Why are some things so difficult - to take apart?

[Tony Griffiths]

Thanks to Mike Costigan for sending this gem:

An engineer sat at his drafting board
A wealth of knowledge in his head was stored
Like "What can be done on a radial drill
Or a turret lathe or a vertical mill?"

But above all things a knack he had
Of driving gentle technicians mad.
So he mused, as he thoughtfully scratched his bean
"Just how can I make this thing hard to peen?"

If I make this body perfectly straight
The job ought to come out first-rate
But that would be so easy to grind and paint
That it would never make a welder faint

So I'll put a compound taper there
And a couple of angles to make them swear.
Although brass would work for this little gear
But it's too damn easy to work I fear
 
So just to make the machinist squeal
I'll make him mill it from tungsten steel
And I'll put these holes that hold the cap
Down underneath where they can't be tapped

Now if they can make this it'll just be luck
Cause it can't be held by dog or chuck
And it can't be planed and can't be ground
So I feel my design is unusually sound
 
"Success!" he shouted "Success at last!
This goddam' thing can't even be cast".

[Bob Culver]

When it comes to accessibility and serviceabilty the designers of cars over the last 40 years seem to have worked to a similar ethos.
Incredibly, persons on here occasionally complain about the Seven! Whilst many aspects could have been more convenient, compared with any modern the cars are a dream.

[Robert Leigh]

Absolutely! I changed the left headlamp bulb on my wife's Citroen C3 recently, which involved at least an hour of time and the loss of some blood; a suitably trained toddler with a small hand could have done better.
Robert Leigh

[bob46320]

Its the same for the headlamps on Renault Modus - Recommended method is to remove the front bumper, but by law, we have to carry spare bulbs !

[A G Wood]

Yep, in my experience, when it comes to modern vehicles I feel accessibility and serviceability can and does play second fiddle to the production engineers and the body engineers . Usually the regular service items such as drain plugs and filters aren't too bad to get at, but as two of the gentlemen here have alluded to, even on less exotic makes replacing globes can be another story... A very common make I used to work with,  most models had the entire power unit, wiring, and ancillaries plus the radiator, a/c condenser, intercooler and transmission coolers mounted on a subframe which was then inserted from below on the production line. Normal practice these days with most cars, good from a production point of view, but a stone damaged radiator say, had to be pulled out downwards, so that meant a hoist tied up for a couple of hours, and coolant dripping in ones face. Whereas when I first started in the late 60's for the same manufacturers product, hood open, four or six bolts, two jubilee hose clips and you're done (in the car park even).

[Mike Costigan]

In fact many modern cars are not as difficult to service as they appear; many have 'short-cuts' which are only made known to authorised dealers, whilst the rest of us are left to dismantle half the car. For instance, the modern VW Beetle is supposed to be a nightmare to change a headlamp bulb; on-line forums talk of lacerated hands and many hours work, whereas in reality all it needs is a special socket to operate a quick-release catch and the job can be done in five minutes.

[John Mason]

I sometimes watch an American mechanic on his “U Tube” channel. The difference in names for various parts fascinates me. However he has a full commercial workshop with every available tool known to man. He does a variety of jobs on cars such as brakes wheel bearing clutch and engine jobs. It is supposed to help amateur diy repairs. He always finishes up saying “If I can do it. You can do it.” And I always think yes if you had a workshop and tools like you

John Mason.

[Nick Salmon]

I long ago came to the conclusion that, when Austin, MG, Morris etc designed something such as an engine, gearbox or whathaveyou, the perfected item would undergo one final stage en route to production...

It would be sent to a tiny department, tucked away in some obscure corner of the design office, where it would undergo a process of 'embuggerance'. This would tweak the near perfect piece so that what would have been an easy job of repair or replacement could now be made so difficult as to be guaranteed to drive the poor owner/mechanic to distraction because now it incorporated some first class piece of awkwardness.

I think for example of the pointless blind spline on the A7 gearbox input shaft, the inability to remove the side water branch without first removing the firmly stuck oil filler tube, the location of the brake master cylinder on MG TD and VA, etc etc etc ad infinitum...

[Tony Griffiths]

I long ago came to the conclusion that when Austin, MG, Morris etc designed something such as an engine, gearbox or whathaveyou, the perfected item would undergo one final stage en route to production...... as we all know so well, the real final development was by the customer.

[A G Wood]

In fact many modern cars are not as difficult to service as they appear; many have 'short-cuts' which are only made known to authorised dealers, whilst the rest of us are left to dismantle half the car. 

Sometimes even the authorised dealers have to dismantle half the car too, due to the pernicious embuggerance factor mentioned above. We used to reckon that they had an in-house competition at the design stage to see which division could make it the most awkward for the poor old dealership tech to perform a certain task.  Bonus points if the department could also develop a 'special tool' to do the job. For a good example of embuggerance from my day,  on one popular Australasian sedan, if your HVAC control unit packed it in [usually down to an internal electronic component fail]  it was necessary to remove the entire dashboard and instrument panel assembly A pillar to A pillar- everything you see when you sit in the front seat- (a two man job btw) to remove and replace said control unit. The dealership I worked at, we would typically replace 1-2  a month.  It wasn't until the last gasp of the model line that they finally made easy replacement possible by making the glove compartment liner removable from inside the car. Word was on the street that the interior styling team hadn't liased with the HVAC team...