I have had DOT5 in my braking system for seven or eight years, no issues. And to this day I have never heard of anybody with brake failures after switching to Dot5. Of course that does not mean that it has not happened or will happen, but if so it is strange that nobody reports it. So appearantly, DOT5 seems to be safe in Morgans, at least the more contemporary ones (mine is 2017). But what I also did, was putting DOT5 in my clutch system at the same time. So aproximately two years ago it began to leak - first the slave cylinder, then a year later the master cylinder. Both had to be replaced, the gaskets and membranes were shot. The slave change was an engine-out job. I cannot say for sure that the DOT5 was the reason, but I am quite suspicious to this not being a coincidence - but it might be. So I think putting in DOT5 is an experiment. The rubber parts might be compatible, or they might not. You do not know unless there is plenty experience of compatibility - as it seems for Morgan brakes. And unless this experience nearing proof exists, I would not recommend it.
