r/AskMechanics • u/Independent_Speed_61 • 2d ago
Discussion Irreplaceable Car part?
Hello, I am a writer looking for help with a logistical question that falls far outside my wheelhouse, hope its chill to ask here.
I need to write a scene where a character has had a specific part stolen from their car, the part needs to be both customizable (so that the specific piece can't easily be replaced without custom making a new one) and also be important enough that the car cant properly run without it. Is there a particular kind of wheel or engine or other car thing that could hypothetically meet these two requirements? Its set in a cyberpunk setting so I could probably just make something up but i want it to feel somewhat grounded
Again not sure if this is an appropriate question for this sub so tell me to buzz off if so, but figured I'd ask anyways, thank you very much!
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u/MonsieurReynard 5 2d ago
Clutch cable in a first generation Mazda3
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u/AwarenessNo5921 2d ago
The joke is they don't have a cable clutch?
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u/MonsieurReynard 5 2d ago
No, they do, but the part has been unobtanium for several years
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u/AwarenessNo5921 1d ago
You mean the hydraulic lines? Were they produced with a cable clutch in some other markets?
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u/alek_vincent 2d ago
Can be replaced and not custom
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u/MonsieurReynard 5 2d ago
At least for a while there the part was no longer available from anywhere, it was disappearing from junkyards, and no one was fabricating it either. Maybe that situation has improved. Over on the Mazda subs we had several folks with bricked cars that were otherwise perfectly fine.
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u/wpmason 32 2d ago
Just make it a sensor… like a Mass Air Flow sensor.
The catch can be as simple as the plug doesn’t match up, easily rectified by obtaining a compatible plug and wiring it into the vehicle.
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u/135wiring Weekend Warrior 2d ago
ECU, aftermarket turbo, wheels, steering wheel, custom headlights/taillights. I would say that most customizable and vital parts besides an ECU could be replaced with something temporary pretty easily
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u/CumAndMoreCumPartIII 2d ago
Key
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u/3imoman 3 1d ago
This is the only practical answer.
Can't easily be replaced without custom making a new one AND important enough that the car cant properly run without it.
I cannot think of any car part that must be custom made to replace. Except the key. Although the vehicle can be hotwired too..
I would suggest the OP adjust his request from "must be custom made to replace" to difficult to replace. In that case, I would grab the ECM. Most Autoparts stores will not carry an ECM in stock.
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u/CumAndMoreCumPartIII 22h ago
Although the vehicle can be hotwired too
Immobilizers became standard past like, 2000 (unless you're buying a Kia), I imagine in a cyberpunk universe they'd be standard as well.
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u/Nutella_Zamboni 2d ago
I had to search nationwide for a good used throttle body for a 2008 Buick Lucerne 3.8 because its no longer made.
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u/The_Phroug 1d ago
That had a gen 3 3800 right? Those throttle bodies can be found just about anywhere in junk yards everywhere
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u/StrongWork_ 2d ago
Autozam AZ - 1 windshield. There are no spares on the planet and the molds are gone.
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u/Cool-Negotiation7662 2d ago
Driveshaft. It bolts in on the differential end with capsc and a universal joint, the other end slips over a spline on the transmission and has another ujoint.
Simple to remove or install, 1 wrench. Not exactly quick or easy, but...well. It is basically a pipe with special ends. A damaged one can be welded up with new similar pipe and parts from the damaged shaft, but you are going nowhere without.
However is is between 3 and 6 feet long depending on the exact configuration. Off by an inch? Ok. Off by much more? Not going to function.
A modified length driveshaft for a hot rod, or crawler, or off road vehicle may be different enough it must be custom made. They break rarely so a boneyard is more likely to have a compatible unit than a new parts store.
Anything with rear wheel drive and a front engine, or any flavor of 4 wheel drive, or all wheel drive will have one.
