Brake pedal excessive travel '92 Olds 98
 

Car flunked inspection due to excessive pedal travel. Otherwise, car in excellent shape all around, plenty of braking power.

Main problem: Pedal goes down slowly when stopped at a light. ABS light on.

Done already: Replaced master cyl twice with proper bleed, repl front pads (noted uneven front pad wear, driver vs passenger side), checked rear shoes (good), no fluid leaks found, adjusted parking brake. Pedal NOT spongy. Fluid level constant. Pedal returns ok. Plenty of braking power, but I must give it a second pump to maintain pedal height.

Pro tells me its leaking out of ABS into master via the return hose to master.
Big book tells me ABS unit is not servicable.

I need to keep car but ABS at parts store big bucks.

Best thing to do Steve is start by finding someone that has a scanner that can read the stored ABS code and take it from there..
If you post back the stored ABS / chassis code, we should be able to determine a repair recommendation then.

The locals have no way to scan an OBD-1 ABS. Dealer might, but $$$. Anyone w/ direct experience, suggest some software so I can scan it w/ laptop? I can make a connector.

Forgot to mention: also replaced the booster, all vac lines, and repl the gasket on the vac box at intake manifold.

If it was the abs doing as you said it seems like it would still do even after the second pump. It sounds like air in the system or rear brakes not adjusted enough. I know you said you adjusted them. When I have a vehicle with the same issue as your that's the two things I check.

I wonder if using the paper clip method to read the code might work?
In other words is there a different jumper position for ABS (or brake codes) it can read back? https://www.gmforum.com/obd-i-troubl...p-test-306836/
Tried Jumping pins A and H in the ALDL connector...?? & If ABS light starts to blink..it's attempting to hand the secret over LOL..

RJ, Yup, it does go down again slowly after 2nd pump.
SoftRide, I'll jumper pins R and H and see if I get blinky. Pretty sure
the ABS brain behind glove box.

BTW, rear shoes, only one shoe per side is designed to brake. There is no adj hole in backing plate. Big Book at page 5C-6 says to pull drum, and
use lg calipers and adj shoe dia to 50 thou less than drum ID. Really.

The ALDL connector is generally located at bottom of trim panel, below steering wheel.
Sometimes below the glove box..might even have a plastic removable trim piece hiding the connector ..not sure on your car.
https://www.google.ca/search?q=aldl+...=1920&bih=1039

SoftRide, oh yeah, ALDL connector is my friend. I relocated it! I was thinking... do the A-H jumpering at the EBCM. I will try the A-H jumper, but don't see an H terminal at the ALDL. I'll look and see if the "H" position might be wired even though the book does not show it.

I did a brief search for a DIY ABS software package I could run on my laptop. None found, but search engines aren't what they once were.

BTW, no TCS on my car.

H should be one directly to the right of G in bottom row.

SoftRide, thanks! I'll check it.

One more thing: after battery disconnect/reconnect, ABS light is off briefly. Goes on again after driving a very short distance, then stays on.