Ok, so I'm gettin rid of my XJ soon for a TJ. Only thing is, the guy will only trade if i fix the uber-stiff brake pedal. It feels like it doesn't even have power brakes. It's been like this since I got it 9 months ago, and hasn't really bothered me, but now i need it fixed. I figure it can be any number of things, including:

vacuum line
brakes need bled
bad calipers

I haven't checked anything, but i am really suspecting there is a vacuum line that's missing. Mostly because when i got this thing every single vacuum line i could find was cracked or missing. So, if anyone has any ideas, or can post a pic of where the vacuum line would go to the master cylinder or whatever, that would be epic-awesome. I need it fixed before he replaces the windshield on the TJ on monday!!

88 XJ 4.0 Auto 167K, no recent brake work done, no side-effects of stiff braking, it can still lock up the tires (though only in the rain....with bald tires...). It doesn't pull to a side when i brake, and is actually significantly stiffer than any other car i've driven.

 

Find out if you have The electronic ABS system! if ya do, take a drive to ur local junk yard, find a 89 XJ with non ABS (AKA normal brake booster, master cylinder and portioning valve) and swap 'em out. total it cost me $75 for all three plus the fittings for the brake lines, but believe me it was well worth every penny spent! entire swap took less than 2 hours from start to bleeding the brakes. If you dont have ABS sounds to me like no vacuum.

 

my 89 does the same thing like theres no power brakes.
I think the booster is just bad.

 

Macky - no ABS. ABS didn't start until the 1989 year. I'm gonna check out the booster and see if it's working by pumping the brakes, holding them, then starting the engine to feel for the brake pedal moving down. I don't think it will, so I need to know where the vacuum line is for the brake booster so i can check it. I'm terrible at finding vacuum lines and distinguishing which one is which.

 

Strange about the ABS i have an 87 lerado that had the ABS :$ and thats what just got swaped out.....now that vacuum line is or should be the only rubber line going into the booster....and should go right into the intake manifold its not hard to find should be right there on the passenger side of the master cylinder tward the top if that makes any sence....

 

Almost a sure thing that the booster is bad and needs to be replaced. Make sure you get a good quality replacement.

 

Checked the vac line, all is good there. The booster seems to be working too. I can pump the brakes 3-4 times, making the pedal harder, then after starting the engine, it sinks lower. I'm gonna bleed the brakes tomorrow - it's raining crazy good right now - and see if that helps any.

 

If you have a vacume brake booster it is bad when the vacum booster goes out you get stiff pedal.

 

Doesn't matter if you can pump and make the pedal harder. If the pedal is hard and it feels like you have no power brakes ie. like braking when the engine is not running, then your booster is shot! Replace it.

 

the booster seems to be working - the pedal will get softer after i start the engine, which was what i was told is how you check the booster.

 

ok then, maybe you've got seized caliper sliders.
remove the calipers and grease up the sliders, then see how that goes.