Wrenching Confessions: What self inflicted idiocy have you achieved?

Go on, we won't laugh. Call them "learning experiences".

What have you screwed up while working on cars?

I'll go first: I've had plenty of palm to face moments as a hobby mechanic. Most memorable of which was likely doing timing chains on a VR6 Corrado while I was in college "just because" as preventative maintenance since I had to do a clutch anyways. I forgot to torque one of the cam sprockets before the timing plate cover went back on. Got it done and it ran great... until the bolt backed out and the cam stopped turning. I then learned how to do a compression test. ...and lap valves. At least it was my own car.

Well, I set my right arm on fire with a torch while changing the rear wheel bearings on the 924 (aluminum 944 arms). I then burned the same arm while trying to put the exhaust back in place on the side of the road a few months later (different spot though).

While changing the oil on my old Daytona, I shorted the alternator stud on the filter and burned a small hole in the canister. Didn't realize that until I had backed the car out of the driveway and my Dad ran out to warn me after he saw the trail of oil headed down the driveway.

On my old Mercedes:

When I bought it, the PO told me "starter is starting to die, so tap it with a hammer to unlock it and it will start." So after a month of doing this, it eventually died. Found a replacement starter. Spent an hour under the car swapping them out. Then I put the cables on.... backwards...

Goodbye Alternator!

13X k 02 Liberty.... #6 misfire. Plugs, induction service first that lead to eventually pulling the head for a valve job for almost free on flat rate time.

Forgetting to seat a cam sprocket on a 4.7 GC that shouldn't have been mine in the first place. Had to grind the pin back into space because I didn't want to replace the cam and emery/scotchbrite the sprocket so it was flat again against the cam....

Anything 2.7..... ends in horror.

Last one, NEVER EVER light a torch with a lighter. 30 minutes under cold water, my thumb still hurt and that oh so wonderful smell of burning flesh....

Where do I start?

At 14 or 15, I rebuilt the top end on a Honda SL100. The oil passage to the top follows one of the head stud holes and it looked like a good place for an O ring. That's when I discovered just how fast a steel cam will seize in an aluminum head when there is no lubrication.

MG's and Triumphs have a 'slinger washer' which goes on the crank nose. If it's not there the front crank seal will leak like a screen door on a submarine. More than once I've gotten the timing cover back on with my favorite gorilla snot, only to see that damn thing on the workbench taunting me.

Curmudgeon wrote: ...only to see that damn thing on the workbench taunting me.

LOL. That reminds of another late night of genius.

mk2 VW Golf daily driver. I got after hours access to a lift at a buddy's shop that we really weren't supposed to be in on a week night. We had to replace the clutch.

After a decent night of leisurely yanking the trans/replacing the clutch with my buddy, and putting it all back together... dropped the hoist back to the ground and just as I was about to jump in to drive it out of the bay we both saw it at the same time; the metal disc that goes on the pressure plate for the pushrod to push... there was two of them. One of them should have been installed. E36 M3. It was now almost 1AM. It's the furthest piece in on the job, meaning we had to do virtually the entire clutch install over from start to finish, and we both had to be at work early in the morning.

I've never done a clutch install that fast in my life. It was like synchronized two man mechanics. Granted it had all just been apart, but we got it done hilariously fast the 2nd time through. Good times.

Oil change on a 1800ES. Installed the oil filter and snugged it down. Put the plug back in, filled the engine with oil, started it up and backed it out of my garage...

"hmm... what's that 'whomp, whomp, whomp' sound?"

"WHY IS THERE A TRAIL OF OIL OUT OF THE GARAGE AND INTO THE DRIVEWAY????"

When I tightened down the oil filter, I caught the oil temp sensor wire under the filter seal, so it... didn't... and pumped the fresh oil right out of the engine...

Dropped the clutch disc and when I picked it back up put it on backwards on the Elantra the first clutch job I did with it. Took me 4 days to figure that one out in the middle of winter.

