Brake help needed

[BigBadVR4]

I just got done changing a Passenger drive axle, and I also changed all four rotors, pads, and brake lines. After I did this I bled the hell out of the brakes. When I first started driving it the brake light didn't come on. After about 1/4 mile it came on. I figured low fluid, but I checked it and it was fine. What could the problem be? Needs to be bled some more?

[Elina75]

How's ther pedal, soft?

Also changed today my brake lines to 3SX Performance SS-lines, and also the fluid to DOT5.1, felt really good in test drive.

[mdcrose]

Shawn,

If in changing the brake lines the master cylinder was allowed to completely drain then the master cylinder needs to be bled:
1) Cover the area under the master cylinder with enough towels to absorb a good amount of brake fluid
2) Disconnect the master cylinder outlet
3) Fill the master cylinder resevoir
4) Have some one depress the brake pedal
5) Place a finger over the master cylinder outlet
6) Raise the brake pedal
7) Repeat steps 4-6 at leat 4 times

Then bleed the brake lines with the engine running in the order of passenger rear, driver front, driver rear, passenger front. The engine needs to be running to insure that the ABS pump is fully bled of air.

-Michael

[Elina75]

Hi Michael,

I think I have the same problem, after changing the brake lines to 3SX SS-lines, I also changed the brake fluid and first pumped the old fluid out as much as I could. I also bled the brakes wrong at the first time, engine not running and in wrong order :O I bled them again yesterday, but the ABS light still comes on after 20-30 seconds. The brakes take very sharply though, if there was air in the master cylinder, wouldn't that make the pedal soft?

Where is this master cylinder located, below the reservoir?

thanks, Elina

Originally Posted by mdcrose

Shawn,

If in changing the brake lines the master cylinder was allowed to completely drain then the master cylinder needs to be bled:
1) Cover the area under the master cylinder with enough towels to absorb a good amount of brake fluid
2) Disconnect the master cylinder outlet
3) Fill the master cylinder resevoir
4) Have some one depress the brake pedal
5) Place a finger over the master cylinder outlet
6) Raise the brake pedal
7) Repeat steps 4-6 at leat 4 times

Then bleed the brake lines with the engine running in the order of passenger rear, driver front, driver rear, passenger front. The engine needs to be running to insure that the ABS pump is fully bled of air.

-Michael

[cbatters]

Originally Posted by mdcrose

Shawn,

If in changing the brake lines the master cylinder was allowed to completely drain then the master cylinder needs to be bled:
1) Cover the area under the master cylinder with enough towels to absorb a good amount of brake fluid
2) Disconnect the master cylinder outlet
3) Fill the master cylinder resevoir
4) Have some one depress the brake pedal
5) Place a finger over the master cylinder outlet
6) Raise the brake pedal
7) Repeat steps 4-6 at leat 4 times

Then bleed the brake lines with the engine running in the order of passenger rear, driver front, driver rear, passenger front. The engine needs to be running to insure that the ABS pump is fully bled of air.

-Michael

I have never heard of anyone bleeding the master cylinder separate from the rest of the brakes......

[mdcrose]

It's in the service manual and I practice I have always followed if the master cylinder is emptied.

[cbatters]

Originally Posted by mdcrose

It's in the service manual and I practice I have always followed if the master cylinder is emptied.

When you remove your finger from the outlet of the master cylinder air will get into the master cylinder so is the goal of "bleeding" the master cylinder to push a little less air through the brake lines??


Clint

[BLACK94TT]

Originally Posted by cbatters

When you remove your finger from the outlet of the master cylinder air will get into the master cylinder so is the goal of "bleeding" the master cylinder to push a little less air through the brake lines??


Clint

The instructions included with a master cylinder I changed recently on another vehicle stated bleeding was necessary to ensure proper priming.

[mdcrose]

Originally Posted by cbatters

When you remove your finger from the outlet of the master cylinder air will get into the master cylinder so is the goal of "bleeding" the master cylinder to push a little less air through the brake lines??


Clint

Air will not get in as the resevoir is above the outlet and when you remove your finger fluid will try to come out. Then just put on the brake line and bleed the system as normal.

[cbatters]

Originally Posted by mdcrose

Air will not get in as the resevoir is above the outlet and when you remove your finger fluid will try to come out. Then just put on the brake line and bleed the system as normal.

Got it - but there will still be air in the brakes line when you connect it to the master cylinder. And while I agree that I saw the procedure in the service manual, I do not see that it offers much benefit because you still have to bleed every bubble of air from the wheel cylinders. (This procedure just pushes a little less air through the brake lines on the way to the wheel cylinder bleeders.)


Thanks,

Clint