BRAKE BLEED HELP

[deadbeat]

I had the same trouble years ago, it was the abs module. I finally got a little peddle by starting at the mc with the truck running, and bleeding each line back until I could get a little fluid to the rear wheel cylinders. Then I took it to a gravel driveway, got about 25, and slammed the brakes forcing the abs to cycle. I would then go back and bleed again. After several times repeating this process I got a pretty good pedal. These days I put the motive pressure bleeder on and the Tech 2 scanner to command it to abs cycle, makes it pretty easy.

 

[delta_p]

The abs is isolated in normal operation unless you have the solenoids powered while you bleed. Something else must be limiting flow to rear bleeders.

 

[96-2D-Hoe]

I just returned a Motive pressure bleeder. It damaged two master cylinders trying to get it to seal. I could only get it to about 8PSI. With all the screwing around and potential damage I gave up on it and just went back to bleeding one man.

 

[Mr_white_obs]

@Dawson Barendregt

"open the M/C cap, and just wait for a while. Sometimes 20 minutes to a half hour. This will allow the fluid to run down and fill most of the line, and then you could try bleed the cylinder again"


Brake fluid is Hydroscopic. It absorbs moisture, even from the atmosphere. Means you just destroyed the brake fluid, lowered the boiling temp, and induced moisture into the brake system.
Poor idea...

Fair Enough. However, i would argue that given that glycol-based fluids absorb moisture from the environment (not direct exposure to water) at a rate of 2-3% per year i wouldn't worry about 20 minutes. Especially given that the DOT recommends a change only after the boiling point drops to that which is equivalent of 3.7% wet glycol fluid. The brake fluid reservoir cap is often off for bleeding anyway, and any fluid in the line that may have been exposed is very quickly pushed out with a few extra pumps of the pedal.

 

[deadbeat]

I think I should mention that when I bough the Motive Bleeder I bought the larger flat cap 1105 instead of the smaller one. I have never even put a C clamp on it, works great, I can get 15psi like needed with little to no effort.

 

[96-2D-Hoe]

I think I should mention that when I bough the Motive Bleeder I bought the larger flat cap 1105 instead of the smaller one. I have never even put a C clamp on it, works great, I can get 15psi like needed with little to no effort.

The 0105 kit fits the GMT400 fine. But the rubber pad was too hard just didn't give enough to seal properly. I was using an aftermarket MC with a ****** reservoir. I just replaced it with a Delco MC and the reservoir is much better and may have sealed more easily, but I had already returned the Motive. It had screwed up one MC reservoir and the seal on another. I wasn't going to risk using it again.

 

[Bloodwater79]

just by a vaccum pump brake bleeder. they are great if you have to do the job by yourself. I have done several brake bleedings with mine with no issues. Great for pulling old fluid out of the system too. link to one below:
https://www.northerntool.com/shop/t...BMSTL91PNguf-DxF7RHK63KZ4ozsf9jcaAn50EALw_wcB

 

[David89gmc]

Use a vacuum bleeder. It's just about the best way to get the air out of the system. The ABS module also needs to be bled.

 

[Erik the Awful]

Homemade one-man brake bleeder. Free because I had all the parts in my hardware buckets. Works great. Don't forget to punch a hole in the lid to let air out. Fill it 1/3 if the way with fluid, slip the hose over the bleeder, crack the line loose, then sit in the driver's seat and pump the crap out of it.
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[Pinger]

Homemade one-man brake bleeder. Free because I had all the parts in my hardware buckets. Works great. Don't forget to punch a hole in the lid to let air out. Fill it 1/3 if the way with fluid, slip the hose over the bleeder, crack the line loose, then sit in the driver's seat and pump the crap out of it.
View media item 32289

A tip given to me for when using that type of bleeder - a dob of grease on the bleed valve threads to reduce the possibility of air being sucked in there. (Helps when they next have to be used too).