[Archived]

Here is a small overview of my preventive maintenance program. It my not be right for you, or anyone else but it works for me.

Every 5000 miles I am under the coach. I change oil, oil filters, fuel filters, and I lube all grease joints. While under the coach I drain the air tanks in sequence to look for moisture, and to verify the protection and check valves are functioning.

I inspect hoses, wires or any other items to make sure nothing is rubbing that shouldn’t, I verify all clamps or wire tires are in place. I do as good a visual inspection as possible. Every other visit under the coach I lift the front wheels and shake and move them to check for any play, looseness, any worn tie rod ends, etc.

I look for wet spots, especially at drive axle hubs. Like my coach you have sealed front and tag hubs, but on prior coaches all hubs got checked.

I look at whatever I can on the brakes, discs, pads, etc. to make sure all is OK. Mirrors and good lights are necessary and even with the wheel on I really cannot do a good job, but I try. When I have wheels off for whatever reason I do a very detailed inspection.

I look at belts, coolant hoses, and what I can see on the turbo system hoses and clamps. I don’t have a real job so I waste a lot of time poking my nose everywhere I can just to make sure nothing seems to need attention.

But those 5000 mile maintenance events are not all I schedule, and depending on miles or calendar time I may include other tasks that I do to my schedule which may differ from what is called for.

Transmission fluid and filters……..4 years.

Coolant change………6 years (OAT coolant)

Batteries (all)……..5 years

Air bags……….10 years

Brake chambers………..10 years (used to be 5 but Knorr-Bremse seem a lot better and have a different design than previous types)

Norgren valves……….10 years

Shocks……….5 to 10 years, sooner if any displays oil leak.

Air filter………..About 3 years, but monitored by a gauge that checks vacuum.

Tires……….Now 7 years due to Michelin change of warranty and visit to factory. Used to be 5 years.

Differential Fluid……….100,000 miles

Air dryer element……….2 years

Wiper blades……..about 3 to 5 years or sooner if streaking

Coolant hoses……….as needed, based on inspection usually to coincide with coolant change if needed.

Notice that I am throwing away a lot of useable parts such as air bags, batteries, brake chambers, tires, etc. I don’t care. If I felt like risking a needed repair or replacement while on a trip I would extend their life, but every single change interval was determined by a previous part failure or anecdotal evidence. I want to do repairs in my garage on my schedule, not when I am on a trip so the money wasted is far less important than having a trip affected.

I am leaving out house maintenance, but as pointed out it includes annual filter cleaning, water tank sanitizing, etc. I did not include normal repairs such as replacing bad relays, light bulbs, chasing air leaks, or any of the other things that pop up.

In addition to all the routine and planned maintenance my pre-trip inspection when the bus is at home is comprehensive. I check tires, not only pressure but checking for damage, stuff stuck in the tread, uneven wear, etc. I do a brake check before moving it from the garage, obviously all fluid levels, etc. A pre-trip inspection is a misnomer because some is done after a trip and before the next, such as transmission fluid level which requires it to be up to temp. I fart around looking at things before a trip, generally checking everything from generator operation to A/Cs to Webasto, to lights, but rarely all at once. My pre-trip inspection usually starts after the bus is in the garage from the last trip. That gives me all kinds of time to deal with anything that might need attention. Remember, I am unemployed so I can fart around with the bus anytime I feel like it.

Part of bus operation has nothing to do with inspections or maintenance. It has to do with the fact it is going to break no matter what I do to try to prevent that. So over the years I have been active in making sure I have a game plan to deal with something not working. I added a back up water pump and modified the plumbing system so a dinky little water pump would still flush the Headhunter toilet. I have a plan to deal with a failed alternator or any of the other systems and devices. Some are going to be serious problems such as a failed refrigerator, but the small one in the bay will protect the expensive stuff we don’t want to spoil.

I cannot solve a problem related to a failed engine, transmission or differential, but we can cope with almost anything else.

Whew.

[Jeff]

You’re on the right path Jeff and I would for sure carry a spare gen fuel pump, I’ve had 3 fail at the worse time and they’re cheap at Napa. I did have in question for you, I’m not familiar with an inverter fan filter, could you explain?

[Jeff]

Awesome, your on the right path of MINIMIZING problems while traveling(happy wife/life).

You have a newish H3 and my Prevost experience is limited to working on our old 96 XL Liberty “Classic” SO, YOUR RESULTS MAY VARY?

Take care of the air systems and they will take care of you.Try especially to minimize the moisture entering the aux air system. Minimize the usage of the aux compressor. Add an extra air/water separator filters? Change the main air dryer filter often.

