Sunday, July 18, 2010

Patch a tire

Patch a tire

I like to do my own tire repairs, I started doing tires when I was a diesel mechanic. Not often but I would repair a tire when need. In big truck land doing a tire by hand is basic 101, you can also dismount a car light-truck or implement tire by hand, the tire shops use a machine on small tires but if you have more time than money read on. Besides, after a collapse a tire shop may not be available.
Start by removing the valve stem core, the top pic is the tool to remove it. Next you need to break the bead on the tire and rim. I use an out-rigger from a crane truck, it hydraulic moves down and puts pressure on the tire breaking it from the wheel. They make a sledge hammer for this but my way is less work, you can also use a tractor bucket to do this or use a bottle jack and position the tire under something heavy like a vehicle and place the bottle jack in between them and jack away. Also you could use a vehicle and drive over the tire to break the bead. However you decide to do it be careful not to bend the rim. If you do bend the wheel use a sledge hammer with a tapered end and pound it back to a reasonably true condition.

Basically you have  two types of set ups for tires most common is a tubeless radial, that's what is on every car and light truck since the 50's older semis and implements have a tube. Some tubes are radials some are not. If it has a tube and the tire says Radial that's what tube goes in it. Today, I'm changing an implement tire.

Now you need two bars the long bar with the curved ends is called a tire spoon. Two spoons are better but I use a pry bar. Stand on the tire so it is half way down the wheel. The wheel is recessed inside at about the half way area of the wheel. Note on a dully wheel the recess is on one side so you need to dismount on the side closest to the wheel recess. Look closely and you will see what I mean. You need to pry the lip off the tire over the rim. The recess in the wheel provides room to allow the side being pried on enough room to do this. After you get one portion over insert your pry bar to hold it out, then remove the spoon and pull another part of the tire over with the spoon, Do this a few times till its over the rim. Do the same to remove the second tire bead. If its a tube and tire just remove one bead of the tire and remove the tube.

Now just follow the directions on the patch kit its available at auto part stores and farm supply stores.I forgot to mention if its a tubeless tire mark the location of the puncture before removing the tire. If you cant find the hole in the tire or tube dunk it under water, I use a horse trough. On a radial tire use a "radial only" patch. On  all others any patch should work. To patch a tube you can also use a piece of an old tire, as a patch. Be sure to rough up any gluing surface of the rubber. The patch kit comes with a metal scoring tab, I use a die grinder with a buffing pad, sand paper will also work.

Now mount the tire with your pry bar and or spoons, then air up. If its tubeless the bead may not seal enough to get enough air in-to seal the bead. I hold the wheel and bounce it as I rotate it  this usually works, to get a seal started. If all else fails use a come-along and chain then wrap around the tread and ratchet down till the wall of the tire pushes out to the wheel then air-up to seal the bead, then bleed the air remove the come-along, and air up again.

Balance: On a tubless tire mark the location of tire in relation to the wheel before dismounting if the wheel is balanced, Then mount it in the same position. On large semis its rare to balance the tire and wheel. Its generally only done if there is a vibration problem. On farm and constriction equipment its too slow moving and wont matter. The thing with balance is on a large tire its less important than on a small tire, because a small tire spins faster to achieve the same road speed as a large tire. Another trick for balance is to add in balls before mounting, golf balls, tennis balls, any thing of the like will work. The balls will balance the tire when it is spinning.

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