Tire/Brake Problem?

My left front tire can’t seem to hold air yet no one can find a leak. Recently, when cutting hard to the left there is a rubbing sound, and only when slowing down the left front tire feels wobbly. What could cause this?

Try having the valve stem replaced. Tom and Ray have commented on bad ones from China.

Do you feel a pulsing of the brake peddle? How many miles on the tyres and car? When was the last time you have the alignment checked?

There are less than 10K on the tires and 62K on the car. Never had an alignment. . . . As for the brake peddle pulsing, I guess that’s what you’d call it. The brake pads were replaced this past August.

I’ve had the tires for about 4 yrs, but the treads are still amazingly good and they still look new. The car has been driven and treated very well except for my negligence with an alignment.

Yes the Chinese valve stems were cheap. Many tire stores and national chains bought them only to find that they are now having to replace tires that have been run low because of them. Wobble can be caused by a broken belt, possibly also caused ny having been run underinflated.

You mention a broken belt - what belt?

The tread area of the tire (annular) is not solid rubber. It is made of many layers (belts or ply/plies), some of which are – in most modern tires – made of steel cords. Hence, the familiar term “radial ply steel belted tires”. Sometimes one or some of the plies/belts in a tire will separate, causing the tire to run thumpy, as if it were out of balance. Often, the balance will seem to be OK. Sometimes ply/belt separation also causes the car to “pull” to one side.

All the above is from experience. Had a thumpy car one time. Sounded like one rear wheel, so I took wheel off to look for evidence of a missing wheel weight. Instead, as I rolled the the tire down the driveway I could see the collapsing spot where the belt had separated. There is no fix except a new tire.

However, I do not know how likely it is that belt separation could cause a slow leak. MAYBE two different problems. But if you have to replace the tire you’ll get a new valve stem anyhow, and maybe all the problems will be solved.

The brake pedal pulsing is pretty common after having the pads replaced. I find a couple of good hard decelerations like 60-5 mph will solve that problem. Don’t lock up the brakes, just hard to the point of almost lock up. Do not come to a complete stop or trapped heat under the pads could warp the rotors.

Be careful where you do this, you want to do it safely.