The brakes on my astro work fine until you hit them hard above 30mph then the front brakes grab and release at about one second intervals and occasionaly the pedal goes to the floor and I lose braking on all four wheels and have to apply the emergency brake in order to stop.I’ve replaced everything but the brake lines and the abs sensors.any useful suggestions?
If you don’t have any leaks you may still have air in the system.
Aside from that, the master cylinder or booster may be faulty.
I would strongly advise against playing Russian roulette with others on the road. Get it towed and fixed.
Thanks(sort of) for the input,I’m really not stupid enough to drive it in traffic.We test drive it in my buddies private,15 acre parking lot.Everything that can be bled has been.I know that even new masters and boosters can be defective but after replacing both items twice,I doubt that they’re the problem.I’ve talked to a few GM mechs in the last few weeks and none seem to have run across a similar problem before.Oh well,maybe I’ll just part it out or use it for a storage shed.It’s not worth letting some dealership charge me twice what the vehicles worth to fix it (or not fix it!).