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So after only 22 years the polyu bushing sides disintegrated.
I really didn't feel like taking it apart again, i just did it in 1995. So i measured the side to side play with a dial indicator. at least .302"
explains why a strong wind would almost blow it into the next lane. Rear steering is scary!
I made shims out of aluminum to fit the 3/4" sleeve from the polyu kit.
Ended up adding .1750" to each side of the arm. They fit in with the alignment shims, so no taking it apart. I didn't even take the bolt out; just loosened it.
So with the am hanging down, wheel off, it has .007", and jacking the arm up, it has .040", an 88% reduction in slop. As you know there is rotational stress on the bushing and it will bind if it is solid. And with no bushing it is now solid, except it can't bind as there is at least .007" minimum. So either you like this fix, or you don't. I'm only going to car shows now and then, so, it works for me.
Last edited by Matt Gruber; 12-02-2017 at 10:32 AM.
Reason: more details
What will you do to take up the difference between the sleeve diameter and the bore in the trailing arm? Seems like you may have helped with the toe movement, but what about the trailing arm moving fore and aft ?
What will you do to take up the difference between the sleeve diameter and the bore in the trailing arm? Seems like you may have helped with the toe movement, but what about the trailing arm moving fore and aft ?
That is a great Q!
The polyu bushing CENTER is still in there. only the sides disintegrated.
I don't know how long the centers will "help" since they are so old. Seems they would be stressed on strong acceleration and heavy braking. I still plan on new bushings someday, perhaps when the diff has to come out.
I'm not even sure what the symptoms will be? will it clunk?
The shims got my 72 back on the road quickly, but i don't consider it permanent, for the reason you mentioned.
Matt, I feel your pain on having to re-do your trailing arm bushings, but this line gave me a real good belly laugh! Thank you, I needed that.
Hi Greg!
Sometimes humor does not get a laugh without next to it. Glad you got a smile!
Just changed the water pump and rad again did them in 1999.
When i buy a new part, i expect it to last forever!
I kinda have to agree. What is bad is that it was done back in 1995 to what some may feel is a really good repair/'upgrade'...but now... 22 years later....it is redesigned...re-engineered to get by.
Originally Posted by Matt Gruber
When i buy a new part, i expect it to last forever!
UNLESS you owned the company making the parts...then you DO want them to fail in time so you make more money.
Originally Posted by Matt Gruber
Has anyone replaced polyu with polyu IN THE CAR?
looks like there is enough room, since they come in 2 pieces, about 1" each.
if i take out all the shims there will be about an inch of total space. I can order
Energy suspension polyu bushings for $34
I might be forgetting something? i have the vettebrakes kit in there now, but it is $64
I take out the trailing arm. You are already having to disconnect the brake hose and other parts. Because if you start messing around with the trailing arm with the rubber hose attached...you are asking for problems. Because I would have to assume they are also 22 years old.
The trailing arm has to be out for the Energy Suspension type of bushing,,,,due to you need a vise or press.
Next time the TA is out, i'll probably make my own solid bushing. Looking at some mower wheels, the bearing and hub just might work. Very similar size! This will be permanent, like on my 61 the factory front solid bushings are original and still tight! The rubber and polyu simply don't last.
Next time the TA is out, i'll probably make my own solid bushing. Looking at some mower wheels, the bearing and hub just might work. Very similar size! This will be permanent, like on my 61 the factory front solid bushings are original and still tight! The rubber and polyu simply don't last.
Check out this global west heim joint option they have on their TA's for inspiration
The trailing arm bushing should NOT be solid due to the x,y z motion that the trialing arm has when in use. The trailing arm is NOT like a control arm.
If a person makes it solid..then the arm will be twisting...and in time THAT will fail and then they will be replacing the entire trailing arm itself....unless the pivot bolt breaks. Having really bad 'popping' noises out of that area when driving it is possible. And having to drive it so carefully is ...in my opinion...pointless and what is the point of having a Corvette if a person can not fully enjoy what they have.
This is a scenario...to each his/her own....that is for sure.
i've never seen anybody give the actual movement EVER!
what is it, a trade secret?
So, i measure part of it, the up and down, and i get .034" which is NOT enough to scare me one bit. (on a 45 year old car) A new car should not have .034", but, say, a 5-10 year old car could easily have more than this.
So guys, give me the other EXACT amounts, and i will judge if it is too much for my car.
I have Herb Adams struts, which have spherical bushings with NO SLOP, so i do appreciate a tight suspension. After 28 years, i'm willing to allow some slop, since i drove it with 3/8" of TA slop, and i could still drift around a corner easily and precisely.
YES i know you can't lock up the TA! BUT you can slip fit it with solid parts.
Give me the other numbers, or you are not helping me.
What numbers are you talking about???? A good bushing should have NO play. You probably can't find them because they don't exist.
The trailing arm bushings should not be a solid bushing such as aluminum or Del-A-Lum. The bushing both has to both rotate and twist as the suspensions travels. It could probably be replaced with the appropriate Johnny Joint to make it both solid and greasable if that was so desired.
So, you can still make it solid if you chose, but it will cause binding and twisting of parts that should not be binding and twisting. That will likely mess with the ride/handling and could lead to a sudden suspension failure when one of the parts being over stressed fails. I do feel concern for the population in your area though.
A solid part will not cause any binding if it too small. i used solid aluminium shims to correct toe, but it does not bind.
can anyone comprehend this?
think about a wheel bearing. you tighten it, and then back off so it won't bind. there is no rubber in wheel bearings, and, set up right, they don't bind.
can anyone comprehend this?
