I thought that would interest you afnid. I don't have another link that speaks to load path vs. non parallel control arm axis but I feel that fellow ED k on the link pretty much nailed it.

If you still plan to do the johnny joint mod I would suggest removing the stock SR mount from inside the frame so as to get the pivot axis centered with the LCA pivot, and I'm sure you understand why now. Really I suggest taking a second look at the RRS ones I posted.

Also, if you get after market adjustable UCA's you can adjust each side a different length, keep the pivot axis parallel, and get the castor you want. You basically end up with left/ right specific arms.

Last edited by Jon Richard (2/17/2015 1:34 PM)

Yes, you should consider the LCA and the strut rod as a rigid assembly, which it is.

Seems like the rear solution would be to convert the front bushing to a pivot bushing with the centerline of the axis of rotation same as the rear bushing, making it a true A-frame lower control arm.  I know one company has done this, but seems like there might be a better way.  I know they are just trying to make something that bolts on, but I think some minor mods would make it possible to do it.  Then, like an old Jaguar, you could adjust caster by adjusting the lower bushings fore and aft on their pivots.

I am installing adjustable strut rods with a heim joint.  I understand the potential down-side with noise and harshness but am doing it anyway.  However, I have an opportunity to move the front anchor point forward far enough to return the axis of rotation to nearly the same as stock.  I have the time and tools to do this and after reading on of Jon's posts above, it would appear that there would be a small benefit to retain the original geometery.  Is there any down-side other than the work?  I'm still dpwn to bare metal on the rotisserie so this would be the best time to have at it.

Steve, do you have any pictures of the setup that used a pivot bushing?  Seems like it would be fairly easy to incorporate at this point.  All I have to do is change out the front section of my strut rod assembly and modify the front mounts on the frame.  It would change the loading under braking, however.  Instead of a nice straight tension load on the strut rod, there would be a bending moment at the pivot bushing.  With appropriate design, I think it would be possible to handle the loads - all sorts of double a-arm systems that do.

There sure are a lot of Lemforders!  Jon, when you have a chance, send a link or a picture.  Looks like some of their control arm bushings would be a good starting point for making a true-er A-arm while moving away from the mounting configuration.

GPatrick wrote:

I am installing adjustable strut rods with a heim joint.  I understand the potential down-side with noise and harshness but am doing it anyway.  However, I have an opportunity to move the front anchor point forward far enough to return the axis of rotation to nearly the same as stock.  I have the time and tools to do this and after reading on of Jon's posts above, it would appear that there would be a small benefit to retain the original geometery.  Is there any down-side other than the work?  I'm still dpwn to bare metal on the rotisserie so this would be the best time to have at it.

i'm not quite sure what your entire question is but one thing you can do is modify the bushing end of the strut rod with a needle bearing and sleeve or a rubber mounted bushing similar to the one in the lower arm.
 
Make this bushing line up with the bushing in the lower arm, meaning that the bushing will now be parallel to the frame just like the one on the lower arm is.
 
Now, mount it so it is also perfectly in line with the lower arm bushing.
 
You have now made a traditional 100 year old A arm just like the upper one is except for the bushing type.
 
Now, the stock rear bushing pretty much prevents the arm from moving fore and aft in the bracket but if the bearing sleeve used in the front needle bearing is .050” longer than the bearing, then this should be shimmed so it is a minimal distance to reduce play.
 
Also, if both pivots were needle bearings and the sleve was .050” longer than the bearing, then obviously the whole arm could travel fore and aft a total of .050”, in which case it would need to be shimmed.
 
They also have seals for this design.
 
One down side to using this type of system is that you have now created a thrust and pivot surface that is subject to some wear from load and the movement.
 
If you use a rod end/rose joint, this will eliminate the thrust problem with the needle bearing design because the rod end will have the force inside between the ball and bushing.
 
 
One way to make it adjustable is to use a sleeve with opposing threads on each end.
 
This is an adjustable upper arm from tcp.
 

