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I have dealt with some cars with the Johnny Joint style spherical bushings and they are quite impressive and the ride quality of it is not that bad....depending on the road that someone normally drives on....and the rear leaf spring design and type of shock absorbers.
I have also dealt with some of the resto-mods I work on that have the C4 rear suspension in them that have the spherical ball type bushing in the 'dog bone' trailing arms for that suspension. Knowing that these cars are not daily drivers...using them as a form of wear data is pointless.
I am sure that is always a trade-off no matter what is chosen for this particular issue in regards to bushing designs...because NOTHING is going to last forever....and thinking that it will...is not being realistic. Face it...things wear out when they are used ...and can wear out even when they are not used.
For me... dealing with these trialing arm bushings are not that big of deal. So if I get 20+ years out of it....I would not be concerned. Because I have already given in to the fact that I will be getting into my rear wheel bearing in 50K miles anyway from the last rebuild.
Hi guys,
thanks for all the replies! i'll study them later.
Just got back from the 1st test drive since adding the shims to the right TA. (i had a feeling something would break, so i was in no hurry to test it).
Sure enough something broke! the door handle snapped in half!
The car is much better, maybe like a 15 yr old car, so i will be jacking up the left side to check/shim the left bushing. The improvement is dramatic, before i would not drive it until i checked it out, now, well i feel safe, but i'm not going fast without checking out the left bushing.
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chevyman77- no more web site, sorry.
Last edited by Matt Gruber; Dec 9, 2017 at 01:41 PM.
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.....
Thanks.
I will report back how this works out, good or bad, it is fun to try something different!
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As for the guys that don't get my joke about things not lasting forever....
Check out this drift girl! Don't watch if you are married! You may want a divorce.
they look fantastic! Too bad they don't have a boot or seal. Dirt must love them.
it is SOLID, no rubber, no polyu, so i want to
like it. they don't seem to sell them without 2 TA, i could not find a price! Maybe some day they will add a boot and sell them for street use!
My experiment is solid sides, and old polyu in center. not sold either! but FREE with my spare time and scrap metal.
edit
so l took off the left wheel, and it is chewed up like the right.
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the spherical bushings for the strut have the dirt seals intact, after 2 decades, i am happy with the Seals-it product.
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did some research on newer models- they have similar stock rubber bushings- so what i learned about my mod is that the #1 possible problem is noise. reminds me of solid lifters vs. hydraulic, with solids you hear the valvetrain banging around . so with .043" (down from .302+) clearance should make a click sound on bumps etc.
Last edited by Matt Gruber; Dec 10, 2017 at 01:17 PM.
did some research on newer models- they have similar stock rubber bushings- so what i learned about my mod is that the #1 possible problem is noise. reminds me of solid lifters vs. hydraulic, with solids you hear the valvetrain banging around . so with .043" (down from .302+) clearance should make a click sound on bumps etc.
Actually the noise is the #2 'problem....because ...in my opinion ...the #1 'problem' is that this mod is allowing your toe setting to move on you due to the .043" play in that area...which can give you the feeling that you have a steering wheel in the rear of your car. Especially a higher speeds and unfavorable road conditions.
Actually the noise is the #2 'problem....because ...in my opinion ...the #1 'problem' is that this mod is allowing your toe setting to move on you due to the .043" play in that area...which can give you the feeling that you have a steering wheel in the rear of your car. Especially a higher speeds and unfavorable road conditions.
DUB
actually .009"
the arm twists .034. does not matter if rubber or poly or heim joint, this is the movement the guys here have been warning me about! You can
not stop the arm from moving or it will jam up and eventually fail!
i've got an extra .009 to be sure it wont bind.
DUB
do you still think .009 will cause rear steering? even .043? after i drove for maybe a year with 3/8" you think .043 is a lot?
thanks for your replies!
Last edited by Matt Gruber; Dec 10, 2017 at 05:47 PM.
thanks mosse
they make interesting parts! i did not know about these.
I wrote about them in post# 21 in the first paragraph.
IF you use these...which are not easy to install...the ones I have dealt with the person removed the zerk fitting and install a tube that threaded into the housing and then a zerk fitting was installed at the end of that tube....so when you wanted to grease them..the zerk fitting was in a location that made it easier to grease these joints.
Takes too much time! i spent 3 hours on the left side, if i knew how much time this QUICK fix would take............
Seems like that is part of doing a modification that is unconventional.
As for when you wrote about .043" play...I was picturing that your trailing arm could slide side to side that much....which in my opinion is too much. Regardless if you have been driving with 3/8" play for a while.
As for .009"..If my memory serves me correctly...that is right about the feeler gauge measurement that Vette Brakes wants when setting and installing their urethane trailing arm bushings kits.
At slow speeds it may not show up and cause for any immediate concern. But if a person looks at their tires and how the tread is wearing ...it may show something entirely different. And if it is not showing cupping of the tread or any thread wear issues and you have all that 'play'...then...do as you see fit. If at high interstate speeds you feel an issue or hear noises...then do something about it or don't do anything about it I have lost count on the number of Corvettes I have taken out for a test drive at interstate speeds and it seemed to be fine and no adverse handing issues....but the rubber trailing arm bushing was designee to be replaced. And the wear on the tire showed it... even though the car did not make the owner have a 'white knuckle' driving experience.
DUB
Have you ever noticed and questioned factory toe-in?
This is the crux of the our disagreement.
