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Author Topic: MC5A settling too fast......  (Read 4559 times)
Stan
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« Reply #30 on: February 23, 2007, 08:32:59 AM »

NCBob: You have reached the point where you have to isolate the problem with some serious testing. You have to make up a test fixture (which I have described numerous times before) and test individual sections.  The most obvious first test is the left rear suspension. If that is good, let us know and I will explain how to proceed after that.

BTW: The genset has no influence on the suspension going down. The sole reason for having a leveling valve is to compensate for weight in the coach.

How to make a test fixture:
Get about six feet of 1/4" plastic air line.
On one end put a T with a pressure gauge, a shut off valve, and a coupler to connect to shop air.
On the other end, put a fitting that is easily adaptable to the various sizes and types of air fittings on your bus.

In your case, start with the fitting similar to the fitting on the air beam or just a pipe thread fitting to screw directly into the air beam. Connect your test fixture to the air beam. pressure it up to about 60 PSI, close the shut off valve and wait.  If you still have 60 PSI the next day, it is likely good and you can proceed to the next section. If you don't have 60 PSI, you have a leak in the suspension somewhere.  Now is the time for the squirt bottle with bubble soap, ultrasonic detectors or anything else you can find to detect leaks in a 60 PSI system.  Start with your test fixture and test every joint and every square inch of the system under pressure that you can get to. If you find no leaks, but know that it is leaking, then it is probably leaking in the top of the air beam. At that point you have to decide if you eant to repair it or if you want to put in the adaptor plates that seal of the beam from the bags.

Take all the necessary safety precautions before going under you bus and good luck.
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sommersed
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« Reply #31 on: February 23, 2007, 08:47:11 AM »

OK, I know that this is not the answer to your question.  Well, not a direct answer anyway.

I also have a 5A that settles overnight. To combat this I used to block up the rig with lumber blocks of different sizes and as I normally sit for at least two weeks each time I stop (full timer) this worked fine with the exception of getting it perfectly level fore and aft, as well as port to starboard.

Just about a year ago I decided to try screw type jacks to see if they would hold up the bus even though they were rated for only 1500 to 2000 lbs.  Much to my surprise they do!

Now when I stop I try to make sure I am level fore to aft for sure, and as close as possible port to stbd.  If I am not level port to stbd, I use the jacks to level it (it will already be close, within a few degrees) by just letting the jack on the rear high side just touch the jack point, then jacking up the rear low side as needed.  This works because as the rig is under pressure, the 1500 lbs jack WILL raise it a little.  Then I do the forward jacks, again just letting them contact the jacking points, and I'm done.

I've been doing this for the whole year and have not lost one of those jacks yet.  They will not LIFT the dead weight of the rig when  the bags lost pressure but are fine for holding the static weight of the bus.  And no people, I do NOT crawl under the rig with only these jacks holding it up.

The new type of small screw jacks used today are best and easiest to use because they come with heavy eyes on the jack and fairly heavy two piece bar stock with turn handle usable at any angle.  The old style with the folding round stock and flat blade insert into the jack work but are a little bit of a pain due to the "connection" between handle and jack.

Ed
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NCbob
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« Reply #32 on: February 24, 2007, 05:09:24 AM »

Stan, your advice will be followed but it sure sounds like pit work to me.  When I go home in the spring I'll probably drop the bus off with my guy in NC and stick around for a day or so while he does the tests.  I'll build the test rig (or perhaps even 4 of them...can't be that expensive) and we can test all the beams at the same time.

I tried a small screw jack on the left front yesterday even though it was too tall to use a sturdy piece of wood under it.  Since the bus is tilted a bit this morning I expect that I'll find the jack sitting in a depression in the dirt.  But that's OK...every experiment is a character builder.

NCbob
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Stan
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« Reply #33 on: February 24, 2007, 05:18:36 AM »

NCBob: I guess it depends on how large a belly you have and if you enjoy the challenge of  making things right. If you put your drive wheels on run-up blocks, you should be able to lie on your back under the bus with all the air off the suspension. If you can't do that, don't go under the bus without supporting the bus body, in the raised position, at the jack points.
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NJT5047
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« Reply #34 on: February 24, 2007, 10:48:53 AM »

Bob...jacking the bus level at the front may be a bad idea.  If you wish to force it back level, consider jacking at the low side rear jackpoint.  That's where lateral leveling is controlled.

Best, JR
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.

Ayn Rand
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