I Need Some ABS Brake Help!

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bobscuda67

bobscuda67

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My daughter is home from school until the 12th. and she has a 2002 Pontiac Sunfire. One of the rear brake lines rusted out and leaked. I replaced all the rear lines and bleed the rears out. The pedal is good and firm and it stops straight. There are no dash warning lights on. But when you step on the pedal firm to stop quicker on dry pavement, there's a pulsating noise coming from the back. Doesn't do it on normal stops. I took it on a snow covered parking lot and locked up the brakes and the ABS works like it should.
Is there something I'm missing in the bleeding process? I read online that some cars have to have the ABS motor reset after opening up the brake system. Could that be it?
I would be grateful for any help someone can offer.
 
Sounds like it's workin right to me.
 
It should be covered in the FSM. Google 2002 Pontiac Sunfire factory service manual.
 
On a lot of ABS cars you can actually feel the pulsating brakes through the pedal, so it doesn't sound totally unusual.

But, if you never noticed that happening before you might want to take it in. Some of those ABS systems are sensitive to changes like that, and need to be reset after any kind of maintenance. Some are more forgiving, but it depends on the year/make/model of the car and the work that was done.
 
If you didn't get the lines replaced exactly, it might be telegraphing sound down the line

Even flex lines, if "in a bind" can do that
 
Never heard of resetting abs.... Does this have rear drum brakes ???? if so ... are they adjusted to tight? if rear drum brakes ... are there hot spots on drums causing rear brake lock up ? Are all the tires same size ? Roughly same tread depth... If you pull abs fuse .. does this pulsating gone ?
 
Thanks for all the replies.
It does have drum brakes and they are newer and adjusted correctly. Newer tires too.
It didn't pulsate before I replaced the lines. It makes the sound only on quicker stops, not panic stops, just before the ABS activates.
If the fluid in the master was low and pumped air in the ABS module, could that do it? Is there a way to bleed the ABS module? I didn't see any bleeders on it. I'll pull the fuse and see what that does. Thanks all.
 
I would pull the fuse and lets see if ABS causing issue first ... lets not jump to conclusions.... TYPICALLY you are able to bleed system without the use of a scantool to cycle abs unit during bleeding .... BUT you MOST likely depleted ALL brake fluid in system during brake line replacement ... which can cause air being trapped in system and hard to bleed without the use of a scantool ... AND depending on brake line routing ... you may need to bleed fronts also .... BUT again ... lets verify if issue is still there without abs fuse installed ....
 
bleed procedure is different for front wheel drive cars. The fluid circuits aren't front and rear, its more like a X with the rabs valve in the center. Regardless, you should bleed all 4 corners.
 
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