ph31mwl

This is a long one but I have questions about replacing the control arm bushings and control arm shafts.

While taking apart the control arms on my 65 I found that the rear of right lower control arm shaft was bent inward and downward. That might explain why the front right could not be aligned properly. Since it appears to have been hit pretty hard somewhere along the line to have been bent like that I assume that the control arms themselves must be bent to some degree (even though there is nothing glaringly noticeable). I have a front suspension from another wrecked 65 that I got back in the mid-seventies that I got for a parts car. The shafts are straight so I am again assuming that the control arms are OK so I am using them.

All the control arm shaft ends are rusty and pitted so since I am doing a total rebuild of the car I have purchased all new upper and lower control arm shafts. All the parts suppliers have the OFFSET Upper Control Arm Shafts so I got that type. Here is my question, what is offset about it?? When I lay the offset shaft next to one of the straight shafts they look the same. Looking at them the holes are in the same place, they are the same length and width, and they are the same thickness.

I received the new shaft kits and they have rubber bushings, not poly. I already had the suspension bushing kit that is all poly. Since it appears the greater consensus is to use rubber bushings for the suspension I will do that.

Is the process for installing rubber bushings on the control arms different (easier/harder) than Poly? Do you lube the shaft end before installing the rubber bushing??

Earlier in January when I was inquiring about the poly bushings one member of the Forum pointed out the following: “And keep in mind it can only go in one way to be correct and HAS TO BE CORRECTLY rotated to rest FLAT against the frame when you install it when completed.” I think I understand the “can only go in one way” part. The hole for the single bolt goes toward the rear. But I do not understand what “HAS TO BE CORRECTLY rotated rest FLAT against the frame when you install it when completed” means. My understanding is that once the poly or rubber bushings are installed in the control arm you do not tighten the end bolts until all the weight is on the car and it is on the ground so you can rotate the shaft to line up with the bolt holes and there is no pre loading of the bushing. I assumed that as long as I don’t put the end bolts in that once in the control arm I will be able to get the shaft lined up with where it mounts to on the frame then (after the weight is on the car) I install the end bolts. Do I somehow need to have the shaft pressed into the control arm in the exact position it needs to be in for bolting to the frame before bolting it to the frame because the rubber bushing will not let the shaft turn once in the control arm??

I thank you in advance for any and all guidance you can provide.

Mark

JohnZ

You're about to make two common mistakes:

1. Unless you plan to "race" the car (road-race, autocross, etc.), poly bushings are a lousy substitute for the OEM rubber bushings - they wear out, they squeak, and their hardness telegraphs every chassis noise/vibration right back into the car. The poly bushings are a slip-fit on the inner shafts, and are also a slip-fit on the sleeves in the holes in the control arms. Everything moves relative to everything else.

2. You don't understand how OEM bushings work. The OEM rubber bushings are bonded to the O.D. of the steel inner sleeve with the serrated teeth on the ends, and are also bonded to the I.D. of the steel outer sleeve that's pressed into the holes in the control arms. When the end bushing bolts are tightened, the serrations on the inner sleeve bite into the shoulder on the cross shaft at one end and into the thick washer under the bolt head at the other end, and NOTHING moves relative to ANYTHING; all suspension movement takes place within the rubber element in the bushing, as the outer sleeve is locked in the control arm, and the inner sleeve is locked to the cross shaft when the bolt is torqued. Many people don't know how OEM bushings work - sketch below shows a typical bushing with the serrated inner sleeve.

The "offset" control arm shaft is also shown below, with the stock shaft - note the difference in the axis of the threaded bushing bolt holes relative to the seating surface of the shaft on the frame; the offset shaft is on the right.

DUB

The offset is seen when you look at the center line of the shaft where the bolts pass through...and then the center line of where your bolts go into the ends....They are OFF...

The process if installing rubber bushing is faster...because in some polyurethane bushing designs...you have to modify and cut or file the inner sleeve to achieve a specific gap between the poly bushing and the flat washer provided in a kit.