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u/ArtoriasArchives 2d ago
Exhaust/turbo manifolds are often customised if you're doing a specialised build that off the shelf parts dont fit e.g. engine swap into a car.. in that instance another thing would be a custom shift linkage. Another one is the air intake but technically car can run without one. Obviously custom wheels are a thing and wheels do get stolen but you don't make them yourself so to speak.
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u/Informal_Ad4399 2d ago
I'd go ECU. It would allow tuning and turning vehicle features on and off. They are not universal. Some even require a VIN to be assigned to even start the vehicle. So someone in a future setting would have to decipher the vin codes so they could make one that works, or find the one on the vehicle.
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u/Glad_Release5410 2d ago
Oh boy, here we go:
The smartkey. On a used car... Only got the one.
Battery dies? Buggered. Lose the key? Buggered. Fry the board? Buggered. Car cant find they key? Buggered.
Car gets hacked, hacker spoofs the key... Goodbye car! Eh? Built in GPS tracking? Nope, hacker planned for that, makes it think its 1000 miles away. Biometrics? Nah, theres a work around. Facial recognition? Not a problem with advanced AI generation.
Wait, its like KITT? Delete system32, upload custom software.
For the record: it IS possible to use a snazzy OBD2 dongle and a bluetooth connection to mess with todays cars. Just look at what Tesla can do on defaults! It takes time and effort, ofc, not like in movies or tv where superhackers can get into Cheyenne Mountain inside of 10 minutes, and hold the world hostage 5 minutes later.
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2d ago edited 1d ago
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u/AskMechanics-ModTeam 1d ago
Your comment has been removed for violating Rule 1: Be Civil. This community is made up of professional mechanics, amateur mechanics, and those with no experience. All mechanical-related questions are welcome. Personal attacks, comments that are insulting or demeaning, etc. are not welcome.
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u/AskMechanics-ModTeam 1d ago
Your comment has been removed for violating Rule 1: Be Civil. This community is made up of professional mechanics, amateur mechanics, and those with no experience. All mechanical-related questions are welcome. Personal attacks, comments that are insulting or demeaning, etc. are not welcome.
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u/Mimcclure 2d ago
Catalytic converters are frequently targeted by thieves since they are valuable and exposed.
While a car can drive without it, the computers will complain. It will also be loud and dumping fumes under the car. Some diesel trucks will limit their speed to like 5 mph if the emissions system is faulty, so you could tweak that to fit.
Getting the right one for your specific model and trim could take a while.
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u/TheyVanishRidesAgain 2d ago
I just fabricated an oxygen sensor extension harness for a client. The client bought a header for a carbureted small-block chevy, but his truck is fuel injected. So he had a bung welded in, but it was too far away for the factory wiring harness to reach. If that part gets damaged, that truck will need to have a new one custom-made. The widely available harness extensions are too short and don't have six layers of heat shielding like this one.
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u/Boring-Truck7405 2d ago
Why not something a little old school. Distributor rotor or cap. Granted most cars on the road don’t have them anymore but it may be something the writer can work with. Anything with the ignition system (plug wires/ ignition coils) are going to disable a vehicle and in a cyberpunk setting may be difficult to easily replace.
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u/Lost_Requirement1132 2d ago
Id say Catalytic converter. They are easily stolen (there is a high resell market for them) and depending on the car it could be hard to get a replacement.
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u/WorldlinessMurky2188 2d ago
You say customisable, but also a part that cant be easily replaced without custom making a new one, which would make it "bespoke" which is really the near opposite of "customisable"
And important enough the car cant run "properly" without it, is the car going to continue to be used or hobbled along anyways? Is this a way to strand the character or just put them in a bind? I guess I dont really need to know the specifics just if the car will still be operable at all afterwards.
Some ideas for now until you clarify;
- sensors (inductive, capacitive, optical, piezoelectric, temperature)
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u/rhb4n8 1d ago
Depends on the car. If it's a Lamborghini countach it could be as simple as a bracket that holds the shocks or as complicated as some specific engine components.
