C4Newb

Hi, does anyone have a '95 and older rear trailing arm (dog bone) laying around? I am interested in the I.D. where the bushing resides, or specifically if this diameter could be bored out to 2" while leaving a reasonable wall thickness remaining. I have a '96 which has composite trailing arms with what appear to be different (smaller) bushings.
Thanks!
Phil

MatthewMiller

Sorry, I meant to answer this yesterday after work, but work kind of never ended. The trailing arms for my 1996 are a about 2" on the outside, and the wall thickness around it is 1/4". So no, you can't bore those out to 2". I'm not sure about any differences in bushings for earlier years. If you look up the bushing replacement kits, they all seem to say they fit all years of C4s.

C4Newb

Thank you....I have my '96 ones out on the bench as well....
The Energy Suspension catalog does not show a bushing available for the trailing arms for '96, but does for '95 and on back. Crudely, using the size of the through hole in the steel sleeve and scaling against a printed photograph the 95 and earlier ones appear to be larger.
I want to try removing the bushings and pressing in a sleeve to take a monoball type bearing with a polyurethane race to gain the ability for the trailing arm to articulate when the suspension cycles while maintaining a stock(ish) appearance.
Guess I will just have to buy a set to try it on.....

MatthewMiller

I did notice that in the ES catalog online. But every other source for bushings I could find says their bushings work for 96 too. This includes places like Van Steel that specialize in Corvettes. Also, Prothane and SuperPro show their trailing arm bushings fitting all C4s. So I wonder if there's just something goofy about the ES catalog - like maybe it was actually written in 95 and just hasn't been updated since then?

I like your thinking on your project. Maximum Motorsports used to make Fox/SN95 trailing arms similar to what you're thinking about.

hcbph

Have you checked out https://www.banskimotorsports.com ? Sounds like they solve the problem you're looking for a solution to.
I've been running the full Banski setup for a couple of years now and I'm well satisfied with the results.

C4Newb

Thanks, yes I have. It looks like a very high quality product and does indeed solve the problem of restricted control arm movement due to stiff bushings. The description of the issue (from a design perspective) that appears on their website is the best out there. I know many have used their system with great success but I do not need some of the features their solution provides. Also, having worked up a price for all the components to build a similar setup I can say their system is a pretty good value for money as well. I just have a different set of criteria in mind that I am working to try and satisfy.......If I end up with any success I will share the results here.

MatthewMiller

They are great, and that's what I run. And Tum Urban from Banski is not only extremely knowledgeable but provides great customer service. But the OP's desire to maintain "a stock(ish) appearance" can't be met by their parts.

rjacobs

If I wasnt interested in going to the full Banski setup I would do the SuperPro bushings...

MatthewMiller

Yes, those are a very interesting alternative. I'd really like to do a bench test comparison of a set of arms with those bushings installed vs stock rubber and "regular" poly bushings. The test would involve bolting each one to a trailing arm mount and seeing how much force it takes to pull it sideways a certain amount.* We know the rubber ones wouldn't take much force, and the poly ones would take quite a bit (which is why they're a bad idea for this application). I'm just curious if the SuperPro folks have figured out the magic sauce that comes closer to the rubber than poly in terms of desirable non-axial compliance.

*How much to pull sideways for the measurement would depend on how much they move sideways through the full range of suspension motion. I'm guessing somewhere between 0.5-1.0", but that's just a guess.

rjacobs

I would be interested to see if something like a Curry Johnny Joint or Metal Cloak Duroflex joint from the Jeep world would work. Its a cross between a heim joint and a rubber/urethane bushing. BUT I can guarantee they dont make them in the size we need and probably costs a lot for tooling.

https://metalcloak.com/metalcloak-du...der-parts.html

​​​​​​https://www.currieenterprises.com/johnny-joint-rod-ends

MatthewMiller

The Johnny Joint looks like a normal heim joint with a urethan liner, essentially. That's interesting, but I don't know if you need it's two main advantages: lots of articulation range and a cushioned ride. The C4 doesn't need anywhere near that much articulation, even in the trailing arms, should be all it needs. Normal rod ends allow that. The Banski arms come with Aurora telfon-lined rod ends that have been totally quiet on my car, and I can't tell the difference in ride harshness. They can wear out, but they are easily and cheaply replaceable as well. The Metalcloak ones are interesting. If you used their 2" bushing and 2.25" housing in threaded rods, you could build trailing arms similar to rod-ended arms. The only measurement that probably won't fit is the 2" width of that bushing: I'm sure that's too wide for the trailing arm brackets. I guess new brackets could be make. But at that point, you're in for at least $600 and some fab work for the brackets. It's hard to justify that when there are rod-end (like Banski) and SuperPro options out there already.

rjacobs

Like I said, if they had a ready made option that could be pressed in to our factory dog bones, it would be interesting to press some in...