I can say this...that I use special made cut tubes that keep the control arms from collapsing when I am pressing in the bushings or the sleeves. If doing this without these 'spacers'...you can easily destroy the A-arm...especially the lower A-arm.

The lower A-arm shaft HAS TO BE CORRECTLY ROTATED....and by KNOWING which way is correct....YOU LOOK at the two holes at the front of the shaft...where it mounts to the frame WITH the 2 long 7/16"-20 bolts and nut plate.

Only ONE WAY will allow the shaft to seat FLUSH against the frame....and if you rotate it 180 degrees...and set it up against the frame...the 'ears' of the arm will have a space between them and the frame where the 2 bolts go....which tells you that you have it in WRONG.

Put the bolts and cupped washer on your control arms but leave them loose so the cupped washers can move or spin....and when you have it on the ground and settled....tighten up the bolts.

I also apply a thin coat of anti-seize compound on the shafts where the bushing inner sleeves are...to aid in stopping any rust from developing.

DUB

ph31mwl

JohnZ & DUB

Thank you very much for taking the time to provide me with detailed, understandable answers to my questions. As I mentioned in one of my other posts on other questions I had, I am more on the body work and paint end of the hobby. I can do the mechanical side but before I do I search out how to do what is needed and if I can’t find it I ask questions…..lots of them.

I am going to be using the rubber bushings and now I understand how the OEM rubber bushings work. So once they are installed in the control arm I can turn them until I tighten the end bolts and washers.

I took my old shaft and laid it next to the new offset one. I did not see the difference before. Now it is glaringly obvious what the difference is. Just want to make sure which side goes to the frame. As I believe you have indicated the seating surface of the offset shaft is the side that the offset ends of the shaft goes toward. In your picture, the seating surface is the right side of the shaft.

Also, what is the point of the offset. The part description says it is to provide additional positive (+) camber adjustment, but isn’t positive camber an amount that the top of the tire is away from the tire’s vertical relationship with the frame? Why is more + camber a good thing? Does it make up for a bent frame (like mine that I am going to have straightened) and other problems with the control arms?

Lower control arm shaft – now I understand that, the side that fits flush to the frame. I looked at the new shaft and see what you have described. Excellent.

Another Forum member who lives close by has indicated that he will help me install the bushings into the control arms. If he does not have the cut tubes to support the ends of the control arms then I will make some.

Thank you once again for your responses. Very, very helpful

Mark

DUB

YES...so the off-set goes towards the frame....or basically when both are installed...the off-sets face AWAY from each other.

Due to the engine cradle collapses over time...EACH time you get an alignment...the UPPER CONTROL arms get closer due to the cradle collapsing.....SO....the alignment shop REMOVES shims to set your camber /caster....and this removing of shims ALLOWS your UPPER A ARM to go outwards. EVENTUALLY...there will be a point in time where there will be NO SHIMS...and you can not align up the car. The 'off-set'...gives you more time due to putting the upper A-arm further out PAST the center-line of the original design shaft.

[QUOTE=ph31mwl;1588807362]Lower control arm shaft – now I understand that, the side that fits flush to the frame. I looked at the new shaft and see what you have described. Excellent.[QUOTE]


You WILL want to fabricate some spacers..and MAKE NO MISTAKE...BE VERY WATCHFUL when you are pressing int eh lower bushing...because they have to go in really straight...and if you get them started in at an angle...and thy do not go into the the inner areas of the lower a-arm where the bushing go...you can EASILY damage the A-arm. DO NOT ask me how I know this.

DUB

ph31mwl

Thank you DUB. Offsets face away from each other. That is easy to remember. My frame must be bent really good someplace on the right side. In order to get the alignment even in the ballpark the alignment shop had to add so many shims to the rear shaft bolt that there was no more room to put a shim in. That is why I am taking the frame to the frame shop to get straightened. After I clear the snow from my driveway and help some neighbors with their driveways I am going to make a couple of the cut tube spacers for the control arms so they do not bend while installing the bushings.

Thanks again, Mark