Replaced a failed polyurethane strut rod bushing today on my '73 Dart and took a videoclip of the suspension movements during a short drive around the garage. Mostly flat road which a few speedbumps halfway the clip.
At 17:22 video-time I'm doing a couple of firm braketests, but I was kinda amazed at the amount of bushing-compression still happening.
On observing your strut movement on typical braking with poly? bushings, Kinda makes one wonder what the big fuss is over adding 11/16" TR to reduce supposed TR deflection.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
The videoclip was made just after I had fabbed up some replacement strutrod bushings from leafspring bushings as one of the previous ones had bailed ship.
2-3 days ago I started noticing the car didn't feel quite right during braking. When I pulled in the garage and had a peek... I noticed the front pass.side strutrod bushing was all but gone except for a little ring around the strut.
Noticed the driversside front bushing was starting to tear from the center too.
Didn't have any new ones laying around so I fabbed new ones with my lathe from a pair of front polyurethane leafspring bushings.
The 'original' polyurethane bushings are a bit larger/beefier around the tapered part than the ones just made and seeing how much they still compress, I will probably machine some new ones out of a piece of 2.5" polyurethane roundbar I've got. Unless I can find/make some affordable articulating strutrods instead.
I wonder if the metal heim type links have a note-worthy advantage in performance vs the poly... poly could self-destruct? I know... the heim type are not advisable for the "street", but which lasts longer??? I'mn at a point in re-assembling my car now to make that final decision (have FF adjustables w/poly bshgs waiting for installation).
I'd only be looking at ~2000 miles max per year.
Last edited by Mopar Mitch; 08/21/1707:06 PM.
Mopar Mitch
"Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers!
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I'm thinking Heim-joints would need to be sealed from the elements to survive.
Perhaps something with a simple and cheap (stock'ish) greasable ball joint mounted/bolted into the front subframe crossmember could be fabbed up with a sleeve&lock nut on the balljoint and remaining strutrod. The ball in the joint can rotate so there would be no need for reverse threads I think.
I wonder if the metal heim type links have a note-worthy advantage in performance vs the poly... poly could self-destruct? I know... the heim type are not advisable for the "street", but which lasts longer??? I'mn at a point in re-assembling my car now to make that final decision (have FF adjustables w/poly bshgs waiting for installation).
I'd only be looking at ~2000 miles max per year.
Im pretty confident a std variety heim will not last longer. I can not really get a good look at the movement inside the K-frame there. And it seems loaded when jacked up. But I can see and feel that my heim UCA and heim tie rods are worn out.
I probably had 50K miles on my poly strut rods when I took them out. Still good.
I believe with any suspension movement, with this particular common mopar design, the LCA and the brake strut are on conflicting arcs, I suspect mopar felt that the "give" needed be in the strut, as it really only is stressed under braking, and toe out on both sides equally, is acceptable for a street car. A solid strut pivot joint would force the lca pivot to give or bind.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
Re: Front Suspension movements videoclip
[Re: BigBlockMopar]
#2357905 08/22/1712:12 AM08/22/1712:12 AM
If you call Hotchkis they offer a boot kit for the heims on different parts. Comes with a bunch of grease too to load up the boot. I install them on all the cars. Does a great job of keeping rocks and the elements out.
Going back to the video-clip; at 3:40 in the clip (17h20m50s videotime), I'm doing a few quick left/right/left/right steering movements.
Besides the light up&down play in the swaybar bushing, I'm also noticing some K-member flexing where the swaybar bushings are mounted to the K-member.
During the entire clip I do see some occassional overal movements but I think most are due to the vibrations and the refresh rate of the camera when it encounters some vibrations through its mounting. The camera was mounted to the fender strut.
(This K-member has not been reinforced, except for the steering box mounting pad.)
I'm thinking Heim-joints would need to be sealed from the elements to survive.
Perhaps something with a simple and cheap (stock'ish) greasable ball joint mounted/bolted into the front subframe crossmember could be fabbed up with a sleeve&lock nut on the balljoint and remaining strutrod. The ball in the joint can rotate so there would be no need for reverse threads I think.
Open up the hole in the k frame, weld a ball joint sleeve to the k frame, thread in an upper ball joint, shorten and thread the end of the strut rod, use a threaded sleeve between the strut and the ball joint. You now have a solidly mounted, fully articulated strut rod. Prepare for road noise.
I understand when one removes a 'soft-mount' from moving suspension parts and replace them for 'solid hardware' then roadnoise will be carried further into the body structure.
But will it be something like running with solid engine mounts, or much less and more like a slight noticable humming noise? All the time or just more when braking?
Maybe one way to check how much noise is really "inside" the strutrod during driving, it would be a fun idea to mount some kind of stethoscope on the strutrod and extended to the inside. But I'm sure someone already has first hand knowledge of these things.
No experience on solid mounts on a street car. The competition cars I've had them in, it does seem more like constant hum or drone along with a more solid "whack" instead of a thump when going of bumps and such. But we also had bronze bushings through out and not just in a single place, so every movement was amplified
Personal sensitivity to it will also be a factor. My hearing is shot, so there is a lot of noise I miss that others may not. I've even seen guys here on moparts complain that hemi sized torsion bars were too stiff, so we all have a personal baseline to work with.
Re: Front Suspension movements videoclip
[Re: BigBlockMopar]
#2380399 10/02/1702:01 AM10/02/1702:01 AM
Just drill a hole to accommodate it. The hole wont affect strength of the K and most people who use something like this does not care about originality...
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Re: Front Suspension movements videoclip
[Re: BigBlockMopar]
#2381573 10/04/1701:22 AM10/04/1701:22 AM