Re: POLY LOWER CONTROL ARM BUSHINGS?
[Re: frank]
#13769
12/21/04 04:51 PM
12/21/04 04:51 PM
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Joined: Jan 2003
Posts: 9,336 central New Jersey
dbdartman
master
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master
Joined: Jan 2003
Posts: 9,336
central New Jersey
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SOME people claim the bushing comes out of the shell easily, causing the alignment to change. I've been running poly lower bushings since the mid 80's myself & have NEVER had one little bit of trouble with them in 4 different cars. As a matter of fact, if you understand the concept: "for every action there's an opposite & equal reaction" then look at how the front end is layed out, you'll see that it's all but impossible for the bushing pull out of the shells.
Now, let's hear the naysayers scream about how bad poly bushings are... (they wear out too soon, they transmit too much force through then hurting the chassis, they transmit too much vibration making the ride bad, they easily come apart when used in the lower control arms, etc., etc., etc....)
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Re: POLY LOWER CONTROL ARM BUSHINGS?
[Re: JohnRR]
#13772
12/21/04 07:58 PM
12/21/04 07:58 PM
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Joined: Jan 2003
Posts: 16,828 Between Houston & Galveston TX
SattyNoCar
Smarter than no class Flappergass by a mile
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Smarter than no class Flappergass by a mile
Joined: Jan 2003
Posts: 16,828
Between Houston & Galveston TX
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With remarks like these, I'm not even gonna post about the problems I had.
John
The dream is dead, long live the dream.......😥
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Re: POLY LOWER CONTROL ARM BUSHINGS?
[Re: frank]
#13779
12/21/04 11:59 PM
12/21/04 11:59 PM
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Joined: Feb 2003
Posts: 4,204 Fort Worth, TX
Clair_Davis
master
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master
Joined: Feb 2003
Posts: 4,204
Fort Worth, TX
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To me, there are 2 advantages of the rubber LCA bushings over any polyurethane LCA bushing. First, they increase spring rate since the rubber twists in the bushing shells. I think E-berg popped off something like 20 in-lbs extra spring rate over the sliding poly bushings. If you're upgrading t-bars, that may not be a big deal, but if you aren't, the reduced effective spring rate may be noticible. Second, the rubber bushings are bonded to the shells, which are press-fit to the LCA pivot stud. That locks the LCA in place, and takes care of much of the production tolerances you may or may not find in the suspension. Poly bushings do not do this, and are designed to slide. If all of your suspension is set up right, you won't have a problem.
IMHO, if you're just going to be driving the car, put rubber LCA bushings in. If you're going to be pounding on the car, or driving in a more sporting way, use poly. Be prepared for squeaks, though, especially when it's cold out. After you've driven a bit, the squeaks tend to go away. And if you DO use poly, measure how your strut rods relate to the K-member. Until I sorted that out, I had a helluva time getting a decent alignment in my car. YMMV...
Clair (no rubber bushings anywhere on the Valiant)
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Re: POLY LOWER CONTROL ARM BUSHINGS?
[Re: SattyNoCar]
#13781
12/22/04 05:02 PM
12/22/04 05:02 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
With remarks like these, I'm not even gonna post about the problems I had.
Oh, come on and do it... You and I both should have kept a word file of the reasons why the poly is not good for the lower control arm unless some precautionary steps are made.
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Re: POLY LOWER CONTROL ARM BUSHINGS?
#13782
12/22/04 06:56 PM
12/22/04 06:56 PM
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Joined: Jan 2003
Posts: 16,828 Between Houston & Galveston TX
SattyNoCar
Smarter than no class Flappergass by a mile
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Smarter than no class Flappergass by a mile
Joined: Jan 2003
Posts: 16,828
Between Houston & Galveston TX
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Yeah, I need a wordfile I can just link to everytime this question comes up. I had poly LCA bushings in my wagon for a short period of time. The ride was down right SCARY! Any kind of bump or dip in the road, I never knew which way the car was gonna go. The bushings were NOT holding the LCA in place, making the car feel as if I had bald bias-ply tires on the front (darting about, following ruts, etc) The problem always happened when the suspension was unloaded, ie; the inside wheel when making a turn, the rebound from hitting a bump, etc, etc. On smooth, fresh pavement, all was great. Oh, and I was getting a real bad CLUNK sound during this too. Putting the wagon up on a lift (with the suspension just hanging), I WAS able to physically move the LCA back at the bushing using a pry bar. Not a lot, if I had to guess about an 1/8th of an inch or so, but isn't ANY fore-aft movement bad? Doing nothing to the front end except swapping out the lower bushings back to rubber, eliminated ALL the problems I was having. Now, let me take my best guess as to why things were moving on me as a lot of people seem to not have any problems. '73-up B-bodies have an 'isolated' crossmember for the T-bar mounts. This crossmember is mounted with rubber bushings. It can't move a lot, but it CAN move. I think when the LCA was moving due to the poly bushing, the crossmember was moving some too, exaggerating what was going on. I didn't think to look while the car was on the lift, but its the only explaination I can think of as to why things were moving so much. If you use them and have no problems, great! The point of my posting is only to show that there is a chance of having a problem with the poly LCA bushing, its not meant as a bash on poly bushings in general.
