I have a 1990 3cx. The hose connections have a rubber seal inside. Is it really necessary when redoing the pipes or can I do without it? Who has experience? Thank you very much!
A pic would help.
If you are using the same pipe for that type of fitting then yes, you need that oring.
I’ve put fittings together without the oring on the BSP and they were fine. The oem fittings on my JCB have the oring, but aftermarket hose fittings do not.