Brake Issues (1 Viewer)

[dougbowman]

I have a 1974 FJ40 original owner. I have totally rebuilt and feel content on the project. I have an issue with the brakes. I have totally installed all new drum cylinders, new master brake cylinder, new shoes. I still have an issue with the brakes. I have bled countless times and spent days on this.... brake pedal goes to the floor like an issue with air in the lines some where. You can pump 3-4 times and you have a brake however, when you release it goes soft again.

My question... I have bled and re-bled several times. There are no leaks, I am wondering if there could be a pocket of air somewhere that cannot be pushed out.

Please if someone knows something I do not on this, give me your thoughts...

Doug

 

[roadstr6]

Did you bench bleed the master?

 

[FJ40Jim]

All 8 adjusters in the drums need adjusted.

It is also likely that the shoes need installed w/ the 'ramps' on the cylinders going the right way.

 

[Gunso]

Did you bench bleed the master?

X2 on the bench bleed the master cylinder. That was my problem on my '96 4Runner after I replaced the master. I had my kids out in the garage on several occasions "up"... "down"... "up"... You get the idea. I took the master back off and bench bled. Fixed it.


...via IH8MUD app

 

[sggoat]

Agree w/FJ40Jim-that many pumps and you finally get a hard pedal indicates you are having to blow the drum cylinders up a lot.
Check the shoe adjustment--tighten them up till the shoes stop the wheel from rotating(bent screwdriver or spoon-adjust from axle outward to tighten), then back off a couple of clicks-see how that works.

 

[vangasman]

Read up on here about "burping" the wheel cylinders. It was the only way I got mine fixed after 20 yrs of bad brakes.

 

[Pin_Head]

As noted above, you have to adjust them properly. Tighten each adjuster until you can't turn the wheel and then back off 2-3 clicks.

You also have to bleed them properly using an assistant to work the pedal. You start by having your assistant pump the pedal until it is firm, holding the pedal down like you were trying to stop rapidly. This pressurizes the system and compresses any bubbles. Then crack open the bleeder and let fluid and bubbles squirt out with gusto. Tighten the bleeder before the fluid stops running so you don't suck bubbles back in. After it is tight, have your assistant let the pedal up and do it again.

 

[edwjmcgrath]

If you followed the fsm, your brakes are probably adjusted too loose.
Follow the advice above to adjust them right. When they are correct, you will barely be able to spin the wheel one revolution with a lot of effort.

 

[unklwedy]

Booster pushrod adjust

With a new master cylinder you may need to adjust booster pushrod. Bubble gum works well to verify clearance. unklwedy