Camber Adjustment

[Joe Flanagan]

When I had about 500 miles on my Plymouth I noticed that the front tires were wearing on the outside edges. According to my manual, this is caused by too much camber (tires leaning out). Using a straight edge and a level (with the straight edge resting on the edges of the rims and not touching the tires), I determined that both front tires were in fact leaning out. Forum member Rich Hartung was good enough to loan me his camber adjustment wrench and I just did the work. The passenger side is now almost perfectly plumb and the driver side leans out a little less than 1/4". The manual calls for 0-3/4 degrees. I assume that means in either direction. Am I OK where I am and can anyone translate what 1/4" would be in degrees? My tires are 16". 

[greg g]

cant confirm the measurements but I do believe that the drives side is set up with initial positive camber (leaning out at the top) so the wheel is plumb with the driver in place.  Perhaps you can have somebody sit behind the wheel while you do the measurement thing again.  

[Plymouthy Adams]

no that is expressed in Positive only..any other specification would say either/or would be expressed  +/- x value and of course it did not...all specifications will be strictly noted + or -

[Joe Flanagan]

OK thanks. If anyone can tell me what 1/4"' is in degrees I'd appreciate it.

[Ulu]

Tell me how tall the tire is, then it's a simple calculation.

[DJ194950]

How do you measure the 1/4" measurement? A straight edge across the tire top to bottom? What about the tire Squat?

 

Pic. in my repair manual shows a gauge attached to the wheel at the beads with a degree measure attached.

 

How about a piece of flat metal that reached across the inner beads of the wheels and buy a cheap degree measuring tool at harbor freight or any hardware store to put against the steel straight edge?

 

DJ

[Ulu]

Yeah, you're not going to get an exact angle by measurement and calculation. A direct reading gage is the way to go.

I just have a cheap magnetic gage from Master Mechanic but it works. you put it on the end of the hub after removing the dust cup.

 

But if you ignore tire squat and have the wheels as straight ahead as possible, you can get a pretty close answer by measurement.

[Joe Flanagan]

The straight edge does not touch the tire anywhere. It only touches the edges of the rim, or I guess what you are calling the bead. You put the level against the straight edge and see how far out of plumb you are. At least that's how it was suggested and what I did. I should look into the gauge Ulu mentioned, though.

[fstfish66]

i used an  angle finder,,,as  described above,,magnetic, on the  outer edge of the  rim,,my 1940 book calls for 0 to 1 degree positive,,,recently read an  artice stating with  power steering at  high  way  speeds will have a better feel at  3 to  4  degrees positive,,  ill adjust  mine  in the spring and see,,,

[Dave72dt]

3 or 4 degrees camber or 3 to 4 degrees caster?  I don't recall any recommendations from the manufacturer's  settings that high for camber.  Most were in the 1/4 neg to 1/4 pos range, depending which side of the vehicle.  Caster settings were somewhat common  in the 3 to 4 range and bumping that up did help with higher speeds.  There was also a difference in the caster settings, side to side, about 1/2 degree.

[BigDaddyO]

If you have an IPhone there is an angle finder app in yer utilities folder. 'Click" on the compass and then 'swipe' to get the angle dealy thingamabob.

[fstfish66]

3 or 4 degrees camber or 3 to 4 degrees caster?  I don't recall any recommendations from the manufacturer's  settings that high for camber.  Most were in the 1/4 neg to 1/4 pos range, depending which side of the vehicle.  Caster settings were somewhat common  in the 3 to 4 range and bumping that up did help with higher speeds.  There was also a difference in the caster settings, side to side, about 1/2 degree.

the factory  service manual calls for 0 to  1 degree positive caster,,an  article  in  street rodder talks about  radial  tires and power steering, says at  3 to 4 degreees of  positive caster for a better feel at high way  speeds this is on an  IFS

camber  is not adjustable on my 1940,unless i have caster and camber  back wards,,,

Edited November 16, 2014 by fstfish66

[Robert Horne]

OK thanks. If anyone can tell me what 1/4"' is in degrees I'd appreciate it.

I believe one degree would make the center of your tire tread move about 3/16 on an inch if you are using a 27 inch tall tire.

Just a estimate, my math is not good lately...

My 38 has leaf springs, try doing the alignment on that.

[Plymouthy Adams]

caster is the inclination of the king pins front to rear and yes you wish to have positive and usually a few degrees more is better up to a certain point then it tends to get heavy feel in the wheel..too little is squirrely and like to lend itself to road walking.....cars without power steering tend to have a bit less positive caster for ease of steering..trade off is however squirrely feeling at road speed ..back in the day on unimproved roads and lower speed limits this was not as noticeable..camber is the upright position of the wheel as measure at the top as a positive or negative lean....as with toe...the tires when spinning at speed tend to self drive to a upright position and straight due to the centrifugal force..that is the why of the light toe in and light camber..to compensate for this at speed but yet not be so bad to do extreme tire wear at the lower speed..

