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What has changed is the frame has sagged over the years. The mounting location for the upper suspension mounts bend inward over time. That’s why you see so few adjustment shims in the old ones. A spreader bar can help prevent further sagging. The offset mounts move the pivots inboard so you can use more shims to set the suspension to specs.
So assuming frame sag, is there an effective way to straighten the upper suspension mounts - has anyone ever done this?
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
a spreader bar like Pete suggested. They bolt in between the upper A arm mounts so you can spread the upper suspension to its normal location adn lock it there. Its great for stiffening the front suspension laterally
Last edited by Rescue Rogers; Sep 27, 2020 at 07:06 PM.
They have to be custom mounting to avoid the clutch fan if you arent running electric fans
I successfully installed the spreader bar on my 69 small block Corvette with an mechanical fan. I had to add a small spacer to move the fan forward about 1/8" so the fan cleared the bar. It's tight, but it works fine. The car definitely feels more solid.
I also replaced the cadmium plated bolts with Grade 8 bolts with shanks long enough to span the two holes in the brackets. My car has stock control arms, not the SpeedDirect arms.
Few do it but this is the correct way to set the lash in the steering box, there are two adjustments that need attention, most only do the top one and call it good.
Last edited by Haggisbash; Sep 27, 2020 at 07:47 PM.
I can't remember if anyone suggested it already, but before you do anything, Put a vise grip pliers on the steering box shaft (below the rag joint), and tie it to the frame or engine with some light rope or whatever ...so the vise Grips won't move.
Then go in and wiggle your steering wheel. You should feel almost no play. If you do, then you know its from the rag joint or any joints between the vise grips and the steering wheel. Rag joints DO get sloppy, and sometimes it's difficult to tell until you do a simple test as I described.
a spreader bar like Pete suggested. They bolt in between the upper A arm mounts so you can spread the upper suspension to its normal location adn lock it there. Its great for stiffening the front suspension laterally
So in the case where you have some sag in the upper control arm area of the frame, installing a spreader bar I assume would help correct the issue? Never used one before, so I don't know a lot about them. Can you change the spreader value to correct the sag?
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Yes, they use heim joint so jthe ends so they can be dialed in or out to get the correct frame angle. There was a thread on it a couple of years back adn someone had the specs of the upper mounts and the stock distance between the 2.
heres van steels bar http://www.vansteel.com/index.cfm?fu...owItem&ID=2693
I can't remember if anyone suggested it already, but before you do anything, Put a vise grip pliers on the steering box shaft (below the rag joint), and tie it to the frame or engine with some light rope or whatever ...so the vise Grips won't move.
Then go in and wiggle your steering wheel. You should feel almost no play. If you do, then you know its from the rag joint or any joints between the vise grips and the steering wheel. Rag joints DO get sloppy, and sometimes it's difficult to tell until you do a simple test as I described.
Yes, they use heim joint so jthe ends so they can be dialed in or out to get the correct frame angle. There was a thread on it a couple of years back adn someone had the specs of the upper mounts and the stock distance between the 2.
heres van steels bar http://www.vansteel.com/index.cfm?fu...owItem&ID=2693
Thanks Rescue - I will be looking for a spreader bar for my 69 small block. Looks like a great idea even if you don't have any Camber issues...
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I did mine all at once. Someone posted the stock disatnce between the pillars and I set it to that distance. I should have written it down. I think its in the AIM or one of the frame threads. If I run acrross it I will post it here.
So I called VanSteel, and they are going to redesign it because they want to improve the original design by making the the heim joint larger. So I'll wait till January and then put it in - thanks to all for the great help!
When you had it aligned what were the caster settings after it was done? Radial tires like more caster than the bias tires that came with the car. When I rebuilt the front suspension on my 71 I purchased new cross shafts that are "stock" on side or you rotate them for more camber adjustments. Back in the day I was a tech at Chev dealer ship and some how got to be the front end alignment guy. Camber should be a little bit different from side to side to compensate for road crown. I don't remember which side has more or less.
Did the alignment shop give you a read out of the settings? Might be helpful if you posted them.
When you had it aligned what were the caster settings after it was done? Radial tires like more caster than the bias tires that came with the car. When I rebuilt the front suspension on my 71 I purchased new cross shafts that are "stock" on side or you rotate them for more camber adjustments. Back in the day I was a tech at Chev dealer ship and some how got to be the front end alignment guy. Camber should be a little bit different from side to side to compensate for road crown. I don't remember which side has more or less.
Did the alignment shop give you a read out of the settings? Might be helpful if you posted them.
I didn't get the spec from the guy, in fact he didn't charge me anything since he could not bring the camber on the front driver side tire into specs. I think what I am going to do is install the spreader bar, get the frame specs in line and then go back and have him re-align it.
He did say that he was able to align the rear wheels properly, but the front driver camber was not quite there.
Is the front end actually LOOSE or is it just very sensitive and "darts" when you turn the wheel a little at speed? If it darts, search the tech forum for REBALANCE OF PS PUMP. It could simply be that your PS assist needs to be re-centered. In my case a couple years ago, it squared away my front end. I also had issues after alignment, but that was not the problem. The front was floaty before the adjustment but drove great afterward. If I find the link I'll post it.
try adjusting the steering bias. It's free... and quick job to try.
Last edited by JoeMinnesota; Oct 14, 2020 at 06:51 PM.
