This is part 2 of (at least) 3. In part 1 I discussed the various issues that have had me dragging my feet about starting to replace the ABS controller, but it was time to put on my big boy pants and really take a chance to screw things up! I didn't screw up (yet) but it's not fixed yet either - that's how I know there will be a part 3.
First, I just swapped the electronic control module from the used pump into the car - wouldn't it be great if that fixed it all? Sure it would, but I got exactly the same set of codes, featuring a bad pump. Time to change it all.
The ABS controller/pump is on the driver's side, just below the brake master cylinder:
Access is pretty good here because I have the radiator overflow tank removed while I'm rebuilding the cooling system. I honestly don't know if you can get the pump out without removing that tank, but I wouldn't want to try it. Just do it in conjunction with an antifreeze change, when the tank will be empty anyway. The hose above the controller is one that attaches to that tank.
It's also a good idea to move the round maintenance connector, since it's so easy to do - you just push a little plastic clip toward the body of the connector, and slide it up. In the photo pair below, the connector is in the left photo, and the right photo shows the side of the connector after removal to show how the clip works. This is not one you want to break - it should be very easy to push.
You can see from the first photo that access to all six brake lines going into the pump is rather tight. I decided that the easiest bet was to fully remove the two lines going to the master cylinder, which would then give clear access to the other four lines heading to each brake.
First step was to remove the electrical connector from the control module. You have to lift the clip farther than you think - left photo below is closed, and right is open:
Once I had the connector unhooked, I removed the four screws holding the control module to the pump and eased it out. That just adds that little bit more clearance to work. Those screws have special star heads in size E5. My cheap Harbor Freight deep E-socket set did just fine.
Next, use a turkey baster to suck as much brake fluid out of the reservoir as possible. Careful - brake fluid is a good paint remover!
To loosen the fittings on those brake pipes, you'll also need a set of flare nut wrenches - those special box wrenches with a cutout for the brake line to go through. You might be able to get by with a regular open-end wrench, but don't come crying to me when you round off that flare nut fitting! I needed 11mm, and the cheap sets skip from 10mm to 12mm. I think that's because 7/16 is a close match for 11mm, (11mm = 0.4331", 7/16" = 0.4375), but the whole point of flare wrenches is a tight fit - I wanted the right one! Try Craftsman #44096 for a good, inexpensive set that includes both inch and metric, including that 11mm wrench.
The Bentley manual just says "plug the outlet of the master cylinder" without giving any good hints on how to accomplish that. You really want to do it - even evacuating the master cylinder as much as I could with the baster, and working quickly, I had a pretty good brake fluid spill. Fortunately, the used part was shipped with the brake lines still attached - they just cut them and crimped them shut instead of removing them. Made a perfect set of plugs (two sizes needed) to stop the flow:
Honestly, if you don't have something like that in hand, I wouldn't start until finding the right fitting to plug the hole. You'll never get it sealed with tape, golf tees or any other backyard methods.
So, once the two supply pipes were safely stowed away, I had clear access to the other pipes for removal:
I labelled everything, swapped the pumps, and hooked it all back up. Replaced the control module, and hooked up the cable. That caused me some puzzlement for a while, because I couldn't get the connector to seat properly. I finally realized that you put it in place, and then pushing the latch down actually draws it tight.
I then bled the brakes with my new Bavarian Autosport Pressure Bleeder, which is one great tool. Search www.bavauto.com for part PB03K to take a look. Then, I hooked up my Bavarian Technic code reader, and turned on the ignition.
Good news: I no longer had an ABS pump code!
Bad news: Now I had a new code about ABS pressure outlet.
According to the Internet, that code is often caused by the electronic control module. So, I swapped the old module (the one that came with the car) onto the used pump. No joy - it returned to the old set of codes. Apparently, both the pump and module were bad on the car. Now, it appears that I have a good pump, but a second bad module.
This is so incredibly common that an aftermarket has arisen to help deal with it. A site called www.modulemaster.com specializes in rebuilding these modules, and their site has incredibly detailed pictures related to my exact module. Remember in part 1 when I told you that there were at least four different versions of Z3 ABS modules? The site shows all four, and only two of them are rebuildable. Luckily, mine is one of the rebuildable ones, for 150 bucks. That's the next thing to try - which one should I send? The original module that matches the car, or the newer module that matches the pump?
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