 

caster can be slightly altered with proper shimming but not a whole lot is really built in..positive is toward the rear..negative is forward

[Dave72dt]

the factory  service manual calls for 0 to  1 degree positive caster,,an  article  in  street rodder talks about  radial  tires and power steering, says at  3 to 4 degreees of  positive caster for a better feel at high way  speeds this is on an  IFS

camber  is not adjustable on my 1940,unless i have caster and camber  back wards,,,

That's why I questioned camber or caster.   finding caster is a process, not just hanging an angle gauge hung on the rim.  When I was doing alignments professionally back in the mid 70's,the setup I used required a  20 degree rotation left or right, depending on side you were checking, zeroing the gauge and then rotating it back through straight and another 20 degrees and then reading the angle.  The initial statement led me to interpret the 3 to 4 degrees as camber.

 

Leaf spring setups could be aligned for camber.   Hydraulic rams were used to bend the I beam axles to bring them into specs and could also be used for adjusting caster.  Shims were used for caster  usually, some you needed to twist with the hydraulics if really far out.

[Ulu]

Joe has a '49?

 

IIRC it's the same adjustments as the '47, but I've never done a '49 suspension. Are the late ones different?

 

Anyhow, the caster and camber are adjusted with the upper cam bolt, and both caster and camber change as you spin the cam.

 

You have to find a happy medium in the relative adjustments, because they are not independent adjustments. 180 degrees movement of the cam is the max camber movement possible, and that movement is achieved with one-half a thread movement forward or back, of the caster. If you turn the cam 360 degrees, the camber change is zero, but the caster moves one whole thread forward or back.

 

While you're moving this cam, the steering arms move around too, changing the toe-in.

 

It's like guitar tuning. You have to keep going back to turn the things you've already turned, until it all comes out at the same time.

 

Normally, none of this should be changed until you've made sure the springs are all OK, and the rear axle is square and centered in the frame. (Sometimes called a thrust angle alignment or rear axle alignment.) You can't get a good thrust angle alignment if there's a sagging spring or worn silent block, and you can't get a good front end alignment until the rear is correct.

[Joe Flanagan]

What it says in my manual is that caster depends on the correct assembly of the upper and lower control arms. 

Yes, I have a '49, by the way.

Edited November 17, 2014 by Joe Flanagan

[Ulu]

What it should say is that a correct camber adjustment cannot be acheived unless the control arms are properly assembled first.

[MarkAubuchon]

Joe, I just rebuilt the front end on my 49, all new bushings and arms.  We used the same method you did to adjust the camber.  I then had the front end professionally aligned, steers perfect, no wear etc.  Drove from st Louis to Port Huron for the POC meet.  All good

[Joe Flanagan]

Thanks, Mark. I also rebuilt the front end with all new bushings, etc. and paid very careful attention to the dimensions of both upper and lower control arms. I haven't had it professionally aligned because I wasn't sure there were any shops that could do it.

[desoto1939]

Joe:

 

Glad to hear that the tools that I sent you were able to help get the setup working for you. These were OTC or Ottawa Tool company old style crowsfeet tools. I think this might be the first time that they were used on a car.

 

Rich HArtung

[Joe Flanagan]

Thanks, Rich. The nut you have to turn is in a hard-to-reach location and it would be impossible without those wrenches. Even with them it took a while to get the hang of it. I'll get them in the mail back to you soon.

[desoto1939]

Thanks, Rich. The nut you have to turn is in a hard-to-reach location and it would be impossible without those wrenches. Even with them it took a while to get the hang of it. I'll get them in the mail back to you soon.

Joe: Take your time make sure you have the car in the proper alignment and then send them back. If you have to take the car to an alignment shop you can take the tools with you but do not leave them overnight or make sure that they return them to you.

 

Having the correct tools helps. If you do a search on ebay they do sell the  single wrench instead of the crowsfoot style that I have.  My 39 does not use these wrenches since my eccentric is accessed via a regular box wrench. The 40 and up need the camber specif wrench to reach inside the control arm.

 

Rich HArtung

[Ulu]

 . . . The 40 and up need the camber specif wrench to reach inside the control arm.

 

I changed out all my bushings & kingpins in '88, and I aligned it myself with the magnetic angle finder, fishing line and stanchions and a 10' trammel made from ET.

 

But I don't recall using any special wrench to turn the cam, and mine is right inside the a-arm too.  Now I'm wondering what I did! it's been 26 years. LOL

 

I know I don't have a crow's foot that big, but a box of my tools was stolen in '2000, and that might be one of the things I forgot was even in there.

 

When everything's new and lubed, those cams turn pretty easily. I might have just used pliers.

[DJ194950]

How about a picture of the tool?

 

DJ