Can't get positive caster

[71 Sebring +]

I have a 71 Plymouth Sattelite Sebring Plus. I'm sure this has been covered before but I couldn't find any exact numbers when researching previous threads on the topic. Recently replaced all the front end parts and had aligned. The closest he could get the caster was -2 degrees. My question is will I be able to get to +2-3 degrees with Moog offset bushings or am I going to need to get adjustable UCAs to get there?

 

[AR67GTX]

Probably not the problem but I once tried to do a garage alignment on a 69 RR for a friend after he installed the k-frame, engine and suspension and I could no get positive camber. I finally spotted that the upper a-arms had been swapped side to side in assembly. I realized the little bump pocket in the a-arm was to the back instead of the front. Once we swapped them side to side it aligned OK.

 

[Fm3 Dart]

Two things to look for, especially on the right side, is the hole in the K frame where the strut rod mounts, and the control arm itself. One common reason is this: When someone angles parks, and runs into the sidewalk curb a bit too fast, the tire is forced back, and as the control arm is forced back, the strut rod pulls the metal at the bushings inward. At the same time, the forged piece that the lower ball joints bolts to that is riveted to the lower control arm will also bend. The end result is negative caster, usually on the right, but can also happen to the left. This will make an alignment impossible

 

[DanielSlocum]

had the same problem years ago on my 72 satellite. turned out to be a bent lower control arm on driver side.
sometimes hard to spot due to rather odd shape of the thing.
good luck.

 

[71 Sebring +]

Probably not the problem but I once tried to do a garage alignment on a 69 RR for a friend after he installed the k-frame, engine and suspension and I could no get positive camber. I finally spotted that the upper a-arms had been swapped side to side in assembly. I realized the little bump pocket in the a-arm was to the back instead of the front. Once we swapped them side to side it aligned OK.

Checked to make sure. They are on with bump pockets to the front. Thanks

 

[RJRENTON]

The last time I had the GTX aligned, I tried to get the MAXIMUM POSITIVE (+) CASTER angle, which helps the car rolls down the road, or tracking, with CAMBER set to zero with 3/4 tank of fuel (at 7,48#/gallon) or as close as possible with CASTER at max and toe at minimum...although Illinois roads are not really crowned for drainage.....its a compromise....but I use the Moog bushings and cams to get as much as possible.....so far so good......
BOB RENTON

 

[71 Sebring +]

Two things to look for, especially on the right side, is the hole in the K frame where the strut rod mounts, and the control arm itself. One common reason is this: When someone angles parks, and runs into the sidewalk curb a bit too fast, the tire is forced back, and as the control arm is forced back, the strut rod pulls the metal at the bushings inward. At the same time, the forged piece that the lower ball joints bolts to that is riveted to the lower control arm will also bend. The end result is negative caster, usually on the right, but can also happen to the left. This will make an alignment impossible

When I replaced the strut rod bushings I remember checking out the kmember, it looked good. Don't remember seeing any specs in the manual to determine if they are bent. Thanks for ideas of what to check

 

[71 Sebring +]

had the same problem years ago on my 72 satellite. turned out to be a bent lower control arm on driver side.
sometimes hard to spot due to rather odd shape of the thing.
good luck.

If its LCAs, they both might be bent. The best he could get was -1 passengers side, -2 on drivers side. That's why I was thinking about trying the Moog offset bushings if I would be able to get to +2-3. Thanks

 

[Kern Dog]

This car:

Has stock based lower control arms, stock upper control arms, urethane strut rod bushings and Moog offset UCA bushings.
I have 5.5 degrees of caster and .75 degree of negative camber.
Do not be afraid of negative camber. Radial tires can handle it. My tires do not wear on the inside edge any more than the outside edges.
Camber and caster are connected. You cannot get much caster with zero or positive camber. You have to have some negative camber to allow enough adjustment to get positive caster.
The higher the front ride height, the LESS caster you can get. These suspensions are designed as such that as the travel nears the full compression (As low as the car can be) the caster is at it's greatest amount. See this chart:

This is an alignment graph of a 73-76 A body but it is close to what a B or E body would have. The -2.25 is actually rise/extension....essentially 2 1/4" over stock height. Note that the caster starts at 1.77 degrees at 0.00. (Static ride height) 2 1/4" lower than stock, the caster sits at 4.892 degrees.
My point is that a car that sits higher than stock will have trouble obtaining enough caster. A car that has zero camber will have trouble too. If your car has a profound rake where the rear is higher than the front, that will make it difficult too.

