MII Strut Failure HELP!!!!!!!!!

[PeterR]

I'm trying to pick up where I crashed 2 years ago. I do not understand # 7.
What is the purpose of cutting off a strut 2" from the bolt holes. Is this going to be my new strut? I hate being a pest . And thanks again for your help! :oops:

Just to reflect for a moment.    

Throughout this topic there have been numerous references to the need for all the pivot holes to be in a straight line if the arm and strut are to operate as a single component which rotates up and down without distorting any part.

Anyone not convinced should think of a trunk lid with three hinges instead of the usual two.  If the hinges are in a straight line the trunk lid can be raised and lowered easily.   If one of the hinges is welded on say ½" out of line, then every time the trunk is opened the lid will be distorted and the hinges overstressed.  Eventually cracks will develop in the hinges or the trunk lid.  

Similarly if the suspension arm and strut pivot holes are not arranged in a straight line something has to "give" when the arm rotates.  This will likely be the strut mount at the frame rail and flexing of the strut at the flattened section where the bolt passes through into the arm.

Item #7 effectively says, if misalignment of the chassis hinges prevents the arm and strut acting as a single assembly, then allow them to act as two components by placing a hinge where the strut joins the arm.

The pivot can be any type that is capable of carrying the quite substantial braking loads and also allows some movement in both vertical and horizontal directions. You could use a rod end, but a cheap, simple and more durable pivot can be made from the eye of a coilover welded to the strut as described above in #7 and pictured below.



The gold colored part is the original strut.   The dark blue parts are the pivot plates welded to the suspension arm, the pale blue part is the shocker eye. The chopped off strut is welded to the shocker eye ensuring that the original distance from arm to strut washer is maintained.

The only other consideration is that when looking at the arm from the ball joint towards the inner pivot, the pivot point where the strut joins the arm should be at the same height as the centre of the ball joint to avoid inducing twisting loads into the arm.

Don't forget all the work-arounds that have been suggested are to avoid the huge effort of ripping out the cross member and starting from scratch; but none will be quite as good as a true duplication of the factory layout which has proved itself over more years than most of us care to remember.

[t-vicky]

Well thanks guys, now you got me worrying about  the thin metal on on my brackets.

[nzsimon]

I always learn a lot from peters posts thanks for going to so much trouble if you type as fast as I do it must have taken a week of solid typing :-)

[rooster]

Item #7 effectively says, if misalignment of the chassis hinges prevents the arm and strut acting as a single assembly, then allow them to act as two components by placing a hinge where the strut joins the arm.

The pivot can be any type that is capable of carrying the quite substantial braking loads and also allows some movement in both vertical and horizontal directions. You could use a rod end, but a cheap, simple and more durable pivot can be made from the eye of a coilover welded to the strut as described above in #7 and pictured below.



The gold colored part is the original strut.   The dark blue parts are the pivot plates welded to the suspension arm, the pale blue part is the shocker eye. The chopped off strut is welded to the shocker eye ensuring that the original distance from arm to strut washer is maintained.

The only other consideration is that when looking at the arm from the ball joint towards the inner pivot, the pivot point where the strut joins the arm should be at the same height as the centre of the ball joint to avoid inducing twisting loads into the arm.

Peter would something like this be ok, adjustable might be a good thing! If I understand right this would be fitted to the long piece of the cut off strut rod then fastened to 2 fadded brackets attacheted to the a-arm. I'm not so clear about the coilovers yet!

http://cgi.ebay.com/ebaymotors/Imca-Drag-car-Two-1-2-hiem-joints-w-Tube-endes_W0QQcmdZViewItemQQcategoryZ34200QQihZ019QQitemZ290140895601QQrdZ1QQsspagenameZWDVW

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Engenjo has suggested this kind , they wont ware out as fast.
http://www.speedwaymotors.com/p/1584,296_Stainless-Steel-Rod-Ends.html

[PeterR]

I had only suggested using the eye from an old shocker because it would be a cheap source of parts, however looking at the price of the parts you have pictured it is not worth the effort of messing around with old bits and pieces.

Spherical rod ends will carry enormous loads for their size, but my experience has been that they have a very short service life in applications where they are exposed to the crud and slush thrown up from the road.

The other units look like they would be ideal, but there is only one small reservation  --I notice they use a nylon bushing.  A rubber bushing will absorb some sideways misalignment if the brackets are not exactly at the correct angle but a nylon bushing will not allow this so you will have to be very careful with your measurements.

Remember the sole purpose of this exercise is to allow for misalignment of the chassis pivot points. It does not reduce the braking loads in the strut which still have to be resisted by the rear chassis bracket.   Take notice of the advise given by enjenjo in the very first response to this thread

it looks like the material it's made of is too light, it should be at least 1/4" material, 3/8" is better. Actually the factory piece is 3/8", and, at least on Mustangs, were connected to a light crossmember to keep it from bending. Third, you should have a gusset at right angles to the strut mount, so it doesn't bend, but forces the bushing to flex.