[spinn]

I can easily identify mopar u joints, but these gms are little different. For a 1985 c10. I believe they are R3 joints on a one piece 55.5" long shaft from a 1985 C10. Cannot figure it , the out caliper states 1.79" dia cap.

Are R3 joints a 85 c10 replacement?

Can you replace the straps for u bolts at the differential pinion yoke? DR\rill the yoke threads out, if one is stripped. Then use u bolts.

 

[SSedan64]

1350 = 1.188"
3R = 1.125"

Do they have Lock Rings?
3R uses injected Nylon if Stock/OEM, Replacements use Internal Rings.

 

[spinn]

They are 1350 my caliper has had a lot of wearover the years. Btween 1.18 and 1.19 so that makes sense. I have a nice aluminum driveshaft from a envoy that i was going to alter.

THey might be called r1 not r3. I know the stardards are 1 3/16th cap and 1 1/4 cap.


Is there a kit to convert to u bolts instead of straps?

 

[SSedan64]

8.5" Rear?
You gonna change the Pinion Yoke or use a Conversion U-Joint?
U-Joint Fasteners - SummitRacing.com

 

[spinn]

Yes a 8.5 rear. I forget the .1 so they are 1.179- ish. That makes them 1350 u joints.

The straps are okay , but im looking for a u bolt retainer. Can I drill the yoke?

 

[SSedan64]

The 8.5" Pinion Yoke will most likely be a 3R size which is small so you would need to change the Pinion Yoke to use a 1350 U-Joint or use a 3R/1350 Conversion U-Joint & drill the 3R Pinion Yoke for U-Bolts or use Al. Caps.
If you want strength you should change the Pinion Yoke and Slip Yoke to 1350 size to match the DS.

 

[SSedan64]

I don't know if they even make a 3R to 1350 Conversion U-Joint.
Look thru these:
http://www.summitracing.com/search/part-type/u-joints?keyword=U Joints