Brake Bleed after Soft Line Replacement (1 Viewer)

[thedoughboy]

1995 FJZ80

I replaced my soft brake lines with a set of Slee SS lines. Everything was going smoothly until the Front PS hardline leaked. I ordered the #9 line and waited 3 days for it to arrived. I installed it and begain bleeding the system with a one-man pressure bleeder.

When I got to the PS Front all I got was a dribble of fluid and air. Then, fluid, followed by bubbles, then clear.

I moved to the DS Front. It bled, a few bubbles, but cleared.

I did a test drive around the block. Brakes were spongy. Stiff at first, but eventually going to the floor.

Sequence again: LSPV-PS Rear- DS Rear- LSPV- PS Front- DS Front
This is done with pressure bleeder.

The rear of the vehicle bled normally. A few minor bubbles but cleared quickly.

PS Front
This time I couldn't fill the bleeder tube with fluid. It seemed like it was blowing air, with a bit of fluid.

DS Front:
Same as PS.

I checked, and re-checked pressure, fluid in pressure hopper and level on the vehicle. Everything looked good, except minimal fluid dripping down bleeder tube.

Is this an ABS issue?

Any adivice is much appreciated. Thanks!

 

[jpoole]

Try adding pedal strokes to your bleed process when the pressure bleeder is also engaged.

There's a ton of info on bleeding brakes on this forum, including some long process writeups that I've added in the past, so I'm going to keep this brief. A few points that may be helpful:

• add grease or similar to bleeder screw threads so that they don't leak past the threads when I'm bleeding. This can stop air from getting into the bleeder tube for instance.
• run the pressure bleeder around 20 psi and open each bleeder port then while the port is bleeding thanks to the pressure bleeder I also stroke the brake pedal a few fast strokes. Don't bottom the pedal out, you could damage the master cylinder, just short/quick strokes in the normal operating range. You can add a block on the floor if needed to prevent over-extension.
• activate the ABS pump a few times during the bleed process to move fluid/air through it.
• bleed all of the ABS pump connections at the end of a fluid flush/bleed process. This allows me to get the MC level where I want it before removing the pressure bleeder and may help get trapped air out of the system.
• you should see a steady/consistent flow of fluid at all 5 bleeder ports and at any line in the system that you crack during bleeding. If you don't see this then there is an obstruction or problem. If you only see a trickle up front you can start cracking brake lines moving from the wheel to the MC to find out where the problem is.
• Once you get all of the air out of the system if the brake pedal is firm and then slowly travels to the floor a likely cause of this is a bad master cylinder. I've seen this many times when an older master cylinder is pumped beyond it's normal range during brake bleeding it then has internal leaks that prevent it from holding pressure with your foot held steady on the pedal.
• Don't leave brake fluid on painted surfaces/etc. Be prepared to rinse brake fluid off with water soon after getting it on paint. This is why I do the abs pump bleed at the end of the process. I then pull the pressure bleeder, replace the MC cap and rinse that area of the engine compartment off with water. From there the truck and ground under it is wet so I need to be done with my work or move the truck to get under it again.

Good luck.

 

[thedoughboy]

@jpoole Thanks for the reply. How are you activating the ABS pump?

I just found this thread that shows how to activate the ABS pump!