Booster Issue?

[Boaf 32]

That is similar to what I did. I angled it so the plunger end was slightly higher. I then used very short movements on the piston. 1/4" max. This kept burping air bubbles out the intake port in the reservoir and none in the clear tubes I used to route fluid from the outlets to the reservoir. It too at least half an hour, but worked perfectly.

Thanks, I just completed a similar approach:

• Jacked the back of the truck up high for a good pitch
  
• connected tubes from the outlets back into the reservoir
• No air bubbles in the tubes at the completion of 5 minutes of pumping
• I bled the brakes after with a vacuum bleeder...better but alas, still need to pump the brakes.

As indicated, will give it to my mechanic to figure out.

Thanks for the tips, it did seem to improve...

 

[Dennis 1970 40]

I'm new to brakes and had similar issues. Finally got things right.
1. I used a replaced brake line and bent up so when connected to master the other end pointed to the filler. I just added fluid and pumped like crazy. There was air in the master that eventually was gone. Sitting in the seat I could look at the master and see the fluid and air or eventually just fluid.
2. I did the same for the other section of the master, same issue, air in master.
3. I put a rubber hose on the bleeder at the farthest wheel cylinder from the master. Next, the loose side of the hose I folded and slipped a rubber band around it; not too tight but enough to keep folded over. I put that end into my bucket.
4. Now with the bleeder slightly open I started pumping the brake peddle and watched the reservoir and added fluid as needed. When I felt enough fluid had gone through the line to cylinder I repeated the process to each wheel cylinder until done.
5. I did put a bit of anti-seize on the adjusting threads of each wheel cylinder to keep from rusting and locking in place.
6. I was confused about adjusting the wheel cylinders, some clockwise (CW) and some counterclockwise (CCW); finally I just marked each on the inside brake plate so I'd know what to do for each one. An expert does naturally, I'm no expert.

Final result is they all work fine, no fade, pull straight. They just don't work as well and disc style but for me it feels right to leave as drums.
Hope this helps.

 

[Boaf 32]

I'm new to brakes and had similar issues. Finally got things right.
1. I used a replaced brake line and bent up so when connected to master the other end pointed to the filler. I just added fluid and pumped like crazy. There was air in the master that eventually was gone. Sitting in the seat I could look at the master and see the fluid and air or eventually just fluid.
2. I did the same for the other section of the master, same issue, air in master.
3. I put a rubber hose on the bleeder at the farthest wheel cylinder from the master. Next, the loose side of the hose I folded and slipped a rubber band around it; not too tight but enough to keep folded over. I put that end into my bucket.
4. Now with the bleeder slightly open I started pumping the brake peddle and watched the reservoir and added fluid as needed. When I felt enough fluid had gone through the line to cylinder I repeated the process to each wheel cylinder until done.
5. I did put a bit of anti-seize on the adjusting threads of each wheel cylinder to keep from rusting and locking in place.
6. I was confused about adjusting the wheel cylinders, some clockwise (CW) and some counterclockwise (CCW); finally I just marked each on the inside brake plate so I'd know what to do for each one. An expert does naturally, I'm no expert.

Final result is they all work fine, no fade, pull straight. They just don't work as well and disc style but for me it feels right to leave as drums.
Hope this helps.

Thanks, did this also. Now that I know my master is "Air Free", I will re-bleed all the wheels in the correct order (seems like I'm doing this forever) and see if it helps. It's nearly road ready...

 

[Dennis 1970 40]

I have a booster question: The original booster had a small vacuum leak when cold and engine first started. My brother as a gift had it replaced with a rebuilt unit. This 1970 FJ40 was at his place last 15 years and out of my view. I got back in PA last year and had a lot of work to do. The brakes were replaced with new almost everything, drums,wheel cylinders, lines, fluid, springs... No leaks, foot pressure normal and solid feel, no fading. The issue and question: It seems like the brakes don't work nearly as good as before. I cannot get to lock up. Other than that they seem fine. It almost seems like no booster help at all. I do have vacuum going to the booster but that's about as far as I've investigated. Any suggestions?

 

[shawnfj40]

Test the booster, if its good then adjust the brakes.

