For years, I’ve wanted an Audi Quattro, but decent ones are now going for insane amounts of money. And buying one is probably the cheapest part of owning it. Still, I watch Craigslist, just curious what might show up. Because Audi originally called a car “quattro”, then later called their all-wheel-drive system the same thing, it’s pretty much impossible to search for one. Fans refer to it as the “Ur Quattro”, but searching for one by that name isn’t really going to help.

So when you search for Audi Quattro on Craigslist, you get hits for things like “Audi A4 Quattro” which isn’t very interesting, and not what I’m looking for. But a couple months ago an “Audi 5000S Quattro” appeared. I was fascinated.

Given that we had a non-Quattro 5000 Turbo growing up, I knew that this was easily the least reliable car in existence. I very occasionally see one on the road and amazed that it’s still moving. And here was one that someone was actually trying to sell. For $1,200.

I decided to go check it out. Astoundingly it started right up and drove just fine, if slowly. Some minor surface rust, destroyed paint, but quite the survivor. All 4 electric windows and the electric sunroof worked, which was quite the shock. Audis in general are quite unreliable, and the electrical bits are always the first to go. I wonder how many motors, relays and switches had been replaced for this feat. Additionally, both differential locks worked!

The guy selling it had purchased it from an old Audi tech who had kept it running, but decided to thin out his collection of Audis.

While it had brand new tires, the windshield was cracked and it was much slower than it should have been. So slow that pulling out in traffic was a bit of an adventure. The power steering rack was leaking. I asked if they guy would budge on his price, and he said no, since he’d just lowered it to $1,200 from $1,400. I told him I’d pass, but later sent him an email that if he didn’t sell it at $1,200 that I’d buy it for $1,000. He caved immediately with, “Fine. Take it.”

Jonah wanted to know why I thought we needed it. “We don’t. No one needs this car. If you thought you needed it, it would just leave you on the side of the road and broke once you paid someone to fix it. I want it, and it’s only $1,000…” “Why don’t you buy something cool you really want, like an MGB or an RX-7?” “There are no $1,000 MGBs or RX7s in running condition.”

Jonah took me to pick it up on a cool Monday morning and it barely started. It died immediately if I tried to give it any gas at all, so I had to sit in the lot where I’d just handed over $1,000 for a few minutes until it was warm enough to move. But it got me to work just fine.

It came with 8 keys, given that apparently every lock had been replaced at least once, but no one had tried to rekey them. There were a collection of spare parts in the trunk, and a liter or so pentosin for topping off the hydraulic fluid from the leaking steering rack.

When it came time to drive home that evening, Highway 24 was closed because of mud and debris from a particularly fierce rainstorm. Rather than waiting for it to reopen, I decided to head up the 20 miles of dirt and mud that is Mt. Herman road in my Audi. Jonah refused to join me, deciding instead to spend the night with her parents, convinced there was no way the Audi would make it home.

I immediately discovered that I got a terrible beeping and flashing warning light because some system believed the engine was overheating even though it wasn’t. Additionally, I got very low on hydraulic fluid, so by the end of the journey I had two simultaneous warning lights–not at all unexpected from an ’87 Audi. I was a bit perturbed by the speed of the power steering leak, but otherwise had an enjoyable drive home on a road that I wouldn’t have dared drive in the Miata.

I bought a copy of the (english) factory repair manuals for $30 on ebay and set out to figure out the cold start problem. I determined that the previous owner had wired the cold start injector to a button on the dashboard. Pressing it was just as likely to flood the engine as it was to get a successful cold start. The idle didn’t appear to be regulated at all, so I set about trying to diagnose the idle computer. Hours of reading and prodding with my multimeter and I determined that there was no power through the idle switch or the air sensor. I established continuity for the power lines from the fuel injection computer to the ignition computer, so I decided that one of the computers or the other was bad.

Fortunately, both were on ebay for less than $20. Unfortunately, I didn’t notice they were shipping from Lithuania. In the meantime, I charged up the A/C, and was pleasantly surprised that it worked. I removed what seemed like 50 pounds of 1990s carphone wiring. I tracked down a replacement for the faulty coolant sensor, which extinguished that warning light.

