For the past few decades, most older jeepneys of today may rely on second hand steering wheel, wheel and axle, shock system, and even include diesel engine. The parts as mentioned may likely made from salvaged vehicle parts such as the likes of Isuzu.
Why not most jeepney manufacturers in the past few generations create their own original parts? Well, they were of little knowledge on that matter but maybe expected to pick up the parts without the consent from, say, Isuzu Motors that was responsible for making buses, trucks, or pick-up vans.
In the case of electrification of jeepneys as a replacement of older diesel engine, one of the challenges involved are finding certified brand new steering and wheel parts without relying on second-hand ones. It's up for jeepney manufacturers to give consent to global EV makers to get the steering, wheels, electric motor, battery, and shock system with properly managed serial licensing once inspected.