You are far less likely to experience axle problems than those, like myself, with later coaches that have the Henschen DuraTorque axles. If your Bubble has its original straight axle with leaf springs, the leaf springs are far more likely to need attention than the axle itself. If the springs do need attention, most larger cities have shops that specialize in rebuilding automotive springs will also rebuild/refurbish RV springs as well.
My information indicates that the greatest probability would point toward surge type hydraulic brakes as the type of brakes that your Bubble would have been found on your Bubble. There are modern versions of this type of system still available, but there is no direct, indpendent control of the trailer brakes from the tow vehicle with surge brakes - - the force of the tongue moving up on the trailer hitch during stopping applies the brakes via a small master cylinder mounted on the hitch that foces fluid back to the brakes at each wheel. My experience towing a car hauler with surge brakes indicates that they can be quite "chatty" in traffic as they tried to lock up too early when slowing for signal controlled intersections.
In most cases, it is possible to upgrade to electric trailer brakes from the hydraulics. A local shop that specializes in utility trailers would likely be familiar with the process.
I can't tell you whether your coach would have had shocks from the factory as my greatest familiarity is with coaches of the 1960s. I do know that the larger coaches with leaf springs often had shocks - - these would have been from the late 1950s - - whether they were factory, I do not know.
Good luck with your project.
Kevin D. Allen
WBCCI (Lifetime Member)/VAC/Free Wheelers #6359
1964 Overlander International/1999 GMC K2500 Suburban (7400 VORTEC/4.11 Differentials)
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado Convertible (8.2 Liter V8/2.70 Final Drive)