The cool thing about the metal cloak joints is they can rotate inside the housing so they dont bind in a rotational motion while still keeping the joint centered in the bracket and allowing articulation. I think the basic design is cool, but for a car like ours the durometer of the bushing could be cranked way up since as you said we arent as worried about articulation.

My 96 only has 40k miles on it and has been a garage queen(and likely to continue being one as I also have an 11 GS vert) and none of the rubber bushings seem to be bad, so for me, looking at all of this is just mental ************, but I enjoy it anyway.

blackozvet

The inside bore is about 38.5 mm and the thickness varies a little bit but is around 7.8 mm
I explored that option with my trailing arms, spoke to the engineer/machinist I know and he sd would def need a sleeve inside the bore to mount the bearing.
you would have to find the spherical bearings that would fit (keeping in mind the front and rears use different bolt sizes 12mm/16 mm)
then work out the thickness required for the sleeve based on the spherical bearing diameter.
the inside of the arm bores and the inside of the sleeve would require slots cutting for the C clips to ensure nothing walks around.
Press sleeves into arms
then calculate and cut crush sleeves for the bolts.
So effectively you could do it, but time and money wise ? - I ended up just buying Banski arms.

just for info when I took my urethane bushed arms out the front bushes with the 12 mm bolt were tight, the rear bushes with the 16 mm bolts were sloppy.
I had another spare set of used arms that had urethane bushes so I checked them, exactly the same - tight front, loose rear.
It would appear that the rear swinging motion does cause a reasonable amount of wrenching on the rear bushes. So really you would only need to put spherical bearings in the rear to overcome the binding issue.

here's a pic when I was thought bubbling.

C4Newb

For what it's worth the Energy Suspension catalog is correct. Having sourced a set of '95 and older trailing arms from a member here and pushed the bushings out, the '96 year only composite trailing arms have slightly larger bores and the Energy Suspension bushings are loose in them.
I am working up a plan to do exactly what is shown in the picture posted by blackozvet and will post back with part numbers ad cost if there is any interest.
Phil

MatthewMiller

That's really strange. That means that there are no rubber OR poly bushings for the 96 arms. I wonder why the hell GM revised the trailing arms for the last year of a 12-year run, anyway?

I would be interested from a curiosity perspective, if nothing else. Thanks.

C4Newb

Resurrecting this because there was some mild interest. Have been driving with these since March. They're working fine and relieve the binding noted with a poly bushing in each end. Installed them on the camber arms as well. I got the self lubricating/sealed monoballs from Rod End Supply and the spacers from Speedway Motors.

Tom400CFI

Part number please!

I've been working not his for a long time, too. I found that late '90's Ford F250 front sway bar end link bushings are actually booted spherical bearings! Can you believe that? What a ****-pile that truck is...and they used booted, spherical bearings on both ends of the sway bar end links!???

Well they did and they OD is just a little bigger than the ID of the trailing arms. I honed out a spare trailing arm I had and pressed in the Phord ball and it works. But I'm totally interested in your solution. Please share more! .

C4Newb

Parts List:
Rod end supply COM14N (4) $11.67 ea. and COM12N (2) $8.91 ea. These are self lubricating and self sealing monoball units. Rod End Supply claims the trophy truck guys run these in dirt with no problems without boots or additional seals.
QA1 high misalignment spacers SN14-109 (8) $8.99 ea. and SN12-108 (4) $6.99 ea.

The COM14N's and SN14-109's are used at the knuckle end of the trailing arms. The COM12N's and SN12-108's are used at the outer ends of the camber arms.

I counter bored each arm to a depth that centered the monoball in the arm and a diameter that gave a .001-.0015 interference fit. The arms are very soft and must be fixtured carefully to avoid distorting them with clamping forces. Give the surface finishes of both parts I calculate nearly 1000 lbs. force required axially to displace the monoballs so no other means of retention except the press fit.

The QA1 website has all the dimensions for the spacers by P/N, for some reason they are not showing the SN12-108 but Speedway still shows it in their catalog.
Once the machining is done it all just bolts up.

Tom400CFI

Dude...HOT DIGGITY DOG!! This is awesome information! Thank you!

I'm off to buy myself some *****! This is so cool.

C4Newb

One caution is not to try to actually press them in. Use a heat freeze method. Monoballs in your home freezer overnight and gently heat the arms with a heat gun or propane torch to ~300f. At .001-.0015 press fit they will drop together. The cast arms are so soft that if you try to press them in any, ANY misalignment will result in plowing up bow waves of aluminum and wrecking the arm (ask me how I know).
Even so not all is lost because Rod End Supply sells steel shells to install the monoballs in (see the UBC series of P/N's) which could be installed in the arms after boring them again but by my calcs the arms get a little thin.......