I have seen several references to people working on Tag axle brakes on the web but it seems most cannot find parts for them. The original Mfg of the brake system (Master Brake Inc.) is no longer in business. Here is some information I located that might help someone in the future:
Basic diagrams of Electric and Vacuum/Hydraulic brake system: http://www.primotrailersales.com/ima...%20Diagram.pdf
Even though trailer brake systems are shown a tag axle works the same way for the type of system (electric or vacuum/hydraulic) installed.
Midland Vacuum Booster/Master Cylinder (Bottom of pdf page 4 [catalog page 6]): http://www.bepco.biz/Catalogs/VacHydCat/S4_BOOSTERS.pdf
. That was from BEPCO Products: Vacuums & Hydraulics
Midland Vacuum Booster/Master Cylinder (bottom of pdf page 100 [catalog page 2-24]): http://www.precisionrebuilders.com/p...ogPHB-0398.pdf
In the same pdf file you will find the OEM Master Brake Booster/Master Cylinder AND the sycronization valve on pdf page 104 (catalog page 2-28). That pdf is from is from Precision Rebuilders: Welcome to Precision Rebuilders.com
While I do not know if the products from this manufacture are compatable with the older systems you could at least upgrade a hydraulic system to their product if need be: ELECTRIC VACUUM PUMP
. Be sure and look at their other pages because they sell both systems and parts for their systems. Their systems are the ones pictured in the first pdf above. You would only need the VB-800 booster (750psi) for a tag axle system. Anything more would to high of a PSI value for the original tag implementation..
Older tag axle systems typically use Dextor axles and brakes. They were produced in both electric and hydrualic brake versions. Electric is controlled by an electric brake controller. There were 2 versions of hydraulic brakes. One has a bolt on wheel cylinder while the other has the wheel cylinder welded to the backing plate. Refer to the Dexter web site for further information. Dexter Axle - Trailer Axles and Running Gear Components - Parts Store
The Coach Mfg to was the one who decided and installed a given tag axle system, not the chassis Mfg.
Most add-on tag axle systems are from MOR-ryde Corportation: MOR/ryde Home
MOR-ryde Legacy Owners Manual: http://www.morryde.com/downloads/tec...s%20Manual.pdf
MOR-ryde Legacy Service Manual: http://www.morryde.com/downloads/tec...e%20Manual.pdf
I located several pictures showing the installed and dissassembled parts here: Pictures by vicNmin - Photobucket
Again, I hope this helps someone in the future