Cruiserdrew
On the way there
I had my FJ40's brake booster rebuilt with Toyota parts from C-Dan, and the actual rebuild itself by Booster Dewey at Power Brake in Oregon. I also received a care package yesterday from C-Dan with a brand new Toyota master cylinder setting the stage for a brake party. This turned into an all day job so I thought I would post the experience here. I thought this would be a remove and replace job but it rapidly became pretty involved. One other thing-I actually had a spare core brake booster from Mudrak, so I sent that into the rebuilder so my original could stay in the truck while the core got rebuilt.
The symptoms that my booster was bad were subtle. It would hiss only will full application of the brake, like when trying to hold the cruiser still on a steep uphill. Otherwise it would hold vacuum and pass the tests in the manual. On rare occasions it would fail to boost the brake application at all but that only happened twice in the last 6 months. Still, it didn't seem safe. I was going to reuse the old master but due to an ordering mistake(on my part), Dan let me trade a Sienna tail light assembly I had ordered for the new master cylinder.
The first step is to remove the old master. The asshat who had worked on it before had rounded the compression fitting so that was a bit of a challenge. After that, 4 12mm bolts and the vacuum line and the master comes off the front of the booster. I found brake fluid behind the master cylinder, so obviously the master was on its way out leaking into the booster, so the new Toyota master was a good thing. Thank you Dan. By the way, the old one was not a Toyota master cylinder, it had no identifying marks of any type.
The next step is to remove the yoke pin from the brake pedal and unscrew the 4 bolts holding the booster to the firewall on the inside. The upper bolts are located in a way that it is difficult to get tools in there to get them off. I had the best luck with stubby gear wrenches. Now is when the fun started. The booster should just slide off the firewall but unfortunately, the carb is right in the way. I spent 15 minutes in denial trying to think of a way to get the booster out but no luck.
So step 3 is to remove the aircleaner and carb! Those lower carb mounting nuts are a real b*tch. In retrospact, this should be step 1.
Once the carb and aircleaner are off, the booster comes right out with some gentle pushing on the hard lines to move them out of the way.
Step 4 is to set the push rod depth before you install the booster in the truck. I didn't have the SST, so Mudrak had a great work around. Put a dab of grease on the pushrod tip. Install the new master to the booster on the workbench. adjust the bush rod until the grease has just barely been touched at the tip. You have to install, un-install, check the grease then wipe offf all the grease for the next attempt. 3 tries and it was spot on-you can tell when the grease has just touched the back of the master.
Step 5 is to bench bleed the new master. I put the master cylinder in the vise, attached some new soft lines I had to the master outlets, and recirculated the fluid in the resivoirs untill all the bubbles were gone. That took more pumps than I would have thought-maybe 20-30. The soft lines I used were the normal replacemnt lines for the front brakes. These were new and spares and worked great for the bench bleed.
Step 6 is to install the booster. You need to set the yoke depth very carefully. I measured the old one and set the new one exactly the same, measuring from the booster body to the end of the yoke. Then line up the slot to engage the pedal properly and tighten the lock nut. Install the booster through the firewall, start the mounting nuts and install the pin in the yoke that holds it to the brake pedal. Use a new cotter pin to lock it and you're all set. Tighten the mounting nuts and you are done inside the vehichle.
Step 7 is to install the master on the front of the booster. I installed it loosely so I could start the hard lines, then tightened the 4 mounting nuts, then finished tightening the brake hard lines. Anyone know what that small device is just below the master? The rear hard line goes into it. Is it a proportioning valve of some sort?
Step 8 is to re-install the carb, and aircleaner. PIA carb mounting nuts grrrr.....
Step 9 is to bleed the whole system carefully. With the good bench bleed there was almost no air in the system so the bleed just took a few minutes. You do have to do all 4 wheels though.
So the results. Whoa Nelly, we got brakes! The old booster must have been worse than I thought because the brakes take much less pressure to actuate. I think the vacuum leak was worse than I thought because the idle was smoother and the seat of the pants power was better too. I did the book tests of booster function and all was good. My FJ40 brakes have never been this good. The front calipers are also new, and the rear brakes were new last year. This must have been similar performance to a new FJ40.
It turned out really well. Booster Dewey was great to work with. He normally does not do the Toyota tandem boosters since he does not like the available rebuild kits. He agreed to do it only because I had a Toyota kit that CDan got for me out of Japan. Booster Dewey bead blasts the whole booster after disassembly, repaints and returns it looking like a new part. The service was really quick too. Booster Dewey told me the Toyota kit was excellent, and that he is willing to do others if you source the kit. If you have a single diaphragm booster, I think he does rebuild these with parts he sources. I'm expecting 100k miles out of this master and booster. At 4k per year, that's 25 years worth of use! If CDan does not get enough kudos here-tracking down that booster kit really helped me out-Thanks Bro.
