My experience shows that it is likely the o'rings as identified by Marauder 2004. I installed 007 the first time but had to redo it in about 6 months and installed 008 the next time. Seemed to seal better. Put a little synthetic oil on your fingers and rub the o'ring to lube it a little before installing will also help keep it from tearing and create a better seal. You can get th o'rings at any hydraulic hose repair place locally. (These are not #7 or #8 from Lowes. They are very small.