New fangled brakes?

My daughter in North Carolina has brought forth a typically vague complaint of a brake problem on her 2000 Alero. Old dad will be packing up the tool box and heading south next week to investigate.

Have never worked on a vehicle later than a '92. Do the brakes on this Alero require any special tools, tricks, or knowledge for someone like me to work on them?

Chrysler service manuals have that warning (bendix system specifically) and my S10 manual specifies a scan tool is needed to properly bleed the whole system so without a manual for the specific vehicle he's talking about its better to play it safe and be careful.

I learned my lesson and got rid of the chrysler as soon as I paid it off, put all the manuals in it. At the time preventing fluid from being pushed back up into the system was a common issue with the ABS on those. Many people reported ABS failures after a non chrysler tech changed their pads and pushed the old rusty fluid back up into the ABS system. Seems one of the many design flaws with that system was the lack of a check valve to keep fluid from going back in this very situation and any dirt/rust in the fluid would cause problems. I changed my own pads (yearly on those underdesigned brakes I might add) and never caused a problem with the ABS but I did have the pump seal failure and an electrical failure with the ABS which was fixed by the warranty recall. I have been told that better ABS systems have check valves to prevent fluid from pushing backwards when compressing the calipers but I haven't yet taken apart an ABS system or seen disassembly instructions specifically for it in a manual (don't have a factory manual yet for my s10) but I've followed the practice of opening the bleeders just enough to get wetness in the hole but not enough to let the fluid run out by itsself and then compressing the caliper and the partially open bleeder will let the fluid squirt out (best to use a hose and bottle, a one man bleed kit is cheap and works here) rather than pushing it back up in the system. BTW this question comes up every so often in many NG's such as this or web based forums and the answer seems to be split 50/50 agreeing/disagreeing with what you saw. Many mechanics and non mechanics with varying years of experience will say "won't hurt the ABS" but just as many mechanics and non-mechanics with varying years of experience will say "be careful you could cause problems in the ABS system".

This is false! I have never seen any damage done to the ABS system and I've been performing brake repair work since the advent of the ABS systems that we have around today. There is no such warning in the service manuals (about not pushing the brake fluid back into the ABS controller while retracting caliper pistons) and there has been no mention of this at any training course that I've been to.

Ian

Bendix is the OEM for many makers. The Chrysler I had was a system 10, but GM used a system 2 at one time or another. It could also be possible that you and other tech you know have just been lucky and haven't caused any problems.

I'm talking strictly about the "damage" to the ABS system if you don't open the bleed screw while retracting the caliper pistons. Using a scan tool to bleed is another issue altogether. But again, I've never had to use a scan tool to do a common brake job...so that won't be an issue for the OP...unless he takes your advise and starts opening up bleeder screws and manages to get air in the system.

As far as the Chrysler service manuals saying what you say "they" say....I'd appreciate a cut and paste on that one. I'd be interested to see this in print.

Ian

You have to plug the scan tool into the ABS computers diag port (or have one that supports the makers OBDII extensions for the ABS) and run the ABS through a bleed procedure.

Don't want to get caught in the middle of this discussion, but while perusing the Bendix site to scope out their brake pad product offerings I stumbled upon this article on the subject there:

Thanks for that, that is the sort of thing I'm looking for. Unfortunately, it's not an OEM type of recommendation.

Ian

Well, we have a technician in our shop that happens to have worked in a Chrysler dealership for about 15 years...I'll ask him what they did where he worked. As it happens...I also worked at a Chrysler dealership about 10 years ago. I worked there for 4 years...never encountered this problem...never saw or heard any documentation/ training to indicate that this procedure was required.

Yep...I've heard some technicians say this (online...never have met any in real life that experienced this). Until it bites me personally, I will continue to chalk it up to some mechanic having an ABS failure right after a brake job and thinking that it was connected. We all do that in this trade...we see something happen once, and for a long time after that, we will modify our procedures thinking that "that" particular problem will re-occur again. Often it never does, was a one-off....or was not even related to whatever happened.

Ian

what's a scan tool for brake jobs? it's been 15 years since i've wrenched...

-a|ex

If you drain someones antifreeze to replace a waterpump or hose and you see rust and dirt in the bottom of the buck you drained into do you pout that rust and dirt back into the radiator when your finished? Maybe there isn't a bulletin because its common sense. Many of the posts I;ve read or mechanics I've talked to say its not a good idea to push the potentially dirty fluid bake up into even a non ABS vehicle. Your wouldn't pour dirty antifreeze back in the radiator or put dirty oil back in the engine would you. The original poster asked if there were any potential problem to look out for and I simply pointed out something that I've been told/heard. been careful of when I've done the job. No person can know everything that is why I read and see what suggestions others have or mistakes others have made. I used to use Fram filters for example and thought the leaky one I had was just a fluke thing until I started to notice how many other people had problems with them. Thats just one example of something else I learned from others problems/mistakes that I don't have to make the same mistake myself.

There is no need for any scan tool for a normal "replace the pads, machine the rotors" type of brake job. But you will hear plenty of people on newsgroups blowing smoke up people's ass about this sort of things.

Scan tools are occasionally needed to "bleed" the brakes on "some" models with ABS. I've run into very few that actually need this. The late model Cadillac's do...and I've done a few of these...so I am familiar with/know the procedure...but it cannot be said that a scan tool is needed on every brake job.

Ian

Being the maker does not mean that they write the manuals and/or repair procedures. And as far as me...and every other GM dealer tech in the city being lucky ( I say this because if there was a real problem with this, there would have been a service bulletin about it, or the training center in the city would have brought the info to everyone's attention and they haven't), I highly doubt this.

Ian

It cycles the different valves inside the ABS system to allow the air to escape according to my service book. I've been extra careful to make sure I don't allow any air in so I don't have to go somewhere and have it bled.

what does the scan tool do? what information does it show that the involves the bleed process? i'm not sure why the abs needs to be monitored. does it tell you the piston position in the caliper or if air still remains in the caliper?

i would assume that after a bleed, the ABS check light is sufficient enough to alert any problems.

-a|ex

If air enters the ABS modulator unit then it may be necessary to use the scan tool to open up all of the valves in the modulator to bleed it out. However, I can't see this happening on even a typical caliper replacement, let alone a brake pad replacement.