Soft brake pedal. New pads rotors and MC.

I just acquired this 93 Xj and have been working on it ever since I gave it to the g/f. It's turning out to be not such a good gift.

I replaced the master cylinder due to the pedal feeling spongy and fading at the top and bottoming out under hard braking. I also replaced the front pads and rotors. The pedal still feels awfully soft till it's pressed in almost 75% of the way. Even took it to a garage to be bled, where they again replaced the MC when I couldn't get the first one properly bled and couldn't spend any more time on it.

Shop got better pedal pressure and brakes work, it just still seems soft. Is this normal? it has 182,000 miles on it. new tires, brakes, shocks and springs now. Should I replace the flex lines Next? Calipers and rear cylinders maybe?

The brakes are hydraulic, that means the pressure is going to build equally (well proportionately with proportioning valves) in all 4 brakes. So if you have a soft pedal, you have to investigate all 4 brakes, not just the front. Although the front are the most important.

Usually, with symptoms like yours, the rear drums may just need adjusting, and activating the self-adjusters by alternating between braking going forward and slamming on the brakes in reverse will activate the self-adjusters and raise that pedal height, where the pressure starts to build quickly right away.

BUT, since you have 182k miles and most people completely ignore rear drums, it would be wise to pull the rear drums and inspect them, correct anything wrong, replace the shoes if necessary and/or turn the drums if necessary. Then adjust the shoes so that they just ever so lightly drag as you spin the tire by hand (obviously the tire is in the air, vehicle on jackstands while you work on the brakes.)

With that many miles on the vehicle, unless the rear drums were well cared for, it is likely some of the parts in the rear drums are seized up and rusted, etc. Rear wheel cylinders often gunk up by that mileage and start to leak, which would drop pressure as well.

I pulled the drums thinking that they'd need replacing too, but it's apparent that the previous owner replaced the drum and shoes as well as the e-brake cable (drum protion) and who knows what else. It looked pretty good.

I'll try adjusting them out this weekend to see if that makes a difference.

I replaced the front cuz it failed inspection. The front pads were good, just the rotors were way thin. I replaced the pads anyway though.

I didn't think about messing with the rear adjuster since I opted to not replace anything back there. It makes sense though.

thanks!

Also, I see you are in Lusby...Ranch Clubber too?

SMALL WORLD

Nope, I'm in Chesapeake Woods, right up against the High School Property, there are putting in that new road right behind my house.

I'm inching to get my XJ up and drive that construction site after hours. Being just a 2WD for my Daughter to drive around, thats about all it could handle, leveled ground, a bit soft and with some hills, not real wheeling, but a dirty run none the less.

Gotchya. I know exactly where you are then. I go by there in/out of CRE.

if ya get stuck, gimme a call. My YJ's on 36's with a winch. It's registered and insured, just not all that legal. For rescue missions and short drives, I'm usually ok.

use a pair of lock grips on the flexi hose to the caliper then try the pedal if the brake is better you know where the air is, try this on all hoses,.........

my xj has a soft spongy pedal. i have rebuilt the MC, then replaced it, adjusted the rear drums, pedal bled, vaccuum bled, gravity bled, pump bled, pressure bled. i had given up about a month ago.

i then baught some yj brake lines to replace my existing brake lines just so i didnt have to worry about the brakes lines when i installed the lift. 2 front lines and the rear line were replaced with lines baught from rockauto.com

MIRACLE! after some searching i found out that many times rubber lines get old and tend to expand under brake pressure; which gives the pedal a spongy feeling.

look at it this way, the lines cost me less than 20bucks each and its one step closer to being lifted and you could might as well solve your braking problems.

cheers

tag said:

use a pair of lock grips on the flexi hose to the caliper then try the pedal if the brake is better you know where the air is, try this on all hoses,.........

Click to expand...

that could tell me if my flex lines are weak too! Good tip!