How can you tell if the ABS has engaged

[tomgagne]

Crazy question, how can you tell when or if the ABS has engaged on a coach? I recently had to make a very hard stop. There was no screech/lock up of the tires and I did stop quickly with all the pressure I could apply to the brake, but there was no obvious indication that the ABS engaged. On a car you can feel the ABS flutter on the brake pedal, I did not notice any indication that the ABS was engaged. Again is there any obvious indication that the ABS has engaged on a coach?

[Aguyfromcalg]

If your back end didn't try to come around and you were able to steer then my guess it was working

[frankdamp]

The frequency at which the pressure is turned on and off is usually within the audible range. Even if you didn't feel it at the pedal, it should have been audible. It's usually about 40-80Hz, I think. I've had the ABS on my daily driver come on twice in 8 years and that's about the frequency of the "buzz" that I recall.

[njs42]

If you made a hard stop applying all the pressure you could on the brake and you did not slide---it is on.

Also I think the sensor warning are pretty sensitive and you would have received an ABS warning on your dash if it was not working. S/B easy to get it checked I think--if you are in doubt.

I made a panic stop and my MH behaved as I described (didn't feel the pedal or hear the noise but I know my ABS works--had it checked) but my toad locked up; by the way a significant reason the stop was successful---had I not had toad brakes I would have crashed for sure ABS or not.

[nodine]

Quote:

Originally Posted by tomgagne Crazy question, how can you tell when or if the ABS has engaged on a coach? I recently had to make a very hard stop. There was no screech/lock up of the tires and I did stop quickly with all the pressure I could apply to the brake, but there was no obvious indication that the ABS engaged. On a car you can feel the ABS flutter on the brake pedal, I did not notice any indication that the ABS was engaged. Again is there any obvious indication that the ABS has engaged on a coach?

Two thoughts. It may not have come on if you were not on a wet or ice surface. Also, air brakes may not have that tell tell sound that you get with hydraulic brakes on cars and trucks.

Bob

[ottffss]

Quote:

Originally Posted by njs42 .... but my toad locked up; by the way a significant reason the stop was successful---had I not had toad brakes I would have crashed for sure ABS or not.

AND, if it you did NOT have toad brakes the likelihood of frame damage on the toad would have been exceptionally high, if not guaranteed. Cars, trucks, SUV, etc. are NOT designed to be violently stopped by applying sudden and massive force to the crush-able frame horns (where the tow brackets are attached).

This (and the fact the RV stops way quicker in a panic as you conjecture) are the MOST overlooked reasons to have a toad brake setup. And yes, I have seen two instances of this very damage - one was to a pickup towed by a panic stopped class C no less. You could easily see the p/up frame arched.

[Mike Canter]

Tom, I agree that if the ABS was bad you will have an ABS light. Technology is right up there on that. I have in fact done a heavy emergency stop from 62 mph in my 46,000 lb MH because I was watching the Alladin computer screen and came around a curve on I-95 and everybody had stopped for a coffee break. I know that my ABS was working because I had my window open and there was a cement wall on the bridge to reflect the sound. Above my silent scream I could hear the tires chirpping and it was not real loud. Don't think I would have heard it with the window closed. I bet if I had looked at the road behind me I would have seen black marks spaced on the road indicating pulsing. Interestingly it was in a curve and it did a great job. Broke two drinking glasses in a cabinet. There was zero pulsations in the pedal because air brakes will not feed back like hydraulic brakes. My 3000 lb Jeep toad does not having an auxiliary braking system and it and the hitch did just fine. Not sure about the cars behind the toad.

[nodine]

Quote:

Originally Posted by Mike Canter Tom, I agree that if the ABS was bad you will have an ABS light. Technology is right up there on that. I have in fact done a heavy emergency stop from 62 mph in my 46,000 lb MH because I was watching the Alladin computer screen and came around a curve on I-95 and everybody had stopped for a coffee break. I know that my ABS was working because I had my window open and there was a cement wall on the bridge to reflect the sound. Above my silent scream I could hear the tires chirpping and it was not real loud. Don't think I would have heard it with the window closed. I bet if I had looked at the road behind me I would have seen black marks spaced on the road indicating pulsing. Interestingly it was in a curve and it did a great job. Broke two drinking glasses in a cabinet. There was zero pulsations in the pedal because air brakes will not feed back like hydraulic brakes. My 3000 lb Jeep toad does not having an auxiliary braking system and it and the hitch did just fine. Not sure about the cars behind the toad.

Mike,

Glad you got it stopped without damage and are safe and sound. Please don't encourage folks to go without supplemental braking in their toad. Your Jeep has a strong front section unlike many modern automobiles which are designed to have crush zones in the front. Often the base plate is attached in the crush zone area and damage can be done on panic stops. Also, if the tow bar is not level the toad may go up over the hitch or down under, depending on the inclination. This will certainly damage the tow bar and their have been cases where the frame was bent on the toad.

Bob

[JimM68]

Mine works. It's kinda spooky in an air brake coach. No tell tales to speak of, but "I Knew"