Replaced a leaking water pump earlier this year, only to find, much to my chagrin, that the new one appeared to be leaking as well. Took it all apart a second time, to discover that the water pump seal was pristine, and showed no evidence of a leak.

Turned out it was leaking from a loose radiator hose.

Anthonyb, I really feel for you. Those water pumps are a real PITA to replace.

Replaced all 4 of my shocks when I installed lowering springs. Biggest waste of $320. I didn't notice a difference at all. I probably could have gotten away with using my stock springs.

Another was installing a "Center-Force" clutch plate. Again I didn't notice a difference (except for my wallet being a lighter)

Lastly tires. Other than looks, I don't notice any difference in performance.

Sometimes I'll replace something if I read about a high failure rate in some forum or other. It saves me the headache of fixing whatever it is when it breaks.

Resoldering fuel pump relays for one. Plastic/aluminum radiators for another.

Replaced the MAF sensor for the check engine light, only to find that it was the ECU.

Replaced the AC control unit to solve intermittent hot air, looks like its the monovalve.

Not a car problem but one I came across several years ago while at a customer’s office. When doing a tape backup, not only would the backup stop at a certain point, but the tape drive would cause the computer to reboot. I worked with Microsoft support, Dell support, even the tape drive vendor’s support. We could duplicate the problem 100% of the time. Along the way, I replaced the tape drive, the tape drive cable, the SCSI host adapter for the tape drive, the system board, the computer's back plane, the power supply the cooling fans, even the video display card and ultimately the hard drive, and the network interface card. Still the problem persisted. Microsoft gave up. Dell gave up. I gave up using the tape drive and had the customer buy another hard drive, put it on a different machine and simply copied data from the problematic machine to the other one. Problem was side stepped.

A little more than a year later I was talking with someone at MS support about a different topic, and mentioned the previous one, and said it was never solved. He did some research and found a case with a similar operating system where a pipe “|” character in a file name caused a similar problem. I went to the customer’s office the next day and looked for a file with a pipe character as part of the file’s name. Sure enough, in a directory with over a thousand files on it, one file had a pipe character. I renamed the file to remove the character, duplicated the test, and the problem was solved. I renamed the file again and put the pipe character back and the problem resumed. That was it! Never did get an explanation why this caused the failure of the backup software....

My A/C was working intermittantly and I bought a replacement Kilma relay. Turns out it was the compressor....still have the relay on the coffee table. There wasted time and money.

Memories
 

This thread brings back memories.
The first time I worked upon a positive ground British vehicle and learned the British wiring code, the hard way. :eek: :eek:

worthless repair
 

I have a british sports car and the front left brake disc brake would lock up on occasion. The caliper was removed and rebuilt, new pads installed, flushed out and renewed the brake fluid, checked the pdwa (a switch which detests loss of brake pressure between the front and rear). The only thing left was the flexible brake line to the caliper. Although it looked perfect from the outside, it had deteriorated internally creating a one way effect not allowing fluid to return when releasing the brakes.

How about just stupid worthless projects - like transferring a factory A/C system into a Ford Pinto? I still cringe at the thought.

Which is the first suspect...very common failure.

switching dashes in a dodge colt....

i just love the problems that i find...

my left front wheel was making a nice clicking sound at all speeds, warped rotor? bad bearings? cracked rotor?... nope.. some idiot had installed the spring clip the wrong way on the ATE calipers.. they put the pins under the clip and the clip was just sitting there doing nothing... might i say i checked all 4 corners and found the same problem...

First project on our '91 190E after driving it home and experiencing a corkscrew motion from the back over freeway undulations was of course to get rear shocks from the dealer (!!!$$$) and replace. When no change, I started shaking wheels and found a loosened track strut bolt on one side. Tightening completely cured the behavior.

Steve

What he said. :rolleyes:

I had an a/c that crapped out and only worked intermittently. I took it to the local mechanic who diagnosed over $700 worth of work (compressor, expansion valve, convert to 134, new dryer). I did the work myself. It worked for a while, but then started to crap out again intermittently.

The problem turned out to be a $25 relay that needed to be replaced!