Clarify for me: dump air, brakes locked?

[theroc]

Originally Posted by Zigzag03

Bill, give us the short how-come on not pumping air brakes please.

Bill may have meant, "never pump ABS to stop." Most newer diesel pushers now have anti-lock brakes. Just as you do in your car, you don't want to pump the brakes in an emergency stop. You want to let the ABS do the "pumping" for you as it can do it much faster and efficiently than you are able to do. With ABS, you just want to keep your foot down on the brake pedal/treadle.

When driving commercial buses back in the 70s, we did have to pump the air brakes in an emergency stop as that was before ABS was common. We called it "pumping the brakes" but the more commonly, it was called "stab braking." This was when you applied the brakes hard until you could feel the wheels start to lock, then release, and apply hard again until wheel lock, then release, etc., etc.

[twinboat]

You don't pump air brakes because you are depleting the air with every pump.

While stopping, the engine and its air compressor are turning the slowest, supplying little air to refill the tanks.

With each pump of the brakes you are depleting the air, in the tanks, faster then its being refilled. The lower the pressure, the less effective the brakes are.

The anti lock brake action dumps less air per cycle then pumping the pedal.

Sit in your driveway with the engine idling and pump the brakes and watch the gauges.

[Zigzag03]

Got it, makes sense. My Ford f53 chassis truly I'm not sure, seems to produce a lot of whooshing and clicking whenever the pedal is pushed and engine not running. As soon as the new cooling element for the refer comes and I get a working fridge, I'm going to study this. I can see the abs sensors in the calipers but also seems more to it than standard truck brakes.

[Zigzag03]

No air gauves btw, aftermarket?

[mattchew]

If there are no air gauges then by law you should not have air brakes. You may have an air released parking brake though. AFAIK you must have gauges on all air brake equipped vehicles per the US DOT.
Matt

[V3600]

Simply amazing. I had to study air brake systems, pass an air brake written exam, pass an air brake pre-trip inpection, and pass a demonstration testing the air brake system all to qualify for a Class B CDL to drive the same motorhomes that people buy and drive with no knowledge, what-so-ever, of their air brakes. What's wrong with this picture?

[twinboat]

Originally Posted by Zigzag03

Got it, makes sense. My Ford f53 chassis truly I'm not sure, seems to produce a lot of whooshing and clicking whenever the pedal is pushed and engine not running. As soon as the new cooling element for the refer comes and I get a working fridge, I'm going to study this. I can see the abs sensors in the calipers but also seems more to it than standard truck brakes.

F53 chassis do not have air brakes.

The sounds your hearing are the backup systems, designed to assist in stopping if the power steering system fails.

The power steering system is what normally gives you your power brake assist.

[MisterT]

let's clarify this discussion:

is the OP discussing dumping 'air bags', or pulling the 'air brakes'?

[Mudfrog]

Originally Posted by Zigzag03

Got it, makes sense. My Ford f53 chassis truly I'm not sure, seems to produce a lot of whooshing and clicking whenever the pedal is pushed and engine not running. As soon as the new cooling element for the refer comes and I get a working fridge, I'm going to study this. I can see the abs sensors in the calipers but also seems more to it than standard truck brakes.

I believe that model came with either the Ford or Workhorse chassis underneath it. Both are gas and have hydraulic brakes. No air.

[Chinewalker]

Originally Posted by V3600

Simply amazing. I had to study air brake systems, pass an air brake written exam, pass an air brake pre-trip inpection, and pass a demonstration testing the air brake system all to qualify for a Class B CDL to drive the same motorhomes that people buy and drive with no knowledge, what-so-ever, of their air brakes. What's wrong with this picture?

+1

Everyone who operates an air brake equipped vehicle of any kind on public roads should have some sort of air brake endorsement on their drivers license.

[twinboat]

Originally Posted by Chinewalker

+1

Everyone who operates an air brake equipped vehicle of any kind on public roads should have some sort of air brake endorsement on their drivers license.

Why stop with air brakes, how about all RVs with brakes.

There are plenty of large, heavy MHs with operators smoking the brakes going down hill.

[Dav L]

The Ford F53 uses the power steering pump to create the primary brake boost pressure.
When the engine is off, or there is a pressure problem with the power steering based pressure, a fairly loud electric motor kicks in to provide braking pressure.

But them ain't air brakes. And no gauge.

ie: CDL...yeah, I am surprised in Michigan anyone can drive a 50,000 lb. air brake equipped 40+ feet beast with zero training. I am not one for much gov't intervention, but this one always surprises me.

[BRex45]

The biggest issue in this thread, as are many others on iRV2, is other posters taking over the thread, relating THEIR experiences even if THEIR experiences have nothing to do with the topic, or their vehicles are so unlike the OP's vehicle that it makes it extremely confusing to interested readers.

Sometimes I feel like I need a score card to keep track of what's going on. Should not have to do that on a two page thread.

Jeeesh.........

[Chinewalker]

Originally Posted by twinboat

Why stop with air brakes, how about all RVs with brakes.

There are plenty of large, heavy MHs with operators smoking the brakes going down hill.

Well, OP was questioning the operation of his air brakes.

Hence my comment.

Maybe you are right. Special training should be required for certain weights, lengths, heights. Corrective lenses, common sense. Oh well...