FJ40 Brake Bleeding troubles (1 Viewer)

[WildernessRimFab]

I'm in agreement with @SonofSonof40 .

One of the best things I've purchased for my '40:

powerbleeder.

0101 - Round Universal Power Bleeder - https://www.motiveproducts.com/collections/brake-bleeder-kits/products/power-bleeders-single-adapter-bleeder-kit-domestic-adapter-bleeder-kits-power-bleeders-single-adapter-bleeder-kit-import-adapter-bleeder-kits-power-bleeders-domestic-bleeder-kits-power-bleeders-import-bleeder-kits

I have bled lots of brakes the old fashioned way, and never got a bleed like you get with a powerbleeder.
Firmest pedal possible every time. Also you dont wreck the seal in your master cylinder from overtravel.

 

[73FJ40]

@jetdude

Circling back to the beginning:

1. Please confirm you have a 1974 FJ40, USA market.

2. Confirm the brake master cylinder and the booster are the stock parts for the 1974 model year. The master cylinder, if it hasn't been molested, has residual valves which keep a little back pressure on the shoes to keep them closer to the drum. Any later model master cylinder may not be designed for 4 wheel drum brakes.

3. There are four distinctly different brake cylinders on the rear axle. Ensure they're properly located. Driver's side are right hand threaded adjusters, passenger side have left hand threads.

4. Power bleeders may be the way to go, but I first bled the brakes on my '73 back in 1977. No extra cash, so I was successful doing it the old fashioned way.

I have had 100% success in bleeding my brakes when I tighten the shoes, using both wheel cylinders, up firmly against the drum. (of course back them off when completed) My theory is that if the cylinders are allowed to move while bleeding, the air bubbles aren't compressed as much. Tiny bubbles (under highest pressure) are easier to disperse than large bubbles. If the cylinders aren't locked solid, when you let up on the pedal to begin the pumping cycle again, the cylinders are retracted by the brake shoe springs, moving remaining bubbles back out of the cylinder into the tubing. Anyway, that's how I've rationalized it.

 

[Pighead]

I adjusted both cylinders on each cprner to where they are draggin just a little bit,

That's not tight enough.
Here's a way to check for sure. Tighten all wheel cylinders so that you cannot turn any wheel by hand, push on your brake pedal. It should feel very solid . If not, check for air again. If yes, then back off each cylinder to where you can turn the wheel with two hands. Check your pedal again.
I always left a fair amount of drag in my adjustments, they self-clear quickly.

 

[ToyotaDyna]

As they said before, tighten each cylinder tight to the drums, spin the wheel by hand and push the brake pedal between every few clicks to centralize the shoes until tight to the drums, as tight as you can adjust, then back off 2 clicks.

Check to see if they drag slightly, let off one more click if really right, but still have a bit of drag.

Are your brake shoes evenly worn on each side of the shoe?

ToyotaDyna

--------

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[Bigstar]

Thanks. I looked yesterday inside, but I have not removed the master to examine beyond looking from inside the cabin. I'll do a few more rounds of bleeding once the speed bleeders arrive and it no luck will swap the master. I did some searching on this site and see where one member made some hard lines to "bench bleed" the master in the truck. Just lines he screwed in the two ports that curved back into the reservoirs so he could pump the pedal and bleed the master. Might try that as well if I swap the master. Heck, might try that even if I don't swap the master. There is air in the system someplace and it obviously likes its new home.

Any photos or videos of this contraption??

