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PST Polygraphite pieces - fit and alignment?
https://slantsix.org/forum/viewtopic.php?t=6173		 Page 1 of 1
Author:  Thom [ Wed Jul 02, 2003 9:57 pm ]
Post subject:  PST Polygraphite pieces - fit and alignment?
:?: I am installing all new polygraphite bushings in the front end of a 71 Swinger (while upgrading to disks from a '76). UCA bushings went well. LCA and strut are causing concerns.

I had the LCA bushing pressed out (very tough) and lubed and inserted the new bushing. With the PST set, you only replace the poly portion itself and reuse the inner and outer shells. The problem is, when I try to install the LCA shaft, the shaft starts to spin before the nut is tight.

The new bushings on the strut rod are so much thicker than the originals that, 1) I can't tighten the strut rod nut enough to insert the roll pin that is supposed to prevent the nut from falling off and, 2) It looks like the strut is 'pushing' the LCA towards the rear of the car too far.

I need some enlightenment. Thanks.>Thom
Author:  '74 Sport [ Fri Jul 04, 2003 10:17 pm ]
Post subject: 
Thom,
Once you find out how to deal with your PST problems, please post the results here. I am about to make a front suspension swap on a Dart Sport, and I would like to know how you handle it.

Jerry
Author:  Brett K [ Sun Jul 06, 2003 11:22 am ]
Post subject: 
As far as the strut rod pushing the LCA back, it's possible you've got the strut rod bushing in backwards. As I recall their bushings are a non symetrical "improved" design. Putting it in backwards might give you some misalignment issues.
Author:  Thom [ Sun Jul 06, 2003 10:14 pm ]
Post subject: 
I've been doing a little digging and have learned a few new things but still could use some clarification on this process.

I checked the PST strut bushings and the bushings are symmetrical so you can't really get them in backwards. They are made up of two identical pieces of polygraphite that are installed with one on each side of the frame member.

Part of my issue may not even be a problem. This is where I need the help. The LCA shaft has (starting from the front of the car) a threaded section for the nut, a tapered shoulder that slides into the K-member, a flange, and then the round portion that slides into the LCA bushing. I have been trying to get the front of the shaft flange to ride solidly against the K-member AND to get the LCA bushing to slide all the way up against the back of the flange. I looked at another Dart yesterday (a'68 ) and saw that the flange on the shaft was, indeed, butted firmly against the K-member but that the forward edge of the LCA bushing was actually about 3/8" back from the flange. In other words, there was 3/8" of the shaft's 'bearing surface' exposed between the flange and the LCA bushing. If his set-up is normal, then I don't think I have a problem at all. Any thoughts from other Dart owners?
Author:  Brett K [ Mon Jul 07, 2003 2:00 am ]
Post subject: 
Grr, that's twice now I've heard of PST sending folks the stock style strut rod bushing. Pity they kepe onsending me the other one. :P
You're right about the visible shoulder on the LCA bolt with stock or rubber bushings. With the PST poly bushings, you'll see a shoulder of the PST bushing instead of the bolt and it'll look like it's 1/4-3/8" loose.
Author:  Dennis Weaver [ Wed Jul 09, 2003 10:59 pm ]
Post subject: 
The PST "polygraphite" stuff is crap, in my opinion. I installed it on my Duster years ago, and it was the one of the biggest mistakes I ever made. Unlike rubber, the polyurethane bushings need lubrication, There is no way to re-lube things once they are installed and they dry out in time. Get ready for "pop-city" when this happens, and also wear. The strut-rod bushings went away after almost no time at all. The ones I got shipped were the one-piece design and they literally got beat out of shape, then the strut-rod was free to move back and forth with a big bang each timeI stepped on the brakes (Oh, yeah, these "poly" bushings NEVER wear out - B.S.).

The other problem with installing hard durometer bushings on an older Chrysler car is that the upper control arm bushings will be forced to distort (won't very likely be on the same axis) when the front end alignment is set. This puts them in a bind. For a car with a single upper control arm shaft like a GM or an F-M-J Body, this is not an issue. On an A-body, for example, the bind condition will be a problem. If you look at the GOOD polyurethane bushings available for a lot of GM stuff, you will see Zerks fittings and grease channels designed in. Not so for the cheap PST crap or the like, unless there is something available I have not seen.

Stick with the rubber. Get the good, thick 2 piece improved design strut rod bushings. I MIGHT consider running a polyurethane bushing in the lower control arm spot, but only after figuring out a way to cut small channels in the bushing or outer shell to distribute grease, and drill and tap the control arm for a grease fitting. I have not attempted this yet myself.

"DW"
Author:  Dart270 [ Thu Jul 10, 2003 7:37 am ]
Post subject: 
The only thing I have Poly bushings on are my rear springs, and front sway bar. Everything else is rubber, and my car handles pretty durn good. Ask anyone who's ridden with me or gotten passed by me on a road course...

Note that the Green Brick guys from Mopar Action also use rubber bushings for the main suspension parts. Get the MOOG improved type strut rod bushings and problem solver UCA bushings.

Lou
Author:  Al T [ Thu Jul 10, 2003 1:20 pm ]
Post subject:  I'll second that
Lou gave me a "ride" thru the rolling hills of North Carolina in April. He cut hard left and my false teeth flew out the window right. The sign for the curve said 30 mph, he did 90! The sign said STOP, he hammered them on at the last minute . . . the seat belt left me with a permanent 24" waist.
Don't give Lou anymore poly!
Author:  Brett K [ Thu Jul 10, 2003 11:54 pm ]
Post subject: 
I've seen and heard tons of complaints about poly suspension components. I've daily driven my 66 Dart for 5 years with a poly front end and not had any complaints about it. But that's just my experience and isn't necessarily the rule of law.
Author:  Dart270 [ Fri Jul 11, 2003 5:57 am ]
Post subject: 
There are certainly many satisfied people with both rubber and poly front end bushings. It is somewhat a matter of preference, and my only point was that poly is not necessary for good handling. :)

Cheers,

Lou
Author:  Dennis Weaver [ Fri Jul 11, 2003 9:36 am ]
Post subject: 
I agree with Lou. You listen to folks who have had some experience, pro, con or indifferent with something you want to try, then you make a decision and form your own opinion. Informed decicions are always better than stabs in the dark.

I'm sure there are many who are completely satisfied with their polyurethane bushed front ends. I remember one guy I rode with who put them in his Charger, he couldn't even hear his front end popping. I'd say "can't you hear that?", and he'd say "What did you say, I didn't hear you!", so I guess sometimes hearing loss cann be a blessing in disguise ;)

I'll always recommend against the type of "poly" bushings sold by PST and others, at least in the critical upper control arm and strut rod locations. I can see a good argument for their use in places like sway bars, spring eyes, etc. For the most part, I believe that the "poly" bushing craze has been all a bunch of hype.

"DW"
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