Are the upper and lower control arms the same on a D250 and D350?
Also the same Question for the upper and lower ball joints?

 

For a Cummins truck...Yes. But if it's a gasser then it could be a 3300lb or 4000lb front end. The cummins trucks only run the 4000lbs front ends, so use this as your guide to parts.

 

Upper arms stay the same all GVWs, but the balljoints get bigger for D350 and CTD D250.

For trivia's sake, the CTD D250 front end is rated at 3850#... but its all 4000# hardware.

 

Note" the upper ball joints are screwed in using a special socket not pressed.

 

I checked the door tag on my 1990 D350 Diesel and it shows 3830lbs for the front end.
The top ball joint is 2 1/8" square and threaded.
Have square tubing that will go right over it for removal with a pipe wrench.
The bottom ball joint is a press fit.

 

update to upper control arms:

For all Arms, there is in fact a difference between upper 3000 and 4000 arms. Some Diesels , including my 1989 D250 had the 3000 arms, which cracked. The location of the failure is where the 4000 lb arms are bolstered by a doubler plate in the inside of the AFT mount of the arm.

I confirmed that a '73 camper 9000 D200 with the 4000 lb (3830) front end as well as a 1978 camper 9000 have both had these arms as well as most all diesels I've checked.

in Late 1988 and early 1989 , preorders for the cummins Dodge were high, and dodge worked overtime to fulfill as many orders as possible, which might be why my d250 had the lower grade arms.

My arm broke at slow speed in a parking lot while bumping up against a curb. Certainly, it would've been a much different story if it broke at speed, very likely in fact with the condition of the roads in many areas.



conclusion: ensure that any upper arm you consider installing on your truck has the doubler plate on the inner/under side aft mount.

 

I jack my frame up on the drivers side and put a stand on the frame.
Next jacked up the lower control arm taking pressure off the upper control arm and was able to move the lower part of the ball joint while the upper part was held by the threads in the control arm.
Think I need a new ball joint?
Looked at the upper control arm and found a small section of metal welded around the rear bushing area. Is that the reenforcing that is talked about?

 

Replaced the upper ball joint by using a jack stand under the frame and jack stand under the brake rotor to hold it up while jacking up the lower control arm to take pressure off the upper ball joint.
The hard part was getting the cotter pin out of the ball joint nut.
I see the two bushings in the upper control arm with the cam bolts to adjust the camber, but how do you adjust the caster??

 

The caster is affected by how differently you index or clock those camber bolts from each other. You may be able to further adjust the caster with the lower strut rod... not sure though.

 

Hi Bruce, yes I believe you've identified that you have the heavier version upper A arm!