Steering is not smooth (u-joint)

"Not smooth" does not say what the symptom or problem is. I have never heard of lubricating a u-joint on the steering shaft. When a bearing in one goes bad, they bind and resist turning. You will feel the tightness twice per steering wheel revolution. The wheel will turn easily, then hard, then easily, then hard again. It wont want to self-center when you let go of it after turning a corner. The only fix for that is to replace the assembly that contains the u-joint. The joint is never available separately.

The binding occurs because the needle bearings have cracked or have become pitted from rust. If you are able to get some type of grease in the bearing cups, it might alleviate the symptom for a little while, but that isn't going to fix the worn bearings.

It is more common to have a sticking rubber boot where the steering shaft goes through the firewall. That can cause a resistance to turning that you can feel and it usually makes a squeaky sound, like dry-rotted wiper blades sliding across the windshield. That will be solved with Spray White Lube but you have to pull the boot back to get it in there. That is a lithium-based grease. Once the juice evaporates, it leaves the grease behind that tends to stay where you put it.