-
What to look for if High Temp Tires
I’ve seen several posts now on possible high temp tires and a couple of possible reasons. On Saturday I took the bus out for some exercise since I’ve been stationary the last month. Eventually my passenger drive tires were 5 psi higher than the other side which is unusual. I shot them with the IR gun and the outside Drives were close, but the inside passenger drive was 114 vs the other side which was 104. Maybe not a big deal, but worth checking out.
My question is how would I know if I have a “dragging brake” and, without getting under the coach, is there anything I can do about it?
Second question is about the hub seal on the drive tires. I removed the hub cap to try to see the fluid level on the Hubs but couldn’t locate it. I did see a hex screw that I think you would add oil. Is it different than the S & T? I don’t see any oil leaking out, but just wondering how to fill if I do and to determine how much is in it already.
-
7 Replies
-
Drive axle oil level is checked and filled at the differential. You have to get under the bus to do it.
-
Tim,
Often a differential between tires on one side of the bus and the other is related to which side the sun is on. It is not unusual for the inner drives to be warmer than the outer ones. What is important is learning over a period of time what is normal. Your temps reflect cooler weather and as the ambient temps increase along with the temp of the highway it is not unusual to see higher temps. As you monitor the temps (and how pressures are affec ted by them) you are going to see a range of temps as well as the relationship of various temps to tire position.
A dragging brake or a bad bearing is going to show an unusual hub temp before the tire is seriously affected, whereas a low tire pressure is going to show a high tire temp with a more normal hub or wheel temp.
On coaches with the oil bath steer and tag axles some of the caps have a removable center rubber plug. Others may have caps with an allen screw that is removed for filling. Both however have an oil level indicator mark that is almost at the bottom of the clear plastic center section of the cap. If you have the allen screw type caps make certain you have an allen wrench of the appropriate size.
You cannot check the drive axle for fluid level without opening the plug in the differential and you cannot get at that without being under the coach. If you have any concerns about hub seal leaks on the tag and steer poke your finger through a hole in the wheel and rub it on the wheel. If your finger is dry but black or a dark color that is normal and it is only brake or road dust. If you finger gets an oily residue on it that is a hub seal leak. If the leak goes on long enough you can see the black grease streaks on the outside of the wheel. Running in rain will produce similar black streaks radiating from the center, but they will be dry dust.
A drive axle hub seal leak is not as easy to spot but it can be done and can catch a leak early if you look beneath the coach to the inner drive wheel on the opposite side. If it is leaking the inner wheel is going to show black greasy streaks on the tire sidewall. A hub seal leak does need to be addressed sooner rather than later, but as long as the S&T fluid levels are maintained it is safe to drive for service. A drive axle leak usually does not require a refilling because there is such a large volume of oil in the differential. The problem with ignoring hub seal leaks apart from the risk of bearing damage is the brakes eventually get coated with grease and are no longer effective.
-
Thanks Jon,
Both S & T Hubs are dry.
Guess I’ll be checking my Hub Temps as well in the future. BTW, I’m checking the mid-sidewalls for the Temps, which I assume is the best location.
-
If a brake is dragging on disc brakes you will not be able to touch the rotor it will be to hot
-
Where you check temps is not as important as being consistent. If you are using sidewall temps, always use sidewall temps so any that are out of what range you expect will be an alert for you.
BTW, I have always used the Michelin tire pressure charts for inflation pressures and over a lot of years the one thing that always has amazed me is when I do that the tire temps are always very close together so if there is an issue it stands out.
-
My right side drives are always warmer than the left, no matter if there is no sun, at night for instance. I always have blamed it on the Bus air exhausting hot air in front of the right side tires, and the crown in the road, making the bus lean more to that side, (on two lane roads) But I may be wrong.
Pressure Pro shows them warmer too, but not excessive.
-
I doubt if this is the difference, but if the hot side is carrying heavier loads, yet the pressures side to side are the same that would be a reason. But that would have to be a lot of imbalance.
Log in to reply.