Problems setting caster

[Dmcbrass]

Had an alignment done on my GT today. The Camber was fine and the mechanic was able to set the toe without problems. The caster was a different story. The factory service manual calls for 3 degrees +/- 1 degree. The left side was at 1.9 degrees and was already set as high as the washers will allow. I feel OK about that one; however, the right side was at -.2 degrees. He installed the correction washers that I furnished and the caster increased to .6 degrees. No more adjustment available. The steering is noticably better. There used to be a noticible difference in the way the car steered on right hand curves and left hand curves, and that is better, but I would like to get the caster right. I assume that one of the control arms or the cross member is bent. Any ideas out there. Or should I leave well enough alone.

[GTJIM]

After years of nudging inanimate objects like curbs and potholes Opel front suspension components do get 'tweaked'
You can alter the castor by using tapered wedges between the suspension cross-member and where it bolts to the chasis to get the adjustment back into the range of the washers on the upper 'A' arm - or even move the lower 'A' arm on its four mounting bolts.
Sometimes it is the 4 crossmember mounting bolts that are loose or the chasis rails themselves are rusty or crumpled a bit. There should be a red fiibre shim in there too.
Just be sure that the suspension bushes are all undamaged and everything is tight .. especially all the nuts.
HTH

[Dmcbrass]

Yeh, I just rebuilt the entire frontend. Took it out of the car and rebuilt it in the floor of my garage. I hadn't thought of shimming the crossmember to the chassis. I guess I would need to tilt the top of the cross member toward the back of the car, correct? I don't remember the red fiber spacer. Though I have seen it refered to in a couple of posts. What is the purpose of it?

[GTJIM]

Originally Posted by Dmcbrass Yeh, I just rebuilt the entire frontend. Took it out of the car and rebuilt it in the floor of my garage. I hadn't thought of shimming the crossmember to the chassis. I guess I would need to tilt the top of the cross member toward the back of the car, correct? I don't remember the red fiber spacer. Though I have seen it refered to in a couple of posts. What is the purpose of it?

Yep - tilt the cross member back to increase castor - just like bending the ends of an old Ford V8 front axle ......

No real explanation has come to light about the fibre spacers - the best we could come up with is that they act as insulators between the front suspension and the frame to reduce the transfer of road noise...

[tomking]

I just used a piece of conveyor belting of same thickness to replace paper shims on mine.

[soybean]

If we are talking about the same thing, the last two front suspensions I dropped had two pieces of metal? with holes in them that were on top of the crossmember between it and the body. Or am I missing something here? (Besides my mind. It comes and goes). I've never seen a red fiber spacer.
Jarrell

[baz]

mine had the spacers and i think it was a quick fix for an engine bay height problem ,i cant think of anything else it could the 1.9 is tweaked to heck to fit it in to a gt , offset engine mounts, changes in inlet manifold heights all to make to tall an engine fit in to short a bay

[jeff denton]

On my front end the holes in the suspension crossmember (where the lower A-arms bolt in) were quite elongated. Is this normal? I don't know, but I made some little L shaped brackets with the right size hole, put them on top before the washer and nut, got caster to spec, and welded the side of the L to the crossmember. So the setting won't move, see?
Later I determined proper geometry for my application needed a 1/4" spacer between the the suspension and lower A-arm. This spacer then had the right size hole and also was welded in so it can't move.
I can also testify that the upper a-arm is pretty weak, it doesn't take much to bend it's triangular shape out of whack. It also doesn't take much to bend it back, and a little plate welded onto it makes it look much sturdier!
These little things are what you discover when you work a suspension as hard as I do, not to mention a bit of tire rubbing with Pintos and Mustangs...

[RallyBob]

Originally Posted by Dmcbrass The caster was a different story. The factory service manual calls for 3 degrees +/- 1 degree. The left side was at 1.9 degrees and was already set as high as the washers will allow. I feel OK about that one; however, the right side was at -.2 degrees. He installed the correction washers that I furnished and the caster increased to .6 degrees. No more adjustment available.

There are two common problems I've seen over the years.

First of all, the lower a-arms on GT's bend very easily. So easily I've probably only torn apart 3 or 4 GT's that didn't have at least one bent a-arm.

Secondly, the upper a-arm pivot point (metal sleeve welded into crossmember) can be way out to lunch as well. I suspect they didn't use an accurate jig (if any) when welding these sleeves in place. I once had 4 separate GT crossmembers in front of me, and I couldn't find two upper pivots that were welded in the same location. The fore-aft locations varied as much as 3/16"! I keep my eyes out for that 'perfect' GT crossmember that has two parallel-mounted upper pivots, but I haven't see one yet. On cars that are critical in this regard (racecars for example), I will cut and reweld the upper pivots so they match from side to side.

Bob

[GTJIM]

Here is a good (simple) explaination in a link to a Corvette (Maxi GT ) site.

http://www.melroset-tops.com/camber_...oe_defined.htm

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