[Mike]

Joel,

I don’t think any of the OEM brakes from Prevost are a bad thing. All drum, disc on steer and tag with drum on drive or all disc are all OK in my mind. Ive had them all and all worked. Newer coaches have better stopping, but I think the retarders have been as big an influence as the type of brakes.

I think every version has been an improvement over the previous design, but each version had its advantages and weaknesses regarding maintenance and life.

I replaced all the drum brake friction material and springs on my all drum brake coach because the original lining on the shoes was cracking and some return springs had broken. I had to replace brake pads on the steer axle of the second coach because for some reason one pad per side had worn excessively while its opposing pad was almost new thickness. I serviced the pins and they wore evenly after that for over 100,000 miles. I now have all disc with the Knorr-Bremse brake chambers and they have not had any issues other than the damage to my wallet when replacing them compared to the common type brake chambers used on previous versions.

Although the permanently sealed hubs on the steer and tag are nice, the drives are still using conventional hub seals and like previous coaches have leaked. In fact I have replaced hub seals on all three of my coaches at one time or another.

I have no prejudices against any of the braking systems Prevost has installed, but I do recognize they all still need service and attention.

[Mike]

No doubt in My mind that Jeff will dial it in. It kicks out the heat for sure, But has Quit a couple of times at night. Simply turning the dash rocker switch off and then back on and everything is good ! It has only made the noises that I spoke of a couple of times. Might never make them again ???

[Mike]

Happy Birthday Jeff… hope you were spoiled today !!

Cheers, Larry & Diane

[Mike]

We’ve used the MSH4024RE on a handful of replacements. Have liked the results thus far.

[Mike]

Would like to give a big shout out to Jeff Rowe(ETLC), Trailwick Coaches and Jon and Tom(PC Community) for their support and sponsorship of Claw Fest. What started out 7yrs ago as some friends getting together has grown into what looks to surely become a significant annual event of the Florida winter rally scene. Also big thanks to Scott Campbell and Neal Nowe, crab cookers and crackers extrordinaire. See you all next year.

[Mike]

Hwy 411 from Maryville,TN running by Jeff’s place and on into the state of Georgia was a major north/south route for many years long before I-75 was built. I grew up in Vonore watching the hundreds of tractor-trailer trucks, Greyhound and Trailways busses along with the Yankee tourists from up north go speeding by on their way to vacation in Florida. It was a two lane black-top road and presented no problem for the semis and busses of that era. So it’s hard for me to imagine anyone being apprehensive about driving a modern Prevost on the modern and vastly improved condition of Highway 411 today.

Here’s a great book about the area around Jeff’s place, it’s titled “Vonore, Today and Yesterday“. Available on Amazon.

[Mike]

BIG AGENDA ANNOUNCMENT

Wednesday is going to be a big day for the Air and Coach
Concours. We have lined up a trip to John’s Pass in Madeira Beach, FL. This
will give those who want to eat, drink and shop all afternoon the perfect
opportunity and it will also allow the rest of us to go fishing out of Hubbard’s
Marina. Tisha and I spent an hour or so there yesterday and believe me there
will be something for everyone! It is an absolutely beautiful setting right on
the water. In fact, as we sat at the perfect Tiki bar we watched no less than 8
or 10 dolphins playing with the pelicans as they swam through the water. Have I
told you how much I like Florida in the winter?

We will gather and leave around the Cessna building after
breakfast around 11:00am. It will take us right at an hour to arrive at John’s
Pass. Those spending the day here can wander around for hours taking in the
sites and taking advantage of some great food, drink, shopping and most
importantly the amazing scenery.

At this point those of us that are going out to catch the
big one that “isn’t” going to get away will cross the street to meet up with
Angela at Hubbard’s Marina. We will head 5 to 20 miles offshore to go fishing for
several different kinds of fish possibly including hog fish and red snapper all
while enjoying some cold refreshments supplied by everybody’s favorite: Fat Point
Brewing! When we get back to port we can walk 100 feet down the dock to meet up
with our land crew at the Friendly Fisherman. It is an open air dockside restaurant
that will even prepare our own days catch (hopefully). Seriously, the will
prepare your own fish for you and your guests. If I catch red snapper I’m all
in on this!

After dinner we will prepare to leave around 8pm arriving
back at SnF around 9 to 9:30pm.

The trip and transportation is included with your Air and
Coach Concours package. The fishing trip will be $95 per person which is all
inclusive including basic bait. Other bait is available for a small free. The
Fat Point is also included!

Here are a few links of interest:

http://www.johnspass.com/

https://hubbardsmarina.com/

Tisha and I are both excited to show you this amazing little
area in Florida. We had a great time just for the hour that we were there and
we can’t wait to go back. Especially to go fishing with our family and friends!

Bill III

PS keep in mind that these pictures are only a very small part of the whole area. look at the link above.

[Mike]

Just be careful Greg. Some aux air is vital to the coach when the coach is being driven or running. For example make sure you are not shutting off air to the suspension or suspension valve manifold. Make sure pneumatic belt tensioners will always have air. If equipped make sure the radiator shutters, maybe wipers, or other chassis devices have air.

