give me a brake!

mncdriver

mncdriver

Well-Known Member
Joined
Sep 28, 2008
Location
Mooresville, NC
Hi i have installed my d44 front and 8.8 disc brake rear axles in my 87 yj. my question is, upgrading to 4 wheel disc and larger calipers on the front i have no brake pedal. i have bleed all the calipers a bunch. I am thinking the master is the problem. in my reserch i also read about a dual booster upgrade but sounds like it wont fit with my 258. what is my best option for a firm pedal? thanks Mark :confused:
 
I used a 78 mercury marque Master cyl. I think the E2000 Van master cly will also work.
 
Probably. Hydroboost m/cs typically have much larger pistons than vac ones. Like... 1-1/2" for HB and 1-1/16" for vac. My guess is that you need the vac one.
 
I am not a YJ expert, but I know some people have weak breakes in their ZJs after the 8.8 swap, and most times it is due to having the left and right brakes on backwards (left on the right and right on the left).
 
1. Check what BigClay said. #1 culprit for brake issues after an 8.8 swap.
2. Remove the o-ring on your proportioning valve.
3. If 1 & 2 don't work, go the route of upgrading to dual diaphragm.
 
cltdba said:
1. Check what BigClay said. #1 culprit for brake issues after an 8.8 swap.
2. Remove the o-ring on your proportioning valve.
3. If 1 & 2 don't work, go the route of upgrading to dual diaphragm.
Click to expand...
What Chris said but a proportioning valve from a Grand Cherokee may work better than just removing you proportioning valve o-ring.
Removing the o-ring worked ok for one of my jeeps but not the other.
 
from what i have read a dual diaphram booster will not work with a 258. I dont know why? Is there any truth to that. i put the 8.8 in first and then drive the jeep to keep from chasing my tail with vibrations and what nots. had 80% brake pedal then. now that the waggy d44 is in, the pedal is on the floor.
 
Does your fluid level stay full when you pump the brakes? Master cylinders are cheap enough. Might as well try fixing that. Definitely not the booster; your pedal would be rock hard.

As for the PB upgrade, why would the 258 matter?? Clearance?? I found many threads on upgrading to a 94+ YJ PB/MC combo.

YJ upgrade on a CJ with the 258: http://www.desertcj7.com/yj_brake_booster_upgrade.htm
 
It will work on a 258, unless you have done the MC2100 swap, then there are some clearance issues

I have used several different masters also

68 Vette master
70's era 1 ton chevy master is a good one also, without hydro boost
E250 Van master, from a 1994

most all of these masters will fit a YJ booster, some take a little mod work
 
im running a 2 barrel webber carb. i think i will go with the master upgrade. what will work best? im leaning of going with a mercury marq. hope it works.
 
ok so here is where i am at. bleed brakes again. i can get a 75% pedal while engine is off. start jeep and pedal goes to floor. i cant really say i got any more air out of syetem. maybe i should think about a dual booster set up? where can i find a dual booster for a late 95 yj? will it clear with a webber carb, and rectangle filter? as with everyone else out there money is tight. i would hate to spend it on the wrong parts. thanks Mark
 
mncdriver said:
ok so here is where i am at. bleed brakes again. i can get a 75% pedal while engine is off. start jeep and pedal goes to floor. i cant really say i got any more air out of syetem. maybe i should think about a dual booster set up? where can i find a dual booster for a late 95 yj? will it clear with a webber carb, and rectangle filter? as with everyone else out there money is tight. i would hate to spend it on the wrong parts. thanks Mark
Click to expand...

retighten every single flare nut on the brake lines, and try again. i have seen them be loose and not have pedal for air leaking in without fluid leaking out.
 
Great advise. I will ad that to my list of things to do.
 
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