This was just a couple of months ago. I needed to replace the air springs in my wifes car. I found a place online that I could order them for WAY less than the Dealer. Ordered the parts and scheduled with my FIL to use his garage, we were cleaning out the basement and my garage was full of crap.

Get the springs and tackle the rear ones first, super easy. Start on the fronts, not so easy. While getting the passanger side spring off the strut I got impatient and messed up the threads and hhogged out the hex socket at the top of the shaft. Fought it and finally got it back together at like 11pm, after starting the whole thing at 9am. My FIL and I get in and go for the shackdown drive. We both hear a strange knocking sound from the passanger side. Pull the car back into the garage, jack it back up and pull the pass wheel. The spring is all out of shape and over extended. I pul it all back apart and call it a night.

Get up the next day, Sunday and try to fix my mistake but I can not get the correct nut and I am worried about the nut holding because of the jacked up threads. I get on the computer and I can not find just the strut to buy. I can find the air spring by its self and the strut\spring together so I bite the bullet and order the combo for $400 plus a $200 core.

In the end this job took 4 days and like $1400 dollars to finish. I still came out ahead money wise but I still get pissed that I cost myself another $600 for no good reason.

Bobzilla wrote: Dropped the clutch disc and when I picked it back up put it on backwards on the Elantra the first clutch job I did with it. Took me 4 days to figure that one out in the middle of winter.

I'm not the only one? I felt like a TOTAL moron after that one.

DrBoost wrote:

Bobzilla wrote: Dropped the clutch disc and when I picked it back up put it on backwards on the Elantra the first clutch job I did with it. Took me 4 days to figure that one out in the middle of winter.

I'm not the only one? I felt like a TOTAL moron after that one.

what's worse.... I brought it in to work for one of the guys ere in the shop to do it after my snip-snip and I was helping him. I even told him "be careful and don't put it in backwards like I did". He did the same thing.

It's a lot funnier NOW than it was THEN.

In high school, I removed the non-working AC system from my old Nova. I didn't realize until winter that I had also removed the heater...

Left my cam sprocket bolt loose on my ka24e once. Luckily it fell off while at idle and did not cause engine damage.

Replaced a cam timing solenoid on a V6 VW. Car ran just as bad with the new part. Instead of realizing I got a bad part, I assumed I screwed up the cam chain timing. After I moved the chain one tooth and started it, I had to remove a head and replace a dozen bent valves.

Replaced a torque converter on an A6 2.7T. Unfortunately I didn't get it completely seated in the front pump. A couple hundred miles later I was removing and rebuilding that transmission due to sheared fluid pump splines.

After about 20 test fits, put the engine/trans in the MG. After it was all buttoned up, I had no recollection of a pilot bearing - one more time. On a different day - set my pants on fire with a cutoff wheel.

When doing the timing belt on a Fiat SOHC, the oil pump/distributor drive indexing is guesswork, apparently I was off a couple teeth, resetting the ignition timing required indexing the plug wires over 1 spot and the vac advance was still nearly touching the timing cover.

Dont forget the PCV valve when doing Buick 3800 intake replacement, the smoke show is impressive.

The worst was rebuilding my DD sunfire after a nasty fender bender in February(bent strut bad, tie rod and and knuckle trashed). The K frame was rusted out and I already had a spare ready to drop in, I PUT THE SWAY BAR ON UPSIDE DOWN. I noticed AFTER I torqued the k frame down and started bolting the front end back on. That was fun, tearing my car apart again in 0* weather.

I plugged in my HF 4" angle grinder while it was sitting in my lap......................with the switch turned on. Fortunately the grinding wheel was down about mid thigh level instead of crotch level. The wound was painful, but it could have been waaay worse.

My grey market E21 still had the early M20 timing belt (the one with the flat teeth, instead of the round ones). I bought a belt for an E30, and just threw it on without really noticing the difference. I tried to start the thing, and immediately discovered that the M20 is an interference engine. I don't think the camshaft moved at all.

My first car was a '75 Nova, which had a dying clutch when I got it.