[Mike]

In the picture above in this post there are two valves shown. The one on the right is the Norgren valve. The one on the left is a Burkett valve. Burketts were valves that Prevost used in the mid to late 90s as a replacement for the Norgren three way valves. They come either NO or NC and they cannot be altered. The first versions of the valves did not have a return spring in them and we had numerous issues where the valve would stay in the midway position. This led to air systems not building air correctly. Normally the bad valve was on the tag lift system and by simply cycling the system you could get the valve to seat itself and the air would build correctly. Burkett came out with a valve with a return spring ( the new Burkett valve) but we went back to Norgren valves eventually. Another issue with the Burkett valves was they were made for a much cleaner, industrial application. The coach pneumatic system in not a completely clean and dry environment. The Burketts did not fair well on the coach. The Norgrens were more robust and did not mind a little oil and water in their working environment.

Most of the people in Prevost service do not know anything about the Norgren numbers. Prevost parts secures the correct Norgren number for the application from the engineering department and then a Prevost part number is generated. To get the Norgren number we would have to get someone in parts to look at the cross reference file for the correct Norgren number. That is why you may get a blank stare from a tech if you come out with a Norgren part number.

As noted also above the type of valve you need (NO or NC) will be dependent upon your pneumatic configuration in the rear of the coach. Up through 1996-1997 the plumbing of the tag axle lift circuit required that there be sufficient air pressure in the auxilary air tank air sytem to properly pilot the valves associated with the tag axle and tag lift system. Thus you needed good aux. air pressure to keep the coach at normal ride height in the rear of the vehicle. Lack of proper air through an air leak would eventually reduce pilot or control port air pressure to the point where the internal spring tension of the valve overcame the control pressure and the system cycled much the same as if you had flipped the tag lift lever. The difference being that there is no aux air pressure left to do anything with the system.

Engineering at Prevost redid the pneumatic “plumbing” of this circuit in 1997 so that there were no control pressures to any of these valves to keep the tag axle down and the tag lift circuits off. There was a maintenance bulletin released “Service Bulletin 96-14B) to increase the reliability of the pneumatic system. The bulletin can be found at https://secure5.volvo.com/technicalpublications/pdf/SB96-14B/pdf. There were various kits made at the time for different models. These would come with instructions and valves that had the proper brass fitting for the application. The kits also included an inversion valve that had to be plumbed into the circuit. Prevost has always cancelled the brake boosters on the tag axle when it was lifted to prevent tire damage. As we were changing the way the axle was controlled we had to change the control of the Bendix R12 valves that controlled whether there would be brake application pressure sent to the boosters on the tag axle or not.

The modification takes some time as the old valves need to be removed and air lines properly identified. Then the new valve installed correctly and the inversion valve installed. Plus the light circuit in the dash had to be changed to reflect the lack of air pressure in the controls when the vehicle was in the normal ride height position.

All that being said: to check your system! Run vehicle and get all air tanks filled. Turn off coach. Open accessory (auxilary) air tank and bleed down the pressure. If the coach has the newer system installed the vehicle should NOT settle in the rear as if you flipped the tag lift lever. If if does squat, then it most likely did not have this modification done.

A bit lengthy but I hope that it helps with the pneumatic valves and systems.

[Mike]

Also make sure the webasto and gen are not going to start up….

[Mike]

I think you will find that some circuits work only on shore/gen power and some only by inverter. The outlets for the TV over the driver and in the bedroom run on inverter, as does the microwave. Probably some other stuff I don’t remember right now. The blender system built into the kitchen counter works only on shore or generator. It was always our joke when dry camping we only needed to fire up the generator to make a daiquiri. The manual I sent should explain that. (The circuits, not the cocktails.) Some of the outlets are powered only by the inverter. We ran the inverter whenever we were in the bus except when dry camping and we were only planning to use the 12 volt lights and appliances.

[Mike]

You are absolutely correct. After I shut the engine off, I hear an air leak from under the coach midship, don’t know where until I take it to a shop where they have a tunnel.

The coach does not lean at all overnight. Matter of fact the air stays at over 100 psi on both dash gauges but the rear dumps in 5 minutes after key off .

[Mike]

Hey Boys and Girls, sounds like ya’ll need Justice Judge Jeanine to sort out all of the above options for you.. Sheeez.

Bill S.

[Mike]

How about slides? Is there any rule of thumb on if and when to pull them in?

[Mike]

Andre just install a norgren water trap like the one prevost has in the steering bay the black one , just before the spitter cup as the aux compressor line comes into the steering bay to go into the spitter cup you can do away with the spitter cup the water trap will take its place and that way there will be no air pressure to the water trap when the compressor is not running that way it can not leak air because the versa valve shuts the air off going back to the water trap and to the compressor, but you will have to drain it manually, this way the norgren water trap will not be a problem with leaking because they are known to leak around the bowl or the o ring on the bowl