Slow Compressor

[RickGyver]

Is there a way to increase the output of the compressor on the engine? Mine seems to take forever! Of course, my air leaks when parked! thx

[AirLift]

The first thing I would suggest is track down your leaks if you can. This is best accomplished using soapy water in a spray bottle. Lightly spray every line, and connection watching for excessive bubbling.

As for the compressor, there really only two options I know of. First, you can replace it with a larger compressor/smaller clutch wheel. The other option is to keep your RPM's up.

Do you know what engine driven compressor you currently have? I'm not sure what engine driven is typically supplied with your motor home, I would assume it is either a York or Sanden.

[RickGyver]

I'll check brand. The air bag leakage is a large pain in the woohoo! I always put jacks down but sometimes forget! Mine goes down far enough to hit the inner fender liner.

[moisheh]

This is a safety issue. Your compressor should be able to build pressure from 50 to 90 PSA in 3 minutes at high idle. If it does not you need find the problem. Could be a plugged air filter or a slipping belt. Your cpmpressor could be toast. This vehicle should not be driven if it fails that test. I did not know York and Sanden made air brake compressors. Bendix is big in that field.

[RickGyver]

Thx for that! I am often coming down the mountain side here in Colorado and braking is quite important! I have never set off the low pressure alarm but have come close! Most people get in trouble when they come off the top of the mountain too fast. I need to investigate this air problem ,,, it's also a giant waste of fuel waiting for the air to build up! I have driven an 80,000lb Freightliner down these same mountains so am familiar with braking techniques! To all the "flatlanders",,,,, please be careful when you drive the mountains! Keep your speed down! Sermon over!

[Papa_Jim]

Rick, if your air system is building air pressure so slowly or leaking air so quickly that you are coming close to setting off the low pressure alarm when you're driving down the road, it's time to park your coach and find out what the problem is before you head out on the road again.

The use of your brakes at any time should not cause your air pressure to lower substantially, unless you start to 'fan' the brakes, which means pumping the brake pedal repeatedly.

[moisheh]

rickgyver: Do you have a CDL? If so you should know that driving with those brakes not only dangerous you could lose your license.

[Mike Canter]

Rick, here are two different air system and brake tests. See if your MH can pass them.

Test One
TESTING YOUR AIR BRAKES AND SLACK ADJUSTERS
Auto slack adjusters are used to maintain proper brake chamber stroke and lining to drum clearance during normal operation.

The entire slack adjuster operates as a unit rotating with the brake camshaft as brakes are applied or released.

THE MOST EFFICIENT BRAKING OCCURS WHEN PUSH ROD TRAVEL IS HELD TO A MINIMUM.

Auto Slack Adjusters adjust themselves automatically during full brake applications to accommodate brake lining and drum wear. The key words here are FULL BRAKE APPLICATIONS.

Have you ever engaged your brakes full.... pedal to the floor... probably not many have. But there is way to do this properly to ensure you get your auto adjusters to work for you. If you have never fully depressed this pedal it is likely that your auto adjust system has not been fully activating its full adjustment potential.

DO NOT RUN OUT AND DO IT NOW....DO THE FOLLOWING PROCEDURE TO ENSURE THE SAFETY OF YOUR BRAKING SYSTEM AND THAT YOU DO NOT DAMAGE IT.

Following is a procedure that should be done every day before you start your drive. Certainly, it should be done if your unit has been sitting for a time without use. This will tell you if your air brake system is functioning satisfactorily and will also adjust your slack adjusters.

1.Start engine and let air pressure build up.

2.Block wheels (use chocks that can be purchased from an RV supply store and chock the outside dual on each side. Be sure to insert a chock in front and behind the tire to ensure no vehicle movement. Parking on level ground when you do this is a big help. After this is done and you are sure your Discovery can not move RELEASE YOUR PARK BRAKE.

3.Your brake pressure should be at max. Now fan your brakes to
85psi. NOW ENGAGE YOUR PARK BRAKE AGAIN. Compressor should cut in and watch to ensure a return to full pressure.

4.When you have reached max pressure and the compressor has cut out RELEASE YOUR PARK BRAKE AGAIN AND SHUT OFF THE ENGINE.

5.MAKE FULL BRAKE APPLICATION (BE SURE you have released your park brake before you do this or you will damage the system.) Hold the pedal all the way to the bottom for one minute. Watch your air gauges as they should not move (allowable loss in this mode for 60 seconds is
3 psi). Listen for audible leaks as you wait for the 60 seconds to expire. After 60 seconds release the pedal. (YOUR AUTO SLACK ADJUSTERS WILL SET UP AUTOMATICALLY DURING THIS PROCEDURE.)

