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Next week I am going to get a 4 wheel alignment on my 69 corvette. I was having a look at the control arms this morning and noticed the excessive amount of shims already used.
Now that I have had a look I can see that the shims have an effect on the castor bring the wheel back. At present on full lock the wheel rubs on the bottom of the inner guard.
Is this excessive number of shims a sign the car has had a major hit at some point in it's life? The driver side only has a couple of shims.
If the shims are removed does that mean the wheel will move forward slightly (castor) and have toe in? I can't see any bent components or anything that's stands out as being repaired.
The shims are pulling the top of the wheel in and back. I think this also effects your toe. That is an excessive amount of shims, my car has one in each.
I would wait for your alignment shop for a determination.
Some one has set the car up with as much caster as they could get,
‘remember these cars were designed when rag tyres were the go, not the radial steel belted we have now.
From: At my Bar drinking and wrenching in Lafayette Colorado
The car has been set up with plenty of positive caster, which gives the car a solid, stable feel. These cars originally had very little caster in them so they could be used with manual steering and bias ply tires. This makes the steering feel very "light," which was the norm 40 years ago.
Example:
Typical caster setup on an early '70s Vette, to get that "light" steering feel, is about 2 degrees.
Typical caster setup on a new Vette, to get that stable, "in-control" steering feel, is about 7.4 degrees.
Caster has no effect on tire wear, and does not affect toe, since toe is adjusted last in the alignment process sequence. Toe is always set after caster and camber has been adjusted, so the big stack of shims is no indication that your toe is off.
If you have power steering, the positive caster alignment setup is good. The fact that your car has enough adjustment range on the front end to take that much positive caster is great - I'd crank in as much positive caster as I could get if it were my car. If you've been driving the car with a bunch of positive caster in it, and you take the car to a shop that sets the camber back to the 2-degree "spec," I think you're going to be very disappointed with "steering feel" after the alignment - it will feel like you're driving on ice...
The positive castor pushes the wheel forward but the rear of the wheel still touches the guard on full lock. That would suggest a hit thats pushed the suspension back, and the rear shims are merely out of neccessity to get the wheel back into position?
Last edited by NJey1985; Aug 25, 2018 at 02:02 AM.
No, positive caster moves the centre line of the spindle to the rear at the top of the spindle , the shims you have is IMO is average for about 4 to 4.1/4 degrees positive caster ,and most likely about one degree negative camber.
Where is the wheel hitting the guard
bfit
assuming a custom alignment spec on your car from all those shims may not necessarily be true. could just be a factory recomended setup.
years and years of weight on that part of the frame plus years of potholes and stress yields to weakness and 'bending' of your components. those shims correct that issue.
looks typical of corvettes... probably the same for all old cars.
I don't believe that control arm shim setup would be typical for a car in good repair. The bushings don't look so good either. I believe a control arm refresh might be in order.
Control Arm Alignment
