Looking at that one, I'm going with 'if he hadn't bent over the folded section that gives it strength, he would habve been fine.'
Looks like he might have landed on a log.
I'm confused. What do poly bushings have anything to do with the fact that that guy blew out a crap strut mount in a couple weeks? His car's probably low and stiff and the strut mounts around these days are garbage hence why the early rebuildable sets are expensive. The only real solution to the problem is rebuilding and installing the early mounts or $340 -
http://www.usrallyteam.com/index.php?main_page=product_info&cPath=76_205_211&products_id=1154Poly everything! including motor mounts! just not the transmission mount
look at the crack in the control arm at the weld..... top side crack.. arm bent... if i did not have 2... one side broke... watched other side for mext 8 mo till it cracked in same place... that guy #3 arm... and ive run non poly stuff for 100+ thousand miles.. im taliking under 20k...
p.s. guy has no clue the poly is what did the damage... i just know what did... as i watched side #2 crack like that.. new arm... vs broken one whee i wondered if they heated uit up to remove old to put poly in... till i watched rust free new arm crack same way...
the issue is the poly does not give... you hit pot holes so on it forces the control arm back at driver.. it cracks the arm from this pretty quick... i had all kinds of poortex tools tell me crap parts so on.. no way poly does that... there.. #3...
his new noise is the poly binding in the frame horn.. he did not lube it up.. but i bet if he looks close at those welds.. he may be desturbed... the car i broke the arms on, my 81 coupe.. finally ate the floor 4 mo ago where the arms mount... but a 500$ rot box that lasted me 6 winters = win... let me down 2x.. dropped valve.. why i had 500 in it.. 300 to fix that... and the lower arm, brown stripe in my shorts, that was almpost 5 years ago..
if you got poly.. watch that area.. top cracks, bottom does not... which to me says it trys to flex when moving down... but there is no load that way... mine was on bilstines and h and r springs... so not dumped... and on sub 40*f days poly makes bad noises when you hit bumps...
On the left in the pic you can see most of the problem. The stock insert looks like this...
the control arm has a radius in the front but not in the rear. It looks like a horn in the control arm see above. The stock front bushing has the rubber to fill the space and is softer. The poly has no radius, it is just empty space. The empty space allows the control arm to rock and slam back and forth...with leverage from the rear part of the control arm being in poly holding that end solid. I worked with my buddy Troy on this as he was having similar issues. If you take a copper tube the same size as the inner part of the control arm and weld that void shut, then ream it to fit and face it off so it is exactly the same length as it was with the radius life is good. Troy has a 12.8 second 1/4 mile rabbit...it is a 1.8 8v with a cross flow head, turbo, and most days nitrous. He goes through 2-3 020 transmissions per year drag racing, it is not a calm ride or trailer queen. He drives it at least 5,000 miles in the summer. Since we did this mod a couple years ago he hasn't had a control arm failure, used to go through them at least once per season. To make it worse on the control arm we seam welded it at the same time, so all the vibration and torque is multiplied in the stiffness of the welds and the poly mounts.
I think you are right Chris, but it is because the poly is not the correct shape for the arm, not just because it is hard.
On the left in the pic you can see most of the problem. The stock insert looks like this...
the control arm has a radius in the front but not in the rear. It looks like a horn in the control arm see above. The stock front bushing has the rubber to fill the space and is softer. The poly has no radius, it is just empty space. The empty space allows the control arm to rock and slam back and forth...with leverage from the rear part of the control arm being in poly holding that end solid. I worked with my buddy Troy on this as he was having similar issues. If you take a copper tube the same size as the inner part of the control arm and weld that void shut, then ream it to fit and face it off so it is exactly the same length as it was with the radius life is good. Troy has a 12.8 second 1/4 mile rabbit...it is a 1.8 8v with a cross flow head, turbo, and most days nitrous. He goes through 2-3 020 transmissions per year drag racing, it is not a calm ride or trailer queen. He drives it at least 5,000 miles in the summer. Since we did this mod a couple years ago he hasn't had a control arm failure, used to go through them at least once per season. To make it worse on the control arm we seam welded it at the same time, so all the vibration and torque is multiplied in the stiffness of the welds and the poly mounts.
I think you are right Chris, but it is because the poly is not the correct shape for the arm, not just because it is hard.
Does this same issue exist with the mk2 control arms?
i think poly in that location is the key to failure... never tried.. but why would you if it breaks a easy to change mk1 vs the pain in arss mk2+... honestly tt solid rear hocky puck bushings is all you need on a mk2... a 4 pt subframe on a mk1 is all that sneeded..