I rebuilt my lower helm pump today & thought I would share some information & pictures so if any of you are looking at this job, I rebuilt the upper in 2010. There are 3 lines coming into the rear of the pump, 1st mark these so they are returned to their proper port & then take a picture with your phone. Place a folded oil pad under these fittings & then loosen & remove the line fitting, then remove the center cover on the wheel, remove the nut & pull the wheel off the shaft, make sure to remove the woodruff key, remove the 4 screws that retain the pump & get it out where you can work on it. This is when you decide if your going to rebuild it yourself or send it out to a shop that does these type of pump. If you decide to do it yourself the 1st step is to mark the block held to the rear of the helm with 4 bolts so you can replace it exactly as it is, then remove the 4 bolts take a small rubber mallet & tap the shaft until the block is removed from the housing, there will be a half cup or so of oil in the housing so be ready for that, I used a oil pad. Once you have all the separate parts out clean them up, you want everything clean & lint free, I used break cleaner. Here are some pictures of how I put it all back together.
This is all the parts after being cleaned up.
This is the individual pistons back in the housing with the springs under them, pay attention to the machined ramps on the pistons that they are all in the position to align with the balls in the plastic holder.
The block has 3 orings & the shaft is replaced in the pistons housing. The main housing has a wiper & one of 2 types of seals, both are in the kit. I used a deep well socket that went thru the hole in the shaft but would contact the plastic bushing (the piece that has the ball bearings in it that push the pistons in to pump oil) and knocked the bushing out. Then I removed the seal & wiper, cleaned the housing up & installed the new ones. Now replace the bushing the thrust bearing assembly then the piston assembly with the shaft in it, don't forget the key in the shaft that holds it to the pistons housing. Then replace the rear block take turns tightening the 4 bolts evenly. When your finished reinstall in the dash. Then bleed the system follow the instructions that come with the parts, there is also a blowup of the unit with the instructions. I found the best price at Amazon $32.15 shipped.
Also got the radar display mounted at the lower helm.