Difference on B Body Upper Control Arms

[RRChris]

I believe the upper control arms (UCA's) on B Body's changed in 1973. What are the differences between the pre '73 and '73 onwards UCA's.
Does anyone have any photos? Are there any measurements that give the game away - bush length, diameter, ball joint size?
The reason for asking is my '71 Satellite has a Master Power Brakes front disc brake system, which I think has the longer spindles. Reading an article it suggests that with the longer spindles the later model UCA's.
I am wanting to re-bush the UCA's and not sure which to get until I confirm which I have. Being on the other side of the Pacific I don't have the luxury of pulling apart to confirm and then ordering parts.

 

[Darter6]

Not sure about 73 but by 74 Chrysler went from Cam bolts for adjustments to slots in the frame and a shaft between the upper control arm bushings. Look up My Mopar you may find a service manual photo to conform.I think that year the ball joints changed too.I'm not sure but I do not believe that they can be used in the earlier cars.

 

[Beekeeper]

In 73 the spindle height changed to a taller one so the a arms where changed according to keep the geometry correct. As long as you match those two you should be good.

 

[moparmarks]

I can get some pictures but the 73-up UCA is way different than the 72-down ones. Is larger and mounts totally different. Would take a lot of work to make it fit the 72- down setup. The 73-up spindles are 3/8" taller then the earlier ones. Your 71 should have the 70-72 B/E spindles, nothing special there. You can use the later spindles with your 71 control arms. Not sure what your wanting to accomplish.

 

[hemi71x]

73 up B body Mopars changed to a totally different UCA design with a "shaft" installed thru it.
Won't work at all on 72 on down, earlier cars.
(See photo)

 

[RRChris]

I can get some pictures but the 73-up UCA is way different than the 72-down ones. Is larger and mounts totally different. Would take a lot of work to make it fit the 72- down setup. The 73-up spindles are 3/8" taller then the earlier ones. Your 71 should have the 70-72 B/E spindles, nothing special there. You can use the later spindles with your 71 control arms. Not sure what your wanting to accomplish.

The set-up I have works, I don't want to change anything, I just want to re-bush the UCA's. All I want to achieve is to identify what I have so that when it comes time purchase new bushes I get the right ones (if there is any difference). The spindles on it were supplied by Master Power Brakes (non OEM).
So from above responses it looks like the bushes will be as per original '71.
Was there ant difference in ball joints IF the longer spindle was used?

 

[moparmarks]

73 had a different ball joints but that was due more to the change in suspension and control arms than spindle height.
Yes just get bushing and joints for 71B.

 

[RRChris]

73 had a different ball joints but that was due more to the change in suspension and control arms than spindle height.
Yes just get bushing and joints for 71B.

Thanks for everyone's input.
It may have seemed like a silly question, but I prefer to ask the silly questions and have a better chance of success when I come to do the job.
It great to have a forum where people's experience can be tapped into.

 

[Darter6]

That's what most of us are here for. To share.

 

[moparmarks]

Yup.

 

[Cranky]

73 up B body Mopars changed to a totally different UCA design with a "shaft" installed thru it.
Won't work at all on 72 on down, earlier cars.
(See photo)

View attachment 883564

Thanks for the pic! Never have worked on a 73 and up B but have worked on the E cars which are all the same as the 72 and older B's. There's always been a fog on this subject with many not knowing exactly when the change was made and even though I've read about it several times over the years, my mind is now clear on it....I hope!

 

[moparmarks]

Here is another pic of the 73-up setup. LCA's are way different too.

 

[Beekeeper]

Here is another pic of the 73-up setup. LCA's are way different too.

View attachment 883874

Wow total change over very different

 

[RRChris]

Clearly big differences.
I've learnt something as well.

 

[SureGrip]

Here is another pic of the 73-up setup. LCA's are way different too.

View attachment 883874

Damn, those LCAs could use a stiffening plate! Never noticed how 'open' they were.

Great, something else to put on my list.

 

[rrTor-Red]

I can get some pictures but the 73-up UCA is way different than the 72-down ones. Is larger and mounts totally different. Would take a lot of work to make it fit the 72- down setup. The 73-up spindles are 3/8" taller then the earlier ones. Your 71 should have the 70-72 B/E spindles, nothing special there. You can use the later spindles with your 71 control arms. Not sure what your wanting to accomplish.

My '71 here. I went with tubular UCA and spindles for disc. Some kind of visual in reference to Moparmarks statement. Cheers

 

[Hemirunner]

73 up B body Mopars changed to a totally different UCA design with a "shaft" installed thru it.
Won't work at all on 72 on down, earlier cars.
(See photo)

View attachment 883564

Ah yes... the Chevrolet design.

 

[YY1]

no sorry

not gm influenced at all

the Mopar design uses no extra parts for adjustment

gm uses shims

 

[YY1]

Although I'll add that changing those UCA bushings an the 73 and up arm is quite the exercise and is not documented in any FSM.

Back in the day you were advised to "replace as an assembly" which is not an option today.

 

[YY1]

I have a how to thread on how to do it using 2 sizes of rigid conduit and custom bracing in a press