Curing Rim Leaks in a Lawn Tractor Tyre
(An Apparent Puncture)
Introduction
I had problems with one of the tyres on my lawn tractor which would not remain inflated for long. I had to pump it up everytime I wanted to use the tractor and it would remain usable during a normal grass cutting session, except for when I went for a break halfway through. After putting it away, the tyre would deflate so that the tyre was completely flat. Om coming to use it again, I often had problems reflating it as the seal between the rim and tyre was affected. To overcome this, I made it a practice to jack up that front wheel when it returned to the garage to stop the pressure of the weight of the vehicle affecting the seal.
This article shows how I identified the source of the problem and cured it using ordinary silicone sealant.
Identifying the source of the problem.
The way to identify the source of any puncture is to inflate the tyre and immerse it in a bath of water. The location of the puncture will be revealed by a stream of air bubbles.
Fortunately, the front wheel of a lawn tractor is not that big and it can be immersed in a large household bowl. OK, I did not pinch this one from the kitchen; it was one we used to mix compost!
The test showed that bubbles were coming from around the rim of the wheel indicating that the tyre was not sealing well against the rim. This is often cause by corrosion of the tyre rim.
Getting access to the back of the rim
Deflate the tyre by depressing the plunger in the centre of the valve with, for example, a crosshead screwdriver
The next stage is to move the bead of the tyre into the central well of the wheel. This frees the tyre and allows access to the back of the rim. Use a tyre level under the rim to lever the bead away from the rim. You may need to go round the whole rim achieving small movements until it begins to get displaced. Do the other side as well.
Once the tyre bead is in the central well, clean the back of the rim to remove flaking paint and corrosion, using emery paper as shown.
Sealing the rim
Now, we put a layer of ordinary silicone sealant on the underside of the rim on both sides. I would have liked to have shown a picture of the sealant gun producing a bead of sealant, but that is not what happened. The first two cartidges of sealant I had in the house were solid and fully polymerised, so they went in the bin. The third showed more promise as it was only partly polymerised, but the sealant would not come out nicely from the nozzle. The nozzle was removed and extreme pressure applied to the gun to push out some sealant which was then applied by finger onto the inside of the rim. The aim is to get a thin layer of sealant all the way round the rim.
The tyre should then be inflated. It may be difficult to get the tyre wall back against the rim as the air will go straight out. Try putting the wheel vertically and press down hard on the top of the tyre. This ahould force the tyre wall outwards and hopefully it will seal.
If this does not work, you might need to apply a tourniquet to the wheel. Tie a rope or strong string around the circumference of the tyre. Put a stick of wood, large screwdriver or metal rod under the rope at right angles to the tyre. Rotate this lever to tighten the rope which will force the wall of the tyre onto the rim. Then try re-inflating.
With the tyre inflated, clean off any surplus sealant around the rim.
Retesting
Go back to your bowl of water and re-immerse it in the water and look again for the bubbles. If all goes well, they will not be there. The picture shows me putting pressure on the wheel to submerge it as a complete check.
Replace the wheel on the tractor and use a new split pin to secure it.
This solved my problem and I hope it will work for you as well.
Article dated: 9 June 2013.
Author: D.Halls
Website: http://www.djhweb.co.uk