I was getting "water knock" (?) in my plumbing, it was really loud up under the kitchen sink.
I bought a new shurflo water pump and added a accumulator tank I got from a friend. Upon taking the old pump out I found that the water line from pump to house plumbing looked to be a flexible hose. It may have been at one time, but not anymore! ( 2005 motorhome) because the pump is mounted under a drawer there is a lot of empty space. I added a big loop of hose because I could! Now there is a reduction in noise level by 95%!
I suspect the old pump was fine, and getting rid of the original tubing and adding the accumulator was all that was needed. But now I have a spare pump!
Mark