on my 61 Pontiac fullsize, it started to have wheel hop. suspension style is original triangulated 4 link. i inspected rear linkage, and found that the rear cross-member started to separate from the frame. crappy factory welds don't necessarily help matters i suppose. first thing i did was fix frame, and build some additional support from the rear cross-member to frame (from directly behind the UCA mounts triangulated to frame). the control arms i had in place were aftermarket tubular arms with fixed poly bushings. they are nice, but i started thinking that the triangulated 4 link with hard poly bushings ~might~ be binding enough to create some twisting forces on the mounts. i decided i wanted heim style articulation and also add adjustability to uppers. so... do you have to give up the ride benefits of poly bushings to trade for the articulation of heim joints? another member here (Jeff K) used Currie Johnny Joints to adapt to the same tubular arms for his Pontiac, but the mounting width of those were too wide for my mounts. i found these similar joints (Ballistic Joints) that have 2 5/8 mount width with 9/16" thru bolt (my stock mount setup), poly bushings, fully articulating, greasable, and adjustable for wear. available either with adjustable length shanks or weld-in cups. also, these are made and forged in USA. cut 1.75" .120 wall DOM to length at a friends shop: welded them up. adjustable joints on uppers have 1.25" shank. came with weld-in tube inserts. each joint has a ball that sits in poly inserts. i think they are strong enough lol: my buddy powder coated them for me, ready to go. but.. 7 degrees F outside and icy, won't be able to comment on ride until that stuff melts.
The Johnny Joints will certainly articulate better, and it looks like you did a really nice job on them, but that suspension design relies on the soft compliance of the stock bushing to do more than just rotate, but actually will compress and extend slightly during full articulation. It is one of the problems with the upper arms being that short. You have improved the situation over the Poly bushings you were using, but you will still have some potential binding at full articulation
True to a point...lots of aftermarket oblique 4-links e.g. DSE get away with bushings that are fairly (or completely) rigid radially, so he might be fine. But yeah, poly is a killer in that application (and just about any other control-arm type of application involving rotational motion, never mind the twisting.) Why do people persist in using that stuff? Body mounts, sway bar endlinks, fine. But not control arms, front rear or otherwise, please folks...
Many of the aftermarket tri-4 link setups also use a rotating joint built into the upper arm to eliminate the tendency to bind.
Jeff, if the mounting holes are on a single line, as in a front LCA, poly is fine. There is not twisting motion as the suspension cycles. I have run solid bushings many times on circle track cars over the years; and found in most cases I had to run a long drill bit through all 4 mounting holes to free the solid bushings up so the arm would rotate up and down.
Twisting/binding side to side is a whole other problem. But this^^^^^^ is what will solve any other issues.Lubrication def helps,and those arms look great. I think you will be fine. Articulating up and down for a small percentage freely will/shouldn't bind with what your doing/installing.
Thanks for comments. I get it that triangulated 4 link requires compliance with not only twisting but also length. My little brain cylcles the suspension in my imagination and it sure seems like if I relieve the twisting that is a big deal for most the driving. From droop to compression, if axle stays level - it doesn't need any length compliance from arms - it will just change pivot angle. But it does need twist compliance in the uppers. When axle leans in a turn, the geometry becomes imperfect and will need length compliance from arms, but I ~think~ very little.
Yeah, the main problem comes from things like steep driveways when you are turning in and going at an angle, that is when you will be taxing the system, so you will be fine. I was just explaining the limitations overall
They installed nicely. Old arms require a drift pin to remove bolts, these of course just line up the joint and slide bolt in. When I let car down on jack it was whisper quiet. First check of a jack point on one side lifting a wheel was 4.9 degrees rotation of axle. Art Carr says their triangulated 4 links have 5 degrees. Suspension design is full of trade offs. This feels like a good trade.
Putting those on both ends of the links might be overkill on a street vehicle. I have them on just one end of each link on my rock rig, with rubber on the other, and it does 1100 RTI on a 20º ramp! (Okay OT, I know) If you need more articulation than this, you're on the wrong forum:
How long are the arms on that truck? If the arms on my street car were that long I could probably weld them in and be fine lol. My uppers are 12 3/4". I think it was pointed out above that short arms aggravate the binding. But ur right, I prob would be fine with only one end jointed, especially on bottom.
I though that you would only put the ball end in one end of each control arm. I have a 65 chevelle and have been thinking of the same stuff for better cornering.
A ball on one end will take care of the twist. There is also alignment that becomes imperfect. But like length compliance, I think alignment is less of an issue than twist (at least when I watch mine cycle). Putting a joint on one end will stop the twist which I think is the biggest problem on mine - and prob similar on 65 Chevelle. Imagine a ball on one end, and a bushing on the other. The bushing sits in flanges. If those flanges stayed perfectly centered, pointed at the center of the ball joint on the other end of arm during full suspension range, then it would stay aligned and bushing would be fine in those flanges, but it doesn't. The longer the arm, the more wiggle room. It prob would have been fine to just put joints on one end my uppers like Jeff did, but I started thinking too much.
Just make sure that you have good quality shock absorbers in there. You're removed the rubber bushings, which act as small torsion springs, bringing the suspension back to center. With much of the built-in friction removed, you will be more susceptible to unwanted oscillation. I had it, even with them just one one end. Better shocks did the trick. You'll know pretty quickly if the current shocks are not up to the task.
Snow melted and I have been able to horse around with the car. Holy crap - the improvement is way more than I hoped for or even realized possible. The wheel hop is entirely gone, but the amazing part is how much smoother the chassis is all around. I was hoping to fix the real heavy throttle stuff, but I didn't expect such an improvement on the part throttle acceleration and cornering also. Super happy with it.
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