DDK - Die Deutschen Klassiker

I got an MOT advisory warning last year about the strength (!!) of my windscreen washers; they are now about useless, and although I don't normally drive in the rain, the MOT is due next month and I think it might fail on this item.
Can anyone advise as to whether this is common on these old (1967) 912s, whether there is an upgraded pump I should be looking for, or whether I should just replace both jets (£21 pound each!!) . Did later models have a more powerful pump?

I have cleaned out all the hoses, so there is no problem with blockages in the pipes.

Cheers

I replaced mine recently, not so much because I was worried about the MOT, just that they didn't work! I also replaced the one way valves at the same time. Although you could blow through them it was hard and they were clearly restricting the flow.

My washer jets were leaking around the ball of the jet itself, so you had a large dribble around the base of the jet and not much coming out where it should.

Now I have a good spray pattern and pressure, and as is always the case with these things I should have done it years ago!