Front LCA Rear bush by Bilstein/Febi

[oragex]

I've added as well small pieces of rubber with glue at the front bush, the steering gets more precise. These front bushes are more durables that the rear vertical ones but still get soft with time

[mrbrian200]

Little pieces of rubber- I tried that but decided it was taking too long and probably wouldn't provide the definitive answer "This bush is responsible for issues yes/no?" I was looking for. The rubber bits were ending up too small and difficult to squeeze in uniformly.

Note to anyone who might come across this and try something similar: I'd be carful not to use general 'adhesive caulks', they tend cure harder and aren't very stretchy (think liquid nails). You don't want to use anything that might 'lock' or resist the LCA's movement against normal suspension travel. I used the roof and flashing poly based 'sealant' you'd use as an alternative to tar around things like roof vents and rain ducts. It feels and acts more like a medium-soft rubber after it's cured. I let the car sit for 3 days before driving it.

I'm still a bit hesitant to go with the aftermarket poly bushes. They're solid yes, but with a durometer hardness around 70 and up I'm not sure about $150 and the trouble of pressing them in to possibly discover I don't like that either (noise/vibration). I drive primarily on some pretty crappy rural roads: chip seal over gravel patched but never milled, or asphalt over ancient broken concrete. AKA Indiana anywhere outside Indianapolis. OE-OEM style bushes reinforced by some means similar to this may well be the better balance. Looking at the design, even new bushes would exhibit the 'behavior'. Just less/not as noticeable.

[mrbrian200]

Ok, my 5 month impression with regard to filling the voids in the front LCA bush with this Loctite PL roof and flashing sealant: This stuff just might last awhile. There were a few days this winter when the air temperature hovered around -20/-25F, I drove the car on those days. The stuff doesn't shows any sign of tearing or stress. It was cold outside when I did this back in November, it's tricky to get the caulk gun in there with the LCA on vehicle, I started getting cold and didn't get the bush on the RH side filled in quite as well as the left that I did first. And I can tell the difference rolling over bumpy pavement or merging across bad expansion joints/large gaps in pavement. The left side glides over pavement imperfections, feels solid as a rock and tracks like it's on rails whereas the right side is more apt to tramline a little with a bit of squirrely/harsh feel. I think the OE design (allowing for more toe in/out deflection over bumps and under torque) thinking it improves grip or ride quality may actually have the opposite real world effect on 'bad poorly maintained pavement'. I 1000% prefer the handling/ride quality characteristics from what I have effectively fabricated as the equivalent of a 'solid rubber bush' up there which more approximates the bush design used on the P80s.
It would be easier/cleaner looking end result to do this with the LCA off the car (such as before installing a new LCA) and let it sit/cure for a good week before installing. It's nice weather today I'm going to get the RH side bush filled in all the way like I did on the left, however I only have the luxury of letting the car sit for about 36-48 hours before needing to drive it.

[mrbrian200]

Ah Ha: while touching up/filling in the RH side that I didn't get too well on the first try, I see now that this stuff doesn't stay bonded to the rubber inside the bush. It ends up just floating in there - I could pull/push it out with a rod if I wanted to. As it's squeezed in as a dense liquid it forms to shape of the air space then stays put to effectively constrain the side to side play in the bush design. Similar concept to the polyurethane subframe bush inserts if those had to 'twist'. Seeing this I might entertain the idea of using a somewhat harder (durometer) material like the loctite poly construction adhesive rather than the roof sealant with is much softer. The softer stuff might be just right with respect to NVR however. The aftermarket poly bushes for these LCAs are all overly stiff durometers in my opinion which is why I am resisting to jump on that wagon. And I really don't like the idea of needing to tear the LCA off the car every year or two to keep poly bushes greased the way the need to be.