Originally Posted by ccooper1234

OK why does my jeep idle high even though its already warmed up. Around 1200 in park

Originally Posted by DESERTXJ206

Is it just mine or do a lot of xjs brakes suck?

Originally Posted by DESERTXJ206

Is it just mine or does a lot of early model xjs brakes suck in reverse?

Both my 88 and 90 are horrible in reverse. They literally seem to only use about 25% of pressure to slow down with the pedal fully pressed.

I've adjusted, bled and re bled the brakes multiple times, all new hardware and new master cylinder and they still suck. Going forward they seem to stop fine. They don't lock up but they are much better than going in reverse.

Is there a reason why?

Originally Posted by salad

Welcome to the site. You got all the info except which axle you're dealing with, is it a Dana 35? 1-1/8" for that axle. Chrysler 8.25" is either 1-1/4" or 32mm.

If you don't know which you have, Chrysler 8.25" on the left, Dana 35 on the right.

Originally Posted by brandonmgd

It looks like an 8.25. The cover isn't indented. Thanks for the help btw.

Originally Posted by cruiser54

Ever cleaned your throttle body and IAC?


Courtesy of TJWalker:
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The Idle Air Control (IAC) is mounted on the back of the throttle body. (front for 87-90) The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is moved in, the air control passage flows more air which raises the idle speed. When the valve plunger is moved out, the air control passage flows less air which lowers the idle speed. Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea.

CLEANING THE JEEP 4.0 IDLE AIR CONTROL

Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a torx driver (2 bolts; one can be kind of hard to get to)

"Gently" wiggle out the IAC from the throttle body. Gasket on the IAC can be re-used if it is not damaged

Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and is best for this task. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.

Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner

It is also a good idea to clean the entire throttle body itself, the butterfly valve inside of the throttle body and all associated linkage as long as you have things disassembled

Originally Posted by Lowrange2

Any vehicle I've ever driven the brakes were far less effective in reverse. I'm sure there's some physics behind it. I couldn't tell you what they were.

Originally Posted by DieselD

I think it has to do with the transfer of motion? Lol. That's why they put bigger/better brakes on the front of vehicles. The XJs brakes suck in reverse because they are drum brakes I'm guessing. Braking in reverse would probably be better if you swapped to rear discs.

Originally Posted by NewKindOfClown

That's half. The other half is weight distribution. Passengers are near the front, and the engine sits right above the front brakes, but the rear of the Jeep weighs very little in comparison.

Originally Posted by DESERTXJ206

Hmm......

I don't see why that effects it. Over all you are still trying to stop an entire vehicle. Do the front brakes just not work when going in reverse? I mean it honestly feels like my rear drums are the only thing attempting to slow the jeep down.

Originally Posted by DESERTXJ206

Hmm......

I don't see why that effects it. Over all you are still trying to stop an entire vehicle. Do the front brakes just not work when going in reverse? I mean it honestly feels like my rear drums are the only thing attempting to slow the jeep down.

Originally Posted by DieselD

It brakes better going forward because there are disc brakes up front. All the weight when braking in reverse goes on the weak *** drums.

Probable solution, get discs.

Originally Posted by DESERTXJ206

Can't get discs a on turdy5 right? At least not cheap?