I was getting the annoying ABS error lights on my 2000 Astro van AWD (pictured here behind the VW) for about the past year. ABS errors can be pretty expensive to repair, and I didn’t have the money really to spend in expensive troubleshooting and repairs by the mechanic, so I set out to see how I could solve it on my own.
Researching on the internet, ABS errors are a common problem on General motors trucks, SUV’s and vans built around the turn of the century. Their bright idea was to locate the ABS brake controller underneath these vehicles on a frame rail….where they are exposed to all sorts of whatever the vehicle is driven through. A real problem on an AWD or 4WD vehicle, as they are frequently driven in snow, mud, sand, and other abnormal materials that end up all over the underside of the vehicle. Couple this, with the fact that this brake module was built just as the electronics industry was moving to lead-free solder, and you have a recipe for failure!
I connected my code scanner up to the van, and found that it was setting error 265, which is the classic symptom of a failed ABS controller. So, the challenge began to get it out of there. The ABS controller is underneath the van, sort of about where the red “AWD” logo beside “ASTRO” is in the left picture below. Likewise, you can see how mud and grime from the wheel goes right up on it!The theory holds, that you can merely remove the controller from the top of the ABS pump, repair it, and return it to the pump. The vehicle can even still be driven during the interim. Now that doesn’t sound like too bad of a design, and it really isn’t.
Now, what works in theory, doesn’t really work in practice. Remember what I said about AWD and 4WD vehicles being driven in mud, snow, and sand? Well, this van has! The T20 screws that held the ABS controller to the pump were rusted on there solid. Any torque I applied to the screws promptly stripped them out….so, the entire ABS pump, with the controller had to come out….Again, I was dealing with rusted, corroded parts. This time it was brake lines. Thankfully, they came out without any issue, but removing the entire pump meant the entire brake system would need to be bled down of air once everything was reinstalled.
By the way, I found that brake fluid is a very good solvent for sharpie marker! …so don’t use that to mark the lines
So, now with the pump out, I began the chore of trying to remove the stripped out screws.
SO there was lots of drilling and grinding the heads off with the dremel tool.
and finally, after lots of work, was able to separate the two!
Then the next task of getting into the controller….more drilling and grinding
then I had to break the silicone seal.
Lots of work! But finally got into it and found immeditely where the problem(s) were. Right by my thumb there was a cold solder joint on one of the solenoids
The spots were re-soldered, along with many of the other terminals on the circuit board, and it was reassembled. You will need to put silicone sealant on the gap to fasten it down just like before, and it’s also a good idea to put some new thermal heatsink greas on those white patches on the circuit board. You can purchase it at any computer shop, and Radio Shack (if you still have one in your area)…This time with stainless steel screws were used to fasten the controller to the pump, so if it needs to come apart again, I won’t need to take the pump off the van because hopefully, the screws won’t corrode or rust
Before putting the ABS brake pump back in, I painted around it, and the frame rails to protect them against road salt and further rusting. In this image, you can see the shelf on the side of the frame rail where the ABS pump goes back in
Remember me mentioning that brake fluid is an excellent solvent for sharpie marker ink? well, I marked all the brake lines before pulling them off the controller, but the marks were now gone, so I ended up having to trace the brake lines through the van and finding out where they went. There are 5 lines. One to the back, one to each front wheel, and two from the master cylinder….They need to be fastened to the proper port on the ABS pump, or it will not work properly!
This diagram should help if you end up in this situation:
Now, with the lines properly connected to the correct ports, the next task was to bleed down the brake system. A P.I A. job. Bleeding hydraulic systems is one of the most nerve wracking parts of vehicle work. This one didn’t go as planned because rust strikes again. I had two bleeder screws rust and break off. In a rear wheel cylinder, and in a front caliper. Instead of trying to drill out the screw, I just replaced both of these. Thankfully on chevrolet vehicles, rear wheel cylinders are about $12, and front brake calipers about $20….that’s cheap enough not to bother with it!
With the wheel cylinder replaced, I could proceed with the bleeding process. A big bottle of brake fluid is needed, and I have found a big syringe is the perfect tool to suck the fluid through the system
The rear brake shoes looked good, so I just reassembled the brake without replacing the shoes. Drum brakes can be a pain in the butt to reassemble with all the little levers and springs inside. The front pads however were looking a little worn, so they were replaced with the new caliper. I got this caliper tool from Autozone that makes pushing the caliper piston back in a snap. I only had to do one caliper, but I had the tool for doing the brakes on my wife’s car too.
With everything bled down, I then went back into the ABS computer and activated the ABS controller to work out any more air, I then went through the bleeding procedure again. I cleared the ABS errors from the system and went for a test drive 🙂 So far, so good…after a week or so, the errors have not returned! My wife and I drove downtown to do some bike riding in lots of stop & go traffic, and I broke in the new pads and didn’t get any more errors.
There were some costs involved with this project, as you read, there were parts and materials involved:
New front brake pads $50
New front caliper $20
New rear wheel cylinder $12
Quart of brake fluid $6
While this was over $80 in parts, it was a significant savings. Shops rebuild these brake controllers for $120, and sell new ones for $300 + I had about 4 hours of labor in this project replacing the brake parts, so this could have easily been a $500-$800 project if I had a mechanic do it, plus I could see to it that it was done the way I wanted it done!