Having alignment issues (caster)

[69chevytrucker]

trust me your specs will come out better as soon as you flip it around

[robnolimit]

Glad you guys caught that. I thought so, but not being a 73-87 expert I was looking around to make sure. Lots of sharp and helpful people here.

[chevyrestoguy]

That's a good catch! That will definitely make a big difference on your camber numbers.

[Acorn]

Any updates on your truck?
Curious to see how much your specs will change when they get everything installed properly.

[Tahiti or Truck]

Hey guys. I just got back from vacation and haven't been able to mess with it. I ll be sure to post when I do.

[SCOTI]

Originally Posted by Acorn

It looks like your a arm shaft is facing the wrong way. The concave part of the shaft and the spacers are supposed to face towards the frame. The shims go between the spacer and frame mount. Look at a service manual ( or a LMC catalog) Can't really tell from the photo but do you also have spacers between the shaft and frame?

Originally Posted by 69chevytrucker

trust me your specs will come out better as soon as you flip it around

Originally Posted by chevyrestoguy

That's a good catch! That will definitely make a big difference on your camber numbers.

I've had more than a few of these front ends apart. While the 73-87's did use the concave washers on one side, I don't recall there being a difference in the depth of the shaft vs the opposite side that utilizes a flat washer.

That being said, I don't see how the orientation would significantly impact the alignment.

What I'm seeing in the pics though is an equal amount of shims/spacers on both the fore & aft studs. Positive caster would typically yield double the thickness on the front stud of shims/spacers vs the rear stud.

[chevyrestoguy]

Originally Posted by SCOTI

I've had more than a few of these front ends apart. While the 73-87's did use the concave washers on one side, I don't recall there being a difference in the depth of the shaft vs the opposite side that utilizes a flat washer.

That being said, I don't see how the orientation would significantly impact the alignment.

What I'm seeing in the pics though is an equal amount of shims/spacers on both the fore & aft studs. Positive caster would typically yield double the thickness on the front stud of shims/spacers vs the rear stud.

My thinking was that the concave orientation was causing the camber issue because it confused the alignment tech. All the pictures I have seen of the upper arms showed no shims installed, and I was speculating that the camber was positive and the tech assumed that because he had no shims to take out to help it go negative that there was nothing he could do, so he left it alone.

I completely agree with you that the shim thickness on the front stud should have been greater to add caster. You can't a whole lot in the stock configuration on our trucks, but even a little bit extra caster makes a huge difference.

[Tahiti or Truck]

What exactly do the concave shims do?

[SCOTI]

Originally Posted by Tahiti or Truck

What exactly do the concave shims do?

They provide a 'better' bite on the shaft to keep it from shifting around the small amount it possibly can.

[Tahiti or Truck]

Originally Posted by chevyrestoguy

My thinking was that the concave orientation was causing the camber issue because it confused the alignment tech. All the pictures I have seen of the upper arms showed no shims installed, and I was speculating that the camber was positive and the tech assumed that because he had no shims to take out to help it go negative that there was nothing he could do, so he left it alone.

I completely agree with you that the shim thickness on the front stud should have been greater to add caster. You can't a whole lot in the stock configuration on our trucks, but even a little bit extra caster makes a huge difference.

The alignment tech installed the uppers that way. Also, there are some shims on the drivers side.

[Tahiti or Truck]

Also, in an effort to get more caster would it be worth the trouble to relocate the upper ball joint 1/2 inch back. My plan would be to take some 1/8 inch flat and drill the bolt holes and cut the b
Large ball joint hole. Then plasma cut out the existing ball joint hole and then relocate, trim, and weld in the new. It looks like I can get it back about half and inch. Any idea if that would work and how much more caster positive caster that would create?

Here is a rough drawing

[Acorn]

Do a search for 'caster mod' There is a good write up with pics. Most people modify their lower controller arm shaft.
I think it would be a lot safer and less labor intensive than trying to modify your ball joints...

[SCOTI]

Originally Posted by Acorn

Do a search for 'caster mod' There is a good write up with pics. Most people modify their lower controller arm shaft.
I think it would be a lot safer and less labor intensive than trying to modify your ball joints...

x2.

[Oldtruckfanatic]

Sorry I was looking at my pics wrong

[Tahiti or Truck]

Yea I read that thread and was excited to do it until I crawled under my truck to see that my lowers are the early style (1966) which are different from the ones in the thread. I know I could get a more modern front clip but that seems like a whole lot more work than modifying my uppers.

[Tahiti or Truck]

Originally Posted by Oldtruckfanatic

Um your upper control arms are on the wrong sides. The bump stop goes toward the front of the truck

Please please someone else tell me they are. That would be the easiest to fix and I thought about trying to swap them but...

[Tahiti or Truck]

Originally Posted by Oldtruckfanatic

Sorry I was looking at my pics wrong

Lol ok

[Oldtruckfanatic]

I was wrong I was pouring over my c20 pics and had one that looked backward because of the angle I was at sorry about that

[Oldtruckfanatic]

I have the whole front group off the truck sitting beside my shop 1966 c20. I have rebuilt tons of the 65-72 front ends I guess im just getting loopy im actually still working.

[Oldtruckfanatic]

Its too bad youre not closer im going to scrap the whole front suspension from the truck im talking about. If you can get it home and need spare parts you can have it Or any parts from it. The steering box is manual but it works fine I drove it 70 on the freeway to get it to the shop before I took it apart.

[Oldtruckfanatic]

Everyone is right about that top shaft though. Maybe when theyre right there will be enough camber adjustment to get the caster right.

[Tahiti or Truck]

Originally Posted by Oldtruckfanatic

Its too bad youre not closer im going to scrap the whole front suspension from the truck im talking about. If you can get it home and need spare parts you can have it Or any parts from it. The steering box is manual but it works fine I drove it 70 on the freeway to get it to the shop before I took it apart.

I just drove back from Reno for a vacation. Lol as in I was there last Tuesday and Wednesday

[Tahiti or Truck]

Any trig experts out there? I don't have a protractor and need to get a 20 deg angle so I can more accurately align it. I plan on cutting a triangle out of sheet metal to lay down on the shop floor. If I did my math right then a 90 deg triangle with an 11" base and a 4" height will yield me a 20 deg angle... Right ?

[MARTINSR]

I have to say, I am an alignment specialist correcting collision damage nothing more, just getting stuff back to specs and knowing by the numbers what is damaged (often you can't see at all) and I am blown away at how little some of these guys at the alignment and tire shops known. It is mind boggling how many will say "There is no way to align it" because the computer doesn't have the correct info, they MUST have the computer tell them how to do simple adjustments! They will have ZERO understanding of the simple geometry!

We have to send stuff out every once in a while because our rack is tied up with a car or something like that and I am always amazed at the stupid stuff that they will say.

VERY few of these guys have the basic understanding of the angles they are working with every day.

Brian

[Oldtruckfanatic]

Originally Posted by Tahiti or Truck

I just drove back from Reno for a vacation. Lol as in I was there last Tuesday and Wednesday

LOL well if you get back this way and need any parts feel free to pm me and you can stop by my shop.