Control arm bushings, what's the skinny?

[Slickster]

While rebuilding the steerimg box, 48 P15, I discovered that the left front lower control arm bushing has alot of play....alot...(been chasing death wobble), the upper has slight play, tie rod ends are ok, RF suspension is good, left front wheel will jump off the pavement at inopportune times....can these bushings be replaced with the arms on the car?  Are they pressed in? What are some of the issues I might run into?  Car is undriveable at this point, also, feel like I am digging a hole at times with expense of this project....thanks

[Sniper]

You need to get yourself a copy of the service manual, they are fairly cheap and available in electronic or hard copy from a number of sources.

 

That said, no you can't replace them on the car.  Yes, there are special tools involved., whether premade you buy or something you need to fab up.

 

The bushings are metal and screw into the control arms, the special tool basically holds the ears of the arms at the proper distance while you torque the bushing.

 

The service manual will give you the proper dimensions you need to meet when replacing the bushings

[Plymouthy Adams]

totally replaceable bushing.....if you do not have the shop manual...it would be worth getting one or maybe get a friend to scan that section...there are special tools for the process...gauges etc....you can get by without these or make your own if you understand first what the objective is.

[Plymouthy Adams]

Sniper...you beat me by a millisecond.....?

[Sniper]

That's me, Mr. Millisecond, lol

 

[Andydodge]

Slick...........ideally the proper tools would be good but here in Oz they are unknown, I have rebuilt the front end of a couple of 40's mopars without the tools over the past 45 years  but keeping in mind the correct specs and the cars have been fine............which bushing is worn?............the lower inners or lower outer?.............either way you jack up the car, support the frame and the lower A arm separately, undo the outer bush them slowly lower the jack under the A arm carefully as the coil spring is under tension until the spring is loose, remove the spring then undo the inner pin/bush assembly from the front crossmember and there you have your lower A arm...........the inner pivot pin is AFAIK the same from 1939 to 1956  as are the bushes on each end..............the outer pin & bush also the same BUT there are at least 2 different sized bush "heads" tho' the internal sizes are the same............reason I mention this difference in size is that the rubber seal is different for each sized bush.........the outer pivot pins are the same tho'..............its a good idea to have a good bench vice to hold the A arm/inner pivot pin ..............assembly is the reverse.............hope this helps....................andyd 

[desoto1939]

Here are pictures of the factory tools to install the new bushings: and how they are used to install the bushings an the control arms.

 

Rich Hartung

Desoto1939@aol.com

 

 

 

 

 

 

[desoto1939]

here is the kingpin tool being used:

 

rich hartung

desoto1939@aol.com

 

 

 

[Slickster]

The lower outer and upper outer need to be replaced, looks like no special tools needed for outer bushings?....I have manual btw.  Thanks

[desoto1939]

the upper outer is an eccentric bushing and control nut.  Moog made these and you need to know which is the proper bushing and you will also need a camber and castor wrench so you can make the appropriate adjustment when you do the alignment.

 

If you are going this far would also suggest that you replace all tierods ends so you have all new parts and also check the kingpins to see if they are worn.

 

Rich Hartung

[James_Douglas]

WAIT!

 

These bushings are SUPPOSED to be loose.

Control_arm_bushing_clearnace.pdf

[Slickster]

You can feel the left front wheel shift and the car jogs a bit left or right....scary....gross amount of play, lower outer,upper outer has some play also, can't detect play in the others...

[James_Douglas]

17 hours ago, Slickster said:

You can feel the left front wheel shift and the car jogs a bit left or right....scary....gross amount of play, lower outer,upper outer has some play also, can't detect play in the others...

Are you sure it is play and not that the front end is way out on Caster?

Check the actual play as in the PDF attached to see how much play is in each part. You will have to drop the springs to unload them to measure the play. I would take them all apart, have new parts handy if needed, clean them well to get most of the grease out and measure each shaft. If within spec, leave it alone. If out of spec or close then rebuild them.

 

BE CAREFUL on the centering. I am fighting a problem on my 1949 Desoto that may be due to the shaft being off center on the control arms. I have the upper tool, but I do not have the lower tool.  If you are off even one turn on those bushing you toss off the caster static geometry.

 

James

 

[James_Douglas]

On 1/21/2021 at 2:47 PM, desoto1939 said:

here is the kingpin tool being used:

 

rich hartung

desoto1939@aol.com

 

 

 

Hey Rich,

 

Any chance you would draw up the C-594 tool so I could make one?

 

James.

[Slickster]

I had the lower control arm loose to remove the steering box, huge amount of play in the lower outer, you can feel it shift while driving, not sure I want to go down this rabbit hole....