I need to replace the front brake pads and rotors on my brothers 2001 Pontiac Sunfire. Since his car has ABS I have heard that I must open the bleeder valve and pinch the brake line when i compress the piston to put the new pad in. Is this neccesary or can I just compress the pistion without opening the bleeder valve and pinching the brake line?
ABS Brake Service questions
- Thread starter wn1998
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The reason you dont want to compress the piston in an ABS system w/o opening the bleeder is possibility of contaminating the ABS modulator/lines with the dirty fluid from the caliper being forced back up; this fluid sees much higher temps than the rest of the system, so it will breakdown faster and get contaminated quicker.
Of course, you could do a quick bleed/flush with fresh fluid, and then not have to worry about opening the bleeder while compressing the piston, or if you are goin to do a bleed/flush after changing the pads, i guess that might work too.
Of course, you could do a quick bleed/flush with fresh fluid, and then not have to worry about opening the bleeder while compressing the piston, or if you are goin to do a bleed/flush after changing the pads, i guess that might work too.
If you do a flush on an ABS system you have to use a scan tool to process the ABS module. The best thing to do is clamp off the brake line, open the bleeder as you are compressing the piston and close back up. Simple and no ABS problems
Don't pinch the brake hoses, you could damage the inner lining and cause a restriction in the hose.
Agreed, squeezing a flexible brake hose closed is asking for problems. It is enough to open the bleeder, compress the caliper piston then close the bleeder.
Some ABS systems require a scan tool to activate the valves and pump motor to circulate the fluid through the valve body/accumulator. Normally this is not required to simply flush new fluid through a system. On many it is mandatory when air enters a system (from m-cyl or valveblock)due to component replacement.
Some ABS systems require a scan tool to activate the valves and pump motor to circulate the fluid through the valve body/accumulator. Normally this is not required to simply flush new fluid through a system. On many it is mandatory when air enters a system (from m-cyl or valveblock)due to component replacement.
Please explain more about the need to use a scan tool if you flush an ABS brake system.
As far as not flushing when you change the pads that is a bad idea. By the time the pads wear out the fluid in the caliper is crap and needs to be flushed.
As Chris said. I generally flush, then change the pads. I do not like seeing all that brown mucky brake fluid bubble up into the master cylinder when compressing the caliper cylinders.
As far as not flushing when you change the pads that is a bad idea. By the time the pads wear out the fluid in the caliper is crap and needs to be flushed.
As Chris said. I generally flush, then change the pads. I do not like seeing all that brown mucky brake fluid bubble up into the master cylinder when compressing the caliper cylinders.
Thanks for mentioning that. It's one of those things that is painfully obvious once someone says it
My brake system shall thank you in the future.
On the topic of flushing a system with ABS with a scan tool as mentioned by DoubleDee....
You can flush your system without a scan tool, you just wont be flushing out the ABS. It still gets the vast majority of old fluid and crud out of the system.
Once you have flushed the system, go romp on the brakes hard enough to activate the ABS (wet pavement, ice or loose dirts saves wear on tear) a couple of times and you will dilute whatever was in the ABS with fresh fluid. Not as good as doing it by the book, but almost as good and a bunch better than doing nothing.
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