The symptoms that my booster was bad were subtle. It would hiss only will full application of the brake, like when trying to hold the cruiser still on a steep uphill. Otherwise it would hold vacuum and pass the tests in the manual. On rare occasions it would fail to boost the brake application at all but that only happened twice in the last 6 months. Still, it didn't seem safe. I was going to reuse the old master but due to an ordering mistake(on my part), Dan let me trade a Sienna tail light assembly I had ordered for the new master cylinder.
The first step is to remove the old master. The asshat who had worked on it before had rounded the compression fitting so that was a bit of a challenge. After that, 4 12mm bolts and the vacuum line and the master comes off the front of the booster. I found brake fluid behind the master cylinder, so obviously the master was on its way out leaking into the booster, so the new Toyota master was a good thing. Thank you Dan. By the way, the old one was not a Toyota master cylinder, it had no identifying marks of any type.
The next step is to remove the yoke pin from the brake pedal and unscrew the 4 bolts holding the booster to the firewall on the inside. The upper bolts are located in a way that it is difficult to get tools in there to get them off. I had the best luck with stubby gear wrenches. Now is when the fun started. The booster should just slide off the firewall but unfortunately, the carb is right in the way. I spent 15 minutes in denial trying to think of a way to get the booster out but no luck.
So step 3 is to remove the aircleaner and carb! Those lower carb mounting nuts are a real b*tch. In retrospact, this should be step 1.
Once the carb and aircleaner are off, the booster comes right out with some gentle pushing on the hard lines to move them out of the way.
Step 4 is to set the push rod depth before you install the booster in the truck. I didn't have the SST, so Mudrak had a great work around. Put a dab of grease on the pushrod tip. Install the new master to the booster on the workbench. adjust the bush rod until the grease has just barely been touched at the tip. You have to install, un-install, check the grease then wipe offf all the grease for the next attempt. 3 tries and it was spot on-you can tell when the grease has just touched the back of the master.
Step 5 is to bench bleed the new master. I put the master cylinder in the vise, attached some new soft lines I had to the master outlets, and recirculated the fluid in the resivoirs untill all the bubbles were gone. That took more pumps than I would have thought-maybe 20-30. The soft lines I used were the normal replacemnt lines for the front brakes. These were new and spares and worked great for the bench bleed.
Step 6 is to install the booster. You need to set the yoke depth very carefully. I measured the old one and set the new one exactly the same, measuring from the booster body to the end of the yoke. Then line up the slot to engage the pedal properly and tighten the lock nut. Install the booster through the firewall, start the mounting nuts and install the pin in the yoke that holds it to the brake pedal. Use a new cotter pin to lock it and you're all set. Tighten the mounting nuts and you are done inside the vehichle.
Step 7 is to install the master on the front of the booster. I installed it loosely so I could start the hard lines, then tightened the 4 mounting nuts, then finished tightening the brake hard lines. Anyone know what that small device is just below the master? The rear hard line goes into it. Is it a proportioning valve of some sort?
Step 8 is to re-install the carb, and aircleaner. PIA carb mounting nuts grrrr.....
Step 9 is to bleed the whole system carefully. With the good bench bleed there was almost no air in the system so the bleed just took a few minutes. You do have to do all 4 wheels though.
So the results. Whoa Nelly, we got brakes! The old booster must have been worse than I thought because the brakes take much less pressure to actuate. I think the vacuum leak was worse than I thought because the idle was smoother and the seat of the pants power was better too. I did the book tests of booster function and all was good. My FJ40 brakes have never been this good. The front calipers are also new, and the rear brakes were new last year. This must have been similar performance to a new FJ40.
It turned out really well. Booster Dewey was great to work with. He normally does not do the Toyota tandem boosters since he does not like the available rebuild kits. He agreed to do it only because I had a Toyota kit that CDan got for me out of Japan. Booster Dewey bead blasts the whole booster after disassembly, repaints and returns it looking like a new part. The service was really quick too. Booster Dewey told me the Toyota kit was excellent, and that he is willing to do others if you source the kit. If you have a single diaphragm booster, I think he does rebuild these with parts he sources. I'm expecting 100k miles out of this master and booster. At 4k per year, that's 25 years worth of use! If CDan does not get enough kudos here-tracking down that booster kit really helped me out-Thanks Bro.
