bad luck 247

Hello. I was drove to my local parts store 11/11/14. When i was leaving i felt my brake pedal drop. I stop and checked it, and saw my left rear line across the rear axle had blown. I said ok no problem i will fix it when i get home. When i came to a stop sign, i was in for big surprise when i hit the brakes and had nothing! I was real lucky no one was stopped in front of me, i just went right threw it. I did gear it down, and pulled the e-brake hard which did nothing. My truck has been sitting a while. My question is why did i not still have front brake operation when my rear line blew? These yota's do have a dual master cylinder i take it by looking at it? It was empty when i got home. Yes i drove it home with no brakes and no e-brake. Sounds crazy, but i did it using gears and a lot of luck. Backed down my driveway in low gear, going backwards using low gear and clutch to stop momentum. I replaced both left and right lines that run across the rear axle. Left was blown, right was very rusty going to blow soon most likely. All forward lines have been replaced a while back. My brakes are working again. I checked my front rotors which were nice and clean from the trip to the parts store,. They were rusty when i left home for the parts store from the truck sitting. The fact they were clean i must have front brake function. Why did i lose brakes completely? Please advise. I got to get my e-brake working. The lever on the right rear is froze up. No e-brake function on RR. Left is working. I don't want to blow a line and have that total loss. That was not a good feeling. Thank you. bad luck 247

millball

Bad master cylinder??

bad luck 247

Thanks. I am not sure of how to check a master cylinder? I know it is working all 4 of the brakes. Why it would not work the front brakes, with rear brake line blown, i just don't know. It was not good. I going to have to figure it out. I dont want to drive much till i get the e-brakes working good.

wyoming9

iTrader: (1)

It is not a real split master cylinder as there is only one reservoir once the fluid drops below the level of the piston your sucking air.

Your first stop is all your ever going to get.

The true dual Master Cylinders have a split reservoir that one side does not go dry if the other fails.

The system is made for the one braking effort you did get because most people would be going home on a roll back or trailer.

bad luck 247

Thank you for the info! Then it does not function like a true dual master cylinder. That explains it then. I better have a good e-brake in case this happens again.

rattlewagon

Your lucky you didnt kill some one our yourself.

Best way to avoid another blow out is to inspect the rest of the lines, and replace if they look bad.

MAINETOY

iTrader: (2)

Hey badluck weird reading this as the same thing happened to me a month ago in my 86 Turbo Truck.I was coming from Home Depot and was on my way to work and a deer jumped out in front of me so i hit the brakes and had ziltch.And of course the E-brake was froze up too as it was rarely used.Turns out i blew a brakeline behind the gastank which is funny because it was a line that i replaced when i got the truck and it blew but the 28 year old original lines were still good!Just shows you the junk parts we have today in this disposable world.

millball

Seems that the plastic reservoirs I have looked at all have internal dams built in that provide for some brake fluid supply even if a failure in one circuit drains most of the fluid out.
Still suspect that the OPs' master cyl is no good.

bad luck 247

The bell crank is froze up on the RR. I tried to get it to free up yesterday, but it did not come loose. I am going to try get both rear drums off, and service them up as needed. I'm pretty sure the adjustment wheels are froze up also. It needs gone over, and done right. The left bell crank is functioning, but i'm still going to do both sides. I need a e-brake that works. Yes i was very lucky to get it home with no brakes. It was not very far. I missed my first turn to get it home, as i could not slow down to make the left! I would not try that again. I am a old timer and should know better, but have always been crazy i guess.

wyoming9

iTrader: (1)

All I can say is looking at what i have here.

A brake Hydraulic failure with the way these that I have you have one maybe two brake applications till you done.

I remember just what your talking about these Master Cylinders are not that style

With the age of these Trucks who can say just what Master Cylinders might be on them.

Once the steel pin holding the bell crank brackets are seized at least here in the Great Brine belt I have never had luck getting them free

lobukbuild

if i remember correctly, arent the front and rear brakes tied together thru the lspv. there for any leak would effect front and rear brakes at the same time, being a complete system failure. im refering to the line coming from the lspv at the rear axle and goes to the passengers front brake line with a t fitting mounted on top of the frame under the front fender.

bad luck 247

Thank you for the reply's! I will be working on it Saturday. If i can't get that Bell crank pin to free up, does anyone know a good place to buy a new bell crank? Please advise. Thanks again for all the help. bad luck 247.

wyoming9

iTrader: (1)

As far as I know only the Toyota Dealer unless some one is selling some on Ebay.

The part you need is the bell crank bracket and the pin the bell cranks you can use over just clean them up.

You might also want to replace the linkage inside the drum for the emergency brake while your doing it.

bad luck 247

Thanks for the info. I will try to find some new pins and brackets.

gandude

The front line that goes to the LSPV works a valve that controls fluid volume to the rear brakes. If the front brakes fail then full fluid volume goes to the rear. Unless the piston seal is broken or the valve is worn (unlikely) the two systems are still separated by the valve.


Since the pedal would travel further if the rear failed, I suspect the front brake MS cup was damaged by contacting debris and built up crud in the MC bore.

Robert m

iTrader: (2)

I am 100% sure the front and rears are connected.
I had the rear passenger axle hard line fatigue and crack on my truck out in the desert 2 years ago. I had to keep adding fluid to not run the reservoir dry. It would have enough brakes for 2 stops but then the pedal would sink to the floor. Fronts did not work enough to stop the truck.
I had to smash and crimp the broken line closed with vise grips and as soon as I did that, and topped it off with dot 3, the pedal returned and I was able to get home. I replaced the hard line and never had any other issues.

gandude

It is possible the can be connected through a failed part, but they are not supposed to be tied together.


Why would they have separate fluid reservoirs, plumbing and MC pistons/cups?


A split circuit braking system is required by law in most countries for safety reasons. It can fail with a bad part though.

bad luck 247

I don't see separate fluid reservoirs? It appears there is only one reservoir. Where are they separated? I got the bell crank on the RR to free up today. Once i got the Drums off it was not too hard. I used PV Blaster on the pivot, and tapped it back and forth. After many tap taps it began to spring back on it's on. I cleaned, and lubed all brake hardware. There is that pivot on the axle housing that is closer to the RR. It was pretty tight. It took some doing to get it moving freely. I think i have a e-brake now. Going out for a test drive now. Thank you.

wyoming9

iTrader: (1)

So some of you are saying this is a split brake system??

So under that theory I can remove either the front or rear line off the master Cylinder and have no ill effects??

There by saving on brake material on which ever is disconnected

So also if one works on only the front brakes and opens the brake lines there should be no reason to ever bleed the rear brakes??

To think of all the unneeded brake bleeding if I had only known.

gandude

I have been on this board for a while, and have tried to help people. Yet, I seem to get in disagreements on the most basic stuff. I'm not trying to blow smoke up your ass, just posting factual information. Take it or leave it.


If you are in the USA, this applies.


Since 1968, dual master cylinders and split brake systems are required by law.


search brake standard FMVSS No. 105 (Federal Motor Vehicle Safety Standard 105


S5.4.1Master cylinder reservoirs. A master cylinder shall have a reservoir compartment for each service brake subsystem serviced by the master cylinder. Loss of fluid from one compartment shall not result in a complete loss of brake fluid from another compartment.