6.Turn on key... fan brakes to 20 psi. LOW AIR WARNING SHOULD START, continue to fan down to 20psi.. by now your park brake will have engaged automatically although you will not have any indication of this. Start engine and run at 1000 rpm using your cruise setting. Time
3 minuets. In this time your air pressure should be up to between 50 and 90psi. This will tell you your Compressor is functioning properly.

8. Apply park brake.

End of Test One

TEST TWO

Brake System Check Procedure

(Note- Damage can occur to your service brakes if pedal is pumped hard while Park/Emergency brake is engaged.)

• Be sure rig is on level ground and/or use chalks
• Start the engine. Let the air pressure build up until the governor activates the air compressor cut-out release of air at about 120-130 psi.

Check the Air Compressor Cut-Out and Cut-In Function

• Release the emergency/parking brake.
• Press the brake pedal several times until you see the needle drop to around 85-90 psi.

At that point the governor should activate the air compressor cut-in and the pressure should build back to 100 psi in about 45 seconds.
Allow the pressure to build to cut-out at about 120-130 psi.

Check for Air Leaks

• Shut off the engine, but leave the ignition in the "on" position.

Watch the gauge for one minute - there shouldn't be more than a 2 psi drop in pressure. (This checks for leaks from the air compressor to the tanks and the one-way check valves.)

• Press the service brake (brake pedal) and hold it down for one minute. There should be no more than a 3 psi drop in pressure. (This checks for leaks with the system under pressure: the air lines, one-way check valves, and Diaphragms.)

Check Audio and Visual Low Air Pressure Alarms/ Adjust Auto Slack Adjusters

• Turn the engine back on and let the compressor build pressure to the air compressor cut-out.

Turn the engine off but leave the ignition switch on.
Smoothly pump the service brake pedal until the low air warning light and buzzer activate. Devices must activate at not less than 60 psi.

Check the Emergency/Parking brake Function

• Continue to pump the service brake pedal until the emergency brake pops out automatically. Application should occur between 20-45 psi.

• Start the engine and allow the air compressor to reach cut-out level.

Remove any wheel chalks.
Shift into gear.
Apply your accelerator, but not over 1000 RPM.
Your Rig should not move.


NOTE: Slack Adjustment

Ensure reservoir air pressure is above 90 lbs on both air tanks and make a FULL brake application and release (Hard application to the floor). Repeat this process 6 times. (These brake applications will be adequate to cause the automatic slack adjusters to adjust)

Note: A light brake application will not cause the adjustment

[RickGyver]

The air stays at about 120psi while coach is in use. Any system will lose pressure after repeated applications. I only lose air when parked and not during operation. Thx for your concern! My leak is in the bag plumbing and when I say fast ,,,,I'm talking hours!

[sdennislee]

Mike, your post should be a sticky. Thanks for taking the time to type all that up.

[RickGyver]

Thx for that, Mike. Can a person print just one post? Would be nice to have a hard copy. Is that '57 still launching?

[Mike Canter]

Email me at mike.c@mindspring.com and I will send you two Word documents with the data.

That green '57 Chevy is up in Finland and the racing season is closed for the winter. I just tuned Adam Flamholc's '68 Camaro with a blown alcohol motor that came over from Sweden to run in the USA this winter. We just ran in the Snowbird Nationals outside of Tampa, FL. We went all the way to the finals but had to shut down in the Final Run due to a wheel bearing failure. Glad it happend right after the launch and not at 240 mph.

See Flamholc Racing at :
Adam Flamholc Racing Update - FastDoorslammers.com
and
Flamholc/MMR Racing - professionellt sportlag - Malmö | Facebook
and
www.flamholcracing.com

[RickGyver]

The weirdest things happen. A wheel bearing!! Come on! My son lost out in a big race in Feb because someone forgot to put the covers back on the brake master cylinders and he ran race with no brakes!

[Mike Canter]

Adams, front wheels just started to shake violently after the car came down off the wheelie bars right after launch. It was disappointing but we had nine runs that weekend and I had the fuel system tuned right on. Did not burn a piston or do any other damage. The car has a lot more potential in it as soon as we get the rear suspension set up correctly.
The crew has gone back to Sweden and left the car here.


Your son was lucky. You don't need no stinking brakes in a race