 
 


 

Thanks Jon, that bending/diagonal moment is what I was referring to in my post.  I think I'll stick with the tension and compression mode and just relocate the mount forward so that my heim joint matches the center of the original bushing.  If the other joint you were referring to will be a better alternative, attach a link.  The pre-made units with the rotating ball assembly are pretty spendy but if I can fab something up from parts it may be a good choice.  The heim joints I selected are not cheap but are easily replaced if/when they get noisy.

GPatrick wrote:

Thanks Jon, that bending/diagonal moment is what I was referring to in my post.  I think I'll stick with the tension and compression mode and just relocate the mount forward so that my heim joint matches the center of the original bushing.  If the other joint you were referring to will be a better alternative, attach a link.

Here's what I posted on page 1-

Jon Richard wrote:

Jon Richard wrote:

I have a set of massive sperical bearings rated for high impact radial loads from RRS that I think are worth consideration...
http://www.rrs-online.com/strutrodproducts.php

I mispoke, I meant "high impact axial loads", big difference. Here's a pic, it should be readily appaerent how these units work in a completely different plane. I've only had mine on the road a year so I can't verify, but in theory they should exibit a longer service life- no clunking- due to larger contact surface area and shear mass.

It's basically a big o'le spherical plain thrust bearing with a greaseable over sized housing having three holes drilled for mounting. It mounts to the front of the factory SR bushing mount so the pivot will end up inboard like 1/4" from the original axis, but I'll take that over 1 1/2" behind it like the heim joint style anyday.

I like these also because you use the stock rod. I have a TCP LCA and it all works so well together, but a bit of warning- the TCP LCA puts the LBJ 5/8" lower than the flat where the SR bolts to the arm and misaligns the steer stop to the spindle. Plus, for me personally I think the big tubular loud blue control arm looks garrish on a classic.

I think the hot ticket for a street machine would be a moddified stock lower with a lemforder bushing like I mentioned in concert with the RRS strut rod bushings, but I'm a big sucker for stock appearing modifieds-

http://www.corner-carvers.com/forums/showthread.php?t=47287&highlight=lemforder

http://www.europartimports.com/catalog/product_info.php?products_id=32


 

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Technically they were designed to use the parts they originally came with which is rubber mounted lower arm bushing and strut rod bushings, both of which are designed to be a specific size and durometer etc . . by installing harder bushings or roid endsw which have no give at all therefore providing no damping/shock absorbing qualities, the design has been changed from factory, so in reality, no one should use anything other than stock for fear of it exceeding some structural limit somewhere.

putting stiffer shocks or shocks with helper springs or air shocks on the rear has caused the upper mount area to crack in many cases . . these csan be reinforced with something similsar to a thick fender washer that is welded on . . i have actually done thos a few times . . it won't break again.
 
A single lower arm will not survive without the “strut.
 
in rough/general terms, an A arm is a single arm with a strut and vise versa.
 
Since the strut is solidly mounted to the lower arm, there is really not much difference between a true a asrm and a single arm and a strut.
 
If you take an A arm and mount the front portion of it like the mustang strut is mounted is it still an A arm or is it now a single arm with a strut.

if one is worried about the front frame or strut rod bracket cracking from using a solid mount on the strut rod [or from calling their arm and strut rod assy an A arm], which i think is a reasonable concern, especially if they road race or auto cross etc, they can simply install a U channel on the strut rod bracket channel in the area of the bracket that is maybe 4" long and 3/16" thick so the load is spread out over a much greater area, then weld a strong mount to it and be done with it . . its not like they are going to run their mustang in the baja 1000 so it will be way overkill this way and it won't look gaudy . . bresides, the factory strut rod and lower arm mounting brackets are only spot welded on anyway if i remember correctly with the exception of a small weld on the strutt rod mounting channel where it attaches to the frame and this area could be strengthened by simply welding it fully and/or installing an L bracket on top that mounts to the frame.

i would also use a new stronger strut rod, especially since its hard to know the history of the existing 40 plus year old one and it could easily be fatigued.

here's just one example of what could be used . . use chromoly if you want extra strength.



or use a taller u channel


or an L channel




in addition, when one installs stiffer springs, it is helpful to reinforce the upper suspension mount, especially if they drive the car hard . . the piece below is availble, however, i am more concerned about the towers cracking where the upper arm mounts as i have seen dozens of times . . this can be strengthened a few different ways.