Had a hell of a time getting the oilite bronze pilot bearing into the crank, but eventually got it bashed into something like the right location. Bashed being an important word.

Of course, when I got it all back together, the deformed pilot bearing held onto the trans input shaft tightly enough there was no way it was going into gear.

Disassemble, try again.

I never did get the three-on-the-tree shift linkage completely right, but I did get good at dangling out of the driver's seat, hanging by the steering wheel, and jiggling the linkage un-jammed at stoplights...

Put the engine back in the GT and found the throw-out bearing on the bench.

my most recently led to the death of my 91 saab 900.. rebuilt the head.. and didn't notice that half the cam retaining bolts are notched to allow oil flow to the cams...

Mounted a 2000 Watt amp to a P71 fuel tank.

water temp gauge broke on the rx7 about 5 years ago mid summer and just as I get onto my friend's driveway, as soon I stop the overflow bottle is just POURING steam out and in shear confusion I popped the radiator cap off (for some reason..) lucky me I was wear sunglasses, got a nice blast of really hot coolant down part of my face and ruined a nice free t-shirt...

another good one was a few years before that when I was 17, the first car I bought (2nd to own, first being a 90 corolla POS) was a 93 240sx and the starter died on me, so I didn't know how to replace it (at the time) and I had some E36 M3ty little shop do it. Starts fine but the 4.25" stroke had vtec! it didn't have power until about 4krpm which is completely natural to that 2.4L undersquare engine.

So I managed to stump many a nissan dealer tech and my own more techy savvy friends, cleaned injectors, cleaned ground connections, changed plugs, wires, cap rotor, fuel filter, cleaned TPS, MAF, IAC, replaced injectors, replaced FPR, as well as fuel injection service/cleaner at the dealer. Still nothing! It had serious WOT VTEC issues, handled mid throttle fine...

So a few months go by and I just live with it until I accidentally rear ended someone. During the time to fix the minor damage, I do what any good "mechanic" does and disconnects the battery, and thats the time I realized those E36 M3ty little shop techs stripped out my connector on that tightens the battery terminal down.

all that hesitation issue was from a loose negative battery cable connector...

I was rebuilding a bad locking hub on my Suzuki Samurai in 35 degree, rain-soaked dusk/darkness on my knees in the grass. Couldn't find my lock ring pliers so I was using two awls to spread the ring. Twangggg... I almost felt it zip past my ear and at that rate figured is was 15-20 feet away... in the grass, in the rain, in the dark, in the cold.

(I actually found it after 10 minutes of crawing around with a flashlight in the general direction of its trajectory. Btw, this was my only vehicle and was my DD.)

Sounds like backwards clutch disk is a popular "WTF!?!" around here.

When building my $2009 Fiero hybrid, I was in a big rush to get the clutch swapped out in preparation for my first competition test...the EV drag races at the track right by my house. In my sleep-deprived haste, I put the "new" (to me) clutch disk in backwards:

http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/west-coast-2009-challenger-awd-fiero-hybrid/10519/page4/#post187790

After breaking and subsequently tossing parts at the problem when I couldn't figure out what was wrong, I finally manned up and pulled the engine to find the REAL problem. I ended up missing the event, of course, but I certainly learned a lesson the hard way. Even when you think you can do the job asleep and blindfolded...you're wrong. PAY ATTENTION!!!

Bryce

After the first oil change on my new truck, I thought I heard a weird swooshing sound. It was the sound of 5 liters of synthetic oil spraying out between the old and new filter gaskets, all over my driveway. I never noticed that the old one didn't come off with the filter.

After doing up a performance head, and cam on my rallycross car, I took it out onto the home track for a little test run. After 2 laps it started to misfire badly. Upon inspection, i found one of the intake valves staying open, and one of the bolts (that I forgot to tighten) for the air filter hold down missing. I was able to pull a plug, push the valve down, retrieve it with a magnet and race the next day.

Ever forget to retorque your aluminum wheels? I have 3 times. Once on my wife's car and she almost lost a wheel on the highway.