Author Topic: Cars Vs. Bullets question... [car know-it-alls, come here!] (Read 4217 times)

TMM · « **on:** February 07, 2007, 12:54:50 PM »

Ok, so, i'm writing a screenplay involving a zombie/doomsday kinda scenario. earlier in the script, one of the trucks belonging to a group was used partially as a barricade against gun-weilding baddies. I wrote it so mostly the upper part of the truck was hit, thus creating little damage except tearing a brake line, which was fixed. then, later in the script, and maybe 3-400 miles later [shootout in connecticut, then to vermont, then to new york where the problem hits] , i'm writing in that a stray bullet hit somthing in the truck that festered as a problem, unnoticed, until this time, where the truck will break down.

my question:

firstly, is it easy/possible to damage a brake line with a bullet and not damage anything else and then repair easily?

secondly, is there any way that a stray round could produce a problem, going temporarily un noticed?

if not, do you guys have any ideas as to how this truck could break down?

Thanks, from a guy who dosn't know much about cars.

~tmm

richyoung · « **Reply #1 on:** February 07, 2007, 01:02:14 PM »

Brake lines operate under high hydraulic pressure - once damaged, they cannot be easily fixed. Further, most brake lines run from the master cylinder to the BOTTOM of the car - they would be unlikely to be damaged by gunfire. This having been said, most modern autombiles have a divided brake system - one half works the front brakes, the other the back. One could suppose damage taking out half of the system, leving hte other half functional - for a while. A more likely (and more easily repairable) damage would be to the cooling system- say a bullet goes through one of hte hoses tothe heater core. Such damage could be repaired by clamping a peice of tubing or even a socket wrench into the line as a splice - such an impromptue repair could also likely fail at an inopertune moment.

Brad Johnson · « **Reply #2 on:** February 07, 2007, 01:09:49 PM »

Bullet ricochets off pavement. Bullet fragments partially cut the accessory drive belt. A few hundred miles later the belt disintegrates, flailing around the engine compartment and yanking the positive cable free of the battery terminal in the process (actor pops hood and utters abbreviated description for audience's sake).

The fix for the belt could be a pair of the heroine's panty hose (hey, you needed an excuse in the script to get her out of them anyway). Getting the cable back on the terminal could be as simle as skinning back the cable with a pocketknife and shoving the frayed ends back into the torn-up terminal strap.

Brad

mfree · « **Reply #3 on:** February 07, 2007, 02:07:01 PM »

My gods man, anything could happen. A bullet to a fuel tank will cause a leak but you'll still make it quite far. You could dent the fuel rail and cause a leanout. You could cause a short that pushes the wiring harness to fail later. It could penetrate the battery and drain the electrolyte... car runs, but the first time you let it idle off charge it's done. You could even go so far as having it penetrate the air intake downstream of the filter and get sucked into the engine and drop a valve or hole a piston. You could cause a slow transmission fluid leak.

let's get wild, say a ground ricochet knocks one of the e-rings off a u-joint and the yoke slowly works loose. Or it cracks the rear end cover and all the differential grease runs out (could take days to cause failure). Crack a brake drum and have it fail radially. Knock an engine-driven fan off balance which makes the water pump lunch it's bearings. Dent the carb float bowl and stick a float (will run flat-out for a while but will flood severely otherwise). Put a hole in the distributor cap so the next time it rains, the car won't run. Have a ricochet hole the exhaust just behind the catalytic converter and burn a hole in the floor over the next few hours. Break the clutch fluid reservoir. Crack the transmission gear retaining plate on a FWD car (beat on it too hard and the tranny pukes it's insides all over the road when the plate gives). Some cars refuse to start if there's no oil pressure, have the bullet ding the sensor. Most cars will refuse to start if you short the water temperature sensor (it thinks it's -40 below and floods the engine). Hit the gas cap and close off the vent, the car will die a few miles down the road when the pump can't suck any more fuel.

I can go on, if you want.

drewtam · « **Reply #4 on:** February 07, 2007, 02:12:06 PM »

Diesel truck (semi or pickup) or gasoline truck(pickup)?