.
Looking at an old bushing shell, it looks to have 1.125" ID.
the rubber bushing is 1.125 minus .75 for the sleeve =.375" divided by 2= .1875" or 3/16" thick.
of polyu or rubber. how much movement is absorbed by the rubber? This is the data i need!
Say, it is .050", then a solid spacer of 1.075" should fit and NOT BIND. but it could be anything between .010-???? this is the number i need to make a solid spacer that won't bind.(to limit forward/back movement of the TA)
Last edited by Matt Gruber; 12-04-2017 at 02:37 PM.
A solid part will not cause any binding if it too small. i used solid aluminium shims to correct toe, but it does not bind.
can anyone comprehend this?
think about a wheel bearing. you tighten it, and then back off so it won't bind. there is no rubber in wheel bearings, and, set up right, they don't bind.
can anyone comprehend this?
Everyone else here is having no problem comprehending how the arm moves except you. It rotates both around the bolt and around a line drawn 90* to the bolt through the length of the arm. You've been told this in multiple responses and yet you're still both not understanding and getting pissy at everyone else for pointing out you don't understand.
Last edited by lionelhutz; 12-04-2017 at 02:36 PM.
Everyone else here is having no problem comprehending how the arm moves except you. It rotates both around the bolt and around a line drawn 90* to the bolt through the length of the arm. You've been told this in multiple responses and yet you're still both not understanding and getting pissy at everyone else for pointing out you don't understand.
A solid part will not cause any binding if it too small. i used solid aluminium shims to correct toe, but it does not bind.
can anyone comprehend this?
YES...but what you are taking into consideration is that you still have bushing in there...that can allow for movement. You still are not taking into account the rotation of the trialing arm.
Originally Posted by Matt Gruber
think about a wheel bearing. you tighten it, and then back off so it won't bind. there is no rubber in wheel bearings, and, set up right, they don't bind.
can anyone comprehend this?
YES..we can think about wheel bearings but it is not the same....and using it as an example just does not work. First off your have 2 bearings that are spaced apart on a spindle that is much thicker than the bolt of the trailing arm...and due to the distance between these bearings..it is providing a lot of support and strength...which is why I have never seen a front spindle snap in half between the inner and outer wheel bearing. As for a rear spindle.. that is different due to it being a drive axle and torque applied is what caused it due to seriously sticky slicks being put on the car and it was getting pounded at the race track.
Originally Posted by Matt Gruber
Looking at an old bushing shell, it looks to have 1.125" ID.
the rubber bushing is 1.125 minus .75 for the sleeve =.375" divided by 2= .1875" or 3/16" thick.
of polyu or rubber. how much movement is absorbed by the rubber?
This is the data i need!
I am not going to get into trying to figure that out for you. It takes me back to engineering class and some of the problems that we had to figure out. The range of motion of the trailing arm..the amount of force being applied ..the strut rods also have to be taken into account for along with the amount of run-out that the side yokes of the differential have in them...and then figuring in how much resistance the bushing is needing to provide to do its job.
Originally Posted by Matt Gruber
Say, it is .050", then a solid spacer of 1.075" should fit and NOT BIND. but it could be anything between .010-???? this is the number i need to make a solid spacer that won't bind.(to limit forward/back movement of the TA)
If you look at what Vette Brakes and Products wants for the amount of feeler gauge play in their bushings....that might help you...BUT they are still using urethane and not solid metal.
Best of luck to your quest to improve on something that wears out
about every 22 years of normal driving....because offering you to try to install an spherical joint in there is out of the question.
I love it when guys try to make something happen outside the box,
Sometimes so called expert predictions prevail and its a hack job failure other times its the new great way to tackle the issue, like the mixed way i view the all hailed borg steering box conversion,
I have interest in this trailing arm bushing subject but not because i want to,
Mine were rebuilt with poly and guys have proved from beating their cars with poly ta bushing they can work just fine,
However, in my case i have zero faith in my vbp bushing,
I thought the johnny joint might be an answer but its got its cons,
When i get to that point im going to use something like this,
It has pros over bushing or the johnny joint that i like,
Will it work, time and my own thinking and testing will tell.....
I love it when guys try to make something happen outside the box,
Sometimes so called expert predictions prevail and its a hack job failure other times its the new great way to tackle the issue, like the mixed way i view the all hailed borg steering box conversion,
I have interest in this trailing arm bushing subject but not because i want to,
Mine were rebuilt with poly and guys have proved from beating their cars with poly ta bushing they can work just fine,
However, in my case i have zero faith in my vbp bushing,
I thought the johnny joint might be an answer but its got its cons,
When i get to that point im going to use something like this,
It has pros over bushing or the johnny joint that i like,
Will it work, time and my own thinking and testing will tell.....
I think that the bushing that you pictured will work, as it appears to have the ability to "articulate", in other words, move in multiple arcs. However, IMHO, it would be too ridged for use on normal roads, where expansion strips and potholes are encountered.
Back in the mid-90s, when I rebuilt the suspension on my wife's then-owned '79, I used the VB&P poly bushings on all of the suspension points. After I did the work, she kept the car for another 3-4 years, and everything was still OK. However, after owning the car for about 19 years, she decided that she wanted something new, so we sold it. Therefore, I don't know about the long term longevity of those parts.
Recently, just for grins, I looked up the car's VIN on the C-3 registry, and it appears that the fellow we sold it to, has retired to Florida, and still has the car.......
12-02-2017, 10:24 AM
Trailing arm quick fix: Bubba or genius?
next to it. Glad you got a smile!
did them in 1999.