If you research factory toe-in all the way back to the source (the engineer that set the spec) you will generally find that the engineer started with toe-in, but never planned for any net driving down the road toe in. This is because the rubber compresses and changes the actual toe when at speed, compared to the reading on the alignment rack.
It is my contention that rubber "slack" is similar to my shim clearance. This is why i will not consider your argument without first calculating the rubber slack from the alignment specs.
All this is academic only, as tire wear complaints do not apply to a car driven 20 miles a month! Yes my 5 year old tires, look new, despite 2 sloppy TA's. My goal is to keep my 72 on the road......so a little shim clicking is not going to bother me.
I do not question the factory 'toe-in'. I will set the toe to what I know the car needs to be., It may be factory specs or it might not. Keep in mind. Many of my customers take their Corvette up in the mountains that are close by and there are some serious roads that allow them to get the full experience out of their Corvette in regards to handling. There are many customers who drive locally and do not take it out on the interstate. So it depends.
So..knowing that a rubber bushing can flex...but it also returns back to its neutral state like when it was compressed and staked. In time...the rubber needs to be replaced due it it will wear out.
You are doing what you feel works for you and if it does...due to only driving the car 20 miles a week....and knowing that if the toe is out enough it is like you are dragging your tire sideways while it is rolling down the road...which heats up the tire and also wears it out may not make a difference to you. If you find that your modification works with no ill effects....I guess you figured out a way to do it your own way.
I know I would not do what you are doing so I see I have nothing else further to add to this thread.
I highly doubt the rear suspension of a C3 with rubber bushings will change from toe-in on the rack to toe-out when driving down the highway. What would be forcing the front of the trailing arms out?
I highly doubt the rear suspension of a C3 with rubber bushings will change from toe-in on the rack to toe-out when driving down the highway. What would be forcing the front of the trailing arms out?
A year or two ago, this discussion came up in the C5 section. Yes, I know that the C5 has a different design rear suspension, one that SHOULD prevent most of the toe change during driving/racing.
However, LG Motorsports, in an effort to show how their suspension bushings eliminate toe change, set up a C5 on a chassis dyno, then set up a video camera, aimed at the rear wheels of the car. They then started the rear wheels rolling on the dyno in a steady state, followed by accelerating, then backing off. They repeated this a couple of times.
You could see the fore and aft movement of the wheels, which, of course, will affect the toe-in. They did this test twice, once with OE rubber bushings in the control arms, and once with their bushings in the control arms. Of course, their arms showed far less toe change, but the point of me bringing this up, is that there is indeed toe change, during acceleration.
AND, I'm pretty sure that worn out, rubber bushings, will "provide" more toe change than either new rubber bushings, new polyurethane bushings, or one of the "solid" bushings that were pictured in this thread.
That's nice info and all, but it's mostly irrelevant to what I wrote and the question I posed. Read this part of the post I was responding to.
Originally Posted by Matt Gruber
If you research factory toe-in all the way back to the source (the engineer that set the spec) you will generally find that the engineer started with toe-in, but never planned for any net driving down the road toe in. This is because the rubber compresses and changes the actual toe when at speed, compared to the reading on the alignment rack.
I interpret this claim as meaning the rear of the car will have toe-out while driving at a steady speed down a road, even though the rear toe was set to toe-in on an alignment rack.
So, I asked HOW? Saying the rubber bushing has give is not the answer. Explaining the forces that cause the toe to change when driving if you want to give an answer.
If you look at forces when accelerating, you'll find that the wheel is pushing forwards, which in turn puts a forward force onto the outside end of the spindle. This forward force is being applied outside of the line drawn between the front torque arm bushing and the wheel bearing. So, as the force transfers through the torque arm to the frame, it will be trying to rotate the front of the torque arm inward.
That's nice info and all, but it's mostly irrelevant to what I wrote and the question I posed. Read this part of the post I was responding to.
I interpret this claim as meaning the rear of the car will have toe-out while driving at a steady speed down a road, even though the rear toe was set to toe-in on an alignment rack.
So, I asked HOW? Saying the rubber bushing has give is not the answer. Explaining the forces that cause the toe to change when driving if you want to give an answer.
If you look at forces when accelerating, you'll find that the wheel is pushing forwards, which in turn puts a forward force onto the outside end of the spindle. This forward force is being applied outside of the line drawn between the front torque arm bushing and the wheel bearing. So, as the force transfers through the torque arm to the frame, it will be trying to rotate the front of the torque arm inward.
But in addition to what you've stated above, you have the wheel on the other side of the car doing the same thing. These "inward" forces then cancel each other out. But then the resistance of movement, supplied by the weight of the car and the rolling resistance between the tires and the road, tends to want to go a little "toe-out", so you set the static toe to compensate for this...
So what if there are forces on both sides of the car? The inward forces on each torque arm cancel in the chassis, not in in each torque arm. The only way for the inward force from each torque arm to get to the chassis is through the bushing, which will tend to deflect the front of the torque arm inward, not outward.
Are you trying to claim there is some "resistance to movement" always pulling backwards on the rear wheels???? I really don't get that claim. The rear wheels are propelling the car, so there won't be any drag/friction force pulling backwards on the wheels when the car is either accelerating or driving at a steady speed.
Odd that you're trying to claim that acceleration forces trying to twist the torque arms inward at the front has no effect on toe, but some vague friction force does have an effect on toe....
Odd that you're trying to claim that acceleration forces trying to twist the torque arms inward at the front has no effect on toe, but some vague friction force does have an effect on toe....
I didn't say that........the video I referred to, CLEARLY shows the toe of the rear wheels reacting to accelerative forces.
