How does air get into a closed system? Break lines power bled and pressure bled, seems to get air in but no leaks?
2009 Chevy 2500 HD 6.6
It all started when I did the rear breaks, thus leading to a piece by piece replacement of the whole system while trying to fix the issue, because of what seemed to be a cascading failure of old parts, most of which did need replacing.
I replaced the entire brake system, less the booster and leads to the caliper. It's been flashed at the dealer, I also utilized an Autel MaxiCom 808 to power-bleed, several times. No visible leaks found by myself or the dealer. On initial bleed, I have tight breaks, a day later, next to nothing, as though air is in system. Even put cardboard under the vehicle to see if anything was dripping... nothing. With the exception of the lead to the calipers and the booster going through the firewall, everything has been replaced, properly installed and bled. I'm clueless. The dealer has nothing, nor did the local diesel shop. I've also utilized a pressure bleeder to force everything through they system, seemingly it worked the day of, but the next day, gremlins?
Any thoughts or suggestions?
Thanks
Turns out, I had a cascading failure that, as one issue was addressed, the next weak link in the chain broke. Started with a break-job, front no issues, however, following the rear, notable issues. Fixed each problem and within two days, new issue, similar, but different. First I replaced the master cylinder, then the ABS module and pump, finally the break booster.
In the end, after everything was replaced, under pressure, I finally found some minor leakage which was easily fixed with a new crush washer. The new master cylinder had an o-ring that was too big, thus creating an issue... the dealers initially stated they couldn't get, suggested purchasing a new master cylinder to get new o-ring... went somewhere else, got the proper o-ring for $4.00 All good now.
Notable issue, when talking with the dealer, because of the VIN, they cannot utilize their Dealer Key when they look up info, the last portion of the VIN is applied to at least three different models of vehicle, two similar, yet very different from mine, and their info seems to direct them towards the other two models... their statement, not mine.
Did you bench bleed the new master cylinder and calipers before installing them?
Thank you for the update. Once again, the dealer doesn't fail to disappoint.
I did bench bleed the master cylinder.
I've never known of anyone to bench bleed calipers. I have replaced calipers on a few vehicles: Grand Waggoneer, Bronco, D150, and a couple cars... never had such an issue.