Morning all. I have studied and understand what is being looked for to pass the test. But what I'd really like to understand is the mechanics behind it.
Example: "thumping" the tires. Exactly how does that tell you that they are properly inflated?
Truly Understand the Pre-Trip
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Thumping's old school, get a thumper, no, don't buy one, get a simple tire iron and thump a tire you know is properly inflated, then thump one low on air. You'll feel the difference and the sound it makes. Years ago, the man only cared that it wasn't flat, now they get anal if one is 110# and it's twin is 70#. From an O/O perspective, tires aint cheap, so to run 'em low means you'll be replacing 'em sooner...
Tires do not.
But on a more serious note, you’ll hear/feel the difference on a tire say 100lb then an 80 lb one.
Some want you to gauge them, now just fuel at loves, get tire pass points and they gauge and add air pressure to them while you fuel.
I thump the tires as well, like Clausland said. I also look at every tire to see if the sidewalk bulge looks the same. If they are not, I check the pressure. I check again after I hook up a trailer.
Checking the tires at every stop goes a long way to keep from having problems. Check them for heat especially.
You can also spot a low tire on a trailer by checking them before you hook up if the trailer has auto-inflation.
Thumping is what I do every time I stop for a load check during the day, for the night, & when I take off after my 10. I thump with my bare fist. Drive & trailer. Look at steers for sidewall bulge. If a tire is low, I will find it like this. The vibration in my bones, & sound is what I'm looking/listening for. Sometimes on uneven ground I hear the "thud" slightly off. Pull forward or back a few feet & try again. Also looking for shrapnel in the tire if the "thud" is off. Off a 2nd time, no shrapnel found, the guage comes out..
I also run the same equipment day in, day out so it may not work as well for trailer swaps..
Ty all. Great info. But I think I hampered my own question with my example. I really mean all of the mechanics. Minus the electronic stuff. Not the "pass the test" answers. But the what should I really be looking for on the TT.singlescrewshaker Thanks this.
Always look under it for puddles every time you get out........tires too.
Lug nuts , wheels every day. Oil level every day/ coolant is easy just look in the jug while Hood is up.
And listen for air leaks when ever you park and it’s quiet.......
It’s a little different when you’ve had the same truck / trailer for 10 years and your the only one who drives it.......
I’d probably fail the pretrip test at the dmv.....
So other than tires we spoke of..
-Gloves on hood up
-Scanning for leaks or anything out of place.
-Pull the puke tank cap & look at coolant level as mine is steel & not see through plastic like new trucks. .
-Yank on the tie rods, drag link, pitman arm, steering shaft looking for play in the bushings
-Scan the drums for oil, no cracks & shoes look good
-scan the leaf pack, u bolts, hangers, & frame for cracks
-check tension of fan & alt/ac belt. No auto tensioner so they need manually tighten time to time.
-check oil level
-start truck, flip on lights & 4 ways
-walk around front checking lights, & latch hood shut
-start down the ditch side now looking for exhaust leaks & at the frame for cracks
-look at air lines for any spot they can "chafe" That's a favorite write up
-check over rear suspension, tires, brakes, 5th wheel mount
-down trailer for lights, frame, load still secure, listening for air leaks
-trailer tires, brakes, suspension
-go around back all lights are working, no lenses cracked
-repeat trailer inspection road side up to the 5th wheel
-ISO pigtail, & gladhands secure
-check apron for cracks, 5th jaw is locked around kingpin
-5th wheel pedestal no cracks, tires, brakes, air bags, suspension
-drain air tanks, check road side exhaust
-pull forward few ft & pull the johnson bar to check trailer brakes
-stomp foot brake hard 2 times & hold few seconds to make sure no air leaks under hard brake
Might have missed something, hard to write up & keep my thoughts together. But that's the jist of what I do. If it looks like rain in the AM, I do this when I stop for the night. Then just check lights, tires, load secured, no puddle under the truck, 5th jaws..
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