Say someone attempted to replace a battery, everything was going ok until said person tried to bolt on the plate (with all the various connections attached) back on the new battery and dropped the bolt (or is it the nut – the round bit) into the engine well never to be seen again. How would you go about sourcing a replacement bolt (nut?).

Note: driving to a scrap yard is not an option in this ‘hypothetical’ scenario.

Could this incompetent fool – somehow measure the bolt and source a generic replacement.

I’d suggest recovering the missing bolt before it bounces off the place it’s currently lodged and jams itself into a belt/pulley junction.

It will be M4, M5 or something similar. I would get on my bike and go to B&Q or similar and get a bag of bolts that look the right size.

Note: driving to a scrap yard is not an option in this ‘hypothetical’ scenario.

cycle to a scrap yard?

I’d go green with anger, lift up the car off the ground and give it a good shake till the bolt dropped out.
Hypothetically.

I ( I mean the fool) did think of that but it is easier said than done. You can hardly see the bottom of the engine well from above and it slopes back so the bolt would have rolled back towards the rear wheels (and I assume not in any danger of hitting any belts etc). The engine well has a substantial floor panel that is screwed on with those screws that you can not easily remove + it is outside my house where I can’t get under it very easily.

M4 or M5? it is quite big about 15mm diameter on the thread.

is there another car handy you can borrow a bolt from..

Car Battery bolts are normally a 10mm spanner so they’ll be M6 nuts, local hardware store will have them. But i’d deffinitley try to recover the one that dropped first..

been a while since i took a car battery out but both land rovers and my van are all 13mm over the flats – no idea what thread. Thats quite a big bolt to leave rattling about on your belly pan ….. just waiting for the next thread ” why does my car rattle when i drive its driving me nuts”

Can’t you (sorry, can’t your foolish mate) get a biggish magnet and tie it onto a bit of string then randomly throw it into the space the bolt fell into?

If you’re really lucky it might just stick to it.

Agreed on getting the nut out but getting the car back to life is the first priority and will make getting the lost nut out a lot easier.

Pinkster, good thinking the access to the bottom of the engine well is minimal, I can only just see a bit if it so it might take a bit of fishing but that might work given the way lt appears to slope to a single point.

What sort of car is it ?

The undertray is normally pretty easy to remove if you jack up one side of the car.
You might not need to remove it completely, just enough to bend it down a bit at the lowest point and retrieve the bolt.

I remember dropping the oil filler cap down the back of the (hot) engine of my Mazda 6 once at a petrol station. That was rather embarrassing, but thankfully, there was a kind mechanic with a torch and a grabby thing to get it out again.

I learned to be more careful where I put the filler cap and to get a car that didn’t drink oil after that.

http://www.amazon.co.uk/MAGNETIC-TELESCOPIC-EXTENDING-LIGHT-USEFUL/dp/B006LLYNM8

I’d curse then wander into my workshop and get the big tin of all things nutty bolty out and then try to find a suitable replacement without having to resort to tipping it out.

and dropped the bolt (or is it the nut – the round bit)

I think you should put away the spanners in the box they came in, take them back to the shop you bought them and tell the you’re not competent enough yet… 😀

Being more helpful, if it is the nut, (that is the round shaped thing with a hole in the middle, !) what size spanner were you attempting to use?

10ml spanner usually is m6 nut

13ml spanner usually m8 nut

i’d look under the car. 90% of time it falls on the floor.

I blame the parents / school.

“When I were a lad, school taught useful subjects, my dad taught me DIY and my uncle taught me cars.”

Is it a nut or a bolt? FFS! 😉 😉 😉

It’s deffo not under the car. The car is a Renault Scenic (I know you don’t need to tell me). The extending torch won’t solve the problem that I can only see about 5% of the floor panel – some sort of endoscopy kit would be the ideal solution here with camera / light / grabby hand but I don’t have one lying around.

Edit: It is a Nut. And when I had an A reg VW polo I used to spanner it a lot, change the oil / plugs / filters etc but that is when they made cars that if you dropped something if fell on the floor and the design was not specifically intended to make it hard to fiddle with it yourself.

the joy of encapsulated engines 🙁

Don’t worry, it’ll eventually fall out.

Just take the other one off and go buy one.

Can’t you (sorry, can’t your foolish mate) get a biggish magnet and tie it onto a bit of string then randomly throw it into the space the bolt fell into?

Yep, that’ll work its not like there is any other metal in there…

Br – good point but the floor pan is plastic as is so much of the other crap in there that serves only to get in your way.

The ‘take the other one off’ comment has inspired me to think that it is the + terminal that is now not connected. Is the – terminal earthed to the frame? And if so would this be less sensitive to a dodgy connection, i.e. if I took the Nut of the – terminal and firmly attached the + terminal then bodged as best as possible the negative the car might start. Is this worth a go? (considers risk of appearing more of a fool / posts anyway)

Simply catch a magpie and shut it in under the bonnet until it retrieves the bolt. Take care to release it slowly so it doesn’t fly away with it. Magpies are notorious thieves.

It was an m8, in case anyone stumbles across this again.

It was an m8, in case anyone stumbles across this again

Well done him.
Wd ur m8 come to help me when I drop one?

If I had dropped a screwdriver into the depths of a Zafira’s engine bay, I’d probably bounce it about a bit, the get underneath to shoogle the undertray to confirm where it landed. From there, I’d theoretically be able to partially remove the tray to retrieve the said tool.
Wouldn’t happen to me tho……