11 degrees of Caster?? HELP!

[deenasty]

Greetings fellas. I need some help. For some background, the car has a Hotchkis TVS suspension setup, s10 blazer spindles and C4 Baer brakes. The car also has HRE wheels 18x9 front and 18x10 rears. I have an issue with the drivers side. The inner wheels is digging into the upper a arm at full turn (right), but magnified much worse in reverse and turning. I recently had both upper and lower ball joints replaced in hopes of fixing the issue, but it did not. Tie rod ends were damn near even from side to side as well.

My concern is that there is 11-12 degrees of caster with this setup. The folks at Hotchkis are telling me, that this is within their spec, but I have never seen that much. Vehicle has been properly aligned. Drivers side didn’t require any shims, passenger side did. I have no problems with the passenger side. I have attached some pictures. Any help will be greatly appreciated.

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[1986 Buick GX1]

The UMI Performance A-arms I installed listed different alignment specs for street use or Auto-X. I don’t have them handy, I can look them up tonight.
It seems they want higher caster for high speed stability compared to street use.

Do the wheels only hit with the Hotchkis A-arms?
Is it as simple as adjusting the steering stops?

I would love to see more photos of the wheels. I have HRE wheels as well.

 

[deenasty]

The UMI Performance A-arms I installed listed different alignment specs for street use or Auto-X. I don’t have them handy, I can look them up tonight.
It seems they want higher caster for high speed stability compared to street use.

Do the wheels only hit with the Hotchkis A-arms?
Is it as simple as adjusting the steering stops?

I would love to see more photos of the wheels. I have HRE wheels as well.

Yes, the drivers side wheel only hits the upper arm, no other hitting anywhere that I can see.

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[1986 Buick GX1]

Yes, the drivers side wheel only hits the upper arm, no other hitting anywhere that I can see.

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Beautiful wheels!!

It seems the alignment shop could add more shims to the front side of the upper A-arms to bring the ball joints forward for less caster. Maybe??

The reason I ask about the steering stops is when I was cycling the suspension using a test wheel to get measurements for my wheels. The only time I had trouble was before I added the steering stops, the test wheel would hit the upper A-arm on the front like yours.
I called UMI to see which stops were the same as stock, I installed the short ones which have slightly more turn angle than stock and no more rub.

Did it just start rubbing after installing the Hotchkis A-arms?

 

[1986 Buick GX1]

I know these are for the UMI setup.
Here’s what they suggest FWIW.

What does Hotchkis use for steering stops?

 

[Chuck Leeper]

No shims one side/ shims on the other:
Car been wrecked?
Ft x member could be folded in toward the center line.

 

[deenasty]

I know these are for the UMI setup.
Here’s what they suggest FWIW.

View attachment 353675

What does Hotchkis use for steering stops?

The steering stops are welded in flat plates, no adjustment.


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[deenasty]

No shims one side/ shims on the other:
Car been wrecked?
Ft x member could be folded in toward the center line.

Car has never been in an accident, 30k mike car.


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[Turbo6inKY]

Greetings fellas. I need some help. For some background, the car has a Hotchkis TVS suspension setup, s10 blazer spindles and C4 Baer brakes. The car also has HRE wheels 18x9 front and 18x10 rears. I have an issue with the drivers side. The inner wheels is digging into the upper a arm at full turn (right), but magnified much worse in reverse and turning. I recently had both upper and lower ball joints replaced in hopes of fixing the issue, but it did not. Tie rod ends were damn near even from side to side as well.

My concern is that there is 11-12 degrees of caster with this setup. The folks at Hotchkis are telling me, that this is within their spec, but I have never seen that much. Vehicle has been properly aligned. Drivers side didn’t require any shims, passenger side did. I have no problems with the passenger side. I have attached some pictures. Any help will be greatly appreciated.


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11-12 degrees caster is NOT ok.
Caster also means jacking force increases.You'll kill your power steering system.

Are you sure you have the arms on the correct sides? Double check. I had a shop once put the upper A arms on the wrong sides and ended up with something similar.

What you want with the stock spindle for a street application is ~4 degrees caster. That's about as much as you can get without some crazy work. Ideal is 9 degrees for maximum cornering performance, but as you've found out, you run into some pretty serious clearance issues with that much caster.

And I'll echo what's been said, UMI's parts for this platform are way beyond Hotchkis at this point. If you can't make these work, call UMI.

 

[deenasty]

11-12 degrees caster is NOT ok.
Caster also means jacking force increases.You'll kill your power steering system.

Are you sure you have the arms on the correct sides? Double check. I had a shop once put the upper A arms on the wrong sides and ended up with something similar.

What you want with the stock spindle for a street application is ~4 degrees caster. That's about as much as you can get without some crazy work. Ideal is 9 degrees for maximum cornering performance, but as you've found out, you run into some pretty serious clearance issues with that much caster.

And I'll echo what's been said, UMI's parts for this platform are way beyond Hotchkis at this point. If you can't make these work, call UMI.

Totally understand. I double checked, and the arms are on the correct sides. It baffles me that the techs at Hotchkis say “this is normal for their spec” I don’t believe the S10 Blazer spindle has anything to do with this issue, because they are identical to the factory spindle.


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[Turbo6inKY]

Totally understand. I double checked, and the arms are on the correct sides. It baffles me that the techs at Hotchkis say “this is normal for their spec” I don’t believe the S10 Blazer spindle has anything to do with this issue, because they are identical to the factory spindle.


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You are correct. The S10/Blazer spindle is the same spindle as ours, but with a different bearing pack. The height and kingpin inclination is exactly the same.

Your problem is with the arms. The pictures don't really tell us anything. The alignment shop's measurements are what matter. And what you've told us is not gonna work for you.

I feel for you. If I were in your spot, here's what I'd do:

1) Find a body shop with a frame rack that will measure your car. I had mine done a few years ago, and it was $135. They'll tell you if the car is bent. If it isn't;
2) Dump those arms for a set from UMI, Speedtech, or Ridetech. All three offer quality and precision and know this platform. For a Turbo car, the UMI race arms have a rod-end instead of poly or delrin bushed upper arm option, which is important for us since the downpipe likes to melt bushings, but the geometry from all three is going to be correct. And don't order off the internet. Call them. Tell them what's going on. They'll help you, and they're smarter than most of us are.

If you're sure they're on the right sides, your arms are wrong. Maybe they sold you B-body or A-body arms? Who knows. But your time is worth something. Don't waste your time, Fix the car.

 

[chopped39]

Right off their site. Up to +6 degrees of caster and -1 to -3 degrees of camber from machined offset Cross-Shafts. Features geometry corrected design. I would call them and ask them to explain this. This is listed under their upper control arms

 

[Turbo6inKY]

Right off their site. Up to +6 degrees of caster and -1 to -3 degrees of camber from machined offset Cross-Shafts. Features geometry corrected design. I would call them and ask them to explain this. This is listed under their upper control arms

I'd put a dollar down they shipped him F-body arms by mistake. They look really close, and the cross shaft mount spacing is identical, so they bolt right up. But the ball joint is very much not in the same place. It also wouldn't be the first time I'd seen it happen.