lml@lancaironline.net Mailing List Archive

Below is a communication thread between Parker and myself about the hydraulic pump on the 360.

I thought it would be helpful for those of you that have not yet experienced the joys of trouble shooting the hydraulic pump issues on your 360, to post this sad story. Even with the help of Randy, Scott, Lorn and Gerard, I was unable to remove the shuttle valves to get to the spool valve. So................... I decided to apply some pressure......bad idea! The pressure needs to be applied in the proper place and to make a long story short...... I damaged the manifold. In my own defense, Parker Hannifin was initially unclear on where to apply this pressure. I do have to commend their customer service which was very responsive but I still had a broken pump. At this point, the remainder of the damaged pump, (after a very detailed explanation by an Oildyne service guy) was performed (it took five minutes) and guess what, the spool valve was reversed.

Oildyne found me a replacement manifold, which comes complete with internal pieces (spool valve, etc.) in Orlando, so after spending some money I was back in business. As I was looking at the new manifold, it occurred to me that Oildyne probably learned their lesson years ago about the correct orientation of the spool valve. They probably received thousands of complaints from the field over the years about the improper assembly issue which did not comply with the engineering drawings and brought this to the attention of their people. I decide to check and low and behold the spool valve was installed reversed!!! I check the drawing again to make sure my eyes weren't fooling me. AGGGGGGGGGGGGGG..........HH. (This is why I haven't bought and American car in fifteen years.)

I reversed the spool valve, transferred the motor and the rest of my good pump pieces to the new manifold and reinstalled the assembly. The system worked perfectly. The gauges read the correct pressures, the high and low were not fighting each other and even the hydraulic gear door cylinders started operating without starts and stops of before. I now have a big smile on my face but my stomach churns thinking about the time I wasted working on this system that had a simple problem. Another lesson learned and now I am a hydraulic pump "expert". Someday, maybe this plane will fly.

ONE MORE SAD BUILDER STORY!

MARK QUINN

From:	<mquinns@aol.com>
Subject:	Oildyne Hydraulic Pump - 108AM19-CLB-3VT
Date:	Fri, 18 Mar 2005 11:36:21 -0500
To:	<vkiffmeyer@parker.com>

Vern,

Mike in customer service gave me your e-mail address so I could communicate with you on a problem I have had with my hydraulic pump. The pump was manufactured in 11/98 and sat on the shelf for six years before I installed it this past January (2005). The unit operates but appeared to be fighting itself when the high pressure circuit was engaged. On advice from a friend, I installed a pressure guage on both high and low pressure side. This was a good move in that it showed that when the high pressure side was engaged the low pressure was operating at the same time (fighting itself). The high pressure side would show 1100 psi at the same time the low pressure side would show 500 psi. A number of friends that use exactly the same pump told me that this was a dead giveaway for an incorrectly (reversed) installed spool valve. They said a large number of pumps left the factory with this problem but it was very easy to correct. I have received a photograph of the disassembled valve train showing the spool valve that should have the O-ring towards the high pressure side. I removed the two end plugs and the small needle valves but have been unable to remove the valve seats from both sides and the spool valve. I was told there can be substantial resistance by the o-rings but am unwilling to apply significant force which might damage the assembly.

Could you give me some direction on whether the above described process and diagnosis is correct. Also if it is, how do I get the seats and spool valve out without damage. I presume I should change the o-rings if it does come out but how much force is enough to get it out. Any advice would be appreciated. THANKS

MARK QUINN

DAYTONA BEACH, FLORIDA