My experiences with pfadt vs. VB&P C5 bushings
#41
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Perhaps my phrase was too harsh, my apologies. What you are wrong about however is your pass-fail criterion. The fact that they may or may not make noise is not the correct thing to evaluate. What I am saying is perhaps if the customer of yours that has 11 months on them were to bring it in, and you were to remove the shocks and springs, I think you will find that there is a tremendous amount of friction and binding. That has been the experience of mine and everyone else I know with any urethane bushing kit for any car. The bushing video that Randy Rippie showed was the first poly bushing kit I have ever seen that actually would move on its' own weight, mine certainly won't nor will any of the other people I know that have it currently. The problem is especially acute when the bushings are not co-axial lke when you do not have the same position on the lower cams, or when you shim the uppers for caster.
#42
Race Director
You know, if DRM or Gary or VBP or any of the great vendors on the forum would offer a rebuild service for the control arms, with a couple grades of rubber,
I think they could make a buck on it & provide a wonderful service to the Vette community.
Can't be that hard to mold up rubber to the right spec & put it into the arm, like stock.
I've got some arms hanging on the wall you guys can experiment with.
Then it's a simple maint item & you don't have to buy a new arm, you don't put up with the shortcomings of poly, you don't suffer from the full race harshness of bearings.
How about it guys?
I think they could make a buck on it & provide a wonderful service to the Vette community.
Can't be that hard to mold up rubber to the right spec & put it into the arm, like stock.
I've got some arms hanging on the wall you guys can experiment with.
Then it's a simple maint item & you don't have to buy a new arm, you don't put up with the shortcomings of poly, you don't suffer from the full race harshness of bearings.
How about it guys?
#46
Race Director
#48
Platinum Supporting Vendor
Yea but there a little on the heavy side. I need something a little lighter than what can carry a couple of tanks. The power level is good though.
Gary, what do you think about the steel bushings with a Delrin liner that used to be popular, you don't hear much about it anymore but I was thinking along those lines for my race car since the bearings are so expensive.
Gary, what do you think about the steel bushings with a Delrin liner that used to be popular, you don't hear much about it anymore but I was thinking along those lines for my race car since the bearings are so expensive.
#49
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St. Jude Donor '03 & '05
So, what is the real problem? QA with the bushings, or the whole A Arm with bushings after install.
I have a C4 and with VB&P poly's they dont squeak.. Yet, the hardest thing about this install on my C4 was finding the Proper Torque for installing the end nuts on the uppers? No one really had a solid answer. I used a reputable vendors suggestion, and the arms move up and down very easily and I have over 2000 miles of use here in Hawaii, and I use Termaline grease, marine type.
So, without going with something like this, http://www.guldstrand.com/scripts/pr...p?idproduct=49
What rubber/Delrin/Poly etc is correct or best suited to our needs of perfection?
I say a loud stereo, sound dampening, and Spherical rods ends everywhere and A Arms like Guldstrand. I think LG makes these too.
I have a C4 and with VB&P poly's they dont squeak.. Yet, the hardest thing about this install on my C4 was finding the Proper Torque for installing the end nuts on the uppers? No one really had a solid answer. I used a reputable vendors suggestion, and the arms move up and down very easily and I have over 2000 miles of use here in Hawaii, and I use Termaline grease, marine type.
So, without going with something like this, http://www.guldstrand.com/scripts/pr...p?idproduct=49
What rubber/Delrin/Poly etc is correct or best suited to our needs of perfection?
I say a loud stereo, sound dampening, and Spherical rods ends everywhere and A Arms like Guldstrand. I think LG makes these too.
#51
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Poly. Replacement
We're offering a replacement service now. Here's a link to the details.
http://forums.corvetteforum.com/auto...t-service.html
http://forums.corvetteforum.com/auto...t-service.html
#52
Race Director
You continue to constantly prove that you are the man. well done, thanks.
#53
Race Director
Hows the GTM coming along ?
The best way to get ould bushings out is to use a ball joint press and some WD-40 or other similar lubricant. Just find a cup large enough and press out bushing. Clean the inside are really well so that no rubber particles are left. I used some green 3M pads and some soapy water.
