Caliper not bleeding with pressure bleeder

[JamesLond]

I'm using the motive power bleeder and I'm attempting to bleed the rear passenger caliper. I also just replaced this caliper.

I initially pumped the brake pedal a few times to try to get some fluid to the new caliper. I then connected the bleeder and pumped it to 15psi. The bleeder screw was then opened. It had a single surge of fluid come out, but then after that, there's a barely perceptible amount coming out.

I see pressure is holding steady at 15psi, but the flow is still basically nonexistent.

 

[Snowbound]

You definitely don’t wanna pump the brake pedal with a empty caliper. Any fluid you have pushed got pulled right back along with air. I always vacuum bleed but that pressure bleeder is actually a better way to do it. Works great when doing all 4 corners.
It should be pushing the fluid out at 15psi. I’ve changed calipers and just left the bleeders open while I was cleaning up and they were dripping within minutes. You sure you have the bleeder open enough to let out the fluid? I pulled my hair out with the back passenger caliper one time and it ended up being the bleeder in the new caliper. The bleeder wasn’t drilled out. These companies are all about quantity anymore and don’t care about quality.

 

[Fless]

Bleeder is on the high side of the caliper, yes?

 

[JamesLond]

Bleeder is on the high side of the caliper, yes?

Yes.

You definitely don’t wanna pump the brake pedal with a empty caliper. Any fluid you have pushed got pulled right back along with air. I always vacuum bleed but that pressure bleeder is actually a better way to do it. Works great when doing all 4 corners.
It should be pushing the fluid out at 15psi. I’ve changed calipers and just left the bleeders open while I was cleaning up and they were dripping within minutes. You sure you have the bleeder open enough to let out the fluid? I pulled my hair out with the back passenger caliper one time and it ended up being the bleeder in the new caliper. The bleeder wasn’t drilled out. These companies are all about quantity anymore and don’t care about quality.

I'd say I got it open enough since the fluid was able to surge out initially. Ah man, I didn't know you weren't supposed to pump the brakes to get fluid to new calipers

 

[Snowbound]

Yes.

I'd say I got it open enough since the fluid was able to surge out initially. Ah man, I didn't know you weren't supposed to pump the brakes to get fluid to new calipers

You should be ok, especially since you have a pressure bleeder. When you pump bleed you push down but don’t let back up until the bleeder is closed.
I just wanted to make sure you were open enough, I didn’t know if you closed it after your initial spit or not.

 

[exp500]

Slowly pump a few more strokes, throw a 2x4 on the floor so you don't overstroke master cylinder. Sounds like you already did that. Hoping it comes back otherwise it's replace.

 

[rockola1971]

Seriously, you wouldnt be dealing with all this nonsense if you had a Tech II clone/original. There is an automated bleed feature in the menu that uses the ABS pump to bleed your brakes. You dont have to touch the brake pedal.

Tech II Navigation:
Using my 2003 Tahoe LT 4wd as an example here is the input to the tech II to get to the Automated Bleed function.

Diagnostics > 2003 >LD, Trk, MPV, Incomplete > Chassis > K > Equal to or under 8600 GVW > ABS > Special Functions > Automated Bleed

Then just follow onscreen instructions and make sure to keep master cylinder topped off!

 

[MassHoe04]

Slowly pump a few more strokes, throw a 2x4 on the floor so you don't overstroke master cylinder. Sounds like you already did that. Hoping it comes back otherwise it's replace.

I did not have a Tech 2 when I did rear caliper replacements on my 05. I did not know about the 2x4 under the pedal trick to save the master cylinder seal. I do now! Thank you guys!! I managed to not damage mine somehow.

That said, this is what I did and came out the other side OK...

I opened the reservoir. Removed the old caliper. With drain pan below the disconnected hose, I pumped a few times and topped off fluid as needed to keep the level high. While I mounted the hardware, I let the hose hang down. It slowly trickled out under gravity. Kept the fluid topped off. Attached the hose and left the bleeder open. Used a home made Coke bottle "one man" bleeder contraption with fluid in it to prevent air getting back into the bleeder valve. A few more pumps until clear no more air came from the empty caliper cylinders and nothing but clear fluid came out. Topped fluid off in the reservoir as needed (never let it down past half at any time in the process). Closed bleeder valve.

Pressure was great. Pedal and brakes have been great.

I think the key that saved me, was never letting air back in at the bleeder or letting the fluid level in the reservoir get anywhere near the bottom.

Tech 2 will make the process easier and now I have one for next time. But, I managed to get by OK with one of those $8 self bleeder hoses with the little check valve in it and a Coke bottle.

 

[JamesLond]

I installed a new brake hose to replace the original hose to rule out a restriction, but it still seems to be the same flow rate.

I do see that if I close the bleeder for a little bit and then open it again, the fluid always has the brief surge I noted in the first post.

Maybe it really does drag a lot. I know @Rocket Man has used this thing. Can you possibly shed some light on this behavior?

 

[exp500]

I think you may have ruined M/C. See Post#6.