I bought my 99 C2500 Suburban LT almost two years ago. I had the brakes checked out then and was told the pads and shoes were thin but ok. The rest was mechanically sound. But they felt softer than I would expect them to, and the truck pulls a bit to the right when braking. From what I've read, the pulling is pretty normal with rear drums.? Since then, much has happened to them. Replaced the front pads with high quality. No change. Had a front caliper seize up, due to a bad line that I probably aggravated while changing the pads. Took the opportunity to replace the both front calipers, brake lines (flexible, not steel), rotors, and bearings, and bled the front lines. No change. So I replaced the rear shoes and hardware, but not the cylinders. No change. Then they got worse. Really soft. Like scary to drive soft. Did some homework and testing and determined the master cylinder was bad. Replaced the master cylinder (bench bled the new one), bled all four lines (in this order: passenger rear, driver rear, passenger front, driver front). Back to start. Still softer than I'd like. Other people that drive it, say whoa, those brakes are soft. They are noticeably softer than my brother-in-law's 3/4 ton pickup. What next? I really don't want to tackle the brake booster because I likely don't have the right tools. I'll replace the rear cylinders if I have to, but my gut tells me that wouldn't cause this, but I don't know for sure. I'm worried about breaking something taking off the old ones. They look pretty old and there is very little room to work between the drum and the leaf springs. My other thought is to take it in somewhere, but I get the impression that most shops will want to re-do what I've already done, at least partially, (like change pads and shoes) and charge me for it. What do folks think should be next? Rear cylinders? Booster? Shop? Something else? Any other tests I can do to pinpoint the source of the issue? Thanks for your help.