Grease up the new fittings and use a vice to press the metal ends back on.
Tony
#54
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Here is a video I just made of the upper a-arm friction before and after new grease. It is my first video edting job, so be kind, I ain't Spielberg!
http://s67.photobucket.com/albums/h2...controlarm.flv
http://s67.photobucket.com/albums/h2...controlarm.flv
#55
Race Director
Here is a video I just made of the upper a-arm friction before and after new grease. It is my first video edting job, so be kind, I ain't Spielberg!
http://s67.photobucket.com/albums/h2...controlarm.flv
http://s67.photobucket.com/albums/h2...controlarm.flv
#56
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Nope, I think the RP grease is probably not as good as the silicone grease these kits come with. All I am saying is urethane bushings require constant re-lubing. Some method of adding grease fittings wold be really nice, because they need it frequently.
#57
Race Director
That is a very informative post. Thanks.
Here is another question/observation.
If you take a STOCK CA with ORIGINAL rubber bushings where would that flexibility & motion be compared to Poly, before grease and after grease?
I think the oem rubber bush is pretty darn stuck to the control arm & is probably stiffer than both of your examples.
Yet, it works pretty good (except for the "pushing out" of the rubber under race conditions.
Could it be that the stock setup is "tuned" to work with stock spring/shock/bar/tire?
If you make the CA really "slick" does that transfer a suspension "problem" to other parts (previously mentioned) of suspension?
I don't know, just asking.
Here is another question/observation.
If you take a STOCK CA with ORIGINAL rubber bushings where would that flexibility & motion be compared to Poly, before grease and after grease?
I think the oem rubber bush is pretty darn stuck to the control arm & is probably stiffer than both of your examples.
Yet, it works pretty good (except for the "pushing out" of the rubber under race conditions.
Could it be that the stock setup is "tuned" to work with stock spring/shock/bar/tire?
If you make the CA really "slick" does that transfer a suspension "problem" to other parts (previously mentioned) of suspension?
I don't know, just asking.
Last edited by froggy47; 04-09-2009 at 07:54 PM.
#58
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It is different, the rubber has shear deflection that has some torsional spring rate, but the poly bushing is a dynamic bearing so there is stiction that hurts suspension response. Don't get me wrong, when they are freshly greased, they work great! They limit deflection that takes camber away like you get with stock rubber, and require less static camber and toe. I am just saying they require alot of maintenance to work correctly (as currently comfigured by all of the vendors discussed).
#59
Race Director
It is different, the rubber has shear deflection that has some torsional spring rate, but the poly bushing is a dynamic bearing so there is stiction that hurts suspension response. Don't get me wrong, when they are freshly greased, they work great! They limit deflection that takes camber away like you get with stock rubber, and require less static camber and toe. I am just saying they require alot of maintenance to work correctly (as currently comfigured by all of the vendors discussed).
Thanks G,
I am just trying to learn the differences. Clearly CA bushings that need lube 2x a year are not going into a stock car where everything is going to longer service intervals.
Also for some race applications (like solo) you are restricted to stock.
Ergo, why I wish there was a vendor that would do a stock bushing install/exchange or just sell the rubber bushing. It looks like it's molded or bound to the metal washers. I have never tried to take one apart.
#60
Racer
Thread Starter
What we really need to know is the stiction of the bushings when the arm is under load, how that affects instantaneous wheel rates, and how these rates change over time as the bushing dries out. Even my VB&P bushings, which were very dry and noisy when I removed them (and they were rubbing against steel, not aluminum like the pfadts) moved relatively freely under no load.
I understand that poly bushings are not a perfect solution, but they have the nice advantage of being usable in control arms with wide production tolerances. I'd really like to know if their stiction significantly affects handling. Currently I'm thinking I'll go with sphericals with Seals-It boots if my pfadt bushings ever start making a good amount of noise (and it sounds like that might take a while).
I understand that poly bushings are not a perfect solution, but they have the nice advantage of being usable in control arms with wide production tolerances. I'd really like to know if their stiction significantly affects handling. Currently I'm thinking I'll go with sphericals with Seals-It boots if my pfadt bushings ever start making a good amount of noise (and it sounds like that might take a while).