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Most aftermarket rear sway bars can not use the factory bracket that attaches to the trailing arm, so the package usually includes a couple flat pieces of steel that clamp to the trailing arm. Most of these pieces eventually bend, as did the bracket for my 7/8 inch rear bar. While my 68 convert is apart waiting for some components to come back from Eckler's, I decided to make a stronger bracket using channel iron, instead of flat pieces. I have two holes drilled for the factory bracket, but this will also work for trailing arms with just the one large hole for the spring bolt.
Most aftermarket rear sway bars can not use the factory bracket that attaches to the trailing arm, so the package usually includes a couple flat pieces of steel that clamp to the trailing arm. Most of these pieces eventually bend, as did the bracket for my 7/8 inch rear bar. While my 68 convert is apart waiting for some components to come back from Eckler's, I decided to make a stronger bracket using channel iron, instead of flat pieces. I have two holes drilled for the factory bracket, but this will also work for trailing arms with just the one large hole for the spring bolt.
Most aftermarket rear sway bars can not use the factory bracket that attaches to the trailing arm, so the package usually includes a couple flat pieces of steel that clamp to the trailing arm. Most of these pieces eventually bend, as did the bracket for my 7/8 inch rear bar. While my 68 convert is apart waiting for some components to come back from Eckler's, I decided to make a stronger bracket using channel iron, instead of flat pieces. I have two holes drilled for the factory bracket, but this will also work for trailing arms with just the one large hole for the spring bolt.
Most aftermarket rear sway bars can not use the factory bracket that attaches to the trailing arm, so the package usually includes a couple flat pieces of steel that clamp to the trailing arm. Most of these pieces eventually bend, as did the bracket for my 7/8 inch rear bar. While my 68 convert is apart waiting for some components to come back from Eckler's, I decided to make a stronger bracket using channel iron, instead of flat pieces. I have two holes drilled for the factory bracket, but this will also work for trailing arms with just the one large hole for the spring bolt.
All you are doing is making it more likely that the constant flex that broke the clamping design will be transferred to the mounting area on the actual trailing arm. And that will then break. The clamping mount is simply a bad design and doesn't account for the needed rotational freedom that the factory design offers.
This is not hypothetical on my part but based on actual experience . And that experience was an odd noise rounding a turn on the way into work. Nothing seemed very wrong until I got home and poked around back there to see that the metal at the top rear of the arm had flexed itself apart. At that point you are then looking at a much more expensive repair or discontinued use of the rear bar.
One way to understand the deficiency is to put your car up on jackstands and note that the TA does not drop down all the way, but only as far as the bending moment on the clamp allows.
That is the reason why a lot of members besides myself advise sticking with the factory design. See Cagotzmann's post above , the two axes of rotation are critical. GM knew it, these aftermarket 'designs' are just cheap crap to get something out the door, IMHO.
Sorry if that seems overly critical as you've obviously put a lot of work into beefing the design up.
This ^^^^^^IMO is the best way to use an aftermarket NON OEM rear sway bar on a C3. You can alternatively use a non OEM rear sway bar with the aftermarket endlink possibly with an aftermarket endlink NON GM design with an adjustable spring in the endlink to allow more trailing arm movement.
Of course, the easiest way to use a rear sway bar on a C3 is to use a factory type GM sway bar and GM C3 endlinks. The factory type bars come in 7/16, 9/16 and 3/4 inch (aftermarket GM style rear sway bar-not ever used on a C3 from the factory in the 3/4 inch size) which is what I use on my 78 Gymkhana C3.
cagotzmann- Is that a heim joint end? If so, it is a lot better than what I made. I have all of the parts for the factory bracket, but when I ordered my SB from Eckler's and it arrived, the hole in the end was rotated 90 degrees and of course would not fit. I have a couple heim joints somewhere on my bench- will see if they will fit, otherwise I will order a couple. (anyone want a hand made sway bar bracket.......free)
ignatz- don't apologize for giving good advice. That is one of the functions of this forum. Not sure why I did not think of using a heim joint end. I was actually going to fabricate some kind of adapter that would fit my factory brackets.
Last edited by ronarndt; 02-14-2019 at 09:52 AM.