 

[Bigstar]

Am I late????? Ok this is the most helpful thread I’ve seen on bleeding the FJ40 brakes. I have spent DAYS trying to get my ‘71 40 drum brakes bled and it’s kicking my ass. At the moment I have all 4 wheels tightened so much the wheels won’t spin. I have bled all wheels several times in correct sequence. When the truck is off the pedal seems a little harder but when I crank the truck up the pedal goes easily to the floor. I used vice grips to pinch off the rear brakes and the pedal still went to the floor. I pinched off the back brakes and I have pretty solid pedal…..even with the truck cranked up. I re-bled the front and got nothing. I resently changed out my front drum cylinders on both sides. I’m getting fluid flowing through with the single person with fluid in bottle method and with pressure pump pushing fluid through the bleeders up through the master.
Help a brother out. Any ideas? When I noticed I had a problem I noticed the front reservoir was empty and the driver side tire had fluyid on it. When I pulled everything off the truck it was obvious that thr front of the two cylinders was the leaking one. All new cylinders on front. FC brand from Japan. HELP!!!

btw… i used techniques some of you guys on this thread suggested like two bleed hoses at a time on both bleeders per wheel etc..

Is it possible to bleed the master cylinder while on the truck if I build my own master bleeder or stick hoses in the holes and route them back into the reservoirs??

 

[pb4ugo]

Disconnect the lines off the master, and make new lines that loop into each reservoir. Make sure the ends are below the fluid level so they don't suck air and pump away while watching for air bubbles. You might find a kit with plastic clear lines at the auto parts store if you don't want to make lines.

 

[Bigstar]

I’m already working on it! Thanks brother

 

[Pighead]

Is it possible to bleed the master cylinder while on the truck if I build my own master bleeder or stick hoses in the holes and route them back into the reservoirs??

Yes, I got a couple of the shortest lengths of brake line at my FLAPS, put a curve in them and use them for bleeding the MC.

 

[Bigstar]

Right on. That’s what I’m planning to do. What size fitting is that? Also why do you have two fittings on there? Thanks

 

[Bigstar]

Anyone want a free FJ40??? I’m almost there. I’ve been screwing around with my brakes for several days and can’t get good pedal with the truck running. I’ve EVERYTHING at least once. I bench bled the M/C, double bleeder bled all 4 wheels, replaced the front cylinders,etc etc. I’m getting pretty good pedal and then when I start the truck I lose the pedal. Any ideas on this? Please help…..

 

[Mr. Green]

Likely still air in there or you have a leak. Especially since you said its reservoir went empty on you previously. If you want someone to pick it up for free let me know. Lol.

 

[RevISK]

Anyone want a free FJ40??? I’m almost there. I’ve been screwing around with my brakes for several days and can’t get good pedal with the truck running. I’ve EVERYTHING at least once. I bench bled the M/C, double bleeder bled all 4 wheels, replaced the front cylinders,etc etc. I’m getting pretty good pedal and then when I start the truck I lose the pedal. Any ideas on this? Please help…..

I got the Motive Power Bleeder and that helped a lot to bleed brakes by myself.

Are you sure you’re not sucking air back into the system around the bleeder screw threads? That has bitten me before.

 

[sterling]

Sounds like there is still air in the system as stated. Recently bought this fella, works well.
You can see the bubbles being pulled from the lines.

Brake Bleeder and Vacuum Pump Kit

Amazing deals on this Brake Bleeder And Vacuum Pump Kit at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[77mustard40]

If it hasn't been mentioned, tap the all the components of the brake system with a wrench as you bleed. This helps dislodge any air bubbles that are stuck to the interior wall of a component like a caliper or cylinder. You don't have to beat it hard, just a quick repetitive rap on all the surfaces, you will see bubbles if its working. I'd do on the MC when bench bleeding as well. I had this issue one time and it was actually a bad seal on a MC. Good luck!

 

[Pin_Head]

I did hundreds of brake jobs back when I was turning wrenches for a living and they were still making FJ40s. We never had a problem bleeding brakes except when the master cylinder was bad and then we replaced it and never bench bled it and never had problems bleeding. The shop I worked used the “two person” bleeding method exclusively. We had a pressure bleeder, but we never used it because it took too long to set it up.

One thing about bleeding brakes is that your will never bleed them if you suck the air back in. You need to make sure that the fluid only goes one way. With the two person method, one persons shuts the bleeder before the other one lets up on the pedal so there is no way air can get sucked back in.

