There is a check valve between the pump and the nozzles. If it’s gone bad you may be able to find a generic one off the shelf.

Note that the 124 sedans and the 126s share the same parts for the headlight washer system so you have more opportunities to find the parts in the JY. But they will be 30 years old too and probably in just as bad of shape.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech