EM - Axle rubbing on A-Arm opening

[joelsplace]

At zero camber your backing plates should have aligned properly. The motor mount correction will allow you to get to zero camber with less than your 21 7/8 lift. I'm guessing 21 7/16".
Maybe your control arms are bent. That would explain the axles and the backing plate alignment.

[Wittsend]

I'm b-a-c-k... - again. I supported the car and then unbolted the rear motor mount. Judging from the distortion of an old mount that I had disassembled it looks like there was no opportunity for the mount to sag/distort more than 3/4". Thus I moved the engine upward (the only direction favorable to the problem) 13/16" and observed the center of the axle and the brake drum situation. It is for all practical reasoning imperceptible that either moved favorably in the pictures below. And it placed the engine side seals well above the opening perimeter at the rear.

To Joel's question about the A-Arms being bent..., the weld seam looks straight where both halves join and I don't see anything unnatural distorted in the metal. It would seem odd that they bent equally on both sides too.

The only thing that would seem to be a favorable movement would be elevating at the trans mount. As is often noted in "lowering" posts radical crossmember alteration is the only real solution. That said since there doesn't seem to be a cause for my problem I will have to work around it as best as possible. I'm curious what gap others have between the trans mount and the crossmember? Using drills as a Go/No-Go gauge I can get a 3/8" drill between them but not a 7/16" drill. This is with a PG mount, not manual if it makes a difference.

I might be able to gain in my favor 3/16" by putting the rubber mount in the lathe and turning down the center, outer post (the one the bolt goes through). But, I'd think there has to be a minimal amount of clearance otherwise it could encounter metal to metal contact. It also looks like I might be able to notch the holes on the metal mount that bolts to the transmission and maybe pick up 1/4" there. It seems anything would help. I've also seen in other posts about washers behind the backing plate. Seems a bit sketchy but this car is going 10 miles on surface streets twice a month to Cars & Coffee and when I breath my last it is likely going to the junkyard.

Lastly, help me with my understanding. The weight of the body bears down on the powerpack through the rubber mounts (the effect of gravity). Over time this weight bearing seemingly would affect the rubber mounts compressing/deteriorating and while the body is moving downward it could also be stated that the powerpack would be moving upward. And the powerpack moving upward is what I need to more center the axles and correct the angularity between the drum and the backing plate. So, I'm not quite grasping why replacing the mounts would be beneficial when in fact (at least in this odd situation) it moves the problem in an unwanted direction???

[joelsplace]

I keep saying it won't help.
Slice the rear mount open and put in a spacer to locate the engine. I think I used a 3/8 nut once. Maybe 5/16.
There is an oval hole in the metal that lets the rubber flex. Just put something at the bottom of the oval to make the mount centered again. You will lose the rubber isolation but I'll bet you won't be able to tell. That will get the engine height correct so you can move on to finding the real issue.
The reason I suggested bent control arms is the backing plates not being aligned at zero camber. They should be straight at zero. That's where I would focus. I guess the backing plates could be bent but that wouldn't bother the axles.

[manvair]

I'm not an EM expert, but you seem frustrated, so I'll offer what random ideas I have. Take this with a grain of salt. The relationship between the axle shaft and the control arm is basically fixed at the outer end by the wheel bearing. So, your trouble has to be at the inner end. I wonder how we could measure the relationship between the axle u-joint and the control arm pivots on your car vs a known good car?

[Dennis66]

I just looked at a '64 convertible that a (new) friend has yesterday. I noticed that his engine is sagging (bad rear mount) and the engine sits much lower on the left side. Can't wait to see what his axles look like (yes, I'll be working on it). Dennis

[jimbrandberg]

One time I was convinced a 64 had bad front mounts because the engine was leaning. It turned out the two 3/8 and one 7/16 bolts holding the bracket to the front of the 4 speed transmission were loose.
Jim Brandberg
Isanti, MN
CorvairRepair.com

[Wittsend]

OK I had some time to check the toe on the rear of the car. I use a plumb bob with marks on the floor. The bob is dropped at the centerline of the axle from a common tread location on both the tires, front and rear, then the cross difference is measured. Unbelievably there is 1-5/16" Toe Out! 59-1/4" Front, / 57-15/16" Rear. I can't see it but obviously it is there.

Toe Measure.JPG (45.23 KiB) Viewed 300 times

Many would be incline to think that the shims are missing but in this lengthy thread it has already been noted that the shims are there and "typical" in number. So, I did some math to get a rough idea of what I'll need to increase the shims. I converted to decimal and rounded numbers to the nearest even number since so much of this is dealt with by two.

1-5/16" Toe Out is 1.33 (so 1.32 for simple math).

At least in theory both sides move equally so to get to zero it would be .66" per side.

But..., because the rear of the tire is moving outward as the front of the tire is moving inward the .66 gets halved to .33.

This only gets me to zero. Factory toe is 0 to 1/4" (.250) Toe In. I'll shoot for 1/8" (.125) and again to half that (per side) to .062.

Thus .33 + .062 rounds up to .40 movement per wheel to eliminate the toe out and get to the midpoint of the recommended toe in range.

But I can't just add that much shim because like oars on a boat there is a non-equal pivot point. So..., it is ROUGHLY 24" from the axle U-Joint to the pivot point of the rear wheel bearing. And it is ROUGHLY 12" of radius from the center of the axle to the tire tread. And ironically those are very common to a square. If I pivot the corner of the square (representing the rear wheel bearing) so the short end (radius of the tire) moves by .40 and measure the change in the long end (axle at the u-Joint) that should give me ROUGHLY the size of the additional shim I need. I'm sure there is a mathematical way of calculating this but I just need to see it visually.

In doing this I measure the need to add ROUGHLY an additional .950 per shim pack (I know the numbers don't quite add up, I was a struggling B- Algebra student and a confident A+ Geometry student). That seems insane. The bolts holding the shims wouldn't seem long enough. There likely isn't enough range in the rear motor mount to compensate for .950 more rearward movement. I have looked the frame/crossmember over and can't see any damage at all, much less to justify the corrective action necessary to get proper toe. I'm utterly befuddled!

[RexJohnson]

I would not trust the tread for measuring toe. It is not actuate. The proper way is to scrib a line all of the way around the tire. Do this and then see what the toe truly is.

[Wittsend]

Rex, I don't think when I have the greater problem of an unexplainable..., enormous..., One and Five Sixteenth's inches toe out that the accuracy of the tire tread is going to make a difference.

That said, and to your point the car has not moved since I measured yesterday. So, I am able to mark the regions of the tread I measured from. I then set up a pointer to the marked edge (1D and 1P respectively) of the tread and then rotated it to the 180 degree opposing marks (2D and 2P respectively). For all intents and purpose it is the equivalent of scribing a line. The drivers side shows no deviation and the passenger side perhaps 1/64th. Image below. So, even if I was setting toe, not just checking to solve my greater issue I would find that tolerance well within the variations of 0" to 1/4" toe in range the factory states.

The greater befuddlement is that the engine/drivetrain seems to be sitting nearly an inch forward of where it needs to be and a likely similar amount lower than it needs to be. Front to back I probably run out of threads on the shimmed bolts to get it 'their' and vertically I only have 3/8" before the metal trans mount hits the bottom of the crossmember. Nothing in the Crossmember, A-Arms and Frame show being bent or distorted. So, I'm lost for a solution.

[Dennis66]

If the power pack is sitting 1'' forward of where it should be, how can this be possible if there is only like a 3/4'' oval hole in the rear mount bracket? Wrong rear mount bracket maybe? Wrong front crossmember (trans crossmember) maybe (wagon vs others different?). Maybe whole rear suspension crossmember different for a wagon? (I believe you described it as a "Frankenvair". Dennis

[RexJohnson]

Those tire treads seem to be quite accurate. I have seen them vary enough to eliminate your problem.

[manvair]

I think there is a difference between the PG and 4 speed cross-members- could that account for the problem?

[Wittsend]

The PG crossmember has provisions for the shift cable and as needed in my case, the trans cooler. Those wouldn't be present on a manual mount. Not sure anything is different between the FC and the cars PG metal trans mount. The rubber trans mounts are listed as the same for the early cars and FC's. If I can bring myself to jack up the car - once again, I'll shoot a video and maybe someone will see something I'm not seeing.

Umpteen posts back I had a picture of the significant wear from the axle rubbing on the A-Arm. So, this condition was present long before the dormant cycle from 1973 to 2024 ended. I myself haven't driven it more that 2 miles because of the problem. Hopefully I'll get a video posted tomorrow.

[joelsplace]

The FC mount is a lot wider. Maybe 4"

[jimbrandberg]

I'm sorry but my head is swimming. Good information but I can't take it all in at the moment. That much shim is ridulous. I appreciate your measuring and approach but an inch of toe-out would have to be visible.
Moving the differential ahead gives toe-out, back gives toe-in.
Regarding rear rubber mounts, 63 and 64 have different offsets with the dangling stud.
Folks will space a 63 engine mount bracket with washers to get the fan belt access on a harmonic balancer engine.
If you can move the powertrain back enough to get toe-in with the rear mount, is there something goofy with the front bracket that bolts to the transmission or the location of the rubber mounts in the horsecollar?
If I was measuring toe I would want the suspension at ride height. If using a plumb bob I may have an assistant hold a 30" 2 x 4 against the sidewall halfway up and dangle to the floor from that ahead of and behind the tire.
Sorry if I'm being too simplistic to be of any real help. I get a little pissy when someone does it to me but sometimes it strikes a chord when I'm missing something.
Jim Brandberg
Isanti, MN
CorvairRepair.com

[Wittsend]

OK, I got a video shot of the car in areas that relate to the excessive toe out. Maybe someone will see something. Thanks for looking. Remember the math says the powerpack needs to go back close to an inch (it might do that, but it is a lot) and the axle (at the diff) likely needs to go upward 3/4" to 1". And for that I can't see getting more than 3/16" if I trim down the rubber trans mounts outer tube (the one around the inner bolt) and leave a little space so the mount doesn't hit the crossmember.