Air bubbles remain after bleeding the brakes

93GRANDAMPROBS

MEMBER
1993 PONTIAC GRAND AM
3.3L
V6
FWD
AUTOMATIC
150,000 MILES

Replace rear brake shoes and wheel cylinders. At that time replace front calipers. Bled the system. When car is not started has a firm brake pedal but when you start the car the pedal goes almost all the way to the floor. Waited a couple of hours and re-bled the brakes. Found more air bubbles. Once all the air bubbles were removed. Had a firm brake pedal without the car being started. Started the car and the brake pedal did the same thing went almost all the way to the floor. Any suggestions on how to get this problem to go away?

Thursday, August 11th, 2016 AT 1:44 PM

4 Replies

CJ MEDEVAC

MECHANIC
11,005 POSTS

Have you let the master cylinder run dry?

Do you have your drum brakes manually adjusted outward, close to, but not dragging the drums?

Bleeding technique?

Please see my link below/ and also the link within it. Study the #1 and #2 man part! Disregard anything that does not apply to your vehicle.

https://www.2carpros.com/questions/brakes-59437189

Return with good news!

The Medic

Images (Click to make bigger)

Was this

answer

helpful?

Yes

No

Thursday, August 11th, 2016 AT 6:36 PM

93GRANDAMPROBS

MEMBER
3 POSTS

Master cylinder was never ran dry. The bleeding sequence was R-rear, L-rear, R-front, L-front. Rear drums are adjusted correctly. Put the emergency brake on and the car won't roll down the driveway and there's no drag.

Was this

answer

helpful?

Yes

No

Friday, August 12th, 2016 AT 8:28 AM

93GRANDAMPROBS

MEMBER
3 POSTS

What I'm not understanding is when the car is not started there is a firm brake pedal but once the car is started the brake pedal drops about 1 inch from the floor. Any information would help greatly.

Was this

answer

helpful?

Yes

No

Friday, August 12th, 2016 AT 8:37 AM