TMM · « **Reply #5 on:** February 07, 2007, 02:22:59 PM »

Thanks for the replies thusfar. Firstly, i'm planning to have this truck go to pieces and be unrepairable, so the partially-broken accesscory belt is not good [though i like it for a fixable problem]

the truck is a gasoline pickup truck.

richyoung:
thanks for the info on the brakes. i like the coolant hose problem instead, though. could you expand a bit on it? where would it be damaged, would you access the hose from the hood or under the car, what will fail if the cooling system is shot[literally...

]?

mfree, thanks for the extensive post. i actually thought up the transmission fluid leak, but i didn't know how probable it would be. would it be noticable right away? how long would it take to drain, and then fail? when failing, what are the "symptoms"? or perhaps cracking the transmission gear retaining plate? sounds kind of similar to a fluid leak, which i assume ends up with the transmission having no gear oil and thus failing?

or perhaps the dfferential grease? would that cause the truck to completely fail?

Thanks for the help, hope my excessive questions don't bother you too much!

~tmm

K Frame · « **Reply #6 on:** February 07, 2007, 02:28:36 PM »

"Truck go to pieces and be unrepairable."

My suggestion would be a ricochet off the pavement creating a hole in the oil pan causing a slow leak that goes unnoticed until the engine seizes.

drewtam · « **Reply #7 on:** February 07, 2007, 02:33:00 PM »

For the coolant, there is a hose that goes from the water pump to the radiator, then from the bottom of the radiator back to the engine. All other passages are internal to the engine.
Water pumps are also sensitive to damage, a failed Water pump would allow the engine the run until it overheats, at which point the truck becomes a 6000lb boat anchor. There is no saving an engine that fails from overheat.
A leak in the radiator, or water hoses would be slower until enough coolant leaked out, that the above failure occurs.

Transimission fluid is red and heavy like oil (its hydraulic oil). A leak would allow the transmission to operate until enough leaks out that it
1. it can no longer shift into a gear or 2. the gears are permanently damaged

Drew

Perd Hapley · « **Reply #8 on:** February 07, 2007, 02:38:53 PM »

I thought cars always blew up in spectacular and colorful explosions when they got hit.

drewtam · « **Reply #9 on:** February 07, 2007, 02:45:13 PM »

Only if they are being driven by middle easterners.

280plus · « **Reply #10 on:** February 07, 2007, 02:49:39 PM »

Quote from: Mike Irwin on February 07, 2007, 01:28:36 PM

My suggestion would be a ricochet off the pavement creating a hole in the oil pan causing a slow leak that goes unnoticed until the engine seizes.

That would work as long as they're not on a mission from God. grin

charby · « **Reply #11 on:** February 07, 2007, 02:52:03 PM »

One bullet nicks brake light wire, finally arcs against frame, sets off gasoline fumes from tank that has a bullet hole in the top of it. Truck goes boom, kills lots of zombies.

Has to be a older vehicle because I think some of the newer ones have to operate on negative tank pressure.

-C

TMM · « **Reply #12 on:** February 08, 2007, 03:58:37 AM »

thanks for the help! ok, so i'm liking the coolant as the fixable repair:

after gunfight, coolant is noticed dripping on ground. guy fixes it by opening hood and fixing with a piece of tubing and hose clamps.

unfixable:

oil pan gets a hole, drip-drip-drips until the engine seizes on the highway.

or..

transmission loses it's oil and tears up the gears over time, or the retaining plate gives way and spills all the oil on the road, and the group knows they have to ditch the truck. on that note, how long could the transmission go without any oil, at about 60MPH?

which is more dramatic? i'd like somthing that's somewhat catastrophic.

thanks,
~tmm

richyoung · « **Reply #13 on:** February 08, 2007, 04:25:01 AM »

