Brake bleed sequence?... and any tips you can give (1 Viewer)

[nov74fj40]

I'm like some of the others that have posted in that I recognize my brake pedal travels further on the first pump (now that it's getting hotter in Mississippi). I replaced the entire unit 1 year ago (booster, MC, etc. from Cruiser Dan). I notice that the booster is cycling more often these days too. I have a 100 series '98, and I'm planning on bleeding the brakes old school 2-person style, and have a couple of questions:

Should I do the 30-40 pump step to bleed the booster before I start?

What caliper should I start with - the one closest or farthest away from the unit? (can't remember - getting old).

Typically, how many cycles of pressing the pedal, bleed, tighten, etc. should I do on each caliper?

All tips are welcomed - thanks!

 

[spressomon]

I use Speed Bleeders so that I can bleed the calipers solo. FWIW: I've always started with the longest run (PS RR); then DS RR; then PS FR; and last DS FR. And I do the 30-40 pumps on each. You probably already know this but just in case you don't: Brake fluid will get contaminated which does affect its performance. Cheap and relatively easy insurance to flush every year or so...

 

[nov74fj40]

THanks - another question...

Should I have the engine running / booster operating when I bleed the brakes?

 

[spressomon]

Engine off when bleeding the brake calipers. FSM states: "With the ignition switch OFF, depress the brake pedal more than 40 times".

FYI: If you are using the Hand Held Tester/SST and bleeding the brake booster then there is another sequence that involves on and off ignition.

 

[D'Animal]

As spressoman mentioned, start with the one furthest from the master cylinder.

 

[nov74fj40]

THanks

Big help - much appreciated

 

[Topoguide]

In my quest to find how to flush the brake system for my rig (haven't sprung for FSM yet) I found the following. This method worked fine, my only caution is that on the back brakes the pump will pump all your fluid out without the pedal hitting the floor and without getting all air bubbles out... my solution was to stop after a few seconds and repump then bleed for another few seconds (after the fluid was clear as I was flushing mine).

And I agree with others for bleeding... go from longest to shortest.

I would flush the brake fluid since you've done most of the work already when you are bleeding. Very easy to do with an assistant.

- Key to "On". (engine need not be running)
- Assistant pumps a few times and then holds pedal down.
- Crack a bleeder (10mm box wrench) and fluid flows rapidly to the waiting jar.
- The fluid moves fast so keep the master above minimum.
- If you lose pressure close the bleeder and have the assistant pump/hold again.
- Right front, Left front, Right Rear, Left Rear.
- According to the FSM all four corners bleed the same.
- If you are going to remove a caliper to inspect or replace a pad crack the bleeder before removing the caliper as it can be much harder to turn them when the caliper is loose
- Bleeders are rated for 8ft/lbs torque. Don't over do it. Broken bleeders are common at repair shops.
- after bleeding use brake cleaner to spray fluid off the bleeder (this will make finding any leak later much easier)
- Take this chance to inspect the "rubber" portion of the brake lines
- Before filling the reservoir to "max" release pressure on the system.
- Key to "off" and pump pedal 40+ times until the stroke is lighter and longer.
- Then fill to "max" line.

Now to clear the ABS components you need to go find a road where you can activate the ABS a couple of times. this should mix the Fluid from the ABS channels with the rest of your fluid. This will not flush the old fluid totally out of the system but will ensure that the fluid in the critical ABS components is at least as good as the rest of the system.

The hard-core (not me) could then flush again to ensure the cleanest fluid possible.

Based on what I've read I would choose from the following fluids:
1. Toyota Brand DOT3 - Conservative choice for seal/master cylinder compatability - may be pricey/hard to find
2. Valvoline Synpower Dot4 - Higher performance at low price - readily available - should be fine $6/QT
3. ATE Super Blue Dot4 - Highest performance - $10/Liter - manufacturer says only needs flushed every three years - blue color makes flushing easy to see. (same as ATE Typ 200 only blue) - may have to order online

 

[nov74fj40]

Excellent

This is what I needed to follow - so the key is activating the booster during the bleed?... this makes sense.

So how many times did you end up redoing each caliper to get all bubbles out... 2, 3 x ?

Just curious why press 40 x on the pedal after the bleed and with the power off?

 

[uHu]

Just curious why press 40 x on the pedal after the bleed and with the power off?

That's to take the pressure off the brake-booster accumulator, and let the fluid into the main reservoir.
Point is to check the fluid level without pressure in the booster.

