space between upper different arms

[LMBRJQ 60]

Hi guys
has any one measured the distance between the upper arm brackets either on the rear end or the frame?
Have a replacement bracket for the other side but seems to want to mount on the different about 1 inch wide apart than what the frame mounts would be.

Steve.

 

[Fathead Racing]

Is the car in the laden position? Are you checking it by bolting one end to the frame bracket and letting the other end fall to the rear housing? Those arms do not come straight back from the frame mount to the axle, they are splayed a little. This is if I"m reading your question correctly.?Did you measure and see if the rear end was centered in the car? Those mounts are a little forgiving as they are rubberized on the pivot points, push it where you want it and see how that goes. With up and down movement of the car the axle will move side to side a little also due to the panhard bar connection. Have I got it Mate?

 

[Phil Reed]

Too much to figure out Ray. You need to take a trip to New Zealand and help Steve do it right!!!! Go now.............it's summer there!!

 

[LMBRJQ 60]

Too much to figure out Ray. You need to take a trip to New Zealand and help Steve do it right!!!! Go now.............it's summer there!!

Phil I agree. I will send Ray a map and some sun tan lotion.

Is it alright if Ray has you and Candy's room while your not here?

Is the car in the laden position? Are you checking it by bolting one end to the frame bracket and letting the other end fall to the rear housing? Those arms do not come straight back from the frame mount to the axle, they are splayed a little. This is if I"m reading your question correctly.?Did you measure and see if the rear end was centered in the car? Those mounts are a little forgiving as they are rubberized on the pivot points, push it where you want it and see how that goes. With up and down movement of the car the axle will move side to side a little also due to the panhard bar connection. Have I got it Mate?

Ray.
I am thinking the same thing re the top arm being on a slight angle away from the center-line of the chassis at a normal ride height (laden?)
Is there a figure for where the normal laden height is anywhere (factory that is) i can then go from that and alter according to my final spring height

My concern is that if i was to put the other top arm on and have it angled the other way to match where it would need to go on the differential housing that it would bind the rear end from moving up and down due to the pan-hard rod pushing the rear against the arm (sideways)
Will do some more measuring today (will keep me out of the sun) need to get air-con in the shed

Had to put in an irrigation system yesterday as all of our grass was dying, bloody summer. nothing a foot of snow would fix eh?

Thanks for the help guys

Steve

 

[Fathead Racing]

Because everything is mounted in rubber or urethane these would be pretty forgiving if they were a little off one way or the other. Try not to overthink it. It helps to have a few stiff shots of your favorite shit when you run out of ideas. Remember, nothing that is done can't be undone.

 

[61BUBBLE348]

Hi Steve,

the Pumpkin of the diff centre is offset, at ride height the second arm and bracket will align partly up the centre housing, unlike the RHS where it is on the axle tube.

I can measure the mounting pad on the chassis, but I don't think it will help much, typically at ride height and everything centralised, the second arm will be where it sits the best.

It is pretty well like most 4 bar setups, the only thing with the Chev system is the panhard bar is really in the wrong spot, technically at ride height it should be parallel with the ground, and really should be adjustable, remember these were mass produced.

cheers

 

[LMBRJQ 60]

Hey Grub.
thanks for the reply. In reality the two top arms don't appear to be parallel with each other. I an doing some more measuring later tonight so will have some more details then. Have you got double top arms on your cars?
Steve

 

[61BUBBLE348]

Hi Steve, not yet, I did it on my first 61 back in 1980 when I stuck a MKIV 427 in.

As Ray has commented, the whole stock setup is (and is designed to be) squishy, if you look closely at all your bushes, they are designed to be flexible, compared to a street rod 4 bar which is almost rigid. The more rubber in bushes and body mounts helps with drive noise and vibration through the body, when the cars are hammered ( either by HP or age) these soft rubber bushes get really distorted.

if you have a chassis drawing it should show the trailing arm mounting points, in general these are symmetrical.

In regards to the stock setup, on full down travel the whole axle assembly moves back and to the the right, this movement can be as much as 1-2 inches.

