az_eaglescout_pilot

iTrader: (1)

88 4runner 3.0 ZUKed to stock ride height:

just replaced the rear wheel seals and wheel cylinders in two separate weekends for some reason. Brake lines were disconnected for both jobs, however i went to bleed the brakes the second time and fluid only came out twice from each side...on the 3rd time i opened the valve and no fluid or air came out. the pedal depresses easily to the stop but with a handful of pumps some life comes back to the pedal...

now i have only bled the rears since they are the only one to have come off...do i need to bleed the fronts for any reason?

master cylinder bad? LSPV bad or out of adjustment? brake lines clogged?

yes the reservoir is and was filled after each wheel was bled...

thanks in advance for the help/suggestions

-Jordan

Sportsmanphil

Bleed your brakes starting at the wheel furthest away from the master, working your way closer (RR, LR, RF, LF)

Make sure you keep the reservoir full as if you pull air you will be going backward.

You can gravity bleed if you think you have a lot of air in the lines. Remove the reservoir cap, fill to the top, remove the bleeder valve at the RR wheel. Leave it out until you get a steady flow of fluid. Cap it, bleed it then move to the LR wheel and do the same.

MuddyGal

Good advice! I have an 89 and I'm falling into the same trouble. Going to do what Sportsmanphil said! Thanks I hate the feeling of the pedal depressing when it shouldn't...and pumping to get some pressure is not fun. Ah breaks.......

Sportsmanphil

One last tip,

IF you are pressure bleeding, cap the valve BEFORE the pedal hits the floor. This will take a pedal man that has a clue, as he needs to tell to close just before the pedal hits the floor.

Also, when you pressurize the system with a few pedal pumps, dont go all 'river dance' on the pedal, be slow and smooth with it. If there is air anywhere near the master you will bust it up into finer bubbles which will slow the process of getting all air out.

Oh yea, one last one. Brake fluid is Hygroscopic meaning it will attract and hold moisture from the air. So dont buy the bulk brake fluid bottles and plan on keeping them. Use it and toss it. Moisture (water) is H2O meaning it has oxygen (air) so moisture in the system will compress like having air in the system.

az_eaglescout_pilot

iTrader: (1)

alright so i bled the hell out of my brakes...went through 20 oz of brake fluid...still getting bubbles from each bleeder valve AND bubbles are coming up in the reservoir. while bleeding the rears fluid and air comes out but the pedal does NOT depress... the final pump and hold the pedal goes halfway then gets solid until pressure is let off the pedal and then it goes back to the floor on the next pump...may have had a river dancer for a pedal man...gonna let it sit till tomorrow and try again and see what we come up with with

angrybob

After the first time apart, it bled fine?

Did you bleed the LSPV?

A couple things to try:
1. Take a plastic dead blow hammer or rubber mallet and lightly tap the wheel cylinders, calipers, LSPV, and master cylinder several times each. This can dislodge stubborn bubbles.

2. If all else fails, before spending any add'l money or time tearing stuff apart, apply a moderate to high amount of pressure to the brake pedal overnight by wedging something (2x4, etc.) btwn the brake pedal and the seat cushion / mount / etc. / this will shrink the bubbles and might allow them to move. The trick is to release the pressure slowly the next day and pump it a few times slowly. It is very possible that you will see air bubbling up through the reservoir. This has worked for my 2 and 4 wheel vehicles.

az_eaglescout_pilot

iTrader: (1)

yea the first time the lines were disconnected was when i had to seal up the diff, less than a week after that my rear wheel cylinders failed comin down Mt. Lemmon and my problems began there...

yep bled the LSPV...when im under the truck bleeding the rears i can hear bubbles coming though that valve...is there just a TON of air in my brake system? i started looking for spots where air may be able to enter the system because of how much air is coming out.

should i have primed the wheel cylinders before connecting the brake lines?

i'll try a combination of the rubber mallet and over night pressure...im in no hurry to get the brakes fixed as my motor is leaking a quart a week through the camshaft caps (but im not going to fix that one myself...motor has a warranty so im gonna tell the shop to fix it...and since its in phoenix i dont want to risk running the motor out of oil so its getting trailered therefore no need for brakes on the 4runner lol)

thanks for the ideers

-Jordan

Sportsmanphil

By chance did you install the wheel cyls upside down? Sounds crazy but make sure the bleeder valve is above the brake line screwed into it.

