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View Full Version : Jeep ZJ Brake Booster Install (Pics!)



mattzj98
March 4th, 2012, 04:15 PM
My brakes were hissing at me, and they weren't stopping the jeep. I had to use both feet and stand on the brake pedal to stop. I checked vacuum lines, the vacuum lines were ok. I also checked the brake pedal, turned the key into ON position (accessories) pumped the pedal (it would normally build up pressure) and the pedal should go down once the jeep starts up.. mine did not. Diagnosed Brake Booster.

Picked up a new booster last night, tried researching some info on the internet on how to get it done, but everyone just vaguely described the things they did to make it work..I didn't really find an actual write up, so decided to write one up myself. I took pics step by step as much as I could.

The tools I used :

ratchet, extensions, a 13mm deep socket, a 14 mm short socket with a swivel, a flathead screwdriver. AND MOST IMPORTANT STEP STOOL!

First step, I took the air filter / intake off and out of the way to make room for that master cylinder.after that, I pulled the vacuum line off the top of the booster and tied it out of the way. Then, got the 13mm socket with a long extension and took off 2 nuts that held the bracket of the brake lines going into the master cylinder.Once that's off, there were 2 more nuts that held the master cylinder itself in place. Once the 4 nuts are off, the master cylinder will be lose enough to move out of the way without taking the brake lines off and losing any fluid.

mattzj98
March 4th, 2012, 04:20 PM
Next thing I on the list was to go underneath my dashboard and TRY to undo the 4 bolts that hold the booster in place through the firewall.I used a 14 mm swivel socket and a long extension.. ratcheted for a while, it was pretty hard since it was hard to see anything up there.. once the 4 nuts were taken off, the brake pedal had to be disconnected. The brake pedal has a nipple that goes through a loop thats at the end of a rod of the the brake booster, there is a clip that hold the pedal to the booster, it simply had to be pried up with a screwdriver and it came right off.

At this time the booster is free and ready to be pulled out

mattzj98
March 4th, 2012, 04:25 PM
Removed the brake booster carefully and compared to the new one..

It's important to re use the spacers and seal from the old booster as the new one doesnt come with anything (no hardware or spacers or any instructions for that matter)

another thing I found was that the new rod in the new booster had a bigger opening for the brake pedal to attatch.. the old one actually has a black plastic fitting in it. Pulled it out and saved to reuse on the new booster

mattzj98
March 4th, 2012, 04:31 PM
I used a step stool to be able to see and make sure I can make the new bolts line up once I swapped the spacers over to the new one. Had a really hard time lining up one of the bolts but finally got it through.

now, it did require me hanging upside down with my head under the dash to get the 4nuts started on the booster bolts. Once I got the 4 nuts tightened up, I instered the plastic fitting on the booster's rod and attatched the brake pedal back with the clip. I re-bent the clip to make sure it wouldn't come out. YOU DO NOT WANT THIS CLIP TO COME OUT, YOU WILL LOSE BRAKES.

mattzj98
March 4th, 2012, 04:35 PM
Once booster was in place and pedal attached, the master cylinder went back on. 2 nuts holding the cylinder in place, and 2 nuts holding brake line brackets in place. all by using a 13 mm deep socket.

when everything was done, I reconnected the Vacuum hose on the check valve on top of the booster and double checked everything, making sure my brake lights work as well.

mattzj98
March 4th, 2012, 04:41 PM
the whole job took about an hour and a half but I think it can be done in less than that as I wasn't in rush to get it done. This should be a similar precedure for ZJ / XJ and possibly a TJ YJ.

I actually think it took me longer to write all this up than to actually do the job! :)

hope someone finds this helpfull one day

Brody
March 4th, 2012, 04:50 PM
Thanks, Matt!!

Heather
March 4th, 2012, 08:59 PM
*where was the pink step stool?*
This is what I was wondering, as well. Great write up and photos - thank you, Matt!

mattzj98
March 4th, 2012, 10:26 PM
Thanks and no there wasn't a pink stool unfortunetely, just a 2 step ladder.. pink stool is good for checking oil but this required diggig deeper :)

Hypoid
March 6th, 2012, 07:07 AM
Good write-up Matt!

Java
March 6th, 2012, 07:32 AM
new parts always look so pretty. :thumb: Good write up!

Popsgarage
March 9th, 2012, 12:49 AM
This describes almost all vacuum booster installs on almost all makes and models. Good write up Matt.