Mega Modding Braking, Suspension & Steering

Updated my specifications section. A lot of info that was in need up updates. It was used as a scratch pad, as I got more involved, things changed, but the page did not.

Also added my latest an last effort vector chart on the final suspension setup.

Will need to ream my Mustang II spindle's upper mounting hole deeper to allow 1/4" more seat with the GM ball joint's long mounting stud. Since 10.50" is the gap between upper and lower arms with all components assembled, will need to make corrections for being .250" too tall. The easiest way is to ream the upper control arm mounting hole to the spindle over sized even more, so the ball joint seats .250" deeper in the hole.

Needed to get all that squared away before final mods to the suspension humps. Since there was concern about needing to drop (cut and move) UCA mounting locations, and enough distance for UCA to LCA offset. Since AMC uses 7° KPI, and Ford uses 10° KPI.

I may have missed some details in the specs, but I was more concerned about getting the more important specs updated. I will go through ojce more at a later time, to check for missed errors.

Edited by 304-dude - Aug/15/2019 at 7:14pm

Decided to drop the use of the K6122 GM ball joints. Mostly because, to make them work for my fully modded suspension with the 10° spindles, would require a band aid correction. Use of a spacer, and deeper reaming of the upper ball stud hole.

I explained reasons in detail, in the using Mustang II spindles section, and partially in the specs section. In doing so, I now have two processes for the spindle install, being that when i started out, 10° oem spindles was what I chose and never thought about using 7° racing spindles.

So, until I decide on which upper ball joint I will use, all the info based around the K6122 is for a slightly modified suspension only (dropped perch mod), required, while using a 7° Mustang II spindle. See the OEM vs dropped perch thread. Its based on stock upright and 7° Mustang II spindle

Since i never had anyone try an follow along and provide feedback, my best efforts, in attempting to cover what is needed or required, for which ever direction anyone may take, has been a bit cloudy by too much mixed in the bag. I admit, i have been caught in misdirection, from so many different changes, that is why I took time to reset and map out things as of recent. At one time I did all the planning on the PC, as i would not have gone this far. But that info is long gone, and what data i did not have on PC, was scattered about on my thread.





Edited by 304-dude - Aug/20/2019 at 7:33pm

farna wrote: You don't get a lot of comments because not many people are going to this extent to modify things. That doesn't mean you're not getting people following though. The only other person I know for sure who is doing something somewhat similar is Tomj, but he's working with the old 58-63 American chassis (his is a 62, IIRC, but front suspension is the same 58-63) and it's totally different. You're using the forum here as a sounding board and documenting everything. Great idea! Takes a bit of thinking to follow everything, but you're doing a pretty good job of documenting your thoughts and results. a few photos of what you've done at some point will complete it!

Thanks farna! Yep, i dont expect anyone to copy me from head to toe... even though the thread sounds like one big mod, it is really a compilation of various mods that can be utilized independently if needed.

Also, by the fact some question has been brought up at various times, i have tried to go outside my work at hand, to include stock setups the best i can. Unfortunately i did not expect to after i started, so a lot of stock details have been to the way side. Only until recent I was able to pull off some comparisons, to show how things will fit and function together.

I did not expect things to get so complicated when sudden branching out of two types of Mustang II spindles became an issue, once i took notice. Mostly because the 7° KPI spindles seem to be more prevelant now, than back when i made my selection.

Not that i expected more comments, just assumed the ones who try to follow along would catch some conflicts or errors. Seeing no question, let me believe things were good, so to speak.

Since, this thread is so large, i have had my own difficulties sorting at times, and done a bit pf clean up as of recent.

Though my upper ball joint selection issue, seems to be a small obstacle considering it was a late change in the overall plan, it has turned out to point me in areas that were questionable, so it has been a good error for now.

Maybe its me, but in digging into the various aspects of the 70 on up AMC suspension, it seems that most all the important details are inherent to the suspension components and their location.

The upper arm needs no relocation on the vertical plane.
The strut rod and LCA, is in proper location and length.

