I just replaced my ride height valve filters and covers. In my experience, these things last three to four years. The rubber splits on the edge and they eventually fall off. Mine looked good but when I laid hands on the covers they just slipped right off.
They are a bit difficult to get on. I put them in hot soapy water and turn them inside out. Then just screw with them until I can get em' to pop into place.
I bought mine from FindItParts (https://www.finditparts.com/search?utf8=%E2%9C%93&s=rn10je&commit=) @ $ $5.31 each. The number is RN10JE. I used to get them at NAPA but the parts guy told me they are unavailable nationwide.
Anyhow, if you haven't checked yours in a few years they are probably in bad shape.
jor
I used rubber ladder feet with a piece of filter cut to fit. Probably 75 cents.
Ould this be the same part for our 99- U320
Thanks
Chris
Yes. They are all the same. Like Twig did, you can always make your own. I used those rubber chair leg tips one time but I prefer these stock covers.
jor
thanks
Chris