Hey everyone looking for an answer to a hyd issue i,m having. 2002 Blaw Knox PF4410, low hours. When the machine gets extremely hot, 90 degree day and paving for half the day, the hyd systems that are all connected to the general purpose pump slow down so much that you cant use more than one accesory at a time. For example you cannot pull both screed extensions in at the same time or the hopper will barely lift the material thats in it. The manual calls for 1800 PSI at the pump I have 2200 PSI. The pump is a dynex PV2029-3197. Fluid and filters were all changed. Any suggestions would be greatly appeciated. Thanks in advance. Scrap
What is the pressure at the GP valve when you operate a function while hot? What is the pressure while operating two functions? 200PSI should be sufficient for any function on the paver. More than Likely the pump is worn where the rotating group meets the valve plate. You can take the case drain line off the top of the pump and route it into a bucket and check flow when operating a function while hot. There will always be flow out of the line but if it increases significantly while trying to use a function or 2 you probably have excessive leakage in the pump. The best route of repair is to get a reman pump. If you take it to a hyd shop dont let them talk you into refacing the valve plate. The valve plate is the end plate of the pump and the surface is treated with a process that hardens the plate. Resurfacing removes this layer and the pump will probaly not last as long. Make sure you cut open the filter and look into the hyd resrvoir to make sure there is no contamination. Verify your cooler and bypass are functioning properly. Use a high quality ISO46 hyd oil and use the correct filters. Don't use cheap filters that fit. They need to be MPG or fiberglass elements rated at 5 micron absolute. Also check your screens in the second hyd reservoir that does not have the cap but has the bolt on cover.