That's a very comprehensive and convincing explanation, maybe I have learned something today
You only need to run 16" wheels if you have the later rear brakes. I changed mine to later from discs and calipers. Older disc size are 280mm later 320mm bolt on conversion real easy.
Pumpy you have 16" rims I am sure of it.
Op I would say coasting down a hill and braking just cooked your brakes. If your not used to a diesel use the engine braking on down hills
Much safer
IMHO you could be right about water in the brake fluid. Especially when you mention it happening on a descend, so the brakes will get hot.
did you already change the brake fluid ? Or at least had it tested for water?
btw is the cummins the pre '97 one without the electronics? I've been driving a Ram in Mexico with that engine. Great machine, albeit not a cruiser...
Where did you get the vacuum for your servo from?
Hi and Welcome Rookie [emoji4]. Sounds as the others have said likely to be fluid related. However, I have to question usage of the brakes downhill anyway. With a diesel like that under your bonnet you should have enough engine braking in the correct gear to be able to crawl downhill without hardly touching the brakes. I certainly wouldn't recommend taking it out of gear to brake downhill especially on the handbrake. Things could very quickly go pear shaped. This could be part of the reason your brakes have let go if you are only relying on them on a steep downhill. Also some of the earlier cruisers had smaller brake discs. More info on your truck would help greatly, plus photos of course when you get to15 posts when the forum allows posting photos. [emoji6]
I overhauled my system after boiling the fluid last year in the Pyrenees
I have used Brembo discs with EBC pads but what made a big difference to my stopping power was I change all my flexible lines for stainless steel braided ones. I also use Dot5 plus fluid
Brake fluid needs to be changed For most cars they say once every 5 years as to not get to much moisture in the system.
Clive i saw Pumpys cruiser at the overland show that you didnt turn upto.........