master cylinder replacement

[kissmyss]

05 Impala SS

I need to replace my master cylinder 4 wheel abs, I've watched some video's on youtube and they bench bled the master cylinder before installation. Once it was installed, they had someone push the brake peddle and they cracked each line connected to the master cylinder to bleed the air. The car was then put back in service and the brakes worked fine. I've read elsewhere that when the master cylinder is changed, you need to have the dealer bleed the brakes. Can I do it like the youtube video and use my power bleeder to bleed the brakes at the caliper?

[55trucker]

Where ones brakes are concerned...

 

If you have to ask what to do........

 

please take the car to someone who KNOWS what to do.

 

none of us want to hear of an accident caused by a member who wasn't experienced enough on repairing their car's brakes after getting instructions from another member.

[digitaloutsider]

Thank you for that completely pointless and unhelpful reply. 

 

It IS a legitimate question.  The reason why the dealer might need to get involved is because of the ABS/traction control unit.  If air gets trapped in there it'd be difficult/impossible to properly bleed without access to a Tech 2/scantool to purge the actuators.  Power bleeder isn't going to help in this case.

[Heartbeat1991]

It wasn't a pointless reply.  If a car won't go, it's a problem for you.  If it won't stop, it's a problem for everyone.  If you didn't get any air in the ABS pump, you should be fine.

[Nas Escobar]

Pointless meaning that instead of answering the question he simply decided to be an arse about it and say if he has to ask questions about doing a job then he should pay to get it done instead. It's an unneeded post.  If we did that every time someone asked questions then we'd be discouraging people to change their starters, alternators, etc.

 

Technically speaking, the late 90's - early 2000s GM cars had special brake bleed procedures. I remember that my 2003 Grand Am, the brakes were not supposed to be bleed the "common way", but rather left rear, right front; right rear, left front. Normally, you're supposed to bleed furthest away from the master cylinder (being the right rear) but in this case you bleed diagonally but bleeding the closest one last. If you ever got air in the ABS module/pump you were SOL because you had to take it to the dealer. There was a claim in that community that if you cycled the key as you bleed the pump (meaning your pumper cycled the key as you opened the line) you could get around it. Now that was never verified and I would suggest against it. So this is a unique situation to GM cars.

 

Now mechanically speaking, if you change your master cylinder, it's best to bench bleed the mc and then bleed the lines going to the mc as well as all 4 brake lines on each caliper/drum (if so equipped). That's the way I did it on my Grand Am.

 

As far as the Tech 2 thing goes, it's not guaranteed that's going to happen. I wanted to have my Grand AM bled that way mostly because that car had brake issues and normal bleeding didn't help it, this was before the MC swap and triggered the MC swap, which helped it but didn't solve the issue. HOWEVER when I took it to the dealership, they claimed that the reason the brakes were bad were because of the front wheel bearings, however in that specific car if the wheel bearings were bad, it would automatically disable ABS and turn on the Brake, ABS, and SVS light on the dashboard.

 

TLDR: You can change the master cylinder without touching the ABS pump, however it is recommended every line is bled before turning the car on. If you get air in that pump you're SOL

[kissmyss]

Pointless meaning that instead of answering the question he simply decided to be an arse about it and say if he has to ask questions about doing a job then he should pay to get it done instead. It's an unneeded post.  If we did that every time someone asked questions then we'd be discouraging people to change their starters, alternators, etc.

 

Technically speaking, the late 90's - early 2000s GM cars had special brake bleed procedures. I remember that my 2003 Grand Am, the brakes were not supposed to be bleed the "common way", but rather left rear, right front; right rear, left front. Normally, you're supposed to bleed furthest away from the master cylinder (being the right rear) but in this case you bleed diagonally but bleeding the closest one last. If you ever got air in the ABS module/pump you were SOL because you had to take it to the dealer. There was a claim in that community that if you cycled the key as you bleed the pump (meaning your pumper cycled the key as you opened the line) you could get around it. Now that was never verified and I would suggest against it. So this is a unique situation to GM cars.

 

Now mechanically speaking, if you change your master cylinder, it's best to bench bleed the mc and then bleed the lines going to the mc as well as all 4 brake lines on each caliper/drum (if so equipped). That's the way I did it on my Grand Am.

 

As far as the Tech 2 thing goes, it's not guaranteed that's going to happen. I wanted to have my Grand AM bled that way mostly because that car had brake issues and normal bleeding didn't help it, this was before the MC swap and triggered the MC swap, which helped it but didn't solve the issue. HOWEVER when I took it to the dealership, they claimed that the reason the brakes were bad were because of the front wheel bearings, however in that specific car if the wheel bearings were bad, it would automatically disable ABS and turn on the Brake, ABS, and SVS light on the dashboard.

 

TLDR: You can change the master cylinder without touching the ABS pump, however it is recommended every line is bled before turning the car on. If you get air in that pump you're SOL

 

Thanks for the info, I've been working on different cars for the last 30 years and just not familiar with abs systems.