Why do designers do this!!

Absolutely agree with Nigel B.

Another favourite trick of car design is to put loads of expensive and fragile components right behind the fragile plastic 'bumper' (misnomer), so the whole lot is trashed when granny in a supermarket car park reverses into your car. More spares supplied = more profits. The insurance companies know all about this, but compensate by raising premiums. The consumer doesn't count, once the product is bought.

Edited By Kiwi Bloke on 08/09/2021 03:40:06

Sorry Mick B1 but not enough room to get a flat washer ,spring washer and full nut behind the torsion bar especially as there is a further 2 or 3 threads sticking out. The correct way to move the torsion bar out of the way is by bolting a plate under the g/box x member bolts with a couple of ins sticking out under the torsion bar. This plate has a hole in it to take a hook bolt 3/8 ins in dia, hook the bolt over the torsion bar and thru the hole in the plate, fit washer and nut then tighten until torsion bar is low enough to slide bolts out. Done dozens of them over the years, had to cut my teeth on them as an apprentice.

There are many reasons for "bad" designs. As noted what is good for production may not be good for repair. White goods are different from carsand cars a different from aircraft.
Requirements for cars can change. I remember Vauxhall making a big thing of one of their cars (Cavalier I think) being able to have the clutch changed without removing the engine or gearbox. This gave them an advantage in the company car market (now insignificant compared to private) where running costs are important. Now it's about the wireless system and variable colour mood lighting.

Many years ago I checked (for radio aspects) a antenna installtion on a business jet. It was in the middle of the roof and used 6 screws with loose nuts inside. A asked the "designer" why the didn't use captve nuts becuase changing the antenna or doing checks on it would mean removing the one piece roof lining which in turn need the seats and side paels to be removed.
The reason? He could not find a stencil for the captive nut! This was pre-CAD.

The other reason I hate is "we always do it like that"

Robert G8RPI

That may be a correct way for a repair shop that has to do it regularly, but it doesn't suit the 'normal' owner wanting to repair the seals without a toolmaking diversion. But it still works the same way of straining the bar to create a passage.

If I remember the manual correctly it started the master cylinder disassembly with "Remove the torsion bar assembly..."