 

[71 Sebring +]

The last time I had the GTX aligned, I tried to get the MAXIMUM CASTER angle, which helps the car rolls down the road, or tracking, with CAMBER set to zero with 3/4 tank of fuel (at 7,48#/gallon) or as close as possible with CASTER at max and toe at minimum...although Illinois roads are not really crowned for drainage.....its a compromise....but I use the Moog bushings and cams to get as much as possible.....so far so good......
BOB RENTON

He set the camber at +.1 LS, and +.3 RS. I've seen where some guys will run negative camber but don't think that will get me to that +2-3 degrees I'd like. Thanks
Brad Beyer

This car:

View attachment 1477765

Has stock based lower control arms, stock upper control arms, urethane strut rod bushings and Moog offset UCA bushings.
I have 5.5 degrees of caster and .75 degree of negative camber.
Do not be afraid of negative camber. Radial tires can handle it. My tires do not wear on the inside edge any more than the outside edges.
Camber and caster are connected. You cannot get much caster with zero or positive camber. You have to have some negative camber to allow enough adjustment to get positive caster.
The higher the front ride height, the LESS caster you can get. These suspensions are designed as such that as the travel nears the full compression (As low as the car can be) the caster is at it's greatest amount. See this chart:

View attachment 1477766

This is an alignment graph of a 73-76 A body but it is close to what a B or E body would have. The -2.25 is actually rise/extension....essentially 2 1/4" over stock height. Note that the caster starts at 1.77 degrees at 0.00. (Static ride height) 2 1/4" lower than stock, the caster sits at 4.892 degrees.
My point is that a car that sits higher than stock will have trouble obtaining enough caster. A car that has zero camber will have trouble too. If your car has a profound rake where the rear is higher than the front, that will make it difficult too.

Not sure if this is the right way to measure the rake. From the floor to the top or the wheel opening, center line of tire I have 26" in the front and 28" in the back. Car had air shocks and traction bars on when I bought it. Only have 50 lbs in them. Have about 2-12" of tire clearance. BTW that's a really awesome looking R/T!
Brad

 

[WileE]

Huh ? Positive camber ? No, no, no,no ,no.... Get at least .5 neg. As correctly stated before, check the k-frame if the strut rod has cupped the k-frame where it mounts.

 

[WileE]

Two things to look for... is the hole in the K frame where the strut rod mounts, and the control arm itself... the tire is forced back, and as the control arm is forced back, the strut rod pulls the metal at the bushings inward.

had the same problem years ago on my 72 satellite. turned out to be a bent lower control arm on driver side.
sometimes hard to spot due to rather odd shape of the thing.
good luck.

A not uncommon condition when doing collision work years ago. A hit on the suspension will push the LCA and strut rod back, and cup the k-frame. Seen-it, done-it, fixed-it.

 

[hunt2elk]

You need to get around a -.5 camber and that will help with your caster. Also, use 4 Moog offset bushings, and not just one on each side.

 

[RJRENTON]

You need to get around a -.5 camber and that will help with your caster. Also, use 4 Moog offset bushings, and not just one on each side.

Just go for positive CASTER....as much as you can get and still get CAMBER within specs.....caster does not affect tire wear but camber does....caster affects vehicle tracking and handling.....just an additional thought.....
BOB RENTON

 

[Kern Dog]

Camber only affects tire wear if it is excessive or with use with bias ply tires. I've run .75 negative camber for 22 years on the red car and longer on my daily driver cars and trucks.

 

[Fm3 Dart]

Adding caster makes cars track nicely, and just a bit of negative camber also helps. from the factory, Chrysler put less caster in the manual steering cars to make the steering effort lower. Fine around town and parking, but it makes the cars twitchy on the highway. I don't mind heavier steering, so I always set up my cars with more caster whether they are manual or power steering. The offset bushings are generally not needed on B and E bodies. You can use just one per side, or two set opposite of each other to allow the control arm to move back more.

A bodies on the other hand often need the offset bushings to get enough adjustment.

 

[71 Sebring +]

Ordered Moog offset bushings today. After I get them installed and take for alignment I'll update on the outcome. Thanks for all your comments. I really appreciate it.
Brad Beyer

 

[StrokerSpanky]

I installed some adjustable lower strut rods from PST and adjusted them a little shorter than the factory rods and got plenty of caster now even with .5 + camber on my 70 Charger. No moog bushings required.

 

[1 Wild R/T]

Ordered Moog offset bushings today. After I get them installed and take for alignment I'll update on the outcome. Thanks for all your comments. I really appreciate it.
Brad Beyer

Don't know if it's been mentioned, the offset bushings come with instructions... Throw them away, they won't accomplish what you want... The bushings are intended to change the camber... We don't use them for that, we install them to change caster....

There are lots of drawings & pictures of how to install them for caster posted on various sites.... I don't waste my time... Just know one bushing is installed with the arrow pointing inward & the other points outward... Now, look at your upper control arm & know you want to move the ball joint as far rearward as you can...

When I install the arms back on the car I install the eccentric bolts to push the upper ball joint even further rearward... That way when the alignment guy gets the car you can tell him you've already maximized caster & he needs to keep as much as possible while getting camber in the .75-1 degree negative range....

Kern is spot on, .75 rarely shows wear but I'll push it to 1 degree and trade a little tire wear for better handling cause even driving as much as I do which is more than most classic car owners I find the tires are usually out of date & need to get replaced long before they wear out...

 

[khryslerkid]

There are lots of drawings & pictures of how to install them for caster posted on various sites.... I don't waste my time... Just know one bushing is installed with the arrow pointing inward & the other points outward... Now, look at your upper control arm & know you want to move the ball joint as far rearward as you can...

This pic is what they've shown on how to install.

I'm wondering about the lack of material on the one side when using the offset bushings. Will they last as long as a standard bushing? Do they bottom out on that side? I don't think there's much weight exerted on these bushings but curious about their longevity.