The other thing about bleeding brakes is some bubbles are stubborn and don’t want to go out. If your wheel cylinders or calipers are installed on the wrong side and the bleeders are upside down, the air just isn’t going to come out until you turn your truck upside down or mount the cylinders and calipers properly. Pressure is your friend for getting stubborn bubbles out and the 2 person method puts more pressure on them than anything else: like 1000 PSI or more.

Some people don’t like pumping the brake pedal to bleed brakes because they think it will screw up the master cylinder by operating outside its normal stroke. My experience is that it doesn’t do this often. While you can easily prevent this problem by putting a block of wood under the pedal, wouldn’t you prefer to know your master is on its last legs before it has to operate outside its normal range in an emergency?

Lastly some people seem to have nobody to help them bleed their brakes. No spouse, no friends and no money to pay for a helper or a hooker. No worry, you can use a 60 pound sack of concrete as your friend. Put the sack on your brake pedal and then get under dyour truck and open the bleeder. Close it before the fluid stops flowing. Then lift up the sack of cement and start again until no more bubbles come out. Any one can do the one person and the sack of concrete method.

Finally, some things don’t seem to matter in my experience. This includes the order in which you bleed the cylinders and bench bleeding your master. If you need to bleed it, bleed it in the truck by putting a rag under the master to catch the fluid and putting your finger over the outlet and having your friend (or sack of concrete) pump the pedal.

 

[Bigstar]

Thanks for the replies guys. I like the idea of getting a hooker who can also pump the brake pedal haha. I wish I had thought of that. So I did everything! All the tricks. I was using a medium length level to hold the pedal down while I bled. That usually works. I’ve even heard of guys using a palm sander to vibrate the lines. I talked to Sonny at FJPart.com where I got the cylinders. Great guy. Funny conversation. I told him I was ready to set it on fire in the driveway. He suggested ….. hear me out…. bleed from the driver’s side front ( front bleeder then rear) , then passenger side front (front bleeder then rear ), passenger side rear (front bleeder then rear) and then driver’s side rear (front bleeder then rear) it spit air out on the last one….. THEN…… do them all over backwards from driver side rear, then passenger side rear, then passenger side front and then driver’s side front. It sounded crazy but I did it and it worked. I texted my neighbor who owed me a favor and he came over and pumped the pedal. I’ve bled the brakes on 20 cars and NEVER had anywhere close to this much trouble. I spent the entire evening with my spoon tool adjusting drums. What a pain in the ASS!!!!! Thanks for the suggestions y’all. Cheers.

 

[Pin_Head]

Yes, hookers are real pros when it comes to fluid exchange.

Another point about brakes is that the dead volume in the brake system increases as the brake pads and shoes wear out. This makes it easier for bubbles to hide in the system and harder to sweep them out. All of the shop work involved new pads and shoes.

When doing the two person method have the pedal pusher pump and hold pressure on the pedal before you crack the bleeder. This compresses the air and creates turbulent flow to blast the bubble out. Tighten the bleeder before the flow stops. It only takes 2-3 strokes per cylinder or caliper and don’t forget to top up the master cylinder so you don’t pump air in.

 

[CruisinGA]

Once I got married and no longer had roommates to help me, I quickly stopped asking my wife to help bleed brakes and bought one of these (air powered vacuum bleeder).
Last master cylinder I installed (80 series non ABS in my FJ40 when I went to 4 wheel disc) I did not bench bleed. No problems.

 

[Bigstar]

Yes, hookers are real pros when it comes to fluid exchange.

Another point about brakes is that the dead volume in the brake system increases as the brake pads and shoes wear out. This makes it easier for bubbles to hide in the system and harder to sweep them out. All of the shop work involved new pads and shoes.

When doing the two person method have the pedal pusher pump and hold pressure on the pedal before you crack the bleeder. This compresses the air and creates turbulent flow to blast the bubble out. Tighten the bleeder before the flow stops. It only takes 2-3 strokes per cylinder or caliper and don’t forget to top up the master cylinder so you don’t pump air in.

Come on dude…. of course I know how to work the bleeders ha