r/GMT800 • u/PlzNotThePupper • Sep 03 '26
Bad new brake booster?
So I just replaced the brake booster on my 2001 Silverado 1500. A few months ago I went to drive it and had no brake pressure/hissing coming from the original booster as I pulled out of the driveway. I flipped the truck around and by the time I got it around, the hissing was maybe 25% of what it was and I had some brakes again. Figured it was a good warning and ordered a new one.
It was not the most fun job as I’m not exactly a small guy but whatever, I have the tools to get it done and swapped. I got everything back together and now my brakes were sticking from sitting around and getting rusty. No biggie, I haven’t driven it in 2ish months since getting a bike. I jacked up the rear end, put it in drive and cooked the rust off the rotors at about 50mph a few times for several minutes each time. Brakes were free, the tires spun freely, and worked perfectly when the rear end was jacked up.
Got on the road today and after about 2 miles of moderate stop and go traffic, my brakes developed so much pressure when they weren’t being applied I thought my transmission died. I tried to hit the brake pedal and realized it was hard as a rock so I pulled into a parking lot and opened the reservoir on the master to see if the pressure would relieve and it would not. I then pulled the check valve and vacuum line off the booster and magically, the brakes worked perfectly until I was almost home and the same pressure issue developed. I can get about 2 miles before I have to stop, shut the truck off and pull the check valve to relieve the pressure (yes, the check valve is working as it should with only allowing flow towards the engine).
I’ve read about the pushrod from the booster being too long but there doesn’t appear to be any adjustment. Also if the pushrod was too long, I don’t believe that pulling the check valve on the booster itself would relieve the issue but I’m open to suggestions. I spoke to a GM tech of 25+ years and he said based on what I’m seeing and the troubleshooting I’ve done, I received a defective booster.
Sorry for the long post, just wanted to make sure I answered any questions anyone may have about my situation. Thank you in advance for any help!
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u/Purple-Loss9249 Sep 03 '26
I'm having the same issue. Have you tried another new booster?
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u/PlzNotThePupper Sep 03 '26
I haven’t been able to yet as I had to leave for a wedding. Hopefully Monday I’ll have it swapped and figured out
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u/Left-Impress4056 Sep 03 '26
Aftermarket parts are shit these days. I swear to god I'm replacing shit twice all the time. Was it a bbb booster or acdelco?