What was the easiest/cheapest repair that turned into an expensive nightmare?

Following along the lines of the easiest/quickest thread below, what was the quick, easy repair that turned into a disaster? I’ve had a few, like proactively changing all the heater hoses because of age and tugging a little too hard, resulting in a 5 hour heater core replacement. A quick serpentine belt change when the wrench slipped and broke the A/C service port on the accumulator resulting in immediate discharge of the refrigerant.

Two others come to mind that came to me for repair.

Toyota Camry V6, died while turning into a steep driveway. I ended up telling him his axle shaft was the reason the engine wouldn’t start. It seems he had his “buddy” replace his noisy CV shaft a few days earlier. On this car, the right shaft is a 2-piece design, held to the block by a carrier bearing. The shaft is held in the carrier through the use of a large snap-ring. Buddy didn’t install the snap ring properly, and the suspension travel into the driveway pulled the cv shaft out, where it swung around and broke off the hydraulic timing belt tensioner that protrudes from the bottom of the engine, resulting in timing belt jumping. Another CV shaft, complete timing belt kit with tensioner, on the road again.

Buick Park Avenue Ultra, 3.8 Supercharged. This engine has 2 serpentine belts, one solely to run the engine supercharger. Customer was advised of a noisy belt tensioner, but decided to wait on the repair until the noise got worse. Car was towed in, seems the noise stopped and suddenly a new noise appeared, the car wouldn’t steer properly and the engine light was on. The noisy tensioner pulley finally seized, the belt started slipping until it broke and came flying off. As it was doing so it flailed around enough that it tore the rear O2 sensor wiring to pieces, shorting the sensor heater feed to ground. The belt also wrapped around and tore open a CV boot slinging grease everywhere. But there’s more…the belt that wrapped around the axle also somehow lassoed itself around the inner tie-rod, and the turning CV shaft tightened up the belt. You’d think the belt would just snap, but instead it tightened up enough that it broke the rack and pinion off of the subframe. So this turned into a replacement rack and pinion (adding a core charge for a broken rack), CV shaft, oxygen sensor, wiring repair, belt and tensioner. I don’t think this guy was happy that he put off his $100 tensioner repair.

Coolant drain and fill on a Mazda B2200 pickup.
After the coolant drained the top radiator hose seemed aged. When I tried to pull it away from the radiator it was difficult but manageable. Put everything back together, filled up the radiator started up the engine and a geyser of fresh coolant started to dump out by the top radiator hose. The welded outflow neck had a crack on it. Now everything had to come apart again plus the radiator out, and wait two days till Monday to the radiator shop to be open and get it welded back together…

A friend had his wife take their Mitsubishi Galant in for an oil change. They showed her a disassembled engine that was destroyed by a failed timing belt and told her it needed to be done immediately. My frien got upset and thought they were trying to scare a poor woman. He told her to leave and not do it. A month later they recalled his car for failed timing belts. He got it done free! Three months after that he called me to come pick him up, his car was dead. He found the timing belt had come off, because the balancer belt behind it snapped. This bent all the valves. Mitsubishi said the balancer belt was not part of the recall and he was SOL.

I would have told Mitsubishi “If you won’t help me out, don’t expect me to buy another car from you . . .”


Have you seen what happened to Mitsubishi? Nobody bought another car from them.

This goes back to the 1960s when I had a 1954 Buick. The ammeter went to discharge and I found that a lead had broken off a brush in the generator. The brushes were less than $5, so I bought a pair and installed them in the generator. The ammeter instantly registered a full charge, so I thought it was fixed. No such luck as the generator continued to indicate full charge. What I had done was to short the field coil inside the generator to the frame of the generator when I installed the brushes. In the meantime, I purchased a new regulator, which made no difference. I finally bought a rebuilt generator for $12 and was back in business. However, what should have cost me about $5 cost me about $20. Back in 1963, that was a lot of money for me.

I’ve been through a number of things. When it comes to nuts and bolts Murphy’s Law is always around.

One that chewed up a lot of time on me involved a Lincoln I used to drive. Doing some maintenance one weekend a ratchet slipped on me during a spark plug change and broke a plastic grommet on the power brake booster. That grommet locates the ABS switch and once I got it off I found that it was formed plastic and not hard rubber. The part number was molded in so I figured no big deal and off to the Ford dealer on Monday. That number was not available and that grommet could only be had with a new brake booster at 350 bucks.

Off to the parts houses for a workaround. No luck. None of the local salvage yards had any Marks they were parting out.

The next weekend I drove nearly a 100 miles to the Pull A Part yard and they were out of Marks. .

So in spite of the time and aggravation I made a grommet on the lathe out of aircraft aluminum. It was a bit tricky to do and my hope were not very high that it would work. The stars must have been aligned because it did work well and was still fine when the car was wrecked. That accident was a doofy Dodge driver error; not a Lincoln ABS fault…

Indirectly, that spark plug change chewed up about 3 or 4 days of time.

A friend had a Mazda with a timing chain that had jumped. (if I remember right) He was able to do the chain and he changed out the top sprocket. He didn’t realize you needed to use Loctite on the bolt that held it in place. The bolt and sprocket dropped off into the oil pan and wreaked havoc before the engine came to a stop. I don’t remember if the top half destroyed itself too, but he engine was toast.

I think we’ve all been in this situation in our various professions: https://xkcd.com/349/