4speedfunk
Well-Known Member
- Messages
- 4,212
- Location
- Tardville
After logging 5000 miles or so on the SAS, I've noticed something weird happening after sitting over night.
In the mornings, I can start my truck...take off down the road...everything's normal. Then when I hit exactly 40mph...the truck will suddenly dart to the right, and slow down. Clearly the right-front caliper is being activated. The RF caliper remains clamping for 5-seconds before releasing itself. After the release, there is a 3-second pause...then the truck darts to the left, slows down again...clearly the LF caliper is being activated. After 5-seconds of clamping the LF caliper, it releases. Everything re-sets and its good the rest of the day. This only happens after sitting overnight...and only happens the first time I hit 40mph. It occurs when driving normally...without a foot anywhere near the brake pedal. No dash-lights whatsoever. No ABS pulsing. Everything works and feels exactly as it should. My brakes are awesome, and I have no other issues. Strange.
I have pulled my front rotors, calipers, and such...to have a look. I've also checked my home-made ABS rings and sensors. Everything looks 100% perfect. TCS, ABS, and VSS all work great, and the only possible thing I can think of, might be some air in the brake lines. I get the feeling this might be tied to the electric brake booster, and the H3 might be performing a "self-check" every time I reach 40mph. I'm guessing it does it every time...but its only noticeable when the truck has sat overnight and somehow lost pressure from the PB booster. After it does it once...I'm good the rest of the day. I'm going to try pumping the pedal 5 or 6 times before I leave the driveway each morning to see if it has any effect on the issue. Of course I'm highly modified...but I'm using all stock brake components. Anybody else experienced this?
In the mornings, I can start my truck...take off down the road...everything's normal. Then when I hit exactly 40mph...the truck will suddenly dart to the right, and slow down. Clearly the right-front caliper is being activated. The RF caliper remains clamping for 5-seconds before releasing itself. After the release, there is a 3-second pause...then the truck darts to the left, slows down again...clearly the LF caliper is being activated. After 5-seconds of clamping the LF caliper, it releases. Everything re-sets and its good the rest of the day. This only happens after sitting overnight...and only happens the first time I hit 40mph. It occurs when driving normally...without a foot anywhere near the brake pedal. No dash-lights whatsoever. No ABS pulsing. Everything works and feels exactly as it should. My brakes are awesome, and I have no other issues. Strange.
I have pulled my front rotors, calipers, and such...to have a look. I've also checked my home-made ABS rings and sensors. Everything looks 100% perfect. TCS, ABS, and VSS all work great, and the only possible thing I can think of, might be some air in the brake lines. I get the feeling this might be tied to the electric brake booster, and the H3 might be performing a "self-check" every time I reach 40mph. I'm guessing it does it every time...but its only noticeable when the truck has sat overnight and somehow lost pressure from the PB booster. After it does it once...I'm good the rest of the day. I'm going to try pumping the pedal 5 or 6 times before I leave the driveway each morning to see if it has any effect on the issue. Of course I'm highly modified...but I'm using all stock brake components. Anybody else experienced this?