Darn fj40 brakes (1 Viewer)

[Notyour40]

G'day. I've just changed my rear cylinders x4 (brakes worked ok but locked up to often) I also accidentally drained the mc. After refilling and bleeding the mc and all lines no peddle. Took it to the mecanic he bleeds it again still no joy, he puts the old cylinders back and mucks about with it for hours inc shoe adjust, no pedal. Any ideas would be appreciated

 

[Notyour40]

This is my daily drive so I could really use some help ta

 

[shawnfj40]

You have either rolled the seals in your master or you still have air in the system.

 

[JAFO2014]

When you pump the pedal and then hold, do you build up pedal and then when you open the bleeder on a cylinder, does the pedal move to the floor? If it does not build up any pedal like said above, master cylinder is having some issue it would seem.

 

[Notyour40]

2 pumps for pressure. I also holds The pressure while foot is on pedal. Strong flow when bleeding. I am assuming there is still air but after excessive bleeding I'm not sure what to do. I do not have the stuff for a bench bleed. Any other ideas? Thanks for your reply

 

[Notyour40]

You have either rolled the seals in your master or you still have air in the system.

Thanks, after excessive bleeding by myself and the mecanic I'm at a loss. I don't have a bench bleed kit and can't get one. I was thinking about putting bleeder nipples from the 2nd set of cylinders into the master and running hose from them back to its reservoir could this work as a makeshift bench bleed?

 

[Curt]

you don't have to bench bleed but it saves you fluid, you can pickup some shorter lengths of brake hose and submerge the ends into the reservoirs. and do it installed on the vehicle. The master will be air free but you will still have to clear all the lines. Worked for me.

 

[Notyour40]

And just keep bleeding until it works? Is there some trick to assist. I live a little out of town so I've called all the stores I can get to within 40min and no joy on fittings. Bleeder nipples won't work?

 

[Notyour40]

Was going to do a bench type bleed while in the 40

 

[Curt]

you can get a power bleeder that uses air pressure to force fluid through your system. I didn't have one of those so i followed coolermans write up Brake Bleeding 101

 

[Notyour40]

Thanks. I'm on it

 

[Curt]

If you don't get a remotely firmer pedal then your master is toast.

 

[Ian Macdonald]

When I first got mine, the brakes were useless. Replaced the slave cylinders, and cleaned the master. After bleeding for^&^&%$#%&^&*ever, I finally realized the shoes needed adjusting. Now it's fine. Before adjustment it would take 3 pumps to get any braking action, now it's fine. I thought it was like my 4Runner, where the parking brake adjusts the shoes with each use.

 

[handcannon]

Yesterday evening I helped my son bleed the brakes on his Acura after he replaced the master. I was surprised at how much work and time was involved in bleeding the master. The clear tubes were extremely valuable when it came to making sure all the air was out of the MC. All my other MC swaps were much easier.

The point is that not all MC swaps are the same. Getting all the air out of the MC is important to a successful brake bleeding. I saw bubbles going back and forth repeatedly. What we ended up doing was a quick push of the pedal downwards to push bubbles out, and holding there while more bubbles slowly rose up to the top curve of the clear tube. Then slowly letting the pedal raise back up to the top. The bubbles kept going back and forth, but by using this procedure more bubbles/air finally were eliminated and allowing the rest of the air inside the MC to be pushed out.

Don

 

[65swb45]

Do a thread search for brakes from @FJROSS . I proposed a novel solution for him that worked out well.

 

[shawnfj40]

Bleeding the Master is pretty simple on the truck. If you bench bleed it you still have to remove the fittings you are using and then hook up the lines and air goes right back in. If you have someone pump up the pedal and hold it, you can loosen each brake line one at a time and let the air out right there. Just make sure you tighten the fitting before the brake pedal is raised. Clean up your mess right away with plenty of water and you will be fine. Start at the master and then work on each wheel starting from furthest to close. You might even have air trapped in your Prop valve and that can be bled the same way as your master.

 

[Captainkrusty]

I just did the same thing with my 1971 FJ40. I bled the brakes until the air was out of the lines but still had a mushy pedal when I first stepped on it. It felt like I still had air in the lines. I adjusted the brakes and this solved the mushy pedal. Having the brakes properly adjusted made a huge difference. If the wheel cylinders leak again, I will replace with disc brakes.

 

[edwjmcgrath]

Ditto on adjusting the brakes especially if you're getting a good strong squirt when you are bleeding.
If you read here on MUD you'll find that the brakes need to be tighter than you think.
If you follow the fsm, they are not tight enough. Tighten them until the wheel is locked then back off two clicks.
Try to spin the wheel. If a good strong spin drags the brakes and gives you about one revolution then you've got it right.
If they aren't tight enough, you can go through a gallon of brake fluid and you'll still have no pedal.

 

[Fast Eddy]

Bleeding the Master is pretty simple on the truck. If you bench bleed it you still have to remove the fittings you are using and then hook up the lines and air goes right back in.

Not true. Bench bleeding pulls the bubble out of the inside, top of the cylinder. The air can't get pulled from the fittings back up into the top. It would have to come from the top by letting the fluid level drop in the reservoir.

 

[Captn Conch]

Replace any Drums with Disc brakes, plug the vacuum at the brake booster to the engine thereby eliminating the power boost, way less headache and expense and much more safety. Don't know your year 40, But on my '71 This has eliminated all my brake issues. But you still gotta bleed it correctly.