Go thru the brake system, everything. Your brakes, Knorr-Bremse, differ greatly from our Meritor brakes, but probably have similar bits and pieces? Here’s a PC thread link I did when changing the diaphragms, piggybacks, etc: Link

Inspect and lube the caliper, slide pins, slack adjusters, pads, shoes, etc. Use the search word “Knorr”, and hopefully there’s a DIYer out there that has done some threads that will help. How about the “article” area here at PC? Maybe you can find manuals online like I’ve found for the Meritor brakes.

Change all the Detroit engine belts and carry the old ones for spares. Change the gen/Kubota water pump belt on the genny, and carry the old one for a spare.

Behind the genny radiator is a BIG squirrel cage fan driven by a large 120v electric motor and a FAN BELT. Change the belt. This belt was probably 20+ yrs old when I came accross it. You may have to pull the radiator to get to it.

I carry a spare Detroit engine fan relay. A spare coil or two for the five stack. A spare armature for the 5 stack Spare relay/solenoids for the Prevost OTR evap & cond fans. Spare fuses. Spare filters.

My maintenance program is progressive and flexible. I sample coolant, atf, and oil from the Detroit and Kubota engines, and send them to various labs for analysis. Analysis can/will uncover hidden problems. For me it also minimizes wasting time and resources. Todays fluids and filters are light yrs better than they were 30 yrs ago

How you care for all your batteries has a great effect on their life span, especially when your not using it.

[Jeff]

Jon! That is awesome – Thank you! I am going to cut, paste, and print to put up inside my bus barn.

I, too, am retired and have the time & interest in doing as much as possible in hopes of limiting down time while traveling. Your list really is a fantastic guide and I truly want and am willing to do all that I can. May I please ask a few follow-ups…

Can you please explain how to verify the protection & check valves are functioning? And, in what sequence you drain the air tanks?

Over the years, have you found coolant or other hoses that have needed to be replaced? Brake lines? What about the various belt pulleys?

And, just curious, will all the miles you have driven, have you ever had to change a fuel filter on the road? If so, how many times? A mechanic one time told me that Dexron III could be used in such situations as opposed to diesel. Thoughts?

Have you found it necessary over the years to replace valves other than Norgrens (curious what you have found to be their life span)

Finally, what is your plan in the event the 50 DN alternator fails? And, I have thought about the what if the large water pump that Liberty uses fails.

If you think of anything else, I am all ears 🙂

[Jeff]

Tom,

I recently built some wooden fender stands as I wanted to see & inspect behind each fender. Each of my Outback inverters had a filter covering the fine mesh metal screen in front of its fan.

My guess is they were original as each was about 50% disintegrated. I made replacements from a cut to fit residential filter I purchased at a local hardware store and will check each at least annually. The units were extremely dirty but now they are clean.

[Archived]

Great info Don! I will do a search for Knorr. I also want to add an additional aux compressor filter right after my compressor and hope to have time just after Thanksgiving. Please see the photo of my aux compressor and note the short piece of 3/8″ copper tubing coming of it. Would it be beneficial to add to that for cooling the compressed air? I have pondered adding a small coil of 3/8″ tubing to cool the air as it comes out of the compressor. Thoughts?

I will have to explore behind the genset radiator. I could see from underneath there is an electric fan, but my view was very limited.

I definitely need to identify relays, 5-stack coils & armatures, as well as the OTR relays / solenoids so I can purchase and carry spares.

I also do oil samples and captured a sample to check the engine oil from this first change. I will also test the genset. I will let you know the results. Thank you!

[Archived]

Better pic of aux compressor showing entire short piece of 3/8″ tubing, and also a better pic of the home-made wooden fender stands in case anyone has interest in making a couple of sets.

[Mike]

Good stuff Jeff:

Only problem (for me) is now I have more projects, copper line at aux comp, fender stands… LOL

Jon:

You noted you now change the tires @ 7 yrs after visiting the factory. What did you learn at the factory that changed your schedule?

Chuck

[Larry & Diane]

Can you please explain how to verify the protection & check valves are functioning? And, in what sequence you drain the air tanks?

I start draining with the wet tank, then primary, then secondary, then accessory. Air should be dry as it leaves the tanks, and each tank in sequence should be pressurized indicating protection and check valves are working as intended.

Over the years, have you found coolant or other hoses that have needed to be replaced? Brake lines? What about the various belt pulleys?