 

[tornio]

HI guys , I have a problem with the brakes of my 42 3b , i read all this tread 3 times and found it very usefull....but still no brakes....

long story short (i hope) :

all started when i done a rear wheel cylinder rebuild (right whell), then i bleed the air a lot of time

thinking that some air may have reachen the master cylinder , i removed it and i did the bench bleed like showed in this tread

now it is in place and i did the wheel bleed in the correct order but still i have problem (less than before)

engine off : my brake pedal need to be pumped 2-3 times before becoming hard and this make me think there are still air somewhere
but after 2-3 pump the pedal is very strong and firm

when i start the engine the pedal goes down ( booster ok i assume) and this is ok like manual say

but why (with engine on) after 2-3 pump the pedal remain strong and firm only for 2 -3 second and then start to loose pressure ??? only with engine on

you guys what think about ??

thanks

 

[JohnnyC]

You need to adjust the drum shoes imho

 

[tornio]

hi john , yes but i have automatic adjust on rear axle and disk in the front..... i'll check again the shoes.


reading this thread i discovered the " residual valve for drum brakes " ... has my bj 42 1983 this residual valve for the rear drums? ? or it is only for the four drum LC because i cannot see where it is ?
i have a master cyl. rebuild kit and there isn't this valve....

thinking about i have some problem in the parkin brake system , the lever which is attacked to the steel cord doesn't move properly maybe the automatic adjust doesn't work correctly and i have one rear cylinder not properly set (too closed) ...
i 'll check

for now thank's i let you know


cheers

 

[emac]

My experience: New calipers, rubbers lines, wheel cylinders, master cylinder, bled, adjusted shoes, etc. I still had a weak pedal. Burped air out of rear wheel cylinders, readjusted the rear shoes pretty tight, and put in a new booster and the brakes became pretty darn good. I didn't read all of this thread, but I think my problem was air stuck in the rear cylinders due to the design of the bleeder not allowing all the air to get out, and a 40 year old booster.

 

[tornio]

yes, if all you had problem with rear drums i start thinking ... or better still i believe that the problem is from rear cylinders , infact the issue started when i managed them the first time...

i have already replaced the rubber line with steel line (motorbike style) , the master cyl was replaced by the PO (i discovered when i took out to bench bleed infact there wasn't the gasket) , it is AISIN 7/8 and looks good .

when i did the bench bleed then i closed the 2 outlet and the cylinder kept the pressure with no subsidence...

the booster instead seems factory but in good working order .

i discovered that when i accidentally touched the pushrod it loose pressure/vacuum , making a sort of "HISSSSS" IT IS NORMAL ?
the toy was sitting by a week and this fact make me think that the booster is ok.... i'm right in you opinion or no ?

be patient my friends , tha gasket missing is 4727522010 somebody know the thickness ?

if i order in Toyota here i have to wait a week so i thought make it myself , i have many thickness of gasket-paper.

thank's and good day to all

 

[tornio]

You need to adjust the drum shoes imho

hi , infact that was !

but before while i was working around bj i discovered this

fxxxing bastard my "new brake tube " is leaking...

i changed for this one that is not the same but temporary will do the job

bleed the air ... and i thought ok now "she " brakes ....

noooo still no brake...i thought it must be like Johnny said ... and yes i took out the drums and i adjusted the shoes again :

NOW SHE BRAKES !!!!

THANK'S

cheers

 

[emac]

Vittoria!!

 

[Bshaunessy]

Boaf32:
I read your thread completely RE serious brake issues but note that your last post was a year ago ( March 2016) and further note that there was no note of how you finally resolved spongy brake issue?

I am having similar "spongy brake" issues ( full body off on 1966 FJ45 BUT with a completely new brake system: new MC, booster, front disc conversion, rear drums with new cylinders x2 per side, all new lines /bench bled MC / .........readjusted rear shoes umpteen times..........the best I can get to is a firm pedal after two strokes to the floor.......ie brakes work , but not reassuringly and don't really want to drive it when need 3 x pedal strokes to get any braking).
I think I still have air in system but have bled 5 litres of fluid through system so can't see how this could be.

So I am quite curious how you finally resolved your spongy brake issues?

Cowboy Bob