Just installed a new one. Im gonna sell this one, needs a rebuild. Looking for a fair price before o put it on eBay. Not sure of the type, may be midland ross? Drum brakes
It's just been my experience that air slips in there, especially on newer silverados, those are a nightmare
Take it out to some loose safe gravel, dnr get it to kick on, then re bleed. Or take it in, that's your choice
There are valves that are actuated by solenoids when abs is applied. They don't move otherwise. Air gets up to the valve, and them gets trapped. Could have a bad abs unit, but doubtful
Id guess there has to be air in the abs unit. Either run it with a scan tool, or get it to activate on gravel, then bleed all wheels. Repeat 2-3 times if needed
I swear someone posted a "poor man's" dual master cylinder upgrade, using a simple distribution block, and people chimed in saying you'll need a proportioning valve, otherwise rears will lock up
Interesting...I always thought they were proportioning valves.. learn something every day! Just like newer ford oil pressure gauges are just off/on, they don't represent actual oil pressure!