Liberty installed hoses for the Webasto or cooling system require attention. Rubber brake air line hoses can age out, but should not be anywhere near end of life on your coach. Blue hoses on the engine have a good life, but keep an eye on them. Large hoses, especially the blue ones on the hit side of the turbo system need frequent inspection. Prevost supplies all blue that are rated for 500 degrees, but only for that temp at 20% of their life. I used red ones rated for 500 degrees continuous. Your EGR system when engaged has turbo boost at 50 PSI (don’t believe your dash gauge) and air temps at the turbo are 500 degrees. I think the plastic hoses (if DOT) will last the life of the chassis unless they are rubbing on something.

And, just curious, will all the miles you have driven, have you ever had to change a fuel filter on the road? If so, how many times? A mechanic one time told me that Dexron III could be used in such situations as opposed to diesel. Thoughts?

I had to change fuel filters once because I used a cheap no-name local diesel fuel station. Never again. I now only fuel at interstate big name truck stops. That will not protect against algae but it has kept my fuel from having dirt and crud in it. I used the coach often enough so algae is not an issue, but when I do not use it during the summer the tank is full and it is in the garage with minimal temperature swings.

Have you found it necessary over the years to replace valves other than Norgrens (curious what you have found to be their life span)

I had to replace a relay valve that was leaking 20 or 25 years ago, I had to replace my ride height valves because one was leaking (old style Haldex with time delay). I probably should think about replacing relay valves and some of the others that Art is changing, but they ain‘t broke and I am getting lazy.

Finally, what is your plan in the event the 50 DN alternator fails? And, I have thought about the what if the large water pump that Liberty uses fails.

If the 50 DN fails it will be a non-event. First, I will start the generator and instead of using the OTR I will set the thermostats and run all 4 Cruiseairs. With the generator running my inverters will be taking care of the house batteries and the chassis 24V battery charger will take care of the chassis batteries. I will not run at night so I will not have lighting loads. When I get home I will deal with the alternator or the regulator.

[Ron]

After having the 50 DN alternator rebuilt three times because of leaks, I replaced it with a air cooled unit and a newer multi-stage regulator. Jon can confirm this, but I believe the 50 DN charges the house batteries. If it goes out you can just run your generator to get you to where you can have it fixed.

[Jeff]

Jon: What kind of chassis battery charger do you have? Wondering if my three or four year old Guest/Marinco smart charger will provide enough juice to keep the chassis batteries properly charged going down the road if the 50DN fails.

Interesting you moved out to 7 years on the tires. When did you start doing that vs 5 years.

[Archived]

Our buses are built for commercial service. They can take a lickin and keep on tickin(thank goodness).

Where do you want the moisture to drop out of the aux comp air at? I want it in a drainable serviceable filter/trap, not in a tubing coil.

At what pressures does your aux comp start and stop? I have mine set at 50 and 70. This in high enough on my bus to operate anything/everything while dry camping. The lower the pressure the cooler the air and the shorter the tubing run can/needs to be between the compressor and the filter/trap(s).

In your original post you stated “ALL fluids and filters were changed (engine, genset, transmission, power steering, brake system air dryer filter, both radiator fluids)” by the selling dealer. Did you choose the fluids and filters and witness their install? If not, I would change everything. TRUST BUT VERIFY. I’m funny that way. I guess that is why I do all my own mx.

IMO, coolant chemistry is the most critical fluid in our bus. Take a sample, send it off for analysis. Detroit sells kits and has a lab they trust to know their coolant spec 93K217. Here is a quote from DDC-SVC-BRO-0002, a DDC pdf titled Coolant Requirements For Engine Cooling Systems.
“Laboratory testing is the best practice for determining ELC coolant quality and will provide vital information regarding the engine performance. A factory coolant analysis program is available through authorized Detroit™ service outlets. To verify coolant acceptability, submit a sample for coolant analysis according to Table “Extended Life Coolant”. However, a laboratory meeting ISO 17025 requirements may be used in place of the Detroit™ Genuine Parts Program laboratory.”

Here is the link to DDC-SVC-BRO-0002: LINK

[Billy]

Roy, I do use the generator if the 50DN pukes. Every converter did things different relating to charging house and chassis. Liberty Elegant Lady Coaches typically use a single 24V 50DN, but the same model year Classic is likely to use a 50DN for the chassis (because of OTR), and a Liberty installed 12V alternator for the house.

Even the same converter as shown above has different ways to provide battery charging so every owner has to learn how his systems are charged and determine how to cope with problems should any occur.

As to the chassis battery charger, I am using the Liberty installed Guest. I rarely use it, but if the 50DN dies I will use it to keep us going until the end of our trip.

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What is 50 DN new guy here trying to learn

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It is an oil cooled Delco Remy alternator, Model DN 50