Question of the Week: What’s the dumbest mistake you’ve made working on your car?


If you turn wrenches on your own car, you have likely done some boneheaded move that put you between a rock and a hard place. Sometimes things go wrong that are out of your control, but the sting is a lot worse when it’s all your fault. We want to hear about the time you broke the bolt, got a tool stuck, or worse.

Even simple mechanical jobs on cars can require close attention and preparation. This isn’t about roadside fixes where the right tool is on your workbench at home. When you have everything you need and still somehow manage to screw it up, all you can do it put your head in your hands.

We have heard stories about broken bolts, dropped parts (here is some help for when it happens next time), or mis-assembly headaches. Those are the basic three, but perhaps you readers have made bigger fools of yourselves?

So let’s hear it. What was that mistake you just can’t believe you made? Come clean in the comments below, and hopefully you’ll help someone else avoid the same fate.

Don’t make these 6 mistakes when working on your car

Replaced the shifter assembly on a 94 Escort GT when I was 18 and hooked it up to the linkage backwards. Almost had a heart attack when I slammed my knuckles into the cupholders.


Used a small, 3/8" breaker bar to tighten up and then snap a valve cover bolt. I learned the hard way that breaker bars are best left only to loosen stuff. I got the bolt out with an extractor, luckily.


Forgot to put thread sealant on the Flywheel bolts of my Corvair. Only after assembling the clutch and attaching the transaxle did I catch my error. Glad I remembered before I put the powerpack back in the car, but still not fun.


Opened the hood of my car!


Had an oil leak on a 340 Mopar crate engine. I removed engine and replaced the rear main seal 3X before I found out that it was a leaky NPT fitting parallel to the crank!


Dropped a washer down the intake of an old Beetle. Had to take the engine out and remove the heads to get it back out.


Asked my girlfriend to ride my new Suzuki (1975) with me. I kicked and kicked but couldn’t get it to start. I checked the plugs, fuel petcocks and then I checked for spark. No spark. So I took off the fuel tank to look for an obvious problem with the coils or plug wires. I pulled out the service manual and followed the wiring diagram all the way to the kill switch on the handlebars. Naturally the kill switch was in the “off” position.


While building a British motorcycle top-end, I placed a towel down to keep things from falling in the crankcase. Forgot to pull it out before putting the cylinders on. Luckily, it clogged up the sump pickup and caused the motor to over-oil (better than the alternative).

The sump had a trap on the bottom… pulled the rag out, refilled the oil tank, and all was good.


(a) Rebuilt carburetor and distributor at same time, then couldn’t start truck. Had dist. turned 180 deg. (b) Dropped 1/2" wrench working difficult nut on firewall of car and it went into open end of frame channel and ended up under front floor and rattled unreachable by anything I tried. Finally put in some expanding foam through a hole to keep it from bugging me every time I drove the car.


If a modern car breaks down, Bill, I always open the hood. This allows me to look bewildered as I close the hood and call AAA.


I was 17 years old, and I picked up a 1972 Dodge D100 pickup truck with a 3-speed transmission. The truck had a strange miss, and also needed a clutch (hey, I only paid $120 for it). The miss is another person’s mistake I will tell on another posting. The clutch mistake though, was my own doing

I pulled the transmission, installed the new clutch, pressure plate and throw-out bearing, then reinstalled the transmission. As I was picking up my tools lying on the ground, I found a small piece of worn out copper - like 1/2 of a piece of pipe, worn paper thin. Just then my dad came home from work, so I showed the piece to him and asked what it was. As I feared, it was the remains of the pilot bushing - which I of course had not thought to check.

Back to square one. Oh well, lesson learned.


