Hey gents. Need some help. I just replaced both rear calipers. I used a vacuum pump to pull fresh brake fluid through the system on both sides. How ever with doing this it seems that the petal is soft. No matter how many times bleeding the brakes. It also seems like there is no fluid going to the rear calipers.
Need some brake:abs help
- Thread starter 07_Envoy
- Start date
flyboy2610
Member
I hope this doesn't sound like I'm questioning your ability, but you didn't accidentally install the calipers upside down, did you? The bleeder screw needs to be at the top, or the calipers will never bleed properly, and the results will be just what you describe.
Mooseman
Moderator
I use a vacuum pump but also push the pedal to force feed the fluid in case a bubble is caught in a corner or something. What I do is take out the bleeder, put some teflon tape on the threads and put it back in. Put the vacuum pump on it and pull a good vacuum and then go to the pedal and give it 2 or 3 good pumps. It's usually still pulling fluid so air shouldn't get sucked back in. Close the bleeder and go to the next one. this method has worked well for me.
Thanks. I will try the Teflon tape, I did try pumping the brakes as well but did not seem to expel any more fluid. I also tried bleeding the brakes brakes the normal way. Back right, back left, front right and front left. It’s still got a soft pedal.
Mathoran
Member
- May 3, 2012
- 54
When I had to bleed my brakes I thought I messed up somehow too. Pedal felt soft etc but the brakes worked fine. I was just hyper focussed on the pedal feel since I had worked on/bled the brakes. I just assume all these trucks have soft feeling brakes. Got used to it again and never gave it another thought. Not saying yours are fine, but just a thought.
I know what your talking about with the soft pedal. How ever I know this is different. As my gage is the rear calipers have not pushed out the pistons to squeeze on the rotor as it still slops around.
Mooseman
Moderator
I had the same problem with my '02 when I bled them for the first time. I went as far as replacing the master cylinder and getting the dealer to bleed them in case there was air in the ABS. They were just soft by design. Once I got the '06 9-7x with its cast iron calipers, those were firmer so I attribute the softer brakes on the older ones to the aluminum calipers. But they were still softer than other trucks.
However, @07_Envoy , you have the cast iron calipers. You might have some air in the ABS module. You could either find someone with an advanced scanner that can activate the ABS module or find a dirt road and hit the brakes hard to cycle the ABS and then re-bleed the brakes. After all that, if they still feel a little soft but don't hit the floor, I think they're fine.
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I've penned a "How To" on this very Topic that has some more information and suggestions that perhaps may prove helpful:
gmtnation.com
How to Perform a Pressurized Brake Bleed on ANY GM Vehicle
I thought it would be a good idea to break out this “Pressurized Brake Bleeding Procedure” from the other Brake Repair Work involved with my 2000 Chevrolet Silverado 1500 Long Bed Truck. I think this Procedure stands out from all others because it is THE Fastest, THE Easiest and THE Most...
gmtnation.com
Ok I’ll give an update here. I tried again multiple times today. I tried the Teflon tape around the bleeder screws. No dic. I thought maybe by changing the fluid I sucked debris through the brake system. I completely drained everything and tried compressed air through all the lines. Still no dice.
I caved and took it to a brake shop. They used their power bleeder and still no dice. Apparently they had to pull the pistons out of the remand calipers as with them fully seated the brake fluid was bypassing the seal.
I caved and took it to a brake shop. They used their power bleeder and still no dice. Apparently they had to pull the pistons out of the remand calipers as with them fully seated the brake fluid was bypassing the seal.
flyboy2610
Member
When I replaced the brake fluid on the wife's '06 TB I used the vacuum pump method. I used Mobil1 synthetic grease around the bleeder screw to prevent air leaks, and used a 1/4" hose clamp to secure the vacuum pump line to the bleeder screw. It worked OK, but that's about the best I can say.
When I replaced the brake fluid on my '04 TB, I used this method:
Again, I used Mobil1 synthetic grease around the bleeder screw, and a 1/4" hose clamp to attach the line. This method worked really well! My TB has the dual piston aluminum calipers on the front, and I think the pedal feels firmer than it does on the wife's TB. From now on, when I bleed brakes this is the method I'll be using.
When I replaced the brake fluid on my '04 TB, I used this method:
Again, I used Mobil1 synthetic grease around the bleeder screw, and a 1/4" hose clamp to attach the line. This method worked really well! My TB has the dual piston aluminum calipers on the front, and I think the pedal feels firmer than it does on the wife's TB. From now on, when I bleed brakes this is the method I'll be using.