An automatic transmission will function OK for a while as it looses fluid - eventually, it will stop shifting, and stop driving hte car, as the fluid is what transmits the engine's force via a turbine called a torque converter. Pressurized fluid is also what engages the friction clutches or bands that engage the various gears, so, eventually, no fluid - no go. Incidentally, sometimes this causes little to no damage tot he transmission itself - I have been involved in incidents where the hole in the tran pan was brazed, the tranny refilled, and the transmissio performed flawlessly for the rest of the life of the car. A manual transmission, much like the rear axle, can go for a while with no gear oil, provided some residue remains on the gears. It depends on load and spead. I have personally seen a new truck whose differential was not filled at the factory - the rear end locked up after only 15 miles of sustained highway speeds.

mfree · « **Reply #14 on:** February 08, 2007, 04:39:11 AM »

Hrmm.... and this actually happened to me once;

1984 Tbird with at the time 175,000 miles under my loving care.... running perfectly, on the way home and driving through Menomenie Wisconsin (I live in east Tenn).

Cruising down the highway... *whump*. Huh? *whumwhump*.... slow down, that doesn't sound *WHUMPWHUMPWHUMPWHUMPWHUMPWHUMPWHUMPWHUMP*

The power steering pump broke... off. It broke OFF. Ford uses a ring mount so it was hanging there and by the grace of the gods the belt didn't come off the pulley, but every time I touched the steering wheel the pump would drag and start whipping around. It got me a couple miles down the road to a Pontiac dealership who chased the broken bolts out and got me back on the road with nothing more than a stinky engine compartment (type F everywhere) and a slightly warped pump pulley.

One more degree and it would have thrown the belt, and I'd have been screwed.

Art Eatman · « **Reply #15 on:** February 08, 2007, 06:24:04 AM »

If the truck is running at speed and the engine or transmission fails in a sharp curve, you're either gonna plow straight ahead or lose the rear end and spin. Just quits, plow; locks up, spins.

I was doing a road test of a nose-heavy '63 TBird, way back when. We'd run the car out of gas, change gas, and do another test. Octane rating thing. Different cans in the back floor of the car. Speeds around 40 to 50 mph.

Anyhow, on one run we were in a very tight loop of return road. The engine ran out of gas and quit. Auto transmission, so no power steering pump. I damned near lost it, needing all of my strength to control the steering wheel and not plow into the guard rail. It was a banked turn and the damned thing still wanted to plow uphill.

So, the engine in this script seizes and the truck plows off into a canyon. Or it just quits and the truck spins into an oncoming semi...

Art

Parker Dean · « **Reply #16 on:** February 08, 2007, 08:54:44 AM »

I can't think of anything that won't be noticed immediately or shortly after.

Engines are pretty hardy pieces of equipment. Sometimes you can even run them to the point of seizure from loss of coolant or oil, and after they've cooled they'll run again. Not well of course but still move the vehicle.

IMO, if you want a failure guaranteed to stop a vehicle it's gonna be in an automatic trans. Even the loss of a couple of quarts of fluid (out of 11-14qts for the typical light duty P/U) can result in slippage. Given long enough this will result in burnt clutches and bands that cannot transmit power. Only fix for this is to tear it down and fix the problem.

Downside to this for you is that the trans will start acting odd by delayed and slipping shifts which any reasonable person will get out and at least check the fluid. I think I'd skip the idea that the disabling failure is related tot he shootout and just have the trans fail where you need it to. I mean it's not like they need a reason (particularly if it's a late 90's Chevrolet Cheesy

)

If you want to do that, tell me the truck and I can probably tell you a symptom that's legit (domestic). Take a GM with the 4L60E (or even it's ancestor the 700R4), it has a stamped steel part called a "sun shell" which transmits power from the Reverse Drum to the Forward Sun Gear. The location where the sun gear connected to the shell is a flange that is internally splined. Before about 2003 the whole flange would break off and then GM thickened the radius of the flange and now the splines strip out. In either event, the trans immediately loses Reverse and Second and maybe Overdrive (never taken one in that condition to that speed myself). The trans will still have First and Direct (Third) and will shift from First to Third if you run the vehicle speed up to about 35-40 in First, so it will go for a while but theres a lot of metal debris running around in there which will tear everything else up in a few hundred miles. GM says this is caused by switching from Reverse to Drive with the vehicle still rolling backward.

