Tires Loaded tires, problem.

   / Loaded tires, problem. #1  

Jibber

Gold Member
Joined
Feb 22, 2003
Messages
324
Location
RD-13, Putnam County, New York
Tractor
Kubota L3130HST 4WD, BX2350
I've had the 3130 for three years now.. decided it's time to check the tire pressure!! These are loaded tires.. no notice of any problem except that there seemed to be a slight leakage of the calcium solution from the inflation stems themselves..

I rotated the tires to the 12 o'clock position and removed the caps.. but the tiny actuator stem inside the Shrader valve fell off as I attempted to check the pressure.. both sides! Probably corroded by the salt solution.

my question. I have replacement valve (internal) assemblies for shrader inflation valves.. but am I asking for trouble trying to remove these? Obviously there is corrosion in the stem itself.. and I wouldn't want to let enough pressure out that the solution itself starts squirting all over the place as I'm attempting to insert a new valve. Now , I'm talking just the actuator valve.. I have no plans on attempting to replace the entire valve stem.. just the insides.

Tire pressure appears OK.. should I just leave this alone? I have no trailer and a trip to the dealer means about a hundred bucks each way for them to come and get it.

any advice is appreciated.
 
   / Loaded tires, problem. #2  
Just went through the same thing with a tractor I was working on to sell. I've had it to happen to several valve stems over the years. Simple jack up the tractor to remove weight from that wheel, let out all the air pressure, then replace valve core with a new one. No big deal. Some cheaper tubes and tubeless valve stems are plain ol' steel. Some are stainless steel. Replace and go on with life.
 
   / Loaded tires, problem. #3  
You might be better off to replace the outer part of the valve stem itself. Tractor tire valves are two piece. The part that goes through the hole in the rim and the part that screws into that. Inside the outer piece is the schrader valve. If the schrader valve has corroded that badly I would replace the entire outer piece. You can get them from any tire store that deals in large tires, or you may be able to get them at an auto parts store. I have had a lot of experience with farm tires and chloride and that is what I would do.
 
   / Loaded tires, problem.
  • Thread Starter
#4  
I did notice the outer collar. That makes sense to replace the entire valve. I'll look for replacements. In the meantime, I'll change the valve core if I can. At least that will allow me to make sure the pressure is right, and maybe stop the leaking.

My biggest concern was letting out the calcium solution.. but I can get the tires up off the ground pretty easy with the backhoe.
 
   / Loaded tires, problem. #5  
Like FWJ said. Just jack up the tire and replace the valve core. Most of the time you can just replace the core and it will be fine.
 
   / Loaded tires, problem.
  • Thread Starter
#6  
Update, finished dressing the driveway with the box blade.. put the hoe back on.. moved the tractor down by the garage and jacked her up using the stabilizers. Moved the right rear so that the stem was at 12 o'clock and screwed out the core.

gusher. salt water gusher.. but I was able to swap in the new core with not that much leaking out.

Moved to the left side.. pulled out the core.. nothing.. no calcium solution.. no air.. nuttin.

figured I had a problem.. jiggered around with a small screwdriver.. and boom.. gusher.. tried to put in a new core.. wouldn't go in.. there was part of the other core still in there.

now comes the knowledge learned from this forum.. two piece stem right.. so I back out the rest of the stem and whoa.. gusher.. I'm not sure how much calcium solution is supposed to be in these tires.. but I guarantee there was too much.. it gushed for a good two minutes before air started coming out.. now remember.. I'm at 12'oclock..

I was able to get the rest of the core out of the stem.. put a new core in and air up the left tire to the spec 20 pounds. I then removed the entire stem from the right and bled off the same amount of calcium solution to equalize the weight.

now I'm soaked with salt water and the tractor needs a bath so that it doesn't rust up like a 65 mustang.

When I got the tractor I didn't have the hoe so I needed the tire ballast for the loader.. not sure I need that weight anymore.. most of the time I have the hoe on there.... but I wonder how much solution was actually in those tires! The manual says to fill to just under the stem at the 12o'clock position.

thanks again for all the info.
 
   / Loaded tires, problem.
  • Thread Starter
#7  
New problem.

It's sitting a little lower. I noticed it right off.. but how it sits in the garage really makes it evident. Obviously the dealer had MORE than 20psi in the Rears.

The manual says 20 for my rear tire size. I'm wondering.. does that change when you add a backhoe? I see no reference to it..

how much pressure is too much? I'll check with my dealer monday.. but just brain picking right now..
 
   / Loaded tires, problem. #8  
You'll probably also notice a big difference in how it acts going over a bump. When I had my rears loaded the ride was a lot harsher. My manual says not to exceed 26psi on 11.2 x 24 4 ply rear Ags on a 2400 lb tractor.
 
   / Loaded tires, problem. #9  
Of course your pressure is going to be higher when you have the hoe on.

You should adjust your pressure for each load... and you should pressure with air, not by adding more CaCl.

My advice would be to attach the hoe, maxing out the weight that the tires have to carry. Then pressurize your tires to the recommended value... if that's 20psi, then stop there.

Check and adjust your pressure again every time you remove or install the hoe. It accounts for a large percentage of the total weight on the tires, so it'll make a big difference in the pressure inside them.
 
   / Loaded tires, problem. #10  
Bad Dog, something isn't making sense here. If you put 20 psi in a tire, that pressure shouldn't change when you hang more weight on it unless you reduce the volume inside the tire. You might make it take on a different shape, but I don't see why the pressure would change unless you compress the air more -- reduce the volume. When I air up the tires on the car or truck, it makes no difference whether the vehicle is on the ground or on a lift. The pressure doesn't change. On my lawn mower, 6 or 7 lb in those little tires doesn't change when I park my additional 30 to 50% of the total weight on the seat.

About the only thing I can think of that might cause the pressure in a tractor tire to go up with a load on it is if the tire is loaded with a liquid (non compressible) leaving a relatively small air volume at the top of the tire where the shape isn't going to change under a load. Then, maybe, when you put something like a backhoe on there, you might see an increase. Otherwise, I can't see why it would happen.

Can someone explain this to me?
 
 
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