Brake line swap then bleed- tips and tricks requested

[Hayes]

Looks like I'm going to install some extended brake lines along with some long travel shocks. My plan is to have a shop do a full brake fluid flush afterword, but I realize I will be bleeding the system prior to this, after I swap out the lines. I've got a couple questions:

1. When removing and swapping in the lines, is there anything that can/should be done to minimize fluid loss and air entry? Bleeders open? Bleeders closed? Anything with the brake pedal? Or is it just remove the old line, attach the new?

2. Is there a verdict on DOT 3 vs. DOT 4 vs. DOT 5.1 fluid in our trucks? Some conflicting reports on the forum.

Thanks for your time.

 

[Skidoo]

It is just remove old lines and replace. Are you going to have a dealer do the flush? It takes one of their diagnostic computers to flush all of the brake control valves because of ATRAC and VSC systems. You can do a pretty good flush just by doing extra bleeding until you have cycled the fluid, expect that is what shops do that don't have the diagnostic computer.

 

[AllLC]

I just swapped my brake lines for stainless. I had no idea the key had to be on ( not necessarily running) in order to bleed back lines

I thought I really messed something up when I couldn't get any fluid out of the back!

You probably already knew this but just in case.

 

[AllLC]

Make sure you monitor the battery if engines not running, that sucker pulls some current!

 

[duggy]

1. Buy one of these Pneumatic Brake Fluid Bleeder
2. Replace your lines and let it all drain
3. Turn your compressor output to about 10psi
4. Hook up your new brake bleeder and let it run for 20 minutes at each corner with the car on while cycling the ABS and ATRAC
5. Confirm that the fluid has no bubbles and looks new
6. Consume beer

 

[cooper30]

Going to jump in with a question here....hope that's ok.

The key has to be on to bleed the rear? Is that specific to certain model years?

I put new calipers on the rear of my 2000 last night. While I haven't pressure bled yet, I did crack the bleeder until fluid started coming out.

I was just going to bleed them like I have on other vehicles.

 

[AllLC]

So I got a little fluid at first but when I did the normal 2 man bleed the pedal would not force more fluid unless I could hear the break booster kick on.

I believe the back breaks on the 1999 lc rely entirely on the break booster

Maybe Duggy could confirm?

 

[duggy]

No, the suggestion to turn on the car was to activate the ABS and ATRAC systems. I do not have ATRAC and was able to bleed my entire system with the car off. I used 5 quarts of fluid to ensure my system was clean and completely bled.

 

[Hayes]

It is just remove old lines and replace. Are you going to have a dealer do the flush? It takes one of their diagnostic computers to flush all of the brake control valves because of ATRAC and VSC systems. You can do a pretty good flush just by doing extra bleeding until you have cycled the fluid, expect that is what shops do that don't have the diagnostic computer.

Hey thanks.
I think I might just cycle enough fluid during the bleed and call it good. How much fluid do you think I should have on hand?

 

[Skidoo]

About a quart and a half.

 

[Hayes]

This was not a big deal.

Bleeding was easy. Followed the FSM and instructions found here. Assisted by my 11-year old. No problem. Bled 5x 12 oz. bottles (DOT 3 Amsoil) through.
The brake line swap was a little more tricky. A few of the hard line fittings on the rear were challenging to break free, and I have a relatively rust-free truck. Had to carefully use vise grips. It all worked out, though.

Thanks for the input folks.