There is a kit rebuild kit for the part of the master cylinder that contacts the brake fluid. I have seen on ebay some units that have been rebuilt I don't know of the quality. Some owners of 01 and 02 will look for some one parting one out and just keep it on hand in case they have a failure ( this doesn't help when your 200 miles from home but from what I have heard the failure happens typically with some warning like extended run time on the pump that you hear when first turn the key on.)
Rebuilding the motor i have not seen not saying there isn't something out there. If some one is putting them on Ebay then some one has worked something out.:guitar3:
Yeah, some have tried rebuilding their motors with varying levels of success. FWIW, our brake systems are very similar to 100 series Landcruiers, FJ Cruisers, and even the 4th and 5th gen 4runners and new Tacomas. They all have the same motor driven pump/accumulator style brake boosters. Maybe they sorted some of the problems since our first gen units, but who knows.
There is lots of info on the forums over at ih8mud.com which is the Landcruiser forum.
From what I've seen, there are several different failure modes with these systems:
1) Brake pedal to the floor followed by loud buzzers and lights in the cabin. This is typically solved by rebuilding the master cylinder hydraulic piston like any normal car master cylinder rebuild kit. There is a ~$50 kit from Toyota for the rebuild.
2) Hard pedal/loss of brake boost accompanied by loud buzzers and lights in the cabin. This would be booster pump motor/pump/accumulator failure, where the power assist is lost. This should be able to be resolved by replacing the motor/pump/accumulator for ~$750 for a new subassembly form Toyota.
3) "Dying seagull screeching" when starting the truck in the morning. This was my symptom, and seems to be the hardest to pin down, and may have various causes and solutions. This seems to be some type of hydraulic cavitation or "fluid hammer" caused by overpressure or air in the accumulator/pump system. Some people have replaced the accumulator and it solved the issue, but some found it made no difference. Others have replaced the motor/pump/accumulator and found it fixed the issue, but others found it made no difference.
After much research and troubleshooting, I found that my high pressure switch within the ABS module on the side of the master cylinder, which is supposed to shut off the motor/pump once proper pressure was reached, was not operating correctly for the first several minutes in the morning. I could tell this by reading the electrical signals from the switch, as well as the fact that I was able to stop the sound temporarily by pumping the brake pedal a few times, lowering pressure in the system. This told me that the motor and pump were operating fine, but were attempting to over pressurize the accumulator. Unfortunately this pressure switch (as well as the low pressure switch) are not replaceable. I could have replaced just the master cylinder/ABS module (without the motor/pump/accumulator) for ~$1200, but on the off chance that my problem WAS with the accumulator or pump, I didn't want to be having to take it all back out again to replace more parts. I just wanted it fixed. So I opted to replace the whole unit for ~$2200. It's been peachy since.
Unit removed:
Old unit removed and kept for spare parts:
New unit:
New unit installed:
