Soft pedal feel - help me troubleshoot

[Super77]

Apologies for the noobish post on this topic, but I've never actually touched the brakes on my 100 apart from replacing pads. I want to address soft pedal feel and am looking for a good procedure/writeup.

Symptom: the brake pedal does not really engage until about ~2" down. The truck stops fine, and a quick pump on the pedal raises the engagement height, but by default it feels a bit low and soft. No warning lights on the dash, no other unexpected behavior, and the accumulator seems to charge as expected. My DD is a SC430 with a similar pump/accumulator brake system design, and it's got a super-firm and responsive pedal.

I've been planning to replace my factory-original rubber brake hoses anyway, so a full fluid flush is on the to-do list. Anything to check or troubleshoot before I open up the system? What are the 'gotchas' of working on the system? What is the right procedure to flush/bleed without damaging anything?

 

[OEMGUY0720]

Having a spongy/soft brake pedal can be attributed to a few things:
• possible air in the line, may need bleeding.
• brake caliper piston/s may be sticking, may need new seal/s rebuild service / if it’s too rusted may consider a replacement.
• brake fluid moisture content is 2% or higher, definitely needs brake fluid flush, bleed and fill.
• pads and/or rotors going out.
Folks have different procedures based on available tools but this video is be a good guide.

 

[Trunk Monkey]

Is this a new thing with the pedal feel or just how it's been and you think it should be firmer? 2001LC has a huge brakes thread, I'd take a look at it.