Well here I am almost two years after the Daizen installation I described in this how-to, and I just took them out and replaced them with Roca OEM type rubber bushings.
Why the 180? The car developed an extremely annoying clunk about a year after the Daizen installation. I looked everywhere for the clunk, except of course the caster arm, because I knew
that the Daizen bushing was new
. Well, after a year of that, and about a dozen attempts to find the source, I took it to a local mechanic to see what the problem was.
Right away he said that he did not like the Daizen bushing. He spent almost two days looking at every nut and bolt, and finally asked me how I would feel about swapping out the caster arm to see if that would fix it. I agreed, he swapped in an OEM caster arm, and the clunk was gone. I could not believe it.
I was going to buy new OEM caster arms, which are now as low as $111 each, but I came across the Roca bushings, which are about $69 for the one caster arm and one lower control arm bushing set. I bought two (enough to do both sides), and today tackled the project.
First I took out the old Daizen bushings (I had to cut them in half, there was no getting them out intact):
It was VERY hard getting the Roca bushings in. I had the 12 ton press maxed out, and it barely pushed the bushings all the way in. But they did go in finally:
My clunk is completely gone, I feel like I am driving a new car. Unbelievable improvement in ride quality and smoothness.
The mechanic and I talked at length as to what could have caused this. I believe that the problem is that the Daizen's inner sleeve has too much slop around the stud, and may potentially be moving around and clunking. The Daizen inner sleeve is 0.806", larger than the OEM sleeve which is 0.751". The stud is 0.735", so the 0.803" Daizen sleeve is very loose on the stud.
Another part of the problem may be the way Daizens are mounted compared to the OEM mounting. In the OEM bushing, the rubber part is kept away from the body and the brace, and the inner sleeve is tightly clamped by the nut:
With the Daizen bushing, there is load sharing between the poly and the inner sleeve, which I suspect is what allows the inner sleeve to shift and clunk. I don't know this for sure, but I did notice that the area where the sleeve sits against the body did not look like the sleeve was tightly preloaded against the body, despite me torquing it to specs several times:
Anyway, I don't know if that was the problem with the Daizens, but the OEM bushing fixed my clunk. I was going to swap the lower control arm bushings too, but after getting one of the arms out I saw that the bushings are perfectly fine, so I put it all back together and had a beer instead