Quote:
Originally Posted by jcslocum
What did you do to replace the bushing?? I would like to improve this spot too.
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This is a good question, and kind of hard for me to explain, but I will try. The bronze bushing was at least somewhat malleable, having been formed into a "c"-shape, apparently during manufacturing, from flat stock. It also had one end flattened out into a thrust surface. The way it was undersized (by design or worn, who knows), it was both too large in its inner diameter, and too thin on the thrust surface.
So I tried fixing both of those issues, I think with success. First, I pressed out the bronze bushing using a socket that fit fairly tightly. Tapped it out with a hammer. Then, I basically axially compressed the bushing, carefully, in the vice. This did I think 2 things: 1. It rolled into a "mushroom" shape the thrust surface, making more thickness than it needed to be. 2. It also seemed to have compressed the walls, thereby thickening them.
After I reinstalled the "squashed" bushing (by basically pressing it back into the bore with the vice), initially the pivot shaft was a very tight fit - so tight that I think I had to press it in using the vice also - and I found when doing so, it even shaved off some bronze material on the ID near the thrust bearing end! Eventually after working it for a while, and installing it backwards (it seems to have a slight bit of taper, so this helped) the ID of the bushing wore into what I considered near-ideal tolerances. To fine-tune the thrust surface thickness, I got it very close just by using the vice to press the mushroomed thrust surface flatter (with the pivot shaft while pressing with the vice).
Eventually I managed getting the e-clip in, but was tight. A bit more thrust surface vice-press flattening, I could get the e-clip on and it was only a little bit tight. At that point, I just worked it rotationally to try to break the thrust surface in, by wearing them without any lubrication, to perfection. (The mating pieces were relatively hard stainless steel, so I wasn't worried too much about them wearing down.). Noticing where the bright spots were where the thrust surface was making contact, I did a bit of sanding (400 grit initially) on the bright spots to help the thrust surface to develop the desired flatness and dimension. I believe this operation is called 'hand scraping' a bearing. Eventually I got it such that, although gravity wouldn't move the bellcrank by itself, a very (I thought acceptably) small amount of rotational torque would, and I called it good at this point. At some point I also added grease, of course. I expect it may wear in a bit further and the small amount of friction that is there may decrease or perhaps eventually even completely go away. Luckily, it's not too much friction to impede the shifting process - it works great and the spring that returns the shift knob to the center gate easily enough overcoming all friction during 2-3 and 5-4 shift motions. (The 2-3 gate movement, if it doesn't work correctly, can easily cause a very expensive "money 2-1 shift"! So don't rush getting enough friction out of this critical system before calling it good. But at the same time, don't rush to remove the friction too quickly or you can overshoot, and have the slop back in there that you wanted eliminated.
PS - attached picture shows the heat shield which the "contraption" is behind. Two 10mm nuts removes this heat shield, and you don't even need to jack up the car to do this job.
Another tip I've learned is to be careful when prying off the ballsockets! Lots of force is required (when dry at least - before getting some grease in there) and if using a pry tool, it's possible to scar up the ball studs if you're not careful. Don't let a metal pry tool touch the ballstuds. And if you scar up the bearing surfaces, sand or file them smooth before reassembling.