Minimal Braking

[flint54]

92 Eliminator, 4wd, 4.0, 5spd. New shoes and pads, drums and rotors are within spec. Rears adjusted for minimal audible friction when on jack stands. New booster (too bad I didn't know about the double booster mod when I did it). Very solid pedal, no leaks anywhere, system fully bled at all four wheels. All four wheels will lock with truck on stands. Now, the mystery: On the road, no matter how hard I stand on the brake pedal, I cannot lock up the wheels. Truck stops okay, straight line and all, but I cannot lock up any wheel, period, with all the force I can muster. Any thoughts?

[CWLONGSHOT]

Because of the funky rear prop valve. There is a very specfic way to bleed the brakes. I'll bet that is the problem...

 

CW

[Ed in North Ga.]

92 Eliminator, 4wd, 4.0, 5spd. New shoes and pads, drums and rotors are within spec. Rears adjusted for minimal audible friction when on jack stands. New booster (too bad I didn't know about the double booster mod when I did it). Very solid pedal, no leaks anywhere, system fully bled at all four wheels. All four wheels will lock with truck on stands. Now, the mystery: On the road, no matter how hard I stand on the brake pedal, I cannot lock up the wheels. Truck stops okay, straight line and all, but I cannot lock up any wheel, period, with all the force I can muster. Any thoughts?

Every once in a blue moon, I run across this problem on a jeep forum-

 

humor me, and try this- its worked for many.

 

go out, and with the engine off and you comfortable in the seat, put both feet on the brake pedal, and try to bend that sucker- stand on it till your back hurts, and push alittle more-

 

inside the master cylinder is a sliderod- anytime you release enough pressure in the system, the rod go`s past the rear hole in the metering block...and does not return- there is a mystical tool that is supposed to help the rod not do this...Ive never seen it.

 

Anyways, while your standing there pushing for all your worth, listen for a click- like a snapping noise- thats the rod clearing the hole- its the only way I know of, sans "special tool", to reset the metering block in jeeps and fords.

 

hollar back if it works-

 

do understand however, its hard to get an MJ/XJ stopped period, without that double diaphram- the brakes on these are marginal fresh off the lot-

 

The rear proportioning valve arm should be level (if working at all)- lower means more front brake, higher means more rear brake- mines tied straight up- I like lots of rear brake.

[flint54]

Ok, I've followed the procedure. It didn't really take all that much pressure to cause the "click". Outcome is:

a) I can actually lock up rear wheels, but barely, and no time soon. Cannot lock fronts.

B) the brake pedal is still solid but not until nearly halfway down now. Fluid is still full.

 

Prop valve lever is horizontal, and when I de-pin the rod I can operate the valve, with some resistance.

I need to study my FSM to see if there's a fluid flow diagram.

 

I also need to (and will) do the double booster mod, along with new MC just for good measure. Might

be awhile (project #3), but will report results when finished. Also going to measure before and after

stopping distance for comparison.

[FxRacing282]

how about a power brake of a full size?