FJ40 brakes.

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Dumpy40

Dumpy40

10 Year
Joined
Oct 25, 2015
Threads
2
Messages
22
Location
Victoria BC
Hi I have a 74 FJ40. I am having problems with my rear brakes. The previous owner did a front disc conversion already on it and when I check the rear brakes 3 out of 4 wheel cylinders were seized. I then replaced the wheel cylinders and the lines snapped so I remade all new line in the rear. Brakes just go right to the floor. Previous owner provided a brand new master so I bench bled that and replaced it as well and pedal still goes to the floor. 2-4 puts it will get a hard pedal. Adjusted my brakes so that they were right tight and that did not make a difference in the pedal. When I vise grip the rear flex line it will have a hard pedal right away. Also Previously how the wheel cylinders were positioned were opposite of the info I see and the part numbers I got. How the cylinders were for the drums were Driver side; Left piston goes up and right cylinder goes down. Passenger side; Left piston goes down and right piston goes up. Would that have a play on my pedal?
 
I have read this a couple of times, do you have a proper Toyota service manual? Post some pictures of how the rear
brake hard lines are hooked up to the wheel cylinders. Also, pictures of each rear brake assembly for both sides.
What kind of parts is the front conversion made up of? GM or Toyota? It is either the assembly is mechanically not
correctly installed. I presume new fluid bled to ensure no air in the system? What kind of condition is the booster in?
It may be the new booster is not a disc brake booster, you can't convert to disc brakes and use a drum booster. Is there
a brake proportioning valve?
 
I will get some pictures tomorrow if I can. It is all Toyota stuff. As for proportioning valve where would that be located? I cant seem to find one on there so guessing it doesn't have it. Unless the proportioning valve is built right into the master? All new fluids because I replaced the master that he included with the truck.
 
How it was before I did anything it had nice pedal feel and all. Just the braking wasn't all there because only 1 rear cylinder was working hense the replacements. But just doesn't make sense to me how it doesn't hold the pressure now that I replaced it all and even put it to how the guy had it before. Might try and flip flop the wheel cylinders from one side to the other to how the guides say online. Maybe the bleeder is higher up or something on 1 side from another who knows. I even used a snap on pressure bleeder we have at work to get out all the air. Cranked it up to 30 psi and it was shooting clean solid fluid through it.
 
If you have installed a wheel cylinder upside down it will never make pressure. The bleed valve is above the line, not below on the wheel cylinder.
Proportioning valve is usually located on the hard line off the booster that is going to the rear brakes.
 
Adjust one shoe at a time, this will make certain your shoes are centered, if not ur shoes could just be shifting inside the drum.
 
Could you pm me a better pic? Also how crutal is it to have the right placement for the cylinders? I just followed how they had it before and its opposite of what it says online. Also for the adjusters only 2 of pistons have a slanted piston groove to ride in and 2 are flat are those right or do they all have to be the slant to center shoes?
 
Can't help you with your brakes, but I can help you find the repair manual for your 40. It's the top link here: Toyota Workshop & Repair Manuals - Page: 3 You will need to install a torrent application if you don't have one. I use bit torrent which seems to work really well for me. I'm downloading it right now myself, and can post a few screen shots of the brakes section if you want....
 
As usual, GTSS you are a wealth of info. As usual, the internet in this hotel is too slow to even bother downloading anything....
Thx, J
 
That's wicked thank you! I flipped my cylinders to the proper sides today and did as Burnz told me to set it up. Gravity bled the brakes then got my buddy to help me pressure bleed the rest of the air out. Brakes got a little better but still not perfect still have to pump it up to get a hard pedal. Will try and bleed it a bit more maybe still have some trapped air in there. Will let you all know once I figure it out.
 
Just pop the vac line off the booster to test, you'll see how it behaves with out one.

The booster should only affect how easily the pedal gets to it's lowest point (brakes fully on) if pedal is still going to floor occasionally, it's probably air.



Do you know what year the master was for? If it was the correct one for a 74 drum brake truck it might have trouble with discs.



I've had more luck with bleeding since I got a little vacuum pump bleeder...
 
Ya, I lost my vacume to my brakes and the pedal is very hard all the time.

Pumping it a few times indicates air or incorrectly adjusted cylinders, those old brakes will need to be adjusted often as they are not like the newer self adjusting drums through the ebrake.
 
That's the master that I put in it that came with truck the other one that was on it looked the same as it. What's that valve on just below the master there? It only goes from rear line to rear line. If it was a proportioning valve it would link the front and rear?
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