Anyway you wouldn't want to go into detail about all that, my point was that you could describe that suddenly the trans no longer has Reverse and Second, perhaps after a hurried Reverse to Drive gear change, and it will sound like a legit failure to those in the know.

The Rabbi · « **Reply #17 on:** February 08, 2007, 09:15:45 AM »

It's the movies! What does verisimillitude have to do with anything?

TMM · « **Reply #18 on:** February 08, 2007, 10:39:56 AM »

Wow, what a bunch of answers, and a bunch more questions!

richyoung:

ok, so the fluid in the auto transmission is necessary to transfer power from the engine to the wheels, so if the retaining plate fails [perhaps by running over a tough bump?] and dumps the fluid on the ground, our heroic driver will need to slam the brakes and haul on the steering wheel to take that dangerous curve that will inconviniently be there.

but, with a manual transmission, he could still drive for a while, because there are actual gears there rather than relying on fluid and turbines? i'd like to have this truck drive a little further and then inconvinently fail in zombie-infested territory.

parker dean:

will this quick reverse/foward shift tear up anything in an auto transmission? because if it's with a manual, our driver will notice that there's a problem.

~tmm

MechAg94 · « **Reply #19 on:** February 08, 2007, 10:47:48 AM »

A ricochet could damage the O2 sensor and give you a Warning Light!!!

grin

richyoung · « **Reply #20 on:** February 08, 2007, 11:00:59 AM »

Quote from: TMM on February 08, 2007, 09:39:56 AM

Wow, what a bunch of answers, and a bunch more questions!

richyoung:

ok, so the fluid in the auto transmission is necessary to transfer power from the engine to the wheels, so if the retaining plate fails [perhaps by running over a tough bump?] and dumps the fluid on the ground, our heroic driver will need to slam the brakes and haul on the steering wheel to take that dangerous curve that will inconviniently be there.

but, with a manual transmission, he could still drive for a while, because there are actual gears there rather than relying on fluid and turbines? i'd like to have this truck drive a little further and then inconvinently fail in zombie-infested territory.

parker dean:

will this quick reverse/foward shift tear up anything in an auto transmission? because if it's with a manual, our driver will notice that there's a problem.

~tmm

Most trucks have a seperate power steering system - independant of the auto trans - althought the fluid in use - (all transmissio fluids and power steering fluids are basically really good 10 weight oils of either vegatible, mineral, or synthetic origin, plus dyes and additives - this as a replacement for sperm whale oil, what was originally used...). Knock a hole in a truck tran pan, and all thats going to happen is that the power will eventuially stop going to the rear wheels - all that will work in the tranny is the park position.

TMM · « **Reply #21 on:** February 08, 2007, 11:20:31 AM »

oh, ok. well, how about the manual transmission? would that still work[temporarily...] with no oil?

richyoung · « **Reply #22 on:** February 08, 2007, 12:31:14 PM »

280plus · « **Reply #23 on:** February 08, 2007, 12:40:34 PM »

How 'bout you just have a tire shot out or just blow out and these guys continue to scream down the road on the rim for as long as you want. Lots of sparks, on the verge of losing it at every turn, nearly running little old ladies and their shopping carts over and then have them wreck in some fantastic way, like over a bridge guardrail clipping the tops of the trees underneath and into the ground nose first.

OK, so I saw it on world's wildest police chase videos and added the little old lady. grin

TMM · « **Reply #24 on:** February 08, 2007, 12:46:18 PM »

Excellent! Thanks guys for your help, as a matter of fact i'm going to write it in right now. what i'm going to have happen is the truck runs over a big bump [maybe he'll hit a zombie instead...] and cause the cracked tran pan to fail. they'll go a little further because it's a stick shift, then the truck will fail in a zombie-infested territory. look for another post soon, where i'll show you guys the fruits of your and my labor as a thanks.

~tmm

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Author Topic: Cars Vs. Bullets question... [car know-it-alls, come here!] (Read 4217 times)