i would like to know what is wrong with my 300 because when ever im in 5th gear the front wheels want to shake really bad and it get annyoing i would like to know if i had to get a new upper bolster pivot shaft or something else?

Replace the worn out parts and it will be fine.

Could be in the shaft, bushings, worm gear shaft or steering gear or a combination. Couple of weeks ago I put a replacement worm gear shaft in my 300 and turned the circle gear 180 degrees and it steers really well now where before I had a lot of slop in the steering wheel and I could see the wheels wandering from side to side. The worm shaft is the same as an H, the gear is full circle instead of half but I think the replacement gears are all full circle now anyway.
Zach

There are many contributions in the archives.
Here are the Jim List features.
Start with the concept of looseness.
At the center of the hood (Under the hood) there is a universal joint. There should be no play in this joint at all, as the wheel shaft turns so should the front shaft. If there is play in it note the play in amount of wheel turn at the circumference of the wheel.
At the point where the shaft disappears into the steering gear box up front, the shaft should be cleaned with some solvent and dried. Have a helper,or tie a brick to the wheel so it turns right, but not hard, just till the slop is out of the wheel. Now Mark the shaft with a magic marker right at the point where it disappears into that steering box. (sheet metal is off) Now turn the wheel the other way till the slop is gone, and look at the mark. If it stayed where it was and didn't come out (away) of the casting all is well with the worm gear bearing.
if it moves in and out as the play is taken out it will need a new bearing on the front of the worm.
Next take off the cover from the gear box. You will see the worm, and sector gear. It needs to be inspected for wear by turning the worm and watching carefully for worm movement without sector movement. Also watch for the sector nut to move sideways before turning. If there is little play there, and no side to side, the worm and sector are OK. If the worm moves but the sector does not, the sector needs to be replaced.
If the sector turns but the nut stays still for a little bit the sector is loose on the tapered shaft and might have a wallowed out Key.
If the sector moves sideways some before turning, the top bolster bushing is bad and needs to be replaced. The shaft is also subject to wear and can be rewelded (built up) and turned back to stock dimensions for the new bushing.
If those are noted, next the lower bolster bushing can be bad (along with shaft wear).
The tractor needs to be jacked up and the lower bolster tweaked front to back and side to side with a prybar to determine the condition of the lower bushing. .005 to .008" might be as good as you should expect for a OK bushing.
Last is to look at the wheel bearings and even the wheel balance. No shake is allowed in the wheel to spindle bearing. if there is it needs to be adjusted. (repacked and adjusted).
The total steering wheel freeplay should be less than 4 inches on the wheel rim.
There are many posts in the archives, and from the H, through the 450, all are worth reading (same system different size. Replace the ball bearing of the worm gear with a deep grove heavy duty bearing with the same size. Jim

My H had every part in it shot, replaced them all and it steers great now.

I"ve been tightening up the steering on my H for years now. Last thing I did was install new worm gear from this web site, after checking everything else. It was all tight. The new worm gear changed things dramatically, until this weekend when the slop came back, bad. Tore into it this morning, and found the top nut on the sector gear hasd come slightly loose. Tightened it up two flats tighter, and this removed all the slop. Steers great, no wobble at all going down the highway.
But I think this is a never-ending quest, I don"t think we"ll ever actually get to completely fixed steering.