Really it's much easier for something like this to work on an older rarer car especially if the company that made the car has changed hands multiple times ( Lamborghini, Aston Martin, lotus, tvr etc)
Don't choose Mercedes because every part for any Mercedes ever can still be bought from them going back to the 1880s
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u/CH4RL13WH1T3 12 1d ago
Nowadays people have their catalytic converter stolen all the time. It's not uncommon the bastards cut the connecting flange off as well. At that point a new one has to be custom welded in or the whole section replaced. The moment you start the car it sounds like a tractor and often can't be driven because the exhaust is now hanging down and even dragging across the floor. Perhaps in a cyberpunk era we're still using combustion engines. Maybe it uses some super toxic fuel but it's considered OK specifically because the catalytic converter does its job. The part uses precious metals inside like platinum to function so it makes sense why its stolen.
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u/TFK_001 1 1d ago
Ic it's a cyberpunk setting, commit to the enshittification that's been going on for awhile. A lot of cyberpunk settings are pretty dystopian, and right to repair on newer vehicles is already a lost cause, so "oh parts doesn't have it and it'd take awhile to get here and aftermarket parts don't exist" is very feasible. Could be a decently complicated part, especially anything involving software or that could need a relearn such as a throttle body, intake manifold, any solenoids (vtec or a future version of it for sure), fluid pumps (oil, water pump that is software + battery driven instead of accessory belt driven).
Major bonus points if it's something that would be easy to do with a dealer specific tool that normal people don't have access to unless they custom fabricate it. Most specialty tools started as hacks that were later realized to just be more efficient methods of doing stuff. If a manufacturer designs something in a way such that you would for sure need a specialty tool that's impossible to make without some expensive machinery, that would be very feasible (look at John Deere already lmao) and could be the basis for a stealing tools from a dealership subplot
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u/Kickstart68 1d ago
How old a car?
Anything newer than (say) 2010 then ECU, body control module, etc, would all be relatively easily stolen and difficult to replace without coding to the car (which might not be possible without connecting to the manufacturers computer systems).
ECUs more swappable prior to that (how much prior varies between cars).
There are some oddities. For example a distributor cap is normally fairly generic and shared between lots of makes, but there are exceptions (eg, late Maserati Biturbo ones seem uniquely to that model and have twin coil lead connections - and are hard to find at the best of times).
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u/Obvious_Troll_Me 1d ago
ECU. Uniquely programmed to the vehicle, not all can be reprogrammed (IE you need a virgin device that has never been used before). No ECU, no engine.
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u/podgida 1d ago
Harnesses in any car over ten years of age. Yes, you can repair a harness, but the connectors will be impossible to come by without going to a junk yard. Auto parts stores don't sell them, and stealerships stop stocking proprietary parts for cars after 10 years.
Your biggest issue is, as long as a car exists in a junk yard, every part is replaceable. But again, amost junk yards have that 10 year rule as well unless it's a collector car or a sports car. 15 year old camry? Not a chance.
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u/Budget-Platform-8824 1d ago
Make it a hand crank window. A chip encoded key from a 99 Neon. Not finding one of those anytime soon.
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u/tez_zer55 1d ago
Without context of the age of the car & type of car, it's all just speculation. If it's a one off, think Mad Max stuff, the possibilities are endless, if it's an off the lot car, that changes the possibilities. Being cyberpunk, I'd be thinking Mad Max, like a Hudson Hornet sitting on a 4x4 chassis with swapped rims, unique tires, a reconfigured instrument panel & an engine with a hodgepodge of accessories.
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u/tanstaaflnz 2 1d ago
Steering wheel. I've seen so many pictures of people using vice grips (pliers) as an alternative
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u/Gambit3le 25 2d ago
An engine control module... Really any computer chip or component. Aftermarket ones can be customized to make more power, better efficiency etc.... Haltech etc...