main air tank

mikke60 · April 13, 2015, 02:56:13 PM

Hi. I am sure this topic has been discussed at some length here,but here goes. I am about to change out the main airtank on my MCI 5a. is there anyone here who as actually done this recently? Also, has anyone ever just abandoned the existing tank and relocated a new one and piped to it. Any feedback would be great before I attempt this task.

thanks, mike S

lostagain · April 13, 2015, 07:03:03 PM

I was at the Fleet Brake store in Calgary this afternoon picking up a part for my dump truck, (this is a commercial truck parts supplier), and was looking at their selection of air tanks. All sizes with bungs in different locations. Surely you could make one of those fit your needs.

JC

Oonrahnjay · April 14, 2015, 08:15:56 AM

Quote from: lostagain on April 13, 2015, 07:03:03 PMI was at the Fleet Brake store in Calgary this afternoon picking up a part for my dump truck, (this is a commercial truck parts supplier), and was looking at their selection of air tanks. All sizes with bungs in different locations. Surely you could make one of those fit your needs.

JC

Yes, JC is right. I checked under my bus soon after I got it and found that the air tanks were deteriorated by rust. If you scratched them with a screwdriver, it was like peeling pages of a wet paperback book -- but instead of paper, the sheets were layers of rusty metal. I HAD to do something. So I redesigned the system to a modern system (including spring emerg/parking brakes) and replaced just about everything between the S-cams to the compressor.
The components are out there.
One caveat. There are performance requirements for air charging and recovery. If you go to a tank that's too big, your system may be slow to charge or recover; is the tank is too small, it may not have enough capacity to provide for brake system use (stop and go traffic, etc.) and other air needs like suspension. You can move it and reconnect it but if you change the size of the tank, you should be sure that you've done your calculations and have the right capacity.

luvrbus · April 14, 2015, 08:30:55 AM

I don't know what he calling the main tank depending on the serial # some have a wet tank then the dry tank which is which my dry tank on our 5 was a pita to change the wet tank was a snap my 5 did not have what is called a ping tank.Eastern Marine is a good source for air tanks fwiw

Dave5Cs · April 14, 2015, 09:00:04 AM

Clifford you beat me to it. I was wondering too what the tank was he was talking about.
If they are the wet or park tanks up front. I loosened the straps thinking they would just slide down but turns out there were fitting and solid copper tubes connected through the lower floor from the tunnel. It would not move and very hard to get a wrench to do any good above to take the fitting loose. I had to cut a hole in the floor to get to it to fix a leaky fitting. It was before we put down the new floor. Dry tank in back is easy to get to as it the Accessory tank in the tool bay ceiling up front.

Dave5Cs

mikke60 · April 14, 2015, 02:31:35 PM

to be Honest, I am not sure if it is wet or dry tank. It is however fastened directly to the backside if the rear storage bay. From the tank,the lines go to the control valves for rear air bags. Is this helping?

Ed Hackenbruch · April 14, 2015, 02:54:39 PM

On my 5 that tank is the wet air tank. The 2 tanks by the front axle are the dry tank, (closest to the driver) and the parking tank.

RickB · April 14, 2015, 03:08:11 PM

I'm not sure if this is the same tank as my 81' MCI 9 but I changed the air tank directly in front of the rear differential and it was honestly the hardest thing I've ever done mechanically. There was absolutely zero room to move and the fittings have to go in perfect or they cross thread. I removed the tires, blocked the bus up and it was still just a god awful job. I will never do that again.... ever

Rick

rusty · April 15, 2015, 05:41:41 AM

Bruce, Tank size has nothing to do with recharge. Recharge has to do with how much air you use when you apply the brakes. DOT requires that you are able to apply the brakes so many times if the compressor dies. You can go larger and it will take longer to charge the system but not that much longer. Do not go smaller.

Wayne

luvrbus · April 15, 2015, 05:55:18 AM

OEM's have always based the tank size on the CFM of the compressor unless that has changed with all the new rules some of these new buses have a 25+ cfm compressor with huge tanks nowadays ,with DOT is more about recovery time

Oonrahnjay · April 15, 2015, 03:41:38 PM

Quote from: luvrbus on April 15, 2015, 05:55:18 AMOEM's have always based the tank size on the CFM of the compressor unless that has changed with all the new rules some of these new buses have a 25+ cfm compressor with huge tanks nowadays ,with DOT is more about recovery time

No, Clifford, Rusty says that that doesn't matter. Try telling that to the inspector that's watching your gauge and his watch ...