Panic stop in a class A

[Droberts9747]

We had to make a panic Yesterday from about 45 miles an hour. We left a lot a rubber on the highway. Afterwards we start hearing a thumping sound. I checked all the tires and they're all inflated I didn't see any flat spots on the tires and the tires are almost brand-new. I had to drive a couple miles before I could find a place to turn off and we could only go about 10 miles an hour. Anybody have any ideas what it could be ?

[steppinstone]

Originally Posted by Droberts9747

We had to make a panic Yesterday from about 45 miles an hour. We left a lot a rubber on the highway. Afterwards we start hearing a thumping sound. I checked all the tires and they're all inflated I didn't see any flat spots on the tires and the tires are almost brand-new. I had to drive a couple miles before I could find a place to turn off and we could only go about 10 miles an hour. Anybody have any ideas what it could be ?

Sounds to me like the brakes were locked dragging caliper that's not releasing all the way. Be careful but did you run your hand around the tire to see if you may have picked up a bolt or something on the road.Can you smell burning brakes when you were doing 10 mph did your parking brake re apply ?

[mel s]

Originally Posted by Droberts9747

We had to make a panic Yesterday from about 45 miles an hour. We left a lot a rubber on the highway. Afterwards we start hearing a thumping sound. I checked all the tires and they're all inflated I didn't see any flat spots on the tires and the tires are almost brand-new. I had to drive a couple miles before I could find a place to turn off and we could only go about 10 miles an hour. Anybody have any ideas what it could be ?

Droberts9747
Methinks you "flat spotted" one or more of your tires.
Tire Tech Information - Flat-Spotted Tires (Due to Brake Lockup / Slide)

Take Your coach to a commercial truck tire shop and have your tires inspected... and "trued" if necessary:

https://www.youtube.com/watch?v=epT1K3M2nIo

https://www.youtube.com/watch?v=5xpID8dG4u8

Mel
'96 Safari

[Pickelhead]

If you have ABS and it is working correctly, none of your wheels should have locked up.

[Atom Ant]

I know for certain my anti-locks work! A little slower than a traditional car.

[B Dubya]

Look closely at the rears. I'll bet you can find a small flat spot. It doesn't take much in these big ol hard tires to make a noticeable 'thump'.

[vsheetz]

I think flat spot is likely. I had a brand new car with not many miles on it. Had to do a all wheels locked up panic stop - with a cloud of tire smoke occuring. Flat spotted all four tires. Could really feel it, especially at certain speeds.

[Skip426]

Originally Posted by Pickelhead

If you have ABS and it is working correctly, none of your wheels should have locked up.

Anti-lock brake systems , depend on wheel speed differential , measured by the controller to operate.
IF you jump on the brakes and all the wheels lock up simultaneously . the controller doesn't see any wheel speed difference and the wheels stay locked up .
To operate in anti-lock mode , the controller ; must see a wheel still turning ; THEN ; the controller will cycle the brakes on the other wheels.

[Pickelhead]

The anti-lock brake controller is also known as the CAB (Controller Anti-lock Brake).[19]
Typically ABS includes a central electronic control unit (ECU), four wheel speed sensors, and at least two hydraulic valves within the brake hydraulics. The ECU constantly monitors the rotational speed of each wheel; if it detects a wheel rotating significantly slower than the others, a condition indicative of impending wheel lock, it actuates the valves to reduce hydraulic pressure to the brake at the affected wheel, thus reducing the braking force on that wheel; the wheel then turns faster. Conversely, if the ECU detects a wheel turning significantly faster than the others, brake hydraulic pressure to the wheel is increased so the braking force is reapplied, slowing down the wheel. This process is repeated continuously and can be detected by the driver via brake pedal pulsation. Some anti-lock systems can apply or release braking pressure 15 times per second.[20] Because of this, the wheels of cars equipped with ABS are practically impossible to lock even during panic braking in extreme conditions.




Insert air instead of hydraulic.

[Skip426]

Originally Posted by Pickelhead

Because of this, the wheels of cars equipped with ABS are practically impossible to lock even during panic braking in extreme conditions.

Key word is " practically " .

In 34 years at a Chrysler dealership , I dealt with many owners; who claimed their anti-lock systems didn't work ,and vehicles with flat spotted tires.
I had to take more than one customer out, and demonstrate it was possible to lock up anti-lock brakes, even with a properly operating system.

[steppinstone]

well some thing is sticking if he couldn't get the coach to go over 10 mph. after the sudden stop. Also I don't think that at 45 mph locked up that would make that much of a flat spot on the tire's ether. the thumping could be the rotors grabbing

[Mike and Cha]

Just curious, if the tires do get a flat spot, will it eventually round out by driving or do you really have to get them trued at a tire shop. And will it cause any damage to just let it round out by driving. I had never heard of this but I can see it happening with that much weight.

[B Dubya]

It would take a long time to smooth that out (if ever), and by the time it did every nut and bolt on the MH would be loose or gone!

[FatChance]

I would think, since most RV tires age out long before they wear out, that the tires could be cut down a little to re-true. Whether it would be cost effective is another issue. How old are your tires?