Found this gem last month. I had to replace the slave cylinder. And although I have no trouble applying brake pressure, I'm hearing an obvious vacuum leak in the brake booster from in the cab, not on the other side of the firewall. Never replaced one. Not scared to try. Any advice?--Melon Moonshine, '71 FJ40.
Nice rig, but flip the bezel, then change the brake booster. It's pretty straight forward. I haven't replaced one in years, but other than the push rod adjustment there's not much to it. The FSM details the push rod adjustment, or someone else hear will chime in.
I have used both rebuilt OEM from Specter-spendy and unit that Racer65 sells which I am currently using and is excellent. And much less spendy. The rod clearance IS critical as Mark mentioned. I had serious brake drag that cooked my new OEM rotors-turned them blue. Was able to turn them down a bit and now fine. It did not matter which direction I turned adjuster with FSM in hand I could not get proper clearance. Took it to my mechanic and he said it is much easier with two people. How he got clearance correct I will never know. From now on it will be a job for the mechanic for me. Brakes excellent now.
I recommend this video to learn about brake boosters and how to adjust. The adjustment portion starts at the 30 minute mark.
Here's the City Racer brake booster page. The booster you pick depends on whether the vehicle has the original drum brakes or if it has been upgraded to disc.
Vacuum leak heard inside the cabin does point to a leaking booster.
