Aux Air Leak/At Secondary SpeedAire Filter

[0533]

I was checking the bus out today, do this everyday and when I got out of the car noticed an air leak coming from under the right front corner of the front bumper. The Aux Air Pump was running as well. I opened both the front bumper and the drivers steer bay under the drivers window to inspect and find the leak.

The leak is coming from what appears to be a secondary air filter called a SpeedAire looks about the size of the Norgren filter in the back wall of the steer bay. The air is leaking from an escape tube at the bottom through a black plastic tube that goes through the bottom of the bus and exits out underneath. The unit is located just inside the bumper to the right. Lines coming down from inside the bus at the top front exiting the top back toward the main Norgren filter.

Anyway I shut off the Aux Air and and disconnected the three lines from the filter two at the top and one at the bottom, unscrewed the four screws at top that hold the housing to its bracket, and took the filter housing out of the bus and took it apart. The filter is in bad shape, the housing is ok but dirty. I disassembled the housing, piece by piece, 5 "O" rings, 1 large at the top, one small at the bottom and 3 in the site glass, one large oval for the glass and 2 for the screws, cleaned them and lubed them back up.

The problem seems to be in the base of the unit. There is a needle valve inside a black plastic sleeve that is part of a black chamber that appears to operate (open/Close) when there is a certain air pressure. I cleaned this carefully along with all parts reinstalled the whole unit and it is still allowing air to pass through the bottom needle valve. I think the black chamber at the bottom is defective and will not close.

The filter chamber is a Speedaire Stock # 2Z328B with a max pressure of 250 psi. Is this a Prevost part? or something Marathon installed, do any of you have this secondary filter to the Aux Air Norgren filter in the Steer bay.

[MangoMike]

Bruce,

I'll check my Marathon tonight to see if I have one.

MIke

[0533]

Hi Mike,

I think I have figured this out, at least for now. The air Dryer/filter Speedaire 2Z328B appears to be inline with the Aux Air Compressor. The air passes through this filter and then to the Norgren filter up against the aft wall of the lower steer bay. The Speedaire filter system is no longer made. I have found 2 new ones online and ordered both, will have them in the am tomorrow. I think that they had installed 2 systems on this bus. 1 Norgren F74G in the steer bay and one SpeedAire just inside the front bumper on the right. Anyway I will replace the defective Speedaire unit, (the entire unit) and keep one as a backup. Thanks for your help with this, I would be curious to see you and others have this type of install on their Marathon's