Okay, here we go;
This is my old/original OPDA. I intent to do a similar mod to my new one soon implementing some upgrades that came up while building this.
The first thing to do of course is to disassemble the unit. The stock bushing needs to be cut down. After figuring how much I needed to remove I cut a sleeve to the proper width and slipped it on the bushing as a guide and used a ball cutter on a die grinder and had at it. I used a flat abrasive wheel in my dremel to finish it.
This procedure must be done with care as it determines the end play of the shaft. Cut too much and you will have issues.
The pic shows the sleeve used to act as a guide for cutting the bushing and the seal holder that fits over the bushing.
The bushing is a little over ¾” in diameter so I had to grind/machine a little out of the 1” OD by ¾” ID DOM so it’d fit over the shaft. I left the top portion alone as the seal I used is ¾” OD.
Next I needed to make a support and washer for the shaft trust washer to ride on.
I brazed the washer to the DOM but I’d guess it could be welded and I bet even JB Weld would work. The DOM sleeve is just to keep the washer from floating free and rubbing the shaft.
The shaft was grooved for oil to run through. Not sure if this step was needed or not but I wanted to make sure the stock OPDA seal below the top bushing gets defeated. I also don’t want a bunch of oil pressure in the unit. Yes, the grooves are ugly, but very functional.
I used some silicon on the bushing holder to both seal it and keep it from spinning.
I also used silicone on the seal to glue it in.
NOTE: On my next version I will use a larger seal with a double lip and rubber housing.
I also used a little silicon on the washer/support assemble to keep it from spinning.
Greased up everything.
Here’s where the oil goes into the unit. I had done the fog mod to this unit so I just plugged the other side. I also ran a 1/16” drill through those 3 oil passage holes at the bottom bushing.
Here is how I plumbed the oil feed at the oil gauge sender unit.
I filled a nipple with solder and drilled a small hole, 1/32” or so, to act as a flow limiter.
This is the tee I used at the oil gauge sender port. The flow limiter only goes to the OPDA.
Here’s what it looks like with the engine running. I really like the extra oil at the gear.
(Yes, this can only be done if you have another OPDA in the Jeep!)
On a cold engine it flowed about 4 ounces in 4 minutes.
So I guess I'll install this and see what gives. I am guessing the added oil to the gear can't hurt and getting oil to the top bushing has to be a huge improvement. I my next unit I will use larger OD DOM to get a 1" seal in there.
NOTE: The seal I used is 1/2" ID X 3/4" OD. The shaft is about .5300 and I could fine zero seals that size. By using a 1" OD seal I have a few more options.