Quote:
Originally Posted by Ernest72
I agree but after 17 years on my WRX, I have had no issues with just bleeding the corners to get the fluid out of the caliper. ABS still works, check it every winter in the snow.
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We’re talking two different vehicle manufacturers here. BMW are NOTORIOUS for making things difficult for the home mechanic. I’d be willing to bet that their ABS system is completely different in design and requires completely different maintenance procedures from that of a 17 year-old Subaru WRX.
Somehow the OP got moisture in his fluid at some point. That fluid is pumped through the system by the ABS pump inside the module.
Think of it like draining your automatic transmission fluid. You’ll get most of the old, dirty fluid out of the pan, but you still have all of that old, dirty fluid in your torque converter left when you’re done. Unless you’ve completely flushed the fluid out using the proper procedure, the remaining fluid trapped in the torque converter will eventually mix with the new fluid that you’ve added to the tranny to compensate for what you drained out of it.
Here’s a story: When I helped my son change his transmission fluid in his Scion tC, instead of dropping the pan and just draining it out, we pumped it out using the transmission cooler high pressure line up by the radiator just by idling his engine and shifting the tranny in and out of all the forward gears and reverse gear. Once the flow slowed down enough to let us know it was empty, (and without running the pump completely dry) we would shut off the engine then pump new fluid back in on the return hose using a drill-operated fluid pump until it showed on the dipstick.
We repeated this procedure several times until the color of the fluid coming out of the high pressure hose looked like the new fluid that we were pumping into it. It took several hours and about four gallons as we were doing this in our garage at home and we were using makeshift tools. It was very messy, and I would hate to have to do it again, but at least we walked away knowing that the job was done properly.
I then had him take his car to a local shop the next day to install a new pan filter kit that he had purchased and top it off using the exact same fluid we used that they drained out during that process.
So basically, we performed the difficult and messy part that none of the local shops around here would do. And yes, we called several different shops and none of them would perform a complete tranny flush like we did.
My point for bringing up this story is that had we not performed a complete flush of his transmission, the nasty burned fluid that was left over in there had we just let a shop perform a standard “transmission service” would have just mixed with the couple of quarts of new fluid. Short of pulling the entire transmission, completely disassembling it, physically cleaning it all out, reassembling and reinstalling it, this was the next best thing we could have done.
Older cars with brake systems that don’t have ABS are simple and flushing the system is as easy as bleeding the lines at all four corners topping the master cylinder off as you go until the fluid is nice and clean. But cars nowadays just AREN’T that simple. You just won’t get all of the brake fluid out unless you follow the correct procedure.