Brake question

[tjmotter]

Is there a big difference between the power brake setup on a '90 XJ and a '92?

My old ride was a '92 XJ that I bought new and the brakes were quite good on it. I am working on a '90 XJ with power brakes and it seems weak. I just replaced the front rotors and pads thinking it would help but it didn't seem to change the braking at all (old ones had sat for 3 years in a barn and were badly rusted so I suspected they were the issue). It takes quite a bit of pressure to get the old girl to stop (it almost feels as if the booster isn't working properly).

I hate the shotgun approach but I can get a rebuilt Booster pretty cheap at the local O'Reilly's however, it looks like a bear to replace so if the issue is that there really is that much difference between a '90 and '92 I will simply redo the rears and call it "done".

thoughts?
Todd

 

[4xBob]

A 1990 XJ has a single diaphragm brake booster. Sometime later (around early to mid-90s) they went to a dual diaphragm booster, for better braking. I replaced the single with a dual from a 1995 or 1996 XJ and improved the braking. You must use the booster from a 1995 or 1996: later years the pedal rod is too long. You will need to drill out the pedal rod bolt hole a bit (easy) and grind a flat on the back of the rod to operate your brake switch (needs to be at the same angle and dimensions). Lots of info available on search. Some years WJ boosters will fit too, but I haven't done that one yet. On the 1990, the fatter booster and later (shorter) master cylinder will run into the windshield washer tank. Some people move the tank frontward and redrill the screw mount holes. I softened the plastic with a heat gun and pressed in the end of the tank (carefully). It worked for me.

 

[Shorty]

could also eliminate your current washer bottle and replace it with one from a late model. It was moved into the fender well in '97 IIRC.

 

[tjmotter]

A 1990 XJ has a single diaphragm brake booster. Sometime later (around early to mid-90s) they went to a dual diaphragm booster, for better braking. I replaced the single with a dual from a 1995 or 1996 XJ and improved the braking. You must use the booster from a 1995 or 1996: later years the pedal rod is too long. You will need to drill out the pedal rod bolt hole a bit (easy) and grind a flat on the back of the rod to operate your brake switch (needs to be at the same angle and dimensions). Lots of info available on search. Some years WJ boosters will fit too, but I haven't done that one yet. On the 1990, the fatter booster and later (shorter) master cylinder will run into the windshield washer tank. Some people move the tank frontward and redrill the screw mount holes. I softened the plastic with a heat gun and pressed in the end of the tank (carefully). It worked for me.

I'll try this.

thanks!

 

[tjmotter]

It is done. I couldn't find a '95 XJ but was able to get a booster out of a '97 WJ. After some research I found it was the same shape as the '95 booster and uses the same MC but had a slightly shorter pushrod. The good news is that the '97 booster had a spacer installed and when I removed it the length was exactly the same as my '90 so I was able to bolt it right in (after doing the brake switch mod). I got around the windshield washer fluid reservoir fit issue by heating mine up with a heat gun and bending the plastic a little so that it fit right in. No metal bending required in the engine bay and the brakes are MUCH better now.

Thanks!
Todd

A 1990 XJ has a single diaphragm brake booster. Sometime later (around early to mid-90s) they went to a dual diaphragm booster, for better braking. I replaced the single with a dual from a 1995 or 1996 XJ and improved the braking. You must use the booster from a 1995 or 1996: later years the pedal rod is too long. You will need to drill out the pedal rod bolt hole a bit (easy) and grind a flat on the back of the rod to operate your brake switch (needs to be at the same angle and dimensions). Lots of info available on search. Some years WJ boosters will fit too, but I haven't done that one yet. On the 1990, the fatter booster and later (shorter) master cylinder will run into the windshield washer tank. Some people move the tank frontward and redrill the screw mount holes. I softened the plastic with a heat gun and pressed in the end of the tank (carefully). It worked for me.