74 drum brake system tech

[rsbcruiser]

Cool writeup, one thing that I had problems with were tightening the wheel cylinders (backing off the shoes) so I could remove the drum. I found that moving the adjusters outwards from the axle, and towards the outside on each adjuster would do this. Is this correct?

Wait, had to read that a couple of times. If I read it right then it sounds like your wheel cylinders are swapped left wheel to right wheel. I plan on going in to that subject real soon here. There is a convention for that as shown in the FSM. This subject drove me nuts for the longest time but once you get it gripped then you will experience much more joy in adjusterville. So hang tight cause here it comes.

 

[rsbcruiser]

Wheel cylinder idenification

I cleaned the wheel cylinder body using brake cleaner and a tooth brush. See the two grooves? One on each side of the body. You will want those clean as well. rubber boots ride in those grooves. You want those cowboys firm in the saddle in order to prevent moisture or dust contamination. MOST important. notice the L. That means left. This wheel cylinder is from the left side of the front axle. It must be installed that way. Do it right the first time so you can adjust your brakes to FSM convention with confidence. The other mark says 1 and 1/4. That is the thrust side bore diameter of the wheel cylinder. Match the diameter to what belongs in your rig. Never trust the parts supplier. The best of them routinely screw things like this up.

 

[e rock]

Cool writeup, one thing that I had problems with were tightening the wheel cylinders (backing off the shoes) so I could remove the drum. I found that moving the adjusters outwards from the axle, and towards the outside on each adjuster would do this. Is this correct?

The way I always remembered it was this: Move the screwdriver handle toward the axle (housing) in order to move the shoes toward the axle (shaft).

At least, I think that was my little mnemonic; it's been a while.

 

[rsbcruiser]

Beer? In MY cooler? I don't drink watered down horse piss...

Only TEQUILA gets to be in my cooler, preferably Patron...

A man with taste, I like that, Jose Cuervo does not say 100% agave, the Miller beer of tequilas. Patron, that I can enjoy.

 

[rsbcruiser]

The way I always remembered it was this: Move the screwdriver handle toward the axle (housing) in order to move the shoes toward the axle (shaft).

At least, I think that was my little mnemonic; it's been a while.

E rock, U rock! Never heard it like that before, thats great! Sounds right and fits right in with the lefty Lucy, righty tighty convention memorization game. I will remeber that one for sure.

 

[rsbcruiser]

Evaluating wheel cylinder condition

First, I cleaned up all of the rusted surfaces (the bores, the piston and the adjuster post) using some fine grit sand paper. Cleaned the boots and all rubber parts. Hosed down the wheel cylinders and wheel cylinder parts with brake cleaner and used compressed air to carry the grit from sanding away. This picture shows two things. Pitting and sand marks on all areas that had rust prior to cleaning. The light pitting that is apparent makes these parts suspect. They should be replaced. This highlights an issue common with these old rigs. These wheel cylinders are not available on the shelfs of any local parts supplier. I must order and wait for them. An argument for maintaining your brake system in tip top shape. picture shows the adjuster post. Notice the hole in the rubber boot. This part is toast. I did that prior to buying a Toyota brake adjuster tool. You will see the afore mentioned tool throughout this thread. Buy one if you don't already own it, you won't be sorry.

 

[rsbcruiser]

More am dam

Picture shows damage caused to the adjuster star by my amateur flailings. Both the adjuster post and the adjuster bolt have to have proper lubrication in order to adjust easily and not freeze up over time.

 

[rsbcruiser]

drum brake cylinder question

I include this reference to a question I had. This cleared up some confusion I had relating to the function of the wheel cylinders. Thanks to the sole contibutor for the help offered.

 

[rsbcruiser]

The relevant literature

finally found it! There is a great source for technical literature related to Landcruisers right here on Ih8mud. to access it go up to the "stickies" located at the top of the list shown on the opening page of the 40-55 tech forum. It is in FAQ, pan down to "Best Manual, factory Service manual, FSM info, etc.". This will show you all of the literature needed to navigate the intracasies involved in repairing your Cruiser.

 

[rsbcruiser]

This cup must be oriented correctly

AMHIK! This picture shows the actuating piston and the cup that sits on top of it. This cup goes concave up on the piston bottom. That is to say, the flat side of the rubber cup sits on top of the piston surface shown in the picture.

 

[mooker82]

Nice work so far. I will see if I can add anything relevant after this weekend. I am rebuilding all my wheel cylinders (if Napa comes through). Should be a fun time.

 

[rsbcruiser]

Nice work so far. I will see if I can add anything relevant after this weekend. I am rebuilding all my wheel cylinders (if Napa comes through). Should be a fun time.

Your welcome on my playground any time mooker.

 

[rsbcruiser]

Brake bleeding equipment

I like my toys. Picture shows my Blue Point brake vacuum bleeder. This tool requires a compressor to power it. It functions very well and makes the act of brake bleeding a much cleaner operation than techniques I have used in the past. There are better ways to do this. There are systems that pressure pump brake fluid into the system, an obvious advantage of that kind of system is that it does not lower pressure in the system but increases it as it fills your brake hydros with fluid. Better at driving out trapped air. Similiar systems are available that are essentially an overglorified pump type sprayer like you see used for lawn applications of fluids and used for spraying insecticides. Also as seen here on Ih8mud there was mention of a one way bleeder valve that will allow you to use the brake foot peddle to bleed your brakes without a second person to help you.

 

[rsbcruiser]

Assemble correctly, don't do it this way

Here is what I did to myself. See the piston with the rubber seal and the spring stacked on top. The seal is oriented incorrectly. I believe I will have to go back into the front left wheel to fix this because, you guessed it, I did this! DANG, oh well, at least I caught this before charging the system. Bet it is UBER important to get that seal oriented right. So once again, the flat of the seal goes against the piston top.

 

[rsbcruiser]

Wheel cylinder assembly

Lets' start to put the wheel cylinder back together. First, I put brake grease in the grooves shown in the picture. These grooves hold the rubber boots in place. I filled them with a thin layer of grease. Use a rubber compatable grease for this and all applications concerning the wheel cylinders.

 

[rsbcruiser]

The adjuster side assembly

Before installing the rubber boot I put some grease in the groove it mates to. The female thread is then given some high temp anti sieze to prevent rusting.

 

[rsbcruiser]

The post side of the adjuster

This side sees no brake fluid so it will remain dry except for the grease you put in here. This post turns only when you adjust the brakes so it is very important to lubricat it to keep it free to rotate.

 

[rsbcruiser]

The actuator side

this pics shows all of the pieces in the wheel cylinder minus the tensioner. Notice the actuator piston. It is the part you see resting against the rubber boot. I coated the sides of the piston with a thin layer of grease. Same for the sides of the rubber seal that goes between the piston and the spring shown. This side will see brake fluid.

 

[rsbcruiser]

The tensioner clicky thingy

Assembled using loctite red on the thread. Take care not to contaminate any surfaces outside the thread area so that freedom of motion will be retained

 

[rsbcruiser]

Wheel cylinder install

I coated the four mounting bolts with anti-sieze. The nut to the brake line got a coating also. There it is, my line wrench. When cinching the brake line nut, take extra care to make sure you don't cross threading the nut. Screw it in by finger wrenching until you are sure it is threading correctly. Once you cinch it down don't try to go for a hard torque on it. Apply enough torque to seat the brake line.