If you are talking about brake lines then you need the ISO bubble end.

I don't know about SLS fittings

In a recent discussion about hard brake lines the most popular solution was to go and buy ready made cunifer lines from an auto parts store.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Sls lines do whatever will work is okay. Brake and fuel lines may cause issues if your region has periodic safety checks.

Our safety checks are now every two years and if they saw any form of rubber coated product other than solid metal with a coating or it was plastic being used. Plastic fuel lines where not original to these cars remember. They would in all probability fail the car here.

Still you might get by with fairly stiff plastic for fuel lines. And maybe not locally.

On my '85 wagon, I bought new lines from the dealer, which came straight and had to be bent to match. One of the new lines had wrong fitting at engine end, so I took both old and new lines to a local hydraulic shop and said "Fix this!". They ended up splicing in a short section of new line, with two new couplings and my old coupling in the correct place.

I then pre-bent the new lines, using the old lines as templates. Installing them between the body and the rear axle subframe assembly was NOT fun, but just possible to do in my driveway.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Where is "here" ? Your inspection regs should be available online.

I don't see nylon fuel lines being a problem if they are properly connected and routed. Nylon lines go back to the 70's on some Euro cars. ( 70 Porsche 914 , 80 SAAB 900) and on USA domestic cars mid 80's . For completeness, Dodge was an early adopter of plastic gas tanks on trucks in the late 70's, SAAB had then in the early 80's.

Brake lines must be steel or factory type flex ( "racing" braided flex lines must have a DOT number ). Compression fittings are a no no.

As for SLS, any quality steel line , proper pressure rubber will be fine.

Yes ,I have a state issued safety inspection mechanic license.

Eastern Canada. Yes I knew some cars like my diesel jettas had plastic fuel lines . Only ever had one problem and it was not the plastic lines. A stone took out the check valve just where it heads upward at the back near the tank once. Scavanged some hose from the engine compartment to eliminate it and got home.