hopefully this helps
I've used both Dultmeier and Windtrax in the past for parts, I haven't had either of them rebuild a pump for me. I've had a few pump problems myself and windtrax has been just a little bit more helpful.I think either company will do a great job of rebuilding a pump for you. If you send your used pump in , You will definitely want to get a new pump to put into service while your old pump is being rebuilt I contacted giant before your post, they e-mailed me a 16 page PDF file on the P56w, it is quite helpful. If you want to rebuild your pump yourself, e-mail me, maybe I can help.just a quick question, how many hours do you have on this pump, and what chemicals are you running through it?