the calipers...nothing, then the master...bingo.