Reason: typo
I'm changing the cheap brackets that came with my aftermarket rear bar also. I bought the factory brackets, expecting to use them, but the Addco bar and many others have the hole on the end of the bar turned 90 degrees so they will not work with the factory brackets. I made a heavy duty replacement, but cagotzmann has a better idea using a heim joint. I will use the channel iron part of my bracket, but add the heim joint. I did not buy the factory rear bar because it is overpriced- more than double the cost of a heavier aftermarket bar.
That looks awesome. Let us know how it works! I have my (stock) brackets installed. I'm just waiting to finish the front end before I hook it up. This looks to be a great hybrid solution if my (stock) 7/16" EDIT 9/16" bar isn't enough.
Last edited by Bikespace; 02-17-2019 at 12:10 AM.
Reason: 9/16, not 7/16, though both were stock.
Bikespace- I would have bought the factory rear bar, except it was way over-priced, compared to much heavier aftermarket rear bars. Just the stock rear 9/16 inch bar is $200 vs about $300 for both an aftermarket 1 1/8 inch front bar and 7/8 inch rear bar. Disadvantage is the rear bar is configured with the end hole horizontal so the stock brackets don't fit and they include the cheap plates to clamp on the trailing arm.
Bikespace- I would have bought the factory rear bar, except it was way over-priced, compared to much heavier aftermarket rear bars. Just the stock rear 9/16 inch bar is $200 vs about $300 for both an aftermarket 1 1/8 inch front bar and 7/8 inch rear bar. Disadvantage is the rear bar is configured with the end hole horizontal so the stock brackets don't fit and they include the cheap plates to clamp on the trailing arm.
I didn't mean to sound sarcastic. You are absolutely correct about the stock bar being overpriced. Between the (stock) 9/16" bar, used from a BB car, and all the assorted bits from three (!) different vendors, I'm probably close to $300-. Fortunately my 80 already has the 1 1/8" bar, so I just needed bushings there. When it's all done, front and back, I'll see if the 9/16" is enough bar. I was worried that 3/4" might be too much, but it's good to see that there is still an upgrade path if I need a bigger rear bar.
So, sincerely, good job with the fix, and the implementation of the heim adaptation to the aftermarket bar.
I didn't mean to sound sarcastic. You are absolutely correct about the stock bar being overpriced. Between the (stock) 9/16" bar, used from a BB car, and all the assorted bits from three (!) different vendors, I'm probably close to $300-. Fortunately my 80 already has the 1 1/8" bar, so I just needed bushings there. When it's all done, front and back, I'll see if the 9/16" is enough bar. I was worried that 3/4" might be too much, but it's good to see that there is still an upgrade path if I need a bigger rear bar.
So, sincerely, good job with the fix, and the implementation of the heim adaptation to the aftermarket bar.
On my 78 L-82 4 speed gymkhana car with the totally stock suspension when new the car would understeer moderately when pushed with the 7/16 inch Stock GM bar. A few caveats here to consider in that my 78 is 200-300 pounds heavier than the 80-82 when the car was all stock and new with thinner fiberglass body and the aluminum batwing diff and carrier in the rear as well as the 255/60/15 tires with frankly poor ultimate grip and tire technology. The last piece of the equation is the front to rear weight distribution of the 80 versus my 78's 48% front and 52% rear weight distribution (a slight rear weight bias is just about ideal for a street car for performance).
Change anything in the equation ^^^^ above and you alter the effect of any one suspension component's effectiveness in stock form and when you change one component for another. Earlier in my 78's life, I changed none of the above except poly endlinks and front 1 1/8 inch sway bar mounting bushings, both poly. This change makes the front bar act BIGGER which increased the understeer built in from the factory. I then added poly/solid rear 7/16 inch sway bar mounting bushings to the stock 7/16 inch rear bar to make that bar act BIGGER to dial out the front push which it did very slightly but not enough. In 1986, I replaced the 7 leaf steel Sport stock spring with a 360 composite which is firm but has different rebound/compression characteristics than steel and seemed to allow more rear roll than the steel spring BUT rides 10X better. This change resulted in more front end push and the reason I went to the 3/4 OEM type non factory GM type rear bar with poly mounting bushings. With that change the car feels very neutral at or near the limit which can result in very slight oversteer that is extremely progressive and controllable BUT I do have a front spreader bar that will make the front stock 1 1/8 inch sway bar more effective by counter unwanted frame flex.