On the 3 Hot Rods that I have built, I have set the 4 bar and panhard bar neutral at ride height (front and rear), this allows the car to behave under rough road driving conditions.

cheers

 

[LMBRJQ 60]

The story now

Im sorry for the measurements being in millimeters but it is what i had at the time

The issue is coming from the frame recess for the second arm

The distance between the centers of the recesses for the two arms on the frame brace is 345mm

The original arm is centered perfectly with this bracket if the rearend housing is centered in the frame (so wheels same distance out from the frame each side and the original brackets line up perfectly for the original top arm)

If you put an arm mounting bracket on the second indentation and bolt it there with an arm in it it wants to be closer to the diff head than the axle tube

The second arm brackets (showcars) are made to fit in a certain place on the housing. that place is 265 centers from the original one. so i have 20mm (around 3/4") distance issue

Options

1. make a new bracket for the rear end and move it closer to center (i dont like this as then there is 20mm more rear un braced out one side than the other, i like things to be even if possible)
2. Cut piece of rearend frame brace out and shift the indentation/recess 20mm closer to the LH frame rail
3. some other idea like an offset arm?????

Any ideas welcome, will try to get some pics on here but it is the south islands biggest car show this weekend and we are getting ready for that. camping on site.
round 1200-1500 cars (big for over here)

Steve

 

[Fathead Racing]

Modify the axle bracket to fit where the arm comes to rest. My axle bracket is up on the differential case on one side, no big deal. What rear end do you have in the car? The upper brackets are not for bracing as much as they are for setting pinion angle and keeping the axle from rotating. The bottom links are the ones that keep the axle in alignment.

 

[Fathead Racing]

While we're at it. Where did I hear that when your adding shims that one side of the upper arm should be what is referred to as prestressed. That is shims added or taken away until you have to pull the arm towards or push it away against the other side.

 

[LMBRJQ 60]

While we're at it. Where did I hear that when your adding shims that one side of the upper arm should be what is referred to as prestressed. That is shims added or taken away until you have to pull the arm towards or push it away against the other side.

HAvent heard that one Ray. I will have to have a think on that to see if I can figure why. Short axle go long axle which side and what way?
my brain hurts

Steve

 

[LMBRJQ 60]

Modify the axle bracket to fit where the arm comes to rest. My axle bracket is up on the differential case on one side, no big deal. What rear end do you have in the car? The upper brackets are not for bracing as much as they are for setting pinion angle and keeping the axle from rotating. The bottom links are the ones that keep the axle in alignment.

Original rear end. Nitro pozi. 3.70 gears. Will run Moser axles. Think I will take your advice and change bracket

Steve

 

[61BUBBLE348]

While we're at it. Where did I hear that when your adding shims that one side of the upper arm should be what is referred to as prestressed. That is shims added or taken away until you have to pull the arm towards or push it away against the other side.

Ray there was a recent thread about this, as long as the car is at ride height with the chassis bracket and arm bolted to the chassis with the same quantity of shims as the existing top arm, then the rear bracket bolted to the arm can rest where it needs to, at the same orientation vertically as the existing (RHS) top bracket, then the new bracket can be tack welded in place.

A point to remember is that any welding on the Diff housing will distort it, and may need to be straightened, typically the weld will shrink that bit and pull up, apply the right amount of heat to the other side usually will pull it back.

 

[Fathead Racing]

Ray there was a recent thread about this, as long as the car is at ride height with the chassis bracket and arm bolted to the chassis with the same quantity of shims as the existing top arm, then the rear bracket bolted to the arm can rest where it needs to, at the same orientation vertically as the existing (RHS) top bracket, then the new bracket can be tack welded in place.

A point to remember is that any welding on the Diff housing will distort it, and may need to be straightened, typically the weld will shrink that bit and pull up, apply the right amount of heat to the other side usually will pull it back.

I probably ran my mouth in that thread.

 

[Phil Reed]

I probably ran my mouth in that thread.

That's probably gotta be a first!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Fathead Racing]

That's probably gotta be a first!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Peep.

 

[Phil Reed]

 

[1961BelAir427]

 

[tripower]

The left side or drivers side stamp for the second upper control arm is 1" further inboard.