Engine Brake, Exhaust Brake again, sorry!

[redeldo]

I hate to show my lack of knowledge but I would like to understand the difference between 2 systems I have driven and which is which, so here goes:

Drove an Allegro Bus, Travel Supreme and Newmar. All had a switch on the side for Brake
which stayed on all the time. Each time I took my foot off the accelerator, I could feel its effect as the coach slowed almost to a stop. Did not even need to touch the brake pedal.

Drove the Monaco Windsor and Dynasty and there was a switch for Brake, but there was also a pedal on the floor you had to press with your foot to make it work. Was told you had to keep the foot on the pedal as it stops working if you lift the foot off. I pressed the pedal but never noticed any braking so I had to use the pedal.

Are these 2 different systems or am I totally mistaken?

Wayne
looking for a 1. Dynasty, 2. Windsor

[redeldo]

I hate to show my lack of knowledge but I would like to understand the difference between 2 systems I have driven and which is which, so here goes:

Drove an Allegro Bus, Travel Supreme and Newmar. All had a switch on the side for Brake
which stayed on all the time. Each time I took my foot off the accelerator, I could feel its effect as the coach slowed almost to a stop. Did not even need to touch the brake pedal.

Drove the Monaco Windsor and Dynasty and there was a switch for Brake, but there was also a pedal on the floor you had to press with your foot to make it work. Was told you had to keep the foot on the pedal as it stops working if you lift the foot off. I pressed the pedal but never noticed any braking so I had to use the pedal.

Are these 2 different systems or am I totally mistaken?

Wayne
looking for a 1. Dynasty, 2. Windsor

[Route 66]

The foot switch is not necessarily an indicator of the type of aux. brake.

Jacobs Vehicle Systems makes Jake Brakes.

There are two types of Jake Brakes;

Exhaust Brake, and Engine Brake.

CLICK HERE for explanations of both types.

PacBrake only makes an exhaust brake.

Engine brakes are normally used on mid to higher priced motorhomes with larger engines.

Many purists will insist on referring to only an engine brake as a Jake brake.

[J Walker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by redeldo:
I pressed the pedal but never noticed any braking so I had to use the pedal.
</div></BLOCKQUOTE>
Wayne, could you clarify this apparent typo. Do you mean that you used the exhaust brake pedal and had no braking so you used the brake pedal? I assume the exhaust brake switch was ON and the accelerator was OFF. If all of that is true then there is something wrong with the exhaust brake.

[redeldo]

Sure, no problem to clarify, guess I was a little vague. On the floor on the left side of the steering column there was a small pedal that I was told had to be pushed with the left foot and hold down so the jake brake would work.

As I came up to stop signs or lights I would take my right foot off the accelerator and press my left foot on the pedal and held it down but noticed no braking. Then to stop I my put my right foot on the "normal" brake pedal to come to a complete stop. It felt odd to me to have to use my left foot. The rocker switch on the panel just had a high/low position so is there an on/off switch somewhere?

On the Allegro and others there was no left foot brake pedal just the normal right foot brake pedal and the rocker switch on the panel to the drivers left under the window. If I remember correctly was always set in one position or another. When you took your foot off the accelerator, you could feel the coach slowing down a stop signs, lights, etc.

I figured that since I am a novice diesel driver looking to purchase, that I overlooked something, the engine brake was not working properly or maybe I had to be doing 60 mph for it to work.

[J Walker]

Someone with the MH you drove or a similar one can answer better than I. One way or another you didn't get the engine brake to activate. Perhaps there is a rocker switch somewhere or maybe you need to tap the service brake in addition to all the you tried.

[mhgypsy]

Know this is late for a reply but we just joined and I'm kind of going back. Exh brake ties to the engine exhaust system, whereas the engine brake commonly called the old "Jake Brake" ties to the valve train. The button on the floor to the left of the steering column engages the Jake and will down shift the trans, one gear at a time. If you are running in 6th at 60mph and your engine is turning at 1800 rpm and you kick on that brake, you will probably bump your engine speed to over the high idle max of 2300 which gives you an engine overspeed and on a diesel it is not a good thing as valve damage can occur. The switch on the panel to the left of the drivers seat is for what kind of application you want. One setting provides to give you utilization of all six of the engine cyls, the other only 3 in an "engine brake" application. It takes a couple of seconds (2 or so) for the brake to kick in after you step on the pedal (left of column), and when you take your foot of, it will disengage the Jake. The Jake is meant to "assist" the wheel brakes, not replace them so the idea in utilization of it is wheel brakes first, then Jake. Anticipate your stopping, slow down to a reasonable braking speed, use your wheel brakes and then apply your Jake. They are most efficiant at higher engine RPM, thus the downshit that occurs when it is engaged. You can get a lot of info if you google Jake brake and get into the info provided there. I hope this helps a bit.

[HighwayRanger]

I just drove a 2008 Beaver (Monaco) Contessa at the Pomona FMCA rally this week. It had the retarder in a red button on the left dash which was either on or off. No pedal was required. The Monaco factory rep described it as a turbo brake of some sort, but it did not require stepping on a pedal. Don't know what your coach had, but this one was automatic.

[Gary RVRoamer]

"Retarder" usually refers to a transmission retard rather than an engine brake or exhaust brake. A retarder is an option on most larger models of Allison transmission and it provides electro-magnetic braking to the drive shaft, slowing the vehicle that way. There is also a similar aftermarket retarder from the Telma company.

All of these are independent of the pedals and switches used to operate them. Some people prefer automatic operating where the braking force is automatically applied whenever the vehicle is coasting, while others prefer to be able to manually trigger it as needed and prefer a foot pedal. It is also possible to change how the automatic functions works on most rigs by altering the programming in the engine and/or transmission computer. There is also an aftermarket product called the Brake Switch which provides for semi-automatic operation of exhaust and engine brakes. With the Brake Switch, automatic braking does not begin until you tap the brake pedal. This allows the vehicle to coast if you want but eliminates the extra floor switch for triggering the exhaust/engine brake.

[HighwayRanger]

I just used the word "retarder" as a generic term for slowing the coach without the wheel brakes. The Contessa I drove just had an on/off switch, and our tour guide implied that it can be a pain in some circumstances because of what it causes the transmission to do. That may be true of all these devices. He was specific that their system involved the turbo charger.

I would think that they would be best at steady downgrades like long hills where the thing is on the whole way down. When you're on and off the gas in rolling hills, it might be best to turn it off, right?

[cb5300]

I have a 2008 Dynasty and I don't have a third pedal on the floor. I've got a brake switch on the left panel that can switched from low/high or off, and it can not be used with cruise control, because as soon as your foot comes off of the gas pedal the brake system kicks in.

[Robin_M]

cb5300,

I'm curious about how the Dynasty system works on the new coaches. I'm guessing you have an engine brake, rather than the exhaust brake. Could you answer a couple of questions?...

1. Does the low/high setting effect the degree of engine brakeing, the gear that the transmission seeks, or both?

2. If you are already useing the cruise control, what happens when you switch on the engine brake? Does it immediately disengage the cruise control?

Thanks.