  


i have seen the upper shock mounting moumntind brackets not only crack but break off at the screw holes . . these can be reinforced with a cou;ple flat washers and full weld around them.
 

or use these cnc'd billet brackets from drake.
..................................................................
 

Last edited by barnett468 (2/19/2015 2:11 AM)

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Yes the rubber bushings do add stress to both the rod and bracket and the engineers that designed these parts knew that and accounted for it . . also this stress is minor and can easily be gauged by simply installing stock bushings and moving the strut rod arm by itself thru its range of operation . . this could also be done with just the lower arm attached and its pivot bushing bolt loose so it moves freely . . I have done this myself by hand on a mustang a few times, but did not measure the force because it was plenty easy enough for me to do, therefore I had no interest in pursuing it any further.

this rubber mounted strut rod system has been proven to work for 50 years in a mustang and 60 years in t bird and 55 chev bel air etc and over several hundred thousand miles in some cases . . using a solid pivot in a strut rod on an early mustang hasn't been proven for even 1/3 rd of this amount of time . . perhaps it will work without causing any cracks for 50 or 60 years and several hundred thousand miles also but it hasn't been proven to do so yet..
 
In addition, if one wants to mount the strut pivot so it adds no bind as the suspension arm goes thru is range of operation, they can simply clamp the mount in place and move the assembly thru its range of operation to insure the strut rod mount is exactly where they want it before they weld it . . this simple test is helpful when trying to determine the correct location if one does not have the proper set up and fancy measuring devices to measure it with.
 
Yes any pivot bearing will eliminate any bending stress caused by the pressure created by the strut rod bushings, however, there is increased stress from shock from a solid pivot like a rod end so which stress do you want . . the bottom line is, it is unarguably better to make the bracket and other affected areas stronger when using the vehicle in a way that it was not intended or designed to be used and/or when adding “high performance” suspension parts etc.
 
The mustang II is not same as an early mustang, therefore many comparisons to an early mustang are not practical imo, plus that was a new design and new designs are occasionally found to have flaws or potential weak areas etc which are often improved upon in the subsequent models, plus none of these cars was either designed or intended to last 50 years etc . . I know for a fact that in many cases the design criteria is “planned obsolescence” . . keep in mind that within the last 10 years, over 1 million or more cars have been recalled due to flaws in a design, so there are design flaws and failures in brand new cars so i am vcertainly not surprised there might be some areas that crack in a 40 year old mustang II.
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Last edited by barnett468 (2/19/2015 3:42 AM)

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I think the lateral, axial rotation of the confibulator arm will cause the seminator joint to deflect thereby allowing the oscipulator bearing to migrate within the hipopotenuse of noahs ark which will create a dihedral motion on the parallellagram as it travels thereby creating an octagonal bozinator wave which could eject the jockey from the jockey box depicted in the photo above.
 
I think this brief video will explain it bit better.

https://www.youtube.com/watch?v=rLDgQg6bq7o
 

Last edited by barnett468 (2/19/2015 6:12 PM)

rpm wrote:

Kudos Barnett! I've never seen your humorous side. That vid is an all time great.

Bob

lol, thanks rpm . . much appreciated . . i am actually a really fun and entertaining guy, lol . . there is just not something i exhibit on the forum.

as we all know, we only have what we read from someone to get any idea about them and this is extremely limited.

i used to race off road and play guitar in a few rock bands and party at the river etc so we [ i ] did one or two "interesting" things along the way when i was young so i'm really not all that anal retentive, lol but i guess now i am definitely a lot more boring.

as far as the video goes, i'm glad you liked it . . my friend posted it on another site saying this was me . . i laughed so hard when i saw it that tears were running down my face.

can you say "prefabulated amulite"? . . sure you can...i knew you could.

by the way . . cool car.

Last edited by barnett468 (2/19/2015 5:26 PM)

I would never thought when I started this post, it go this long. Does anybody have a link to torque specs for the front suspension members. Somebody linked info for 65/66, but mine is a 67 and I didnt know if those specs are the same.