John
The dream is dead, long live the dream.......😥
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Re: POLY LOWER CONTROL ARM BUSHINGS?
[Re: SattyNoCar]
#13783
12/22/04 08:48 PM
12/22/04 08:48 PM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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Satilite73, Listen here Buster, I have the Polys and ,,, Just Kidding. thanks for posting. I have been considering the Polys myself so I like to see everybodys experience. I definatly appreciated yours. I may just stick with the rubbers. I have the 73 A Body Kmember so maybe the polys wouldent be a problem. But your problem with the LCA sliding back and forth was not good and down right dangerous. I dont know what would cause that. I would think the polys would keep the LCA more perfectly in a stable in its travel. But I am not at all familer with the way either of those bushings go together. I am going to learn though because I just peeled what was left of my 1973 factory rubber LCA bushings out by hand. And there wasnt much bushing left. I pretty much made my last pass of the year with no LCA bushings at all. Again thanks for your input. mike
73 Sport 440, 509 cam w/Eddys 3.91 and 28.1"/27.3 tire. Et. 60 ft. 1.435, 1/8th. 6.61 @ 101.80 mph. 1/4. 10.472 / 127.78 mph. 2950# race/with me,and pump gas.
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Re: POLY LOWER CONTROL ARM BUSHINGS?
[Re: Sport440]
#13784
12/22/04 10:54 PM
12/22/04 10:54 PM
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Joined: Jan 2003
Posts: 4,323 NY NY
340duster340
master
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master
Joined: Jan 2003
Posts: 4,323
NY NY
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my 30k mile duster still has the original rubber lca bushings and they are fine, so thats what i am putting in when i do a v8 swap and rebuild the front end. USE MOOG problem solver series bushings, they are the best if you decide to keep the rubber style.
in my opinion you really only need the poly if you agressively race the car.
1966 Dart GT
...down to only 1 mopar for the first time in 15 years!
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Re: POLY LOWER CONTROL ARM BUSHINGS?
[Re: Sport440]
#13786
12/22/04 11:28 PM
12/22/04 11:28 PM
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Joined: Feb 2003
Posts: 4,204 Fort Worth, TX
Clair_Davis
master
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master
Joined: Feb 2003
Posts: 4,204
Fort Worth, TX
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Quote:
...I have the 73 A Body Kmember so maybe the polys wouldent be a problem. But your problem with the LCA sliding back and forth was not good and down right dangerous. I dont know what would cause that. I would think the polys would keep the LCA more perfectly in a stable in its travel... mike
Mike, What makes the poly lowers funky is they won't cover any other problems in the suspension like the rubber bushings will. The problem I had was not with the poly bushings themselves, but with the MP poly STRUT ROD BUSHINGS. They appear to have been cast from molds for the original rubber strut rod bushings. Cool, right? Exactly the same as OE... *Except* that the poly SRB's don't compress much at all, and the rubber ones DO. What happened was two things. First, when I torqued down the nut for the strut rod bushing (this on a 73+ K-member, too), the bushings didn't compress as far as the would have if they were rubber. The second thing that happened was that the steel sleeve that came with the bushings was about 1/4" longer than it should have been, so the nut bottomed on the sleeve before it even finished compressing the bushing. So, between these two issues, the strut rod was effectively longer than it should have been. This pushes the LCA towards the rear of the car, and since the poly bushing can't resist the push, it slides back on the LCA stud. Variable suspension geometry... The fix for me was to measure how long I needed the strut rod to be when everything was torqued, and then to trim the REAR strut rod bushing half by whatever amount that was. Also, trim down the bushing sleeve so the bushing would compress properly. With those two problems fixed, my Valiant drives like a dream. A squeaky dream, but a dream none the less. The attached photo shows the rear bushing after being trimmed, and the sleeve with about 1/4" hacked off with the wheel o' death. So, you can use the poly lowers and they WILL work great. You just have to invest some more time and thought in the system than you could get away with using rubber bushings.
Clair
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