Hello all. Sorry for the slow response. I've had stuff keeping me busy.
I'll begin with a text writeup then I'll post pictures. I do have some videos that I have put on YouTube. Links at the very bottom.
OK, first, my experience may be unique. However, because I can't be sure what caused the problem and the ones I bought were from Dean's store, I didn't want a repeat. I am not suggesting that the parts are faulty or sub-par. I just don't want to do this again in a few years.
Second, I searched high and low online to see if there were any off-the-shelf replacements but my experience was that if I found the right length, the ID or OD didn't match. Or if the OD was correct, the ID and/or length weren't compatible, etc.
I watched a number of videos on YouTube on creating homemade polyurethane bushings but most of them were more for what goes in the rear eye of the leaf spring. I figured I could adapt the two to come up with a solution.
My bushings had the rubber literally run out of them in a sticky goo. It took a while to figure out where it was coming from. At first I assumed it was some cavity wax that was melting in the hot midwest sun but the residue on the floor wouldn't harden like wax. It would "dry" to a consistency of used gum. I could peel it off my shop floor pretty easily with a putty knife.
Because there was no rubber to speak of between the inner and outer metal cylinders, it was fairly easy to clean them off to prep them for the replacement. I was able to use brake cleaner as the primary solvent and that made me wonder if the rubber didn't get cured fully because I don't think that brake cleaner would dissolve a hardened rubber. I may be wrong.
I boogered up my "sleeves" a little bit trying to get them out without removing the spring but I ended up just doing the right thing and pressing them out properly. Nothing so bad as to make them unusable. I smoothed out the rough spots then "scuffed" up the outside of the inner cylinder and the inside of the outer cylinder (where the poly would be poured).
I needed a way to hold the parts so I designed in CAD a stand that would do two things: One, hold the two cylinders concentric to one another and, Two, hold the inner cylinder below the upper cylinder since it's longer. I took the difference of the two lengths and divided by two to give me the proper offset. I also lined the bottom with some simple plastic wrap to ensure that the poly didn't stick to my 3D printed parts. Not that I needed to save them, I just didn't want the hassle of trying to peel them off. The plastic was an easy thing to remove.
Based on one video, I bought a Smooth-On trial set of Poly from Douglas and Sturgess (PMC-770 or Shore hardness 70). It cost $43.75 plus $20.00 shipping. I didn't find any store that offered the poly kits that didn't have about a $20 shipping fee (if you find one that doesn't, don't tell me). The directions were clear and straightforward. 2 parts A, one part B, mix well.
Here's a link:
https://douglasandsturgess.com/products ... 88ea&_ss=r
I didn't want the poly to run into the inner cylinder so I just plugged it with a wad of paper towel. It actually came in handy because I was then able to pour over that plug and the poly would run into the gap. It's a very small gap and the time to fill was quite long.
I also borrowed a vacuum chamber from a friend to de-gas the poly after mixing. This meant more time for the poly to sit before pouring. That created some minor inconveniences. For example, the poly tends to set faster in a higher temperature setting. My shop is not cool in the summer. I thought I had started early enough in the morning but it was apparent that my prep time took longer than I anticipated and by the time I got the poly mixed, the temperatures were nearing the mid 80s. I would definitely suggest doing this in a cool environment.
Once I was satisfied that the poly was degassed enough, I began my pour. I used paper cups because I could bend the rim into a spout. That worked great for the first bushing. However, by the time I got to the second bushing, it was beginning to thicken. It was the consistency of cool honey. It still poured but the final 0.1" or so got kind of rough. I poked some down in with my stir stick (a plastic knife) just to be sure it was near the top and I was satisfied it was fine.
After it sat (16 hours is the recommended time), I then put them in my oven at 170 degrees F for 4 hours. The recommended temperature is 150 but my oven doesn't go that low. According to the instructions the poly can be baked up to 8 hours. It states it "improves the performance" or something to that effect. I thought it may have been good enough as-is but I baked it anyway. Some on YouTube say that it will stink when baking but I didn't notice any real smell.
I've had them in the car since Saturday so that's not very much time to have any real testing time but I can say that they sure feel better than the ones without any rubber.
Here are my pictures.
This is what I was seeing on the shop floor. It's sticky so dust sticks to it quite easily:
Screenshot 2023-09-06 at 5.40.56 PM.png
Here is a picture of one of the bushings on the car. The drip is pretty clear but because I didn't suspect it coming from there it took me a while to figure it out:
Bushing.jpg
This is my setup prior to pouring:
IMG_2212.jpeg
This is the vacuum chamber I borrowed:
IMG_2214.jpeg
The first bushing after the pour:
71537914296__C7D937EF-8844-4042-8A3A-495B4EA7BEEE.jpeg
The second bushing:
71537915080__F950697E-BCC4-4BC1-A313-185498D5E8C9.jpeg
Both bushings with the offset for the inner cylinder visible:
IMG_2229.jpeg
After baking (no real difference seen or noted):
71548542631__B76F799A-7BC7-4744-834F-565370F629A4.jpeg
Installed in the leaf eye. There is still a bit of old rubber on the eye but I didn't bother to clean it off.
IMG_2255.jpeg
Videos:
https://youtu.be/4ZjRLuzY30Q?si=uMdpGW9T3r4EPX-s
https://youtu.be/YU_ON0S5OCg?si=cjC03ePMy5eZf5SB