streetlancer

iTrader: (1)

A couple of days ago i posted my truck would not pass inspection because of leaking wheel cylinders so i got to it today.I purchased Brakeware wheel cylinders from the local autozone to replace them.
Wednesday afternoon i removed the the right rear drum to find the whole brake assembly covered in brake fluid, all of the paint had bubbled. I deassembled everything, cleaned and gave it a fresh coat of paint. I removed the old wheel cylinder and a left a pan to catch the dripping fluid from the line. Left it overnight and the next morning put everything back together with the new cylinder. I then moved on to the other side, removed-cleaned-reassembled. Put the drums and tires back on and adjusted the parking brake by tugging on the cable until it stopped clicking.
Now, my problem is when i went to bleed the brakes there was no fluid in the mc container. So i filled her up and bled the mc by having someone hold down the brake pedal while i loosened the lines and tightened them back before releasing the brake. Did this a couple of times until fluid came out every time. Next i moved to the rear driver side and held the pedal down with a block of wood by adjusting the seat. Cracked the bleeder open, attached a hose and the other end to a gatorade bottle which sat above the bleeder with some brake fluid in it. I pumped the pedal with the wood several times but i did not go all the way down nor all the way up while someone else observed the the hose until clear fluid flowed into the bottle. Repeated on the rest of the wheels and finished with the valve that sits on the side of chassis.
After this the pedal felt firm like it should be but when i went to turn the engine on it just sunk to the floor and no brakes. I read many posts in here all suggesting different ways of bleeding and no luck so far. I have already ran two and a half bottles of brake fluid.
Any suggestion?

limon32

I have litterally answered this question twice in the past week, for a more detailed answer scroll down the forum a bit and you'll see the others, in any case, you still have air in the MC. The ONLY way to properly bleed the MCs on these trucks is to push fluid from the resevoir inlet to the bleeders. You will not get all the air out any other way, trust me i've tried them all.

toyota_mdt_tech

Easy fix. You have air trapped in the LSPV valve, this is the load sensing proportioning valve. There is a bleeder screw right on the top of the LSPV valve, open it up, air will come out.

abecedarian

Point blank- if the master cylinder went dry, you need to bench bleed it, treat it like it never had brake fluid in it, before going off to the wheel cylidners, calipers and then LSP-BV.

streetlancer

iTrader: (1)

limon32 I read your previous post before making this thread, but did not find sufficient information on how that works.

As for LSPV valve i hooked the hose to the bleeder and loosened the bolt beside it, i didn't notice any screw at the top but i will check and try again 2morrow.

abecedarian

The LSP-BV bleeds like any other brake cylinder or caliper. If you have to loosen any of the other fittings in order to bleed it, something else is wrong. It acts like a bias valve between the front and rear circuits and allows the rear brakes to get full brake pressure if the front looses pressure. Unless you have some other reason to change the pre-loading on its internal valving, do not mess with anything in the LSP-BV (that's its proper name, not LSPV) other than bleeding it through the apparent bleed valve.

limon32

Don't worry about the LSPV, or bench bleeding. Bench bleeding these doesn't do you any good because you will suck air back into the MC the first time you let up on the pedal.

Let me know what is unclear about my previous posts and i'll help you out. I would bet lots of money you are having the same issue I did.

I love these smileys, they make this site so fun!

abecedarian

I'm waiting for the full write up.

I could've bench bled the MC, and bled the rear brakes, front brakes and the LSP-BV in less than an hour, and this thread is much older than that.

And once again, it's a Load Sensing, Proportioning, Bypass Valve, not a Load Sensing Proportioning Valve.

cody_brush

i am having the same problem bleed all the brakes then start it up and the pedal goes to the floor... it pisses me off soooooo much..it blows
but ive been reading up and asked some people on here and theres two solutions/problems it could be
1)air in the master cylinder ~solution bench bleed the MC
2)air in the brake lines that needs to be pressure bled or reverse pressure bled

because air wants to go up and some cant always be removed from regular bleeding

galooph

I replaced the MC on mine yesterday and was a bit concerned about bleeding after reading about all the problems people have.

