Actually, Dan..
I had one that kept filling up and it was brake fluid..
So, anyone that has to keep adding fluid to the res. and can't locate a leak or sees fluid in the trap , check
the booster . A good trick here is to take the vac hose off at the booster and insert a small vac hose . Push it to the bottom of the booster tank and blow in it . If there is any fluid, you will hear it bubble.
I think that when they went with the larger booster, they prolly omitted the trap cuz the later seals were prob newer tech gas resistant polypro of some type...