I dont think the Toyota's bolt holes in the wheel cyls will allow them to be installed upside down, but some can be. I would go look at mine but im too lazy.

You may want to consider bench bleeding your master. This will not only remove any air in the master but also let you see if you are getting pressure out of both sides.

For future reference, pinch off your flexable brake lines next time you open the system or plug off the open lines with rubber plugs.

You may consider removing the LSVP rod and moving it up (full load) allowing more volume or pressure to the rear system. Might help moving fluid to and through the rear brakes.

Im running out of ideas at this point.

wyoming9

iTrader: (1)

If you are having all these problems.

I would bet you have air being pulled into the system some place at the connections you took apart or on the new wheel cylinders a bad bleeder or poor threads where the line connects.

It can be such a small leak but pull in enough air to frustrate you!!

If the Master Cylinder ran dry it can take quite a long time to get all the air out.

I gave up trying to bleed brakes by pumping the pedal and invested in a vacuum bleeder one of the best things I did now I am not waiting around for a helper

angrybob

One other thing to try first if you are certain that you did not run the m/c dry is to simply pump fluid through not under pressure. There is a misconception that you actually draw air in by releasing the brake pedal. Doesn't happen that way as it is not an expansion bladder that contracts, but a sealed rigid system.

Fluid is returned to the m/c by the caliper & w/c piston seal geometry retracting the piston and knock back not by some vacuum created by letting go of the brake pedal. The reason to bleed the brakes under pressure is to shrink the size of the air bubbles and you will 'feel' stiffness the pedal every time.

Crack the bleeder in one w/c then cycle some fluid through by yourself, then do the other one. See if that helps. Its a quick, cheap, and easy check. I would use the mallet, then this, and check the pedal. If all else fails, put it under pressure overnight.

Vacuum bleeders work great but you have to be careful not to crack the bleeder too much otherwise you will draw air in thru the bleeder threads and it will appear as if air bubbles are being bled out.

Team420

rear brakes adjusted properly? Had the same problem not too long ago, turned out I had too many beers and forgot to adjust them properly... got those puppies tightened up, and voila... able to bleed all the air out.... Good luck!

O...btw... It is very difficult if not impossible, to properly adjust those things, if u have a warped drum... food for thought....

az_eaglescout_pilot

iTrader: (1)

sportsman- no the wheel cylinders only go in one way so they are correctly installed

wyoming- i went through and double checked every brake line connection that i removed, all were tight

team-i know i had to adjust the pads to get the drums on, figured that would be enough adjustment for the brakes...whats the correct adjustment? move that little wheel till the pads touch the drum then back it off a few clicks?

az_eaglescout_pilot

iTrader: (1)

i tried the techniques suggested and nothing worked...went through another 32 oz of brake fluid and there was no end to the air bubbles...

finally got the idea to jack up the rear axle and spin the wheels then press the brake...nothing...i have no rear brakes! and the fronts do not engage until the pedal is almost all the way down...

to me this is pointing to the master cylinder...sound right?

also i know people have swapped out the stock LSPV for a manual one...pros? cons?

angrybob

I don't think its the LSPV. Reading this again, you said you got bubbles coming out into the reservoir from the m/c. This should not be the case from disconnecting the rear lines...even twice.

I wonder if the fluid level got too low in the m/c. I would bench bleed the m/c because its pretty easy to remove and do.

az_eaglescout_pilot

iTrader: (1)

update:

Master Cylinder was toast...new one installed after bench bleed
bled all the brakes via the old school way and reverse bleeding with a Phoenix bleeder adjusted rear shoes...pedal still has no stiffness...shoes and drums are in great condition. replaced front discs(what a PITA, the discs were way below minimum specs too) and pads also. still have very little pedal. ordered a MPV from jegs...it will be here on the 6th so hopefully after i get that dialed in i will have a better pedal.

i will follow up after the new MPV is installed.

interesting how the entire brake system went after the wheel cylinders died...but with this project there is not a single system untouched on the Runner...5 months of ownership 3 weeks of being able to drive it...