Brake booster replacement
2000 Jeep Grand Cherokee Limited 2WD 4.7L
I got enough pieces-part info from other threads that I replaced my brake booster myself (I'm no mechanic). So I thought I'd try to consolidate what I did to help out the next guy...
Symptom: hissing noise from brake pedal near firewall when brakes released. Brakes seemed to work fine otherwise.
Purchased: brake booster from Autozone. About $125 after core turn-in.
I decided to try it myself without removing the master cylinder. The master cylinder is connected to the brake lines with 2 flexible/braided lines that allows for some movement. I can say that things were very tight and I was a little nervous about something breaking, but things turned out okay.
See picture for reference....
Make room: remove every connection with orange arrows... 3 connections on the front of the ?vapor canister? plus whatever it is that is kinda sitting on the front. 1 wiring plug that is removed by pulling up on the tab while the plugs slides backwards. 1 brake fluid sensor. 1 vacuum hose on the booster itself.
In red, remove the vapor canister with brackets from the side using a 10mm wrench on 4 fairly short screws.
In red, loosen the master cylinder using a 13mm socket on the 2 bolts. Let it stay there loose for now.
Under the dash (no picture reference), remove the clip holding the brake pedal to the booster's eye hook with a small screwdriver and pliers. Loosen the booster using a 13mm deep socket on the 4 bolts.
So now you have room and everything is loosened up. Here is where it gets a little tricky. You'll have to tilt/bend the master cylinder forward/down/over while you pull the booster forward/up/out. It'll take a bit, but it will find it's way out. Removal took maybe 45 minutes.
Putting the new one in is just the reverse. One thing to note is that the booster should come with a new ring that goes between the master cylinder and booster (so replace the old ring before you start putting things back together). Another note is the brake pedal switch. You'll probably push the tab/rod in while under the dash so that it doesn't make contact with the pedal. No problem, push the pedal in and yank the tab/rod out with some needle nose or wire cutters (release the pedal and it should work fine). Install took another 45 minutes.
I did a test drive through the neighbor and things seem okay. The pedal pushed a little more smoothly and "felt better". So hopefully things will be better for a while (at least until something else breaks). Hope this helps!!!