DDK - Die Deutschen Klassiker

Does anyone know how to remove this fitting from the oil line that loops underneath the transmission and connects to the oil tank?

No idea how to hold the inner fitting whilst turning the outer fitting...

The hose twists out of the Aluminium collar anti-clockwise. Best to make yourself a wooden clamp to hold the collar whilst twisting the rubber hose. Easy does it as the collar can crack easily.

Ok thanks for the advice I will go away and try this, however I suspect that the old hose will rip/tear at the collar base before it turns in the fitting, my other ones were very difficult to pull out of the sheath even once the center fitting had been removed. I would then be left with a fitting with the remnants of the old hose still inside.... I was thinking of maybe burning it out? but they are ally so I suspect wont take much heat...

I don't quite understand what you are trying to do.
The rubber hose is crimped very tightly to the inner sleeve, the sleeve is machined with barbs to stop the rubber coming off under pressure, sure all mine are steel (1973T).
The nut freely rotates on the sleeve, so assembly is nut over the sleeve, crimp sleeve over the rubber hose, press rubber hose and sleeve over the inner barbed sleeve and then crimp the lots in a special crimping machine (ie as Pertec do)
I thought these terminations were not stripable without cutting the crimped sleeve, then pull the rubber off the barbed sleeve by cutting the rubber and then re-use the nut and inner barbed sleeve for a fresh hose and outer crimped sleeve.

911hillclimber wrote: ↑Mon Dec 19, 2022 6:06 pm I don't quite understand what you are trying to do.
The rubber hose is crimped very tightly to the inner sleeve, the sleeve is machined with barbs to stop the rubber coming off under pressure, sure all mine are steel (1973T).
The nut freely rotates on the sleeve, so assembly is nut over the sleeve, crimp sleeve over the rubber hose, press rubber hose and sleeve over the inner barbed sleeve and then crimp the lots in a special crimping machine (ie as Pertec do)
I thought these terminations were not stripable without cutting the crimped sleeve, then pull the rubber off the barbed sleeve by cutting the rubber and then re-use the nut and inner barbed sleeve for a fresh hose and outer crimped sleeve.

The 69-71/72? hoses are not crimped, they can be taken apart and rebuilt in theory. They are made from 2 fittings threaded together, an inner fitting and an outer collar. As below.

This has been a total old git. Needless to say when I tried to turn the pipe out of the fitting it simply tore at the neck of the collar as expected. This left me to spend an hour with a fine screw driver trying to chisel out the rubber part fixed inside the fittings. Having done this I assumed it would come apart with ease, but noooo. the threads are obviously corroded together somewhat... the problem persists, I cannot see any way to hold the inner fitting whilst turning the outer fitting.... im not sure why they have used this fitting design on this one coupling, the other 3 had fixed hexes on them to hold the inner fitting but this one doesnt, what a shite design.

I learn something every day!
What a silly design as you say.

If it is any help, the Boxster has such silly designs too, so there is someone in the drawing office who needs training in SIMPLICITY. (KISS)
Is it worth keeping this lot aside and simply use the usual crimping design of a 73 hose?
IIRC the nut is an awkward thread today, so you need to keep that but a Pirtec visit could be worth it.