The Leans

[Jon Wehrenberg]

Jerry,

If you are blessed with the ability to decipher a pneumatic system diagram such that you can isolate the source or sources of the leak that makes your coach lean we are going to nominate you the POG vice president in charge of the leans.

On my 87 I had the Prevost portion, but lacked the full system diagrams because Liberty added their portion. Despite my best efforts I never could conjure up any reasonable semblance of logic to how the whole thing worked. I felt fairly inadequate until I watched the Prevost techs at the factory attempt to isolate a problem. They did the soapy water squirt bottle thing.

Over the years I watched the techs at the NJ and FL service centers do the same thing at about $80 an hour.

Without a pit (which was my circumstance when I tackled my 87 coach leans) I found I could take the valves from the bus and test them, fix if required, and replace them almost as quick as the method the techs use. Most of the valves do not have to be removed to have the spool replaced.

Before you go crazy looking for valves verify it is not an air bag. Before corrosion of the bottom "can" shows up as a leak you can hear, there will be microscopic pin holes that will allow air to escape one bubble at a time. All of the bags on one side in the rear are tied together so a leak in any one lets them all sag. It is very difficult to get the soapy water spread all around the bottom of the air bag and its support surface so a leak will blow visible bubbles, but that is how you have to do it. It is made more complex by the fact that the height of the air bag may affect how it seals at the bottom, so if your leans are intermittent and you see a pattern of leans based on how much or little the air bag is extended that might be a clue it is a bag.

If you start tackling this problem now, you will be ready for the rubber room by the time you get to the rally.

[Jerry Winchester]

I may be ready for the rubber room just talking about it.

But I have not reached Mike's level of anality such that I have the laser levels out in force and taking measurements with a micrometer.

Airplanes are somewhat easier but much less forgiving. If you drop a screw in an unretrievable place, just change the empty weight of the plane............

[Jon Wehrenberg]

Planes are almost equally frustrating.

Several months back I had my alternator drop off line. No CB popped, but it would just drop out and I would not be charging.

If I cycled the alternator side of the master it would come back on. Maybe for the rest of the flight, maybe for 10 minutes. Since I routinely fly to JHW and an approach to minimums is not uncommon during snow squalls I decided not to let the mechanics play "try this".

I had everything changed, including the master switch, alternator control unit, alternator and the over voltage relay.

After about two flights guess what? The CB for the alternator control unit (voltage regulator for you bus guys) started to pop out. That turned out to just be a lazy CB and since that was changed I think my little electrons are all running around the way they are supposed to.

Now my turbo is bootstrapping and tomorrow I am going to massage the wastegate with a little mouse milk (no joke bus guys) and see if that fixes it.

Anybody want to trade a nearly new bus for a 97 bus and a great P210?

[Jerry Winchester]

Mouse Milk is a sure lube-er-up-er for something stuck.

Since my plane has fewer moving parts than yours, it would stand to reason that yours would promote entry to said rubber room sooner.

But you must have some serious amp draw at times. I think the only time my alternator is taxed is when the gear is being cycled. I changed out the landing light and installed one of those "Boom Beam" lights from LoPresti, so I went from 70,000 candlepower, to about 500,000 with half the amperage and no filement to break.

I really just wanted the tower guys at DWH to mistake me for a jet on approach..........

[Jon Wehrenberg]

Big current draws:

Gear
Windshield de-ice
Prop de-ice
Pitot (which includes stall warning)
Headlights

Nothing really big, but lots of little things. About 40 or more circuits. 95 amp alternator and 7 amp standby generator for emergency use.

So far seven electrical system failures over 20 years from things like alternator and alternator control failures to broken field wire, failed alternator CB, broken belt, etc.

In 16 years of driving bus three alternator failures and one failed field wire. I guess if it is mechanical it will break.