How Long to Air Up....

[Iver]

On previous posts I mentioned problems with my compressor.  I'm not sure if I fixed anything but so far I have replaced the governor and rebuilt the air dryer.

A month ago I had no problems.  I had  one issue one day where the compressor would not air up the coach at all. That was the only time that happened.

Today I started the bus with the air gauge reading zero and timed the compressor to cut out and purge.
I ran at idle until 65 lbs. and then fast idle until cut out.  It took 5 minutes.

I pumped the pedal down until the compressor loaded again at 85lbs. and timed it to cut out. It took 30 seconds.

After 5 hours the main gauge dropped 35 lbs.
After 5 hours the rear gauge at the drain  dropped  45 lbs. I filled the line from the rear drain after with shop air with around 80 lbs. to check for leakage.

How does this compare to anyone else with a MCI-9.
            Iver.

[travelingfools]

Thats about how long mine takes to air up...Cant tell you about holding though as my dryer needs to be R&R'd

[Busted Knuckle]

Iver,
As far as the "first" build up time after the coach has been sitting for a period of time 5 mins is very acceptable! OK I'll explain why, from zero gauge readings the system has to fill the tanks, which then at around 80-90 lbs fill the air suspension, the beams, bags, etc. Also around that pressure it starts filling axillary systems (separate from brake & suspension air) such as a tank for door locks, baggage locks, horn, door openers, etc. So from dead zero filling you are literally starting from the bottom and filling a lot of areas.
Now after "pumping it down" to whatever or starting with 35-45 lbs on the gauges you already have pressure in the main tank, secondary tank (the 2 gauge readins you have), the air bags, and some in the aux systems too. (you almost never have gauges for these systems, unless you put them in yourself.And it's really irrelevant as long as the primary & secondary systems have air!) So it doesn't take near as long when they already have some pressure, as when it's from scratch. Just like building a conversion, if you start with one that has already been converted or started, there is less to do than starting from scratch! FWIW   BK     

[Jriddle]

I'm not sure how long it should take but my MC-9 from no air in system to 120 take about 30 to 40 minutes. I know I have a few leaks to fix but  5 minutes seems real fast. If mine did it in 15 minutes  I would be happy.
John

[coachconverter]

I agree, those figures sound pretty decent.  I've worked on well maintained, charter buses that take twice as long to air up and 1/4 the time to air down.  Run it!

[gus]

Iver,

You're really kidding us and rubbing it in at the same time, right?

My 4104 takes longer than that to air up after it has been sitting a half hour and my system is probably half the size of yours.

We should all be so lucky!!

[buswarrior]

Here's one way to check it:

let the coach air system build to maximum and cut-out.

Set the engine to base idle, fast idle turned off, lowest RPM it normally runs at.

Pump the system down with the brake pedal to below 85lbs.

Measure the time it takes for the air compressor to raise the air pressure from 85 to 100lbs.

Under 2 minutes is acceptable. 45 seconds is excellent. Over a minute and a half, I'd be looking really hard at fixing what is leaking.

happy coaching!
buswarrior

[travelingfools]

Left camp this am..6 mins from no air to blowoff..guess Im doing ok..

[Iver]

I took the coach out for a run tonight and everything worked well.  No compressor problems.

As for the timing.......My airbags don't deflate when the air goes down.  The air in the beams and bags stay up all the time.  Well for weeks anyway.

So my timing does not include the air which has to fill the air ride system.
I'll use Buswarrior's check to see how mine compares.
   Thanks for the input,  Iver