The last two times I have bled the brakes (for 2 year maintenance) I have just used the 2 quart gravity bleed method. I crack the RR, drain fluid via gravity into a bottle, close bleeder, then do LR, RF, LF, while keeping the master cylinder full.

This past weekend, I changed the shuttle valve seals in the ABS unit, which required disconnecting the lines, pulling the valves, replacing seals, reinstalling all.

Obviously, on engine start, I had a very weak brake pedal due to ABS fluid loss. While bleeding this time using the gravity method, once the end of the tube was below the level of fluid in the bottle, I started the engine, and pumped the pedal about 6 times. I continued this for all 4 wheels, then made a few laps around the block in low with HDC engaged.

After doing this, the brake pedal feels as good as it ever has. I haven't measured the pedal travel, but if I assume the pedal has 6" of travel from no pressure to full, normal city braking only takes the first 2".

I have read about the need for Testbook when bleeding the brakes, and I have seen a writeup about removing the ABS relay and jumping the wires during bleed to activate the pump to ensure the ABS system has no air...

...but my pedal feels just the same as it always has for the past 4 years.

Am I being paranoid?

 

I did the shuttle valve seal and switch replacement this week while also doing the ABS wiring fix. Like you, I did the full two quart bleed using a One Man Bleeder.

I did the first quart, RR, LR, RR, LF until I got clear fluid out of each corner, then took a drive. I engaged the hill descent and got the ABS pump working for several passes down a long descent. Returned to the garage and repeated the bleeding process.

I too have a very firm pedal now. While I had intended on taking it to a shop for the Testbook bleed, I don't think it warrants a special trip. Maybe if the truck is at a shop anyway (unlikely as I'm trying to do all my own work) I'll have it done but my brakes feel better than they ever have.

 

Actually the best way to bleed the modulator after removing it is to have someone pump it five times, hold down open the lines on the modulator for a few seconds till all are open. close them up and pump five times and repeat procedure. The trick is to open the first hose on the top with the first procedure. then the next procedure you open the second hose first and then all the others. then the third and then the fourth on top. Then tighten them back up and fill it back up and you got full strength. not need to take off any wheels at all. Works everytime.
i have done the procedure hundreds of times. no need for testbook.

oh and it works on all modulators.

including the new ones.