I couldn't find this answer in a search, so I'll make a new post for those searching in the future:

What's the proper procedure for bench bleeding a 97 4Runner brake master cylinder with the cardone brake tool (http://my.cardone.com/techdocs/10908...%20flyer.pdf)? The instructions have two different methods - one you open both ports as you inject the fluid, the other method you leave one port plugged as you inject.

Does anyone know which method our MCs use?

Got a "page not found" error when clicking your link, but check out this video, this guy builds a "tool" that allows an air compressor to charge the whole system, may be of use? This is the second time I posted this video here today lol Tundra Brake Upgrade on 3rd Gen 4Runner - YouTube

Strange about the website.

Anyway, it's a tool that looks like a big syringe. You fill it with brake fluid and inject it into an open port of the MC. Once the bubbles are not longer present, you do the same thing with the secondary port.

Apparently there are 2 types of MC. One type requires you to leave the 2nd port closed while injecting and the other requires both ports to be open.

Does anyone know what type of MC is in a 4Runner?

One of the ways to bleed the MC is to use the plastic adapters that came with it, as well as the hoses, and just pump until there's no air that comes out anymore.

I accidentally let my master cylinder go empty gravity bleeding the new to me 97 of all the nasty brake fluid.

I did a Hail Mary and hooked up my motive pro pressure bleeder and bread all the brakes at 10psi. Brakes feel great. No bench bleeding required.

If I had to bench bleed it I would have just spun short brake lines into the MC fittings and bent them to go into the master cylinder resivour and pumped until no air bubbles.

Yes, the MC came with two needles and tubes and outlines this procedure: use a vice, fill the MC with some fluid, and manually activate the piston until there are no more bubbles. It says that it can take 70+ "pumps" to get the air out.

The cardone bleeder is supposed to allow you to get the bubbles out in 3-4 "injections". It ultimately comes down to whether or not I am to unplug one or both ports. I'm not sure if it matters or not. The 4runner's MC looks different than most MCs anyway (two reservoirs with two different caps that can be removed); the 4runner has one cap only (cant really see the secondary reservoir).

The "typical" MC bleeding procedure:

The following process is supplied with each CARDONE replacement master cylinder. You can help our customers by stressing the importance of following every process we include with our parts, to prevent warranties and increase sales.

Transfer proportioning valves, switches or other components to the replacement master cylinder (as applicable).

Tighten bleeder plugs into ports (bleeder plugs may be in parts kit or master cylinder reservoir).

Support the master cylinder in a vise in a level position. Never clamp onto the body of the master cylinder.

NOTE: Units with remote reservoirs should be bled on the vehicle. It is VERY IMPORTANT that the body of the master cylinder be kept level during the bleeding process.

Fill reservoirs halfway or until reservoir ports are covered. Always use new brake fluid from a sealed container as specified by the vehicle manufacturer.

Install reservoir lid so brake fluid does not spray from reservoir during bleeding process.

Using a blunt tool or dowel (brake pedal if mounted in vehicle), SLOWLY press in and release the master cylinder piston using short strokes of 3/4” to 1”. NEVER STROKE PISTON MORE THAN 1”. Repeat this step until resistance to piston movement is firm and less than 1/8”.

IMPORTANT NOTE: On step-bore master cylinders, WAIT 20 SECONDS BETWEEN STROKES. This will allow air trapped in the quick take-up valve to rise into reservoir. MASTER CYLINDER BODY MUST BE LEVEL.

Install master cylinder on vehicle. DO NOT remove bleeder plugs until brake lines are ready to be installed. This prevents air from entering the unit and brake fluid leaking out.

Remove one bleeder plug at a time from the master cylinder and connect the proper brake line to that port. Repeat this step for remaining brake line ports. Be sure fluid level is maintained during installation of brake lines and that all fittings are clean before installation. Bleed brake system according to vehicle manufacturer’s procedures and specifications.

Verify proper pedal action before moving vehicle. Do not road test vehicle until correct pedal feel and travel are obtained.

NOTE: If firm brake pedal action results using bleeder plugs, but becomes soft after installation in vehicle, the problem is not the replacement master cylinder.

Using the "syringe":

CONVENTIONAL MASTER CYLINDERS
1. Mount master cylinder in a vise by the mounting lugs as level as possible.
2. Remove plug from one brake port (if installed).
3.Attach supplied rubber grommet to the tip of the bleeding syringe.
4.Fill reservoir with new fluid from a sealed can of the type specified for the
vehicle until reservoir is at least half full.
5.Hold empty syringe tightly against uncovered brake port.
6.Slowly pull syringe plunger until syringe is approximately half full. See
picture 2.
7. Purge air completely from syringe but leave the syringe at least half full of
fluid. Hold syringe tightly against uncovered port and inject fluid back into
the master cylinder. See picture 3.
8. Repeat steps 5 through 7 until no air bubbles are observed rising in
reservoir.
9.Replace port cap.
10.Repeat steps 2 through 7 for all other brake line ports.
Refer to supplied installations and vehicle service manual to complete
master cylinder installation

