Control arm bushing tech(general operation questions)
12-05-10, 09:58 AM
#1
Control arm bushing tech(general operation questions)
So looking at the front LCA as I am replacing the bushings, I have a couple questions. First of all, the bushings on the front LCA are bonded to the inner sleeves as well as to the LCA bore. How does the arm articulate, unless it relies on either:
A: The inner sleeve rotating on the bolt, or:
B: The rubber twisting inside of the arm bore, but not actually spinning against the arm bore or inner pin...
I guess B would explain why the rear bushing on the arms were torn, since the rear bushing has smaller attachment points between the inner sleeve and arm bore.
At any rate, when I replace the bushings with the poly ones from Prothane, it appears that the function changes slightly on the bushings.
The prothane bushings seem to rely on the bushing actually slipping in relation to the inner sleeves, since the poly wont give like the rubber, allowing for arm movement.
I can tell from the ridged ends on the rear, steel inner sleeve that it is meant to be clamped once installed and remain stationary. I assume the front is designed the same way? Though it is not ridged like the rear one to prevent movement?
Does anyone follow me here? I am just trying to verify what actually moves in regards to stock bushings, and the prothanes.
TIA for any insight.
A: The inner sleeve rotating on the bolt, or:
B: The rubber twisting inside of the arm bore, but not actually spinning against the arm bore or inner pin...
I guess B would explain why the rear bushing on the arms were torn, since the rear bushing has smaller attachment points between the inner sleeve and arm bore.
At any rate, when I replace the bushings with the poly ones from Prothane, it appears that the function changes slightly on the bushings.
The prothane bushings seem to rely on the bushing actually slipping in relation to the inner sleeves, since the poly wont give like the rubber, allowing for arm movement.
I can tell from the ridged ends on the rear, steel inner sleeve that it is meant to be clamped once installed and remain stationary. I assume the front is designed the same way? Though it is not ridged like the rear one to prevent movement?
Does anyone follow me here? I am just trying to verify what actually moves in regards to stock bushings, and the prothanes.
TIA for any insight.
12-05-10, 04:14 PM
#2
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On the stock bushings, the rubber is bonded so it twists and flexes around the inner sleeve (one reason why they disintegrate over time, and also why they shouldn't be tightened when the suspension isn't in a normal position, ie. while drooped!). With the poly bushings, the bushing slips over the inner sleeve, which is why they need to be lubed periodically and why they can make noise sometimes.
12-08-10, 11:31 AM
#4
use lots of the grease provided and make your inner sleeve as clean as you can before you pop em in. I used a torch to melt off all the rubber bushings. messy, but very effective if you get the torch hot enough. then scrub off the remains and try and get the sleeve surface as smooth as possible, apply lots of grease and insert into poly bushing.
The cleaner the sleeve the easier it will slide into the bushing.
By the time you get to that part you will be really annoyed and tired, but don't skip the cleaning step, its important. I also had to sacrifice a swaybar endlink that refused to come off (Toyota thinks you can untorque this part with an allen key after 140k, while holding the outside bushing with a plier/wrench... ya right) its a 50% shot if yours will come off unless its been taken off once before so I recommend getting some new links beforehand, they are cheap and a good upgrade.
The cleaner the sleeve the easier it will slide into the bushing.
By the time you get to that part you will be really annoyed and tired, but don't skip the cleaning step, its important. I also had to sacrifice a swaybar endlink that refused to come off (Toyota thinks you can untorque this part with an allen key after 140k, while holding the outside bushing with a plier/wrench... ya right) its a 50% shot if yours will come off unless its been taken off once before so I recommend getting some new links beforehand, they are cheap and a good upgrade.
12-09-10, 05:28 AM
#5
Thanks Ali. Yeah, I hit the endlinks with the impact and they spun right off.
I was on hold waiting for a new inner sleeve to be made for the one that I killed with a drill getting it out. I have that now, so it all goes back together this weekend.
What a fun learning experience this was!
I got new shocks and did this all at once, so I should notice a huge difference once its all said and done.
I was on hold waiting for a new inner sleeve to be made for the one that I killed with a drill getting it out. I have that now, so it all goes back together this weekend.
What a fun learning experience this was!
I got new shocks and did this all at once, so I should notice a huge difference once its all said and done.
12-09-10, 08:55 AM
#6
nice, the impact didn't work for me.
Its a huge difference. In fact your alignment specs may change a bit from stock.
after the bushings I could not run the factory Caster, it was lower by a few degrees on both sides. The trick is to just set them equal to each other as close as you can get to factory. all it seems to affect is the steering wheel wanting to return to center after a turn. Its actually better for performance driving I hear.
Its a huge difference. In fact your alignment specs may change a bit from stock.
after the bushings I could not run the factory Caster, it was lower by a few degrees on both sides. The trick is to just set them equal to each other as close as you can get to factory. all it seems to affect is the steering wheel wanting to return to center after a turn. Its actually better for performance driving I hear.
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12-09-10, 10:43 AM
#8
are you doing the uppers as well? I only did the lowers, my poly uppers are still sitting in the box. maybe next year i'll have the time to install them as well. maybe thats why my caster is off but it seems like most people just do the lowers and call it a day.
12-09-10, 02:19 PM
#10
My brother told me not to install the uppers because it would become too stiff, but im starting to think thats why my car wanders on large bumps in the road sometimes. Im sure those bushings change some geometry. I would trade some more stiffness to get rid of the wandering, its almost as if the car just suddenly decides after a bump it wants to go hard left or hard right, makes you really hold on to the wheel sometimes. either that or my rack bushings are starting to go... either way im gonna install those uppers and see what happens.
Last edited by Ali SC3; 12-09-10 at 02:23 PM.
12-09-10, 02:44 PM
#11
If you haven't replaced the rack bushings yet, they are probably shot. What you describe is what my car did before rack bushings.
I am only doing LCAs for now BTW. I was also worried about the "too stiff" ride, but I also know that the current springs and struts are only going to be in until I can go coilovers. I cant afford coilovers right now, but the stock shocks were so gone it was pathetic, so I bought some Tokico blues to hold me over.
Anywho, I figured that if I do decide to do the uppers, I can do them later when I go coilover.
I am only doing LCAs for now BTW. I was also worried about the "too stiff" ride, but I also know that the current springs and struts are only going to be in until I can go coilovers. I cant afford coilovers right now, but the stock shocks were so gone it was pathetic, so I bought some Tokico blues to hold me over.
Anywho, I figured that if I do decide to do the uppers, I can do them later when I go coilover.
12-12-10, 01:03 AM
#13
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I replaced my LCA bushings at about 120k, and it seemed to make a good difference. At 160k, the front end was showing some serious slop. Poly steering rack bushings made a huge difference. Ball joints were also bad so a set of Supra LCAs went on and it is driving better than it has in ages.
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