Update...There were a couple of aftermarket kits to convert the DH3 to coil spring, but some would simply use the springs designed for an early Marz Bomber. Simply remove the top air-valve assembly (TAVA), insert spring, and re-install TAVA. This "ghetto" mod (we use to call it "shade tree") left the fork with no "sag" or pre-load adjustment. But, it was considered more cost effective than replacing seals if there was an air leak. Many also believed that the addition of coil springs to the DH3 was a definite improvement in a sus fork already considered to be ahead of its time. However, the fix canceled out one of the forks most attractive features; its lightweight. I had one well-respected fork mechanic tell me that the circlip that retains the top air-valve assembly would not withstand the forces exerted by the coil spring, and yet 20 years later the mod on this fork has yet to fail. I will say that pushing the TAVA far enough into the stanchion to remove the circlip seems almost impossible. Removal of TAVA and full compression of the fork is required to achieve the correct oil level (and to drain the existing oil). I fashioned a "dip stick" from a coat hanger, and then guesstimated the distance from the top of the stanchion to the correct oil level, allowing for the 77mm of travel of the fully extended fork. Adding 77mm to 33mm, I came up 110mm as the distance from the top of the stanchion to the level of the oil in a full extended DH3. I made marks on my dipstick at "0" and "110", then I added oil by removing the valve stem and attaching a rubber tube between the Schrader valve and a plastic syringe (oil injection?). When the oil level in each stanchion reached the 110mm mark, I declared victory. I replaced the valve cores with new ones, in the hopes that a defective valve core was the cause of the air leaks. But, that was not to be the case, as neither stachion would maintain 40psi for more than a moment before leaking back down to 5psi. With everything back together, I took the Parkpre for a ride on my local river-bottom single-track. My fork travel indicator zip tie hit a high of 34mm, so no bottoming-out. (This is probably more reflective of my cautious riding style). Rebound was vastly improved, so the oil dampening was working. No oil leaks after about 60min riding. While an obscure topic, I hope this is helpful to someone else.
