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

Replacing an intake on a 289 Ford. I missed a piece of old gasket on ftont left corner, so when I torqued it down the ear snapped off my nice high rise Edelbrock intake. Yep - i JB welded it back on and it was good for 20 years!

 

I was watching one of those mechanic shows a couple of weekends ago and this Man and this Woman were rebuilding a Ford 9 inch rear diff. They had it put back together and they painted the gears and were checking the wear pattern. The conversation went just like this.

Her: What happens if the pattern is NOT right?
Him: Nothing will happen, It will just make noise.
I was like WTF

I turned the channel until the next show came on.

 

Oh me either. Those old Chevy motors were bullet proof, though. Idled just fine in park, just couldn't keep an idle in gear due to the vacuum leak in the cylinder.

 

Once again it was the 70's... did a tune up to a Mercury 400 cid. During the test drive I got on the highway at the top of a hill and floored it to listen for knock (at the bottom of the hill is a 50 mph corner) getting close to the corner I took my foot off the gas but it stayed on the floor, I shot that corner at about 110. Turns out I had left the old rotor on the intake and it got wedged in the carb linkage. What a ride. No wonder my folks never thought I'd make it to my 20th birthday.

 

A lot of these are coming from the old days . My best friend back in about 78 had a 70 Torino 351 Cleveland . Well we did a timing chain change ( if I remember right ) and being teens we didn't have the hood latched when we went for the test ride . The hood flew back , it looked like it was about 8 foot by 8 foot coming up . Didn't break the windshield but did put a dent in the roof and destroyed one of the hood hinges. My friend who was wild decided we we had to break the other hinge so we spun the hood around in circles over the roof over the headlights about 5 times till it broke . We threw it in the weeds and headed to town .

 

I had a hood blow open when I was on a bridge and nowhere to pull over till the other side. It did not break the windshield either but hood hinges and the cowl were bent to hell.

 

My stepfather did that with a Timex watch. He lived the rest if his life with a nearly perfect brand of a twist-O-flex watchband. The amazing thing is that the watch was still running...backwards.

 

probably the worst one i can think of i was in the process of removing brakes etc to do kingpins on a dumptruck and they were dirty and covered in grease so i brake cleaned them off walked away for a few minutes to grab the torch so i could heat the anchor pins up to get them out, well as soon as i lit the torch the whole assembly catches fire, apparently the grease kind of held the brake cleaner, in a panic i grab a rag to put the fire out, well the rag was soaked in brake clean as well... thankfully a fire extinguisher was nearby and nobody was there to witness it and give me shit about it

 

I was helping a friend change motors and the battery hot post was about an inch from the inner fender and he tac welded his wedding ring in the gap and couldn't get it loose for a few seconds . It was glowing red all the way around . It was winter and he ran outside and held his hand under snow .

 

Had '99 explorer that I used to pull several vehicles out some mud at a friends place. Including a Rubicon and the owner was not happy having to be rescued by a "the soccer mom mobile" as he like to call it.

Well the transmission was starting to slip before a bit and this put it over the edge. After a n expensive rebuild of the transmission and just paid the dam. Bill off for that. The left rear timing chain went.

And shortly after that, the explorer got sent out to scrap yard, just was so fed up at that point another 3 grand for work...

 

I actually bought it with the timing chain out of it and actually had to pull the motor twice. The jack shaft that runs the oil pump, snapped and we didn't know it.

 

Not me
https://www.tacomaworld.com/threads/help-truck-won’t-start-after-cmc.596432/

 

Could be his biggest mistake ...

 

Not many wrenching mistakes. Now... home improvement DIY stuff. Hold my beer.

 

That is an easy one. Small block Mopar W2 econo head. Block and heads O-ringed. 11:1 compression, setup for nitrous. Should have put the sparks in during before installation, but didnt want to chance breaking a $2 spark plug. #8 cylinder access very difficult with headers. Cross thread plug. I guess I could have chased the threads with the head off. If I had, every time I nailed the throttle I would have imagined a spark plug denting my shiny black hood. So, $700 for a new head and $400 for machine work. To this day, I am anal about putting in spark plugs.

 

I work in telecom and the entire network is DC powered. (In case of an outage) The entire network is powered off battery banks that are charged off AC/DC rectifiers. If all the straight power company feeds die the network can survive (once the generator set dies after a week) for another few days.

200 000 Amps of 48 VDC running through copper bus bars as thick as your thigh.

I saw a big ass crescent wrench get dropped across two bars and it exploded into silver spray!

 

"200 000 Amps of 48 VDC" is that about 1.21 jigawatts?

 

Moved my remote resi from shock to frame because it got hit. Didn’t clearance the shock mount for the hose which obviously got pinched when flexed out. Ran the rest of the trail with no shock oil it sucked and cost me a couple hundred bucks.

 

Changed the oil today. Had just tipped over the five quart jug and started filling her up, and had the immediate realization that I hadn’t put the drain plug back yet. Fortunate to have left the drain pan in place and only poured in half a quart. This could have gone so much more wrong.

Why do we screw up the easiest things sometimes?

This pales in comparison to the kid tearing down my street in a Dodge pickup, took a turn too hard and ended up in a ditch. The wife of the state trooper who lives in the neighborhood happened to drive by just as I went over to check it out. There was a patrol car there within minutes. All this interrupted my peaceful oil change and so I blame the Dodge kid for my forgetfulness.

 

This happens, my book for the Ford Taurus back in the day had the wrong firing order and I set it up by the book. I gave up and had the dealer fix it. Being told the firing order, I ran home and checked the book to find the error