What is the worst mistake you made doing your own wrenching?

Broke a bolt replacing the valve cover on my old '03 Neon. And I will say that I'm not touching suspension ever again. My '08 Caliber taught me that I HATE it.

Oh, and replacing my alternator pulley on that Caliber with a standard pulley instead of the fancy dual-clutch one that was on it. It chewed through AC compressors after that until I replaced the alternator with one that had the right pulley.

 

Jump starting my 2nd gen in the dark and rain. Definitely crossed up Neg and Pos and blew several fuses and the fusible link.

Once I got all that replaced, though, the problem I had of blowing headlight and license plate lamps every few months was gone.

 

Cross threaded one of the 3 starter motor bolts in the aluminum block on a Honda Accord. It was a bolt that underneath and was felt but not seen. Using the braille method I had to drill, tap, and helicoil a fix. It held for many years though.

 

I guess it counts...but I was putting a small leveling kit on my wifes 4Runner and I go to take the shocks off the springs after compressing them and I shear the shock strut bolt. the bolt had corroded and when I went to take it apart it sheared. ended up having to put new struts and take them apart. I prob shouldnt have put that type of lift on it in retrospect. but I was newb, It did look good though once I finished.

 

Um....

Never mind.

 

The other day I was replacing the spark plugs and spark plug wires on my 3.4l. When re-tightening one of the coil packs I over tightened and snapped the bolt. Was too scared to drive it like that and it's my only vehicle, so I had to take a $35 round trip uber to go get a replacement bolt

 

About 15 years ago I swapped the U-joints in the driveshaft on a '94 Nissan 4x4 without realizing that I'd seriously jammed a needle bearing in one of the caps (bent it right in half) when I was pressing the new joints into place. Put it all back together and tested it out, and as soon as I locked the hubs in it hopped around the yard like a bucking bronco because that joint didn't want to flex for sh*t. Had to take it all apart and do it over again with a fresh joint, and you can be damn sure that I tested it off the truck before I put it back together a second time.


Other than that, I've been lucky that the worst I've screwed up since then was when I welded new spring perches on to the rear axle of my 84 W150 plow/work truck a couple of years ago. I didn't let the axle tubes cool down enough between welds and I overheated the passenger side axle bearing & seal. Ended up noticing some slop a few weeks later and had to replace them.

 

More than anyone else in my life, I too have been my own worst enemy at times. The most egregious of these times are when I had a tool in my hand...

And never more obvious than when I am sitting in my yard with my hand stuck inside the bung hole of my 1997 Chevy truck's gas tank that I had dismounted to put YET ANOTHER in a long string of fuel pumps in it, and while I am sitting there my college roommate calls me and tells me to look up. There he is, up above me in a Citation corporate jet, flying over my house with some of his oil patch executive friends, going to stay at Halliburton's private estate outside Agusta, to attend the Sunday round of the Master's golf tournament. The tools I have held, and the tool that I am.

 

Yup. 1976 going to replace the trans in a 65 Olds Delta 88 (425 big block), car rolls off the ramps and the front tire just missed my head, onto my shoulder, down my chest and finally stops with my shirt pinned under it. The guy helping me cut my shirt off and pulled me out. Went to the ER later that night and found out I cracked all my ribs on that side and bruised my heart (you could see the tire tread marks on my chest perfect for a few days). They wrapped me with a bandage and sent me home with a bill.
I have not worked on a vehicle using ramps since. With age come wisdom (unless you are just stupid).

 

Its a skill knowing when you're in over your head.
Hell the fucking bakflip cover 10 min youtube install is a joke. It took me 4 hours.
My three year old was "helping" though.

 

Changed the radiator on my Jeep XJ, left a socket near the fan which then shot said socket through the new radiator.

 

I had always known that the resistance of human skin played a role in the effect of the electrical shock, but always thought it negligible at high amperage.

Your reply reset my assumptions.

This article was eye opening to say the least. Did not know that higher amperage can be less fatal than smaller amperage.

https://www.asc.ohio-state.edu/physics/p616/safety/fatal_current.html

 

Water content will play a role. After all that’s how the electricity is flowing through your body.

 

Helping a friend install a freshly rebuilt (by us) 1776 motor in a 1951 VW split window. Motor goes in super easy, we hookup wiring, fuel lines...etc. He gets in, cranks it up and instant flames. We forgot to the tighten the fuel line T fitting for the 48 IDA Webers and it spewed raw fuel all over the coil and distributor. We had an extinguisher fairly close, but it still ended up with a few blister scars in the paint and little discoloration. Good thing we had not installed that electronic fuel pump or the additional 2 seconds of pressure could have made things a little more interesting. Man I miss the air cooled scene.

 

One more - my stainless steel watch band became a 5 million watt heating element while working near the positive lead on the battery. It was bright red in no time. I even burned my right hand fingers getting that sucker off. I had quite the blister around my left wrist for weeks. I NEVER work on my vehicles with any jewelry now.

 

I made the mistake of loosening the upper bolts first on a Texas flanged Spicer/Dana 20 t-case.. it rested on that lower bolt fora few days before it broke off the lower ear.. cast iron can't be welded that easily... wound up getting anew transfer case that did not have the holes in it for the shfiter rods of the stock t-14 trans on my 74 CJ-5.. wound up having to replace the transmission.. (excused my upgrade to a T-18a...

another one:

I was replacing the front wheel bearing on my fathers 2000 GMC 2500 duelly 4x4 plow truck.. I had removed 2 of the 4 bolts holding the bearing on... the top left, and bottom right were frozen solid/rusty, and were recessed in the knuckle.. so I could only get at it with a shallow socket, and a breaker bar/ratchet.. I had a propane torch, and my impact would not fit, and the head of the bolts were starting to strip the corners.. I heated the bolts as much as possible.. soaked them in PB blaster, deep creep, marvel... etc.. tried heating again.... eventually I got the top one loose, and out, but the bottom one was frozen solid.. I wound up drilling it out... took me about 2 hours with different sets of drillbits as the ones I had were not up to the task of cutting the hardened grade 10 steel bolts. eventually I got it out, and replaced the bearing.... never worked on a rusty GMC again...

I have more... but....

 

And since you were on US ships, that boat is probably still working today.

 

Even an auto could have been shifted to neutral...

 

You have it backwards. Higher voltage shocks can be less fatal than lower voltage ones, not amperage. However usually most higher voltages have dangerous currents available.
Example 20,000 volt static shock (next to 0 current available) vs 45 volt (high amperage supply available) shock. Current through your body is the key factor, especially across the chest.
Higher amperage is more fatal. Look at the chart.
Bottom line if one does not know what they are doing seek assistance.

 

My headass stripped the flare nuts at the end of my brake lines while trying to install extended brake lines. Still currently trying to figure out the best solution lol