Any ideas for a pin that won't take grease ?

I have an old Case 580B. Its been real good to me but I had a problem today with two pins that won't take grease. The one I got to work by replacing the grease nipple and spraying some SeaFoam in it. I let it sit for a while then once I put some pressure on the grease gun I heard a pop and it started taking grease. The other problem pin is on the bottom of the yolk of the backhoe section. It is the main pin at the bottom that the whole back end swivels on. I tried the same thing with it but it didn't work. I even cleaned all the old grease out and heated the pin up with hopes that might release the bunged up grease blocking the holes.
Anyone have any tricks or advise they could offer ?
I really don't want to remove the pin to fix it if possible, that's a fair big job and I was hoping someone might have a trick up their sleeve ?
Thanks
Dave

Last resort. Remove the pin and use a small pin punch to determine if the bushing rolled on you. The punch should go through an you will be able to see it. (a coat hanger, piece of gas welding rod, or other shop junk will work too) If blocked, either get a small drill bit and bore through the bushing and expect the same in the future. Or replace the bushing if it has rolled.

Thanks for the reply...I was hoping to get it to take grease without removing the pin. I have a degreaser soaking in it right now and will have another go in the morning. Will hit it with some heat again, justnot sure how much I should heat it. I have a feeling that pin would be a bigger to get out. I have had the machine for over 30 years and I have never had it out...

Can try to have someone operate the hoe to take some pressure off the pin while you pump sometimes there is a sweet spot that they will take

You could try adapting a porta power to thread in where the grease nipple would go and put some pressure on it that way too....

Jonas302 has the idea, crank up the pressure on the grease gun, push the dipper out a few feet, lower the boom onto the bucket, then curl/open the bucket to change the pressure. You'll likely have to have the boom swung off to the side while you do this.

Thanks...I will give that a go in the morning and see what happens. Do you think heat would help or am I wasting my time?

A little heat may help, just get things moving along but its a good sized heat sink, perhaps use a propane weed burner.

I use one of these. I had two on my Cat CTL that wouldn't take grease at all. I pulled the zerks, formed a small hook on a stiff wire and dug all the old grease out that I could. I loaded the tool with hydraulic fluid and was able to open up both clogged passages.
https://www.zerkzapper.com/

cutting torch works good, good shot of hot oxygen to remove old grease with a woosh!

Well...tried everything, nothing worked. Got looking around my shop and found a new pin for that joint that I got years ago and never used. I guess the thought of changing it freaked me out then too. So, i bit the bullit and finally took the pin out.
No way would I have ever got grease through it without taking it out. The hole was jammed so full of old hardened grease that I had to use a drill bit to get it out. Well it has a new one in there now and I will clean up the old one for a spare. I think it's the same pin in the joint right above the one I just fixed.
Thank you everyone for your suggestions and ideas.
Dave