I bench bled the new MC and then made a pressure cap out of the old MC reservoir cap - just an airline connection. Hooked up air at 15psi and cracked open the bleed screws, topping up the reservoir when needed.

Ended up with a nice solid pedal and the brakes are now better than when I got it.

wyoming9

iTrader: (1)

The first poster has drum brakes.

Now all most all my fleet have drum brakes but one Celica and One Supra.

If I don`t adjust the rear brakes up to the correct drag i was also never able to get a good brake pedal. Because the wheel cylinders are pushing nothing .

Of course I have been using a Vacuum bleeder for years . I also have not bleed a Master cylinder since the seventies .

Also all the LSP-BV `s I have looked at it would take just buying new ones to to get the bleeder screw out. i gave up on bleeding them also.

tim a.

Im wit ya,wyoming.My harbor freight vacuum bleeder was worth twice the $20 I paid for it.If you cant get air out with that you got a hole somewhere.I cant remember last time I bled a master either and my lspv wouldnt like any tool placed on it at this point.The vacuum bleeder is nice because you dont need anyone else to help,and I have used it on many abs systems,which are way worse to bleed than any toyota pickup.Its also dandy for cleaning out caterpillar cylinders when changing injectors.

limon32

You guys are killing me! Go to the parts store, look at the syringe and stopper that come with the new/reman. master cylinders. There is a reason they supply them, its the only way to get all the air out!

Bench bleeding doesn't do any good on these. There will be air in the lines when you reconnect them and that air gets sucked into the MC the first time you let up on the pedal and then you will NOT get it out. You MUST push the fluid from the MC to the bleeders, literally the only way I was able to bleed my brakes. I tried many other methods, vaccum, traditional...

wyoming9

iTrader: (1)

What is the difference between a pressure bleeder on the Master cylinder end and a air operated vacuum bleeder pray tell on the bleeder .

If you can tell me the advantage of the former I will have one by the end of the day Monday .

Like all perhaps they did get better with new advances in materials

cody_brush

if i was going to go out and buy ANY bleeder i wanted i woud get a REVERSE pressure bleeder so you push the air up through each wheel so theres 0 chance of air....just my opinion....

limon32

I have not idea, however I tried two different pressure bleeders, one from the autoparts store and one from SnapOn that the mechanics at work use and neither would pull the air out of the MC.

The only thing that worked for me was the $2.00 syringe!

streetlancer

iTrader: (1)

So i went to the parts stores to try and find this syringe, I even asked to see the master cylinder for my truck. The master came with a bleeder kit but it was just fittings and two hoses to hook to the fittings and back to the master. I asked about the syringe and they had no idea what i was talking about
I already had those fittings and hoses from a previous master cylinder that was bought for my mom's van. I bled the master using that method and then bled the wheels once more. Afterward i had some brake power at the very bottom. After a long day and completely covered in brake fluid i decided i wasn't gonna bother anymore. So i took it back for reinspection with no brakes and asked them to bleed it. After what seemed to be two hours i got my truck back with a new decal a 25 dollar charge and brake power at the bottom of the pedal (takes a while to stop not sure if i want to drive it like this).
I am now starting to think about a new master and stainless brake lines, i might have busted the master when pumping the pedal. I believe it is the original booster and lines.

Outsane

pain... must fine syringe..

limon32

Hmm, the sad thing is its a normal syringe, i'm sure any pharmacy would have one. Its a bigger one, like you would use to wash out a wound with. The key part is actually the rubber piece. Its a bit larger than the resevoir inlet to the MC so that it sits on top of the MC, then there is a hole drilled through it about the size of the outlet of the syringe, then you just slide it over the outlet of the syringe, put the whole assebly on the MC and push down while pushing in the pluger on the syringe. I bet you could make one, maybe even with a wine bottle cork?

I don't know what parts store you went to but Schucks had the one I used.

cody_brush

THERE A LINK AND ON THE PAGE IS A PICTURE OF THE SYRINGE HE WAS TALKING ABOUT I THINK??http://www.rodandcustommagazine.com/...kit/index.html