redfishsc
Tired of fixing lousy engineering.
I've owned 4 GMT400 trucks. Two pickups from 1990 and two Suburbans from 1999.
The 1990 ones always had good brakes but I prefer the 4 wheel ABS of the later 90's models.
Those later models are PLAGUED with mushy brakes. Threads everywhere about what to do about it.
Here is what I've discovered.
1) If you can bleed the brakes and get a firm pedal that only lasts for a few months, you probably have a caliper (or perhaps wheel cylinder) letting air in.
2) (Pertaining to vehicles with 4 wheel ABS)..... If you can bleed a 55 gallon drum of fluid through all 4 brakes and still get a mushy pedal, you likely have air in your ABS. Pay someone else to use a scanner to do an "Auto-bleed" which will cycle the ABS system on a few times to piss out all the air trapped in it.
One of my 99s had mushy brakes for years until I had it auto-bled. The pedal was WONDERFULLY firm for maybe 3 months. It was a glorious 3 months, then they got mushy again. I discovered that I had a caliper that was allowing air into the system over time. I swapped the calipers (which functioned just fine otherwise) for new ones, problem solved.
Brake pedal stayed plenty firm for about 2 years until a dumbass pulled out in front of me and I had to stand my truck on its face to keep from T-boning him. That blew a wheel cylinder which obviously made the pedal feel like a slice of pound cake.
The other I had 99 always had a nice firm pedal. But then again I never needed to do anything other than change pads/shoes until I sold it, never needed to open the fluid system.
The 1990 ones always had good brakes but I prefer the 4 wheel ABS of the later 90's models.
Those later models are PLAGUED with mushy brakes. Threads everywhere about what to do about it.
Here is what I've discovered.
1) If you can bleed the brakes and get a firm pedal that only lasts for a few months, you probably have a caliper (or perhaps wheel cylinder) letting air in.
2) (Pertaining to vehicles with 4 wheel ABS)..... If you can bleed a 55 gallon drum of fluid through all 4 brakes and still get a mushy pedal, you likely have air in your ABS. Pay someone else to use a scanner to do an "Auto-bleed" which will cycle the ABS system on a few times to piss out all the air trapped in it.
One of my 99s had mushy brakes for years until I had it auto-bled. The pedal was WONDERFULLY firm for maybe 3 months. It was a glorious 3 months, then they got mushy again. I discovered that I had a caliper that was allowing air into the system over time. I swapped the calipers (which functioned just fine otherwise) for new ones, problem solved.
Brake pedal stayed plenty firm for about 2 years until a dumbass pulled out in front of me and I had to stand my truck on its face to keep from T-boning him. That blew a wheel cylinder which obviously made the pedal feel like a slice of pound cake.
The other I had 99 always had a nice firm pedal. But then again I never needed to do anything other than change pads/shoes until I sold it, never needed to open the fluid system.
