wow ok guys thanks, ill check it out today sounds very important, the seller owns a repair workshop for dozers so he could have either fixed it "mexican style" but also he could have missed this issues because he was just the middleman between the owner and me and the "owner" had no idea about anything farm related so who knows when this dozer was last used. But i will text him later to ask him whats going on.

Im looking for a diagram of the tracks to identify everything ill post an update in the evening thanks guys this bulletinboard is very cool!

I do not like what I see on the track frame nor the master pin coming out of the rail and appears to have been welded previously.  You are fortunate that pin has not come out and caused further problems.
Sprocket shows some uneven marking too, may be indications of misalignment of the track frame which also relates to the other problems mentioned.
Look at the equalizer spring too, make sure nothing is broken there.
Recoil Springs ( the big coil spring behind the track adjustment screw) should be looked at too, are they broken?

Post some pictures of the front idlers, the adjustment screw, recoil spring.   You have some eyes looking at it closely.  
CTS



 

Have you checked the wear on the pins and bushings? Are they round and even? Feel them, is the track pad (plate side) worn and not round?)
Shoot a couple of pictures of the inside of the track, between the rails.
Both sides of the machine and be sure to look at the master pin on the left side of the tractor too. Is it also welded.?
(The master pin looks different than the rest of the pins as you look at the track, you should be able to identify it)

Also be sure to look closely at the rollers, make sure they are rolling and not wobbling. A bad roller can make an awful lot of noise as it does not track properly.
CTS

Wow so the right side master pin was lose and I was able to unscrew it using just my hand 😱

Here are some photos:

that’s a video of the master pin lose, I hope that’s the master pin I think it is 

youtube.com/shorts/P6-skugZ_MQ?feature=shared

so tomorrow I’ll screw back the pin which will tighten the recoil spring and the track will loosen up a bit I hope

My 2003 Toyota tundra is not shifting into reverse I sold my 2017 truck to get the money to buy the dozer 😂 I have to fix the truck first then the dozer tracks  lol

Thats not a master pin,they are in the track.
That is a center bolt that is used to put the spring together and hold the guides in place.
Don't run the tractor with out that bolt in place'
Tightening that up won't relive the tracks.
You really need someone who knows these tractors to help you before you kill or hurt youself.
Bob

Captain Beans there’s a lot of tension on that spring the bolt is broke and the other side is probably broke as well. I highly advise you to not operate the bulldozer until all this is fixed, you could end up dead or hurting someone else around it. Have someone come out and look at it in person please!

ok, thanks for the advice, yes i wont be using the dozer for the time being, the thing is i will probably need to figure out myself what is going on considering i bought this machine 2 weeks ago and the mechanic that sold it to me told me it was in good shape and that i will have no problems with it in the near future, I called him today he was mortified about the center bolt being so lose i was able to unscrew it with my bare hand. He didnt mention anything about the master pin or anything being hack repaired, welded, etc.

So I as I am understanding, there are four things to check and repair:
1. The spring bolts on each side:
    1. a):  Spring center retaining bolt right side: The one I unscrewed with my hand looks ok although it shouldnt have been so lose as to be able to unscrew it with my bare hands, I wlil screw it back and tighen it then proceed to losen up the tracks as per the instructions on the copies I got (I thought this bolt had to be tightened for the tracks to lose up but apparently no, however it looks very risky to try to adjust the tracks with this bolt unscrewed from its place) :
               
        

     1. b) Spring center retaining bolt left side:  the other side looks broken, and its the one that should be flush with the housing  but its sticking out,  so I was going to try to unscrew that one too and replace it with the right part, but according to the guy that sold me this machine this is very dangerous because the spring could kill me, I will ask the seller what is going on though:

So this retaining bolts help keep everything in position I am assuming although they dont directly losen or tighten the screws.

2. The master pins on each side: I cant find the photo where the master pin is coming out of the rail, please guys if you could tell me exactly what im looking at because im so confused right now.

Thanks for everything guys looks like you saved me from destroying the machine or worse hurting myself.

LIKE i SAID THE CENTER BOLT IS NOT USED TO ADJUST THE TRACK SAG.
Those bolts don't look like the right ones anyway.
Adjust the tracks like your page says.
If your front spring guide still has a grease fitting go ahead and grease it first ,
don't worry it won't blow out like some people would lead you to believe.
The bad master pins are the ones with the washer welded on them.
Bob

Yes bluox, sorry for being stubborn, I edited my message quickly after posting it, you are right, that bolt does not tighten or losen up the tracks.

Thanks!

Track Chain Master Pin

Look back in the threads to the replies, you are missing some good information.
LOOK at the picture you send and I have marked in RED

That pin comes out, the track chain is no longer a continuous loop, besides, that pin will probably tear something up as it comes out.
The repair is not correct, that rail segment does not look great either from what I can see in you photo.

Do check the pins and bushings wear, they should be round with no flats or wear through the bushings to the pins.

CTS