OR

STEP BORE MASTER CYLINDER
1. Mount master cylinder in a vise by the mounting lugs as level as possible.
2. Remove plugs from both brake ports (if installed). Place a pan below
brake line ports to catch fluid during bleeding.
3. Attach supplied rubber grommet to the syringe tip.
4. Partially fill reservoir until inlet ports are completely covered using brake
fluid from a sealed can of the type correct for the vehicle. Fill syringe
with new fluid, being sure to purge all air from syringe.
5. Place rag under primary brake port. Hold syringe tightly against reservoir
inlet and slowly inject fluid. Repeat until fluid flows from brake port and
all air is purged. See picture 2.
6. Fill syringe with new brake fluid. Be sure to purge all air from syringe.
7. Hold syringe firmly against the primary brake line port and slowly inject
fluid into port. Observe fluid rising within reservoir from primary inlet,
checking for air bubbles. See picture 3.
8. Repeat injecting new fluid until no air bubbles are observed.
9. Cap port.
10. Repeat steps 6 thru 9 for secondary port.
Refer to supplied installations and vehicle service manual to complete master
cylinder installation


So, is the 4runner a "conventional" or "step bore" MC? My guess is step bore, but I want to make sure.

Or would it be easier/more prudent to do this method (found on Yotatech):

From the 2001 Tacoma Factory Service Manual;

BLEED MASTER CYLINDER
HINT:
If the master cylinder was disassembled or if the reservoir becomes empty, bleed the air from the master cylinder.
(a) Disconnect the brake lines from the master cylinder. SST 09023–00100
(b) Slowly depress the brake pedal and hold it.
(c) Block off the outlet plug with your finger, and release the brake pedal.
(d) Repeat (b) and (c) 3 or 4 times.

So my thoughts are that it may be "easier" to hook up the MC (I'm going to be swapping out the brake booster at the same time), fill it up, put the hoses on (looped back into the MC), and have an assistant slowly pump the brakes until the air is gone. Basically, what seems to be the best (and easiest) method to go with?

Im getting ready to do this over the weekend. Any advice would be great...I don't think I can use the tool to bleed because it wont fit in the reservoir of the MC. Since I wont have access to a vice, can I use the below procedure to bleed it (installed on vehicle):

BLEED MASTER CYLINDER
HINT:
If the master cylinder was disassembled or if the reservoir becomes empty, bleed the air from the master cylinder.
(a) Disconnect the brake lines from the master cylinder. SST 09023–00100
(b) Slowly depress the brake pedal and hold it.
(c) Block off the outlet plug with your finger, and release the brake pedal.
(d) Repeat (b) and (c) 3 or 4 times.

I don't know about a new one, but that worked like a charm for me after I effed up the first time I pressure bled my brakes and ran the reservoir dry.

A whole thread to turn a procedure that's pretty simple into an complex procedure?

Remember that the web is full of info outside this forum as well.

Thanks for the help! This is the first time I've ever had to mess with a MC, so I'm learning as I go. I found that procedure over at Yotatech (in their 95.5-04 Tacoma/96-02 4runner section). I wasn't sure if depressing the brake all the way down would hurt anything (since during a traditional bleed you aren't supposed to stroke further than 1").

As to csp saying I'm over complicating the procedure, this is my first MC swap and want to make sure I do it correctly and not eff anything up, so I'm asking a ton of questions. I guess he decided that ridicule was the better way to go rather than contributing to the conversation/being helpful to someone who has never done it before.

Oh, just so you feel better, that's a direct quote from my '99 FSM, so it should work on your '97. As I recall, the reason for that rule is so you don't push old crap out of the MC by going beyond normal travel. Should not be an issue on a new MC with new fluid. But I'm just making that up, don't call it gospel. Brakes are not my specialty. Hence the screw-up on the bleed.

Thanks Durk. My plan is to do this this weekend. I'm going to hook the MC up to the brake booster and install everything at once. Then start the bleed procedure with a helper. I'll post up the results as soon as I get it done. Once again, thanks for all your help!

I completely forgot to update this (in case someone is searching and finds this thread):

I replaced both the MC and brake booster. It must've been one of them, because I had decent brakes after the swap.

Which master cylinder bleed procedure did you use? You mentioned that you were going to try the FSM one mounted on the car. Did you have to make sure the master cylinder rail was level? I'd have to jack the rear end high in the sky before my master cylinder rail is level since it sits so raked mounted against the booster.

I only ask before I did a bench bleed with the two tubes into the reservoir on a new OEM master cylinder, Then I bled the entire system on the car using power bleeder once I reinstalled the master cylinder. I'm getting really bad brake booster delay unless I pre prime the pedal prior to engaging the brakes fully. I have to press pretty hard to lock up or engage ABS in rain which is sad. Literally all the foot strength I've got. My next stop is to try and replace the old nasty gasket between the master cylinder and the booster as the booster function tests seems to pass.

FYI, the part number for that gasket is 47275-12020...should cost about $1.50