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Gary, Buick Technician
Category: Buick
Satisfied Customers: 16893
Experience:  15 years master GM tech and mater ASE tech
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buick century: master..cylinder..abs cover gives a warning

Resolved Question:

Instructions on how to replace the Buick Centry master brake cylinder.


The problem is seperateing  the Mastercylinder and the ABS unit.  The ABS cover gives a warning of severe injury.  I would like to avoid this possibility.


Thanks for your help...Jim



Submitted: 5 years ago.
Category: Buick
Expert:  Gary replied 5 years ago.
that ABS unit MUST be deactivated with a scan tool to release the tension on the gears inside the ABS unit BEFORE it is removed from the master cylinder.if this is NOT done with a scan tool you can get hurt from the tension on the gears inside the ABS unit.after that is done you remove the unit as one piece and then swap over the ABS unit to the new master to bleed this system when you are done it will again requier a scan tool to reactivate the ABS and also that scan tool needs to be used to bleed the brakes.there is a function in the tool that tells the ABS you need to bleed the system and will purge out any air into the brake lines to then manually bleed all 4 brake lines at all 4 wheels.if you do NOT have a scan tool do NOT attempt this repair at home.have a profesinal shop do this job for you
Customer: replied 5 years ago.

Ok but I need more info before I sign off (the Accept Answer button).


When you mention a scan tool, Could you be more specific? To me scan tool sounds like you wave a wand over the whole device and the energy of the of the ABS unit relaxes itself.


How does it work? and what type of shop should I go to? A Buick dealer, PepBoys, or do you have a suggestion more likely to do this?

Expert:  Gary replied 5 years ago.
the scan tool is tool that most shops is used to retrieve trouble codes and to perform functions such as the ABS motor relieve gear tension and then to tell the ABS to re tension the gears when the job is plugs into the ALDL connector under the drivers side of lower dash and is used to communicate with most modules/computers in your car.any dealer,Pep Boys has this tool.basically any ASE certified shop can perform this repair for you
Customer: replied 5 years ago.

I have already remover the Mastercylinder/ABS. Can I just take this unit to the shop and they can do it without the car ALDL access?



Expert:  Gary replied 5 years ago.
it will need to be plugged back into the cars wiring harness for the scan tool to comunicate with it to perform the gear tension release.that unit needs to be in the car
Customer: replied 5 years ago.

This is a setback for me.


I guess the scan tool is too expensive to purchase or rent?


This means I will have to reassemble the MC/ABS which means any shop will not let one do his own brake job with their scan toll.


I guess owners can't do their own MC/ABS replacement, right?



Expert:  Gary replied 5 years ago.
if you hunt around see if any rental places around you will in fact rent you one.if they do then you can do it that buy one is well over $ 2000 and up.i do not know what the mentality of the engineers who designed this system where thinking either.owners would need the scan tool to perform a MC/ABS replacement.yes they are making it harder on owners these days to perform repairs at home
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