So, my conclusion is that in general on a stock type gymkhana suspended car, the sweet spot with the rear sway bar is the 9/16 rear swaybar...my guess....
The posts about overall handling illustrate the problems with dialing in a car's suspension. I don't race my 68 convert. But I have a 93 RX-7 that I spent over $100k modifying almost 20 years ago. I have four sets of Hypercoil springs, two sets of shocks for the coil-overs, three sway bars, three sets of tires/wheels plus numerous bits and pieces to fine tune the larger parts. I lived in NC near Dale Earnhardt Chevrolet and was there one day (after the crash) looking to buy a truck when Dale Jr. pulled in. I got to talk to him and asked about his advice for setting up a car's suspension to get the best performance. He said it varies and if he knew the answer, he would probably win all the time. So welcome to the world of suspension tuning.
The heim joints I ordered arrived. Here is the modified bracket suggested by cagotzmann before attaching to the trailing arm.
Thanks for the photos and discussion on rear sway bar end links and creative solutions to mounting aftermarket bars with modified OEM style end links. Before I abandon my NOS 3/4" VBP rear sway bar for an OEM 9/16" bar (& the $$), I'd like to try the solution ronarndt and cagotzmann developed in this thread, with great input from others, of course.
So, my questions are: What are the dimensions of heim joints that mate well with the OEM end links and the aftermarket sway bars? The primary dimensions of interest are the width of the joint and the length of the threaded end (I think). Once I order & receive the parts for the modified end links, I can determine the dimensions required for the bushings - but if those specifications are easily shared, they would be also appreciated. Lastly, are there any updates available on how this end link modification and the bar have worked for anyone ?
Thanks also to everyone for all of the great discussions on the forum & happy motoring !
Thanks for the photos and discussion on rear sway bar end links and creative solutions to mounting aftermarket bars with modified OEM style end links. Before I abandon my NOS 3/4" VBP rear sway bar for an OEM 9/16" bar (& the $$), I'd like to try the solution ronarndt and cagotzmann developed in this thread, with great input from others, of course.
So, my questions are: What are the dimensions of heim joints that mate well with the OEM end links and the aftermarket sway bars? The primary dimensions of interest are the width of the joint and the length of the threaded end (I think). Once I order & receive the parts for the modified end links, I can determine the dimensions required for the bushings - but if those specifications are easily shared, they would be also appreciated. Lastly, are there any updates available on how this end link modification and the bar have worked for anyone ?
Thanks also to everyone for all of the great discussions on the forum & happy motoring !
Mine have worked well. I'll see if I can find the part number for the joints I ordered.
I'm changing the cheap brackets that came with my aftermarket rear bar also. I bought the factory brackets, expecting to use them, but the Addco bar and many others have the hole on the end of the bar turned 90 degrees so they will not work with the factory brackets. I made a heavy duty replacement, but cagotzmann has a better idea using a heim joint. I will use the channel iron part of my bracket, but add the heim joint. I did not buy the factory rear bar because it is overpriced- more than double the cost of a heavier aftermarket bar.
Your doing this correct, solid mount maintaining a vertical 0 degree alignment between the bar and trailing arm. Not sure on the heim joint now. Standard bolt with poly bushing sway bar link.
Last edited by Gunfighter13; 10-18-2019 at 02:44 AM.
Mounted like that, the sway bar is useless. The Geometry is incorrect making the bar ineffective.
What????????
The picture above is a stock rear gm sway bar endlink, and yes that is the geometry GM used on C3's with a GM rear bar with the factory GM vertical endlink holes, with a modified heim joint, adapted to the incorrect horizontal sway bar endlink (for a C3 corvette with a factory rear end sway bar). The heim joint is allowing the use of the correct GM Rear sway bar endlink with a front incorrect type sway bar endlink for a C3. There are quite a few posters on this forum with that rear sway bar setup used on the street and raced effectively. That sway bar heim joint with the GM endlinks will work actually better than the factory part since it is a heim joint with no bushings and poly rubber...........
02-13-2019, 09:28 PM
aftermarket rear sway bar bracket