Yours is the best reply


Had the engine out of my '72 911, replaced cams, converted to Webers, etc. Get it back together, it’s up on jack stands in the garage, I start it up. I’m thrilled that it started on the first try, no pistons hitting valves, etc. Letting run as prescribed to break in the cams, start to see a little smoke. I just assume it was a little oil on the headers. More smoke. I bend down to look under the motor. FIRE! Holy s@#t! I grab the fire extinguisher and douse the motor. I simply forgot to tighten one of the oil lines and it shot oil on the header. No harm other than I had completely cleaned and detailed the motor while it was out. Now its covered in white powder. Stupid me.


I lose tools while working, ALLOT! And never find them until I, grudgingly, replace them with a New one!


Simple midnight oil and oil filter change on daughter’s car. Drained oil, pulled old filter, replaced filter, secured oil drain plug, filled crankcase. Started and checked for leaks. Do you know how much oil will leak out in thirty seconds between a new oil filter gasket and the old oil filter gasket that gets stuck on the filter mount? Yeah, you know, ALL OF IT! It would have been easier to burn the house down than to clean up the mess and degrease the engine compartment, brakes, subframe, garage floor, nearby things. I always check that the oil filter gasket comes out with the old oil filter, except when I don’t.


Part 2 of the 1972 Dodge - The Engine Miss

So back to that 1972 Dodge I purchased with an engine miss. To pinpoint the engine miss, I checked all of the obvious things. Spark plugs were clean, wires seemed fine and were properly routed, cap and rotor looked new.

When I checked the points, they were way off, so I adjusted them to the correct gap setting. Unfortunately, that did not solve the problem, as the same miss was there. Replaced the condenser. Still no improvement.

Just then, my dad came out to the garage to see how I was doing. He said “seems like the points aren’t set correctly.” I said that I had adjusted them, and they were now set correctly. He double checked and found that the points were way off, so apparently I had not tightened the screw sufficiently. But still, the engine ran rough. After checking a few more things, my dad said “it still sounds like the points to me.” So he (now tripple) checked the gap. Again, the points were way off. That gave him an idea.

He had my turn the engine over by hand, while he checked the gap on each of the 8 distributor cam lobes. Interestingly, when one lobe was perfect, the one completely opposite it was way off. We pulled the distributor to find that the distributor shaft was bent. I replaced the distributor with another we had in the garage, and the engine ran perfectly.

The big mystery though was, how in the heck did the distributor shaft get bent?

Well, the mystery was soon solved.

The first day I drove the now smooth running truck to school, a classmate told me the truck used to be her dads. She then went on to tell me that her dad and her uncle pulled the engine from a good running Dodge Dart to put into the truck, but after they put it in the truck, they could never get the engine to run well again. Apparently her dad gave up after a while and sold it to her uncle. The uncle in turn, gave up and traded the truck in to a local car dealer. The car dealer could not get it running, so sold it to a customer who thought he could fix the problem. And it was that guy who sold me the truck.

But at least the mystery was now solved. You see, the engine was a 318 small block Mopar. The distributor stand in the very back of the engine (behind the carb). Apparently when the guys were changing the engine, they must have bumped the distributor sufficiently hard into the fire wall as they were installing it, thus bending the shaft.

Amazingly, about a decade later, I ran into the same thing again on another old Mopar I picked up on the cheap. This time, it took me about 5 minutes to pinpoint the problem.


I rebuilt my first engine (383 Mopar) and reinstalled it in the Road Runner. I hooked everything up - except the throttle return spring. I was under the hood playing with the distributor, and my best friend was in the car cranking away. When it fired for the first time, the engine freewheeled up past the redline before he could shut it down. That isn’t the best break-in procedure, but the engine survived with no apparent damage…


1969 refurbished MGA, rebuild gearbox, reinstall… down the hill, could not
engage second gear. Out with gearbox, discovered, synchro ring that
i had put in backwards… much consternation from my dad,(a fair master
mechanic) i still have that lump on side of my head.


I punctured the underside of my 1969 Mustang cowl with a screwdriver when it slipped off a screw and didn’t realize what I had done until it leaked and rusted through my floor board enough to need replacing