Ok so to start I have a 1990 cherokee 4.0 I6 with a 3 inch lift and size 30 tires.

My brakes seem really weak i have to put the pedal to the floor to get the vehicle to stop so initial thoughts were bleed the brakes so I did that and no air. Then I replaced the master cylinder and replaced the fluid bled again and still have mushy brakes.

Anyone else have this problem or can help me out with some suggestions?

 

Adjust your drum brakes manually.

 

mushy means air. try to drip bleed them. it takes time and a lot of brake fluid but i think its the most effective way to get all the air out.

 

would you suggest getting new self adjusting drum kits, and drum all-in-one kits? probably new shoes as well?

 

what is drip bleeding. i have an 89 with this same problem.

 

My 87 has the same problem and has for two months, since I bought it.

Here is what I have replaced:
Master cylinder
Rear wheel cylinders
Rear hard lines
Rear flex line
3 big bottles of fluid to get air out

My shoes and drums are within spec and the fronts work fine. Put your on jackstands and I bet your rears aren't working because you have the same problem I have

 

my brakes were mushy on my 87.When I did my lift inspected the brakes they were fine.I upgraded my brake lines,and the mushy feeling went away.

 

pump up break system as best you can. open the master cylinder, loosen the bleeder screw and let it drip. make sure the master stays more than half full. this takes time. if there is a lot of air in the lines and system then you could spend half hour doing this.

 

You coud have it pressure bled by a mechanic. Most of your braking power comes from the front so you could also change your front calipers. Just a thought.

 

yup, could be the front caliper sliders.
take the calipers off the rotors, and remove the sliders that the bolts go through and grease them up.

 

How do you do this?

 

you could swap out the single diaphragm brake booster for a newer dual-diaphragm booster. i got one from a 2000 cherokee and put it in my 89. what a difference. it went from barely adequate to lock the wheels up whenever i want. i also have zj rear discs and SS braided lines. i have wj front discs to go on soon.

zedpapa

 

was the dual diaphragm a bolt on or was modification required? I heard 96 xj's were but anything other than that required various mods.

 

check this link, it explains everything.

http://www.4x4wire.com/jeep/tech/bra...kes03/booster/

they used a wj booster/master but you do the same mods to the xj booster/master.

zedpapa

 

also the xj booster does not require a spacer or need any sheet metal bent to fit.

zedpapa