(The LC100 has an electric brake booster that comes on with the ignition, which gives you full effect even without the engine running, and with an accumulator that gives you several full stops even after ignition off)

 

[nov74fj40]

Bleed sequence?

one post: "Right front, Left front, Right Rear, Left Rear."
then another post: "And I agree with others for bleeding... go from longest to shortest"

????

And

So how many times did you end up redoing each caliper to get all bubbles out... 2, 3 x ?

Thanks.

 

[Topoguide]

When I did mine I had rebuilt the calipers so I probably had more bubbles in it than you as you have bled yours previously, I was also flushing mine.

On my fronts it was just flushing so I just kept going until it was good fluid coming out (so no bubbles there) with the rear I let each side pump for several seconds, until the fluid was clean, then I used the method I suggested (starting, stopping, and re-pumping) for about 6 times. The bubbles were gone in three but I wanted to make sure I got them all as I had a really strange experience with the brake fluid being very foamy when I started the bleed/flush on the rear; I figure it was because of the pressure the fluid was entering the empty chamber of the caliper due to the pump (foam was gone by the time I saw clear fluid).

As for relieving the pressure with ~40 pumps you will see that a significant amount of fluid goes back in the reservoir. If you don't do this and add fluid to the full line there will be WAY too much fluid in the system.

 

[nov74fj40]

Good deal

Thanks Topoguide....

That's what I was looking for.

 

[GOT@TACO]

Have you ever used a hose in a jar trick . Get a jelly jar and put a hole in it and a hose about 10'' long. Make sure the hole is on top of jar . Put about 1'' of brake fluid in the jar make sure the hose is in the brake fluid ! Start pumping one wheel at a time . Don`t forget to check your brake fluid !

 

[nov74fj40]

.....

This is the only method I know.

 

[Topoguide]

I have tried the "hose in a jar" trick... they sell a set up like that at local auto parts stores with all the needed items. Didn't like it much.

The power bleeder seems like a good option, but my buddies had broken plastic parts from the summer heat.

The two person method does have the downfall of requiring two people... but it has the bonus of requiring two people. That means you get to chat with your buddy about Cruiser stuff or plan the next weekend trip. So for now that's my preferred method.

 

[DWSD]

I just did mine a few weeks back to drain the old brake fluid. Note for folks who don't know, brake fluid is hygroscopic, meaning the fluid absorbs water. Over time, the water along with the old fluid must be changed to avoid problems within the braking system, including corrosion and premature boiling of the fluid under higher braking temperatures. Most manufactureres recommend changing brake fluid every two years. In race applications, many change fluid every single event, including more than once a day - this prevents fluid from absorbing water from the atmosphere and boiling prematurely under extreme temperatures.

Once you bleed the pressure from the rears, you will not be able to build up new pressure until the engine is restarted and vacuum is re-stored in the booster. Massive fluid will come out of the rears when the booster is operating and pedal pushed, so you barely need to crack the line to either drain old fluid or for bleeding purposes. For some reason, pressure is not built up until the engine restarted.

The front braking circuit seem to operate more traditionally where you can build pressure with your foot without use of the booster.

This took me a bit of time to figure out. I only just recently found this forum.
Hope it helps someone!

Doug

 

[Topoguide]

Once you bleed the pressure from the rears, you will not be able to build up new pressure until the engine is restarted and vacuum is re-stored in the booster... ...For some reason, pressure is not built up until the engine restarted.

Doug,

Did you try just turning the ignition to the on position without starting? The pump is electric so as long as the key is in the on position the pump will work (the engine does not need to be running).

In the instructions I posted (quoted) the entire system can be done with the engine off, until you get to the part of activitating the ABS. You must be driving the truck to do that step.

 

[Topoguide]

Oh and welcome to the forum Doug!

 

[robertlans]

And remember that brake fluid is the best paint remover there is, so be careful not to get any on any painted surface. One trick that was shown to me years ago when changing brake pads was to remove the cap on the master cylinder and slowly compress the caliper open with a c-clamp, this way you need not open the bleeder letting in air so there is no need to bleed, unless you need to flush out the old fluid then it is unavoidable.

 

[DWSD]

Doug,

Did you try just turning the ignition to the on position without starting? The pump is electric so as long as the key is in the on position the pump will work (the engine does not need to be running).

In the instructions I posted (quoted) the entire system can be done with the engine off, until you get to the part of activitating the ABS. You must be driving the truck to do that step.

DOHHHH! I just read your instructions. They make sense. I did not realize the pump was electric and had assumed it was vacuum boosted.

I have yet to do the ABS bleed, but will do that in a safe location. I should have searched here first!

As for the welcome, thank you! Glad to be aboard. These are great vehicles. I've had mine about five years and it will last a L O N G time!

Doug