Residual Pressure Valve..

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1974FJ

1974FJ

10 Year 15 Year
Joined
Dec 1, 2006
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84
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NC
Searched...and i think im the only one that isnt familiar with the residual valve. I was told and read that im to get rid of them to help my brakes. Ive got a 74' fj40 that I put a 78' disc in the front of and want alittle more pedal. Does this help..and how exactly do i do this? Do i remove front and rear pressure valves or is there only one for the front? Fixin to add an extended brakeline to the rear and need to bleed brakes anyway.
 
Thanks Alot Grant5127, Never thought to look in the tech section:doh: After reading, i have to ask.. Why remove both residual valves? If the MC for a 76+ had one for the rear, shouldnt i leave it in though? see here "If running a 75-older master cylinder, pull both." "A 71 drum brake FJ40 master cylinder should have this valve in both fittings....a 76+ drum/disc combo would only have one for the rear drum brakes."
 
The valve hold pressure in the line that's needed for drum brakes.... only remove the valve for disc conversion.....which ever that might be....
 
I have, Alot! Its that my rear wants to lock up real quick. i just feel like im getting and stoping from my front discs. Ive been told numerous times to take this residual valve out, figure ill give it a shot.
Oyeah! Poser, i got that Brakeline from Marlin Crawler. Thanks for helping me find that. i plan put it on this weekend, and yeah..i got the red line:smokin:
 
my64fj40 said:
I believe you need them no matter what brakes you have. IIRC they have 10lb ones for drums, 2 lbs ones for disc.
Click to expand...


This is true for drum brakes......



There is not a residual pressure valve in a 40 series Land Cruiser disc brake master cylinder for the disc brake circuit.


I have removed them from the rear of a disc brake master cylinder and not used any residual pressure valve and the rear disc brakes work great.


I have removed them from a drum brake Land Cruiser master cylinder for only the front when installing disc brakes on the front axle only and not installed a residual pressure valve and they work great.


I have also used a drum brake Land Cruiser master cylinder with a four-wheel disc brake conversion after removing the residual pressure valves from both the front and rear circuits with great results.


:beer:
 
1974FJ said:
I have, Alot! Its that my rear wants to lock up real quick. i just feel like im getting and stoping from my front discs.
Click to expand...




The rear brakes no matter if they are drum or disc will lock up easier on the truck because of weight transfer/inertia when braking going forward.




Glad that you got the hose!

:beer:
 
Poser said:
I have removed them from a drum brake Land Cruiser master cylinder for only the front when installing disc brakes on the front axle only and not installed a residual pressure valve and they work great.
Click to expand...

So, does my 74' MC have residual pressure valves. Im not sure i understand what you just wrote. "and not installed a residual pressure valve and they...." so you did remove the front residual pressure valve and left the rear pressure valve in on the drumbrake MC and it worked pretty good? or is that not what you were trying to say?
 
1974FJ said:
So, does my 74' MC have residual pressure valves.
Click to expand...


Yes.


Your original 1974 master cylinder does have residual pressure valves in both circuits. You will need to remove the residual pressure valve in the circuit that you have your disc brakes plumbed into.





1974FJ said:
Im not sure i understand what you just wrote. "and not installed a residual pressure valve and they...." so you did remove the front residual pressure valve and left the rear pressure valve in on the drumbrake MC and it worked pretty good? or is that not what you were trying to say?
Click to expand...



That was in reference to my64fj40’s comment about a disc brake circuit requiring a two-pound residual pressure valve.



:beer:
 
In my 78, stock master, disk front , drum rear. 2lb residual in the disk and a 6lb in the drum line. There is also a proportion valve in the rear line, mounted directly under the brake booster. When I went to 4 disk, I replaced the 6lb in the rear line, and replaced it with a 2lb from another master. Has worked fine four over 5 years. If you look at the residual valve with a magnifing glass you can see a 2 or a 6 stamped on the valve
 
Plowboy said:
In my 78, stock master, disk front , drum rear. 2lb residual in the disk and a 6lb in the drum line.
Click to expand...



I guess someone must have been messing with things on the disc masters that I have been into...

I will go tear a few more down and see what I find....

Thanks for the heads up!


:beer:
 
Any up-date information on the valves antFJ :confused:
 
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