When I got both computers in the mail, installed them, and there was no difference at all. Before I could determine that, however, I had to charge the battery because it was completely bad. I couldn’t figure out why, but wondered if the aftermarket radio drained too much power. Before giving up for the day, to determine if that was the battery draw problem, I pulled the fuse for that circuit and stuck the fuse in an empty slot. When I did so, the car started idling perfectly. The slot was, according to the factory manual, unused. But according to the label on the fuse box, it was labeled “Engine Timing” which sure sounded important. Now cold starts worked great!

I excitedly drove it to work the next morning. It started immediately and even let me set off while it was still cold. I drove the whole way without a single warning light. The climate control system did go rogue and decide at some point that I wanted full heat blasting in my face, but I was eventually able to coax it back to air conditioning.

On the drive home, the odometer stopped working at 185,999 miles. I worried that this was a bad omen, but was determined to see if I could drive it to work two days in a row.

The next morning, I hopped in, it started right up. As I started going down the road, I tried to shift into second gear but my foot couldn’t find the clutch pedal. In disbelief, I looked under the dash and found the pedal–stuck to the floor. No amount of pumping or pulling it would disengage the clutch, so I limped back into the driveway and drove the Miata to work.

I ordered clutch master and slave cylinders for less than $100 total. I wanted to install them last Sunday, but discovered that I had a case of the shingles that morning and had to visit an urgent care center instead.

So this weekend, I used the Audi as a distraction from the shingles pain. The slave cylinder was not particularly fun to change, given that it’s behind the engine on top of the transmission and under a pile of goo from the leaking power steering rack. I managed to get it replaced in an hour or so. The master cylinder is stupidly attached to the clutch pedal, and I broke the old fitting trying to remove it, which resulted in quite the spill of brake fluid in the driver’s side foot well. After getting it replaced, I solicited Jonah’s help in bleeding the clutch.

We bled forever, and I couldn’t get any real pressure built up. But on a whim, I started pumping the clutch with the bottom couple inches of travel where there was some resistance. After a few minutes of this, the clutch started operating normally. Worried that there was still air in the system, I bled again, but the pedal immediately got stuck on the floor again. There wasn’t any air this time, so I repeated the pumping process and when the pedal felt good, pronounced it done. I have absolutely no idea how pumping the clutch pedal with the bleed valve closed achieved the desired result.

I pulled apart the instrument cluster, removed the speedometer and determined that it was bound up in a strange way. I managed to fiddle with the gears and make it happy again and reinstalled it. I did not focus on the fact that the previous owner had used purple duct tape to hold the speedometer cable in place. It appears that this guy viewed duct tape as his signature, and he left some in basically every system he touched.

Then I went for a test drive. Everything seemed great, until I tested the differential locks. I try to test them regularly on our dirt road to make sure the mechanisms are free and still work. They completely stopped working. So, back in the garage…

I pulled apart the center console and discovered the differential lock switch is nothing but a giant vacuum mux. One input, and 4 outputs. The input is teed to another line. The lines kept popping out, so I added zip ties to try to keep them in place. Realizing that there was nothing but vacuum needed to activate the locks, I decided to plug the vacuum source up to my vacuum pump. When I did, the system worked great. But it wouldn’t work with the engine source. About then I went to bed.

The vacuum diagram in the factory manual is woefully vague. It shows the source for the differential locks as coming out of the intake manifold, and being teed into the climate control. I was super excited when I found a disconnected vacuum line at the intake manifold. I reconnected it, but the locks still didn’t work. But with some more persistence I found another disconnected line, this one in a position that I was likely to have interfered with while replacing the slave cylinder. Sure enough, this one did the trick.

I replaced the radio head unit with a cheap unit from Amazon. The one in there worked for about 30 seconds at a time, and had no aux input. My $65 Amazon special has bluetooth! That took hours, and then it took another hour to get the differential switch happily routed back to where it goes with all the vacuum lines attached. I changed the oil and air filter. I thought about changing the differential and transmission oil, but I couldn’t find fill plugs for the diffs and the drain plugs appeared to be something like an 17mm allen key, and I didn’t have a tool for that. While tracing vacuum lines, I noticed that the vacuum dump switch on top of the clutch for the cruise control had popped out. It had plastic threads that were stripped, so I put some epoxy on it and threaded back in. I filled up the spare tire. I cleaned out the trunk, and tossed some spare parts that didn’t even appear to be for this Audi.

And then I went for a drive. Everything mostly works! The diff locks work, the radio works, and astoundingly: the cruise control works! We’ll see how some future attempts to drive it to work go.