The only limiting factor is how the suspension is raised or lowered to get the dialed in operstional requirements.

I think that because I chose to lengthen and move things around, many may not see the reasons why, and assume its all for handling. The handling will be better, but not enough to warrant doing such work, unless building for track.

The non oem KPI and wide wheel and tire combo is the deciding factor, first and foremost. Heck, if i had kept my limits to my original pick for wheels and tires, I'd be done right now with the front suspension.

Its nice to see others do their own take on mods... Dairyland Fabricstions aka 343sharpstick helping out pre 70 cars.

Also, I have yet to see GreyhoundsAMX start up on his strut rod replacement, possibly over the winter... and am looking forward to hearing about it when completed. The two kit options he has found, are the only kits that follow AMC oem mounting location pivot points.

Thanks for following along, and your input... there have been a few things that have been enlightening, some of which may be indirect, by me going off tangent, in looking at the question at a different angle.

I try to add pix time to time... just not the best of lighting, and very cramped. Once things are fitted more images and details will come.

I'll do a before and after suspension hump mod side by comparison, once the set is welded, and I have removed one for swapping out.

Still haven't gotten around to cutting and fitting reinforcements to the upper and lower arms, to be welded. The welding snafu of my brake pedal too the life out of me, in expecting to having any further welding done this time of year. Then when done, I can clean them up and paint for assembly. Though i can always assemble when needed, as the reinforcements are not required for fitting and testing. I tend to do things in priority level.

After a bit of weighing how far to set the depth on the upper tapered hole on the Mustang II spindle's upright, for use with GM ball joints. I Looked over the sweet spot to get both upper and lower arms with symmetry on upper and lower angles.

Assuming 1/8" variance for upper and lower arm pivots to make total vertical distance between them around 10.125", I can safely ream oversize the taper to allow a .250" deeper seat, which will make the hole proper for the .6125" GM truck ball joint fit. The K6122 and K6174 (depending on manufacturer), will allow a smaller hole since they have full taper from the thread, though the height or seat depth will be only beneficial if using stock compontents and geometery, to compensate for camber gain.

Be careful with ball joint selection, as some have an oversized step above the threads, which expect the hole taper start to start at .6125". Also some have an upper protrusion (dome) that will block the lowered spring saddle from pivot operation.

Anywho, i can safely set the seat to proper depth in the hole, and allow the distance between upper and lower arms to be around 10.25" to 10.33".

Basically its back to my original calculation, as i changed thoughts during my other calculations with stock components, and figured it was safe to go deeper on the seat.

Starting at 10.25" will place the setup close enough for minor tweaking, but only if there is something noticabley off. Getting the suspension within .3° on the arm angles would only be a requirement for all out race, which would not be noticable on the streets.

So the basic dial in is for 5°/-5° lower arm travel, with 8°/-8° upper arm travel symmetry. Having symmetrical angles will give the maximum travel distance of 2.7" within the angles given. Though suspension travel can move above and below the values given, if not exceeding limits via obtruction. Just camber gain may effect how far outside travel limits given are exceeded.

If distance between upper and lower arm pivot points are .125" below or above my set value, the angles will very about 1° with the upper arm, which is ok, since the lower arm angle will not be as effected. It wont effect camber gain much, as it is <=1° max for the given angle range.



Edited by 304-dude - Aug/26/2019 at 8:20am

Updatedo the poly madness section. Will not use Teflon washers, since the oem steel washers are large enough to keep any side loading from the arm walls from directly touching the poly.

Added a few more pictures, and will reorganize details much better later on. Seems like by trying to show various methods to modify, they conflict and may confuse some.

All in all you must modify the kit to makeep each bushing fit like OEM. Thus, the oem washers are critical when assembling. Since I have two upper bushings without washers, I will look into modifying steel washers to function in their place. Probably be best to use one oem washer on each new poly sleeve, and add the modified washer for completion. It would at least make all 4 bushings more or less the same.