98-00 Lexus LS400 Brake Calipers Rebuild
After putting some miles of driving on our vehicles, maintenance will always catch up to it. And nothing is more important than the system that stops the car. It is ideal to flush and bleed the brake fluid system every 80-100,000 mile interval. Even though the system is sealed, the fluid is designed to absorb moisture and it accumulates dirt after some time, which leads to the deterioration and failure of the brake calipers seals. Once dirt or corrosion start to build up in the brake caliper piston chambers, the piston have a harder time sliding in and out of the chambers and do its job of squeezing the disc brakes with the brake pads. This can cause overheating of the brake calipers, and you'd know it when your steering start to pull in either direction when you pump the brakes, then it's time to rebuild your brake calipers. I decided to get my LS400 brake calipers polished back when I did the swap so they're nice and shiny since the material is cast aluminum.
The brake calipers are two halves bolted together by these four star key bolts.
The torx/star key size is T-47.
Make sure to keep the two small rubber gaskets that goes in the brake fluid holes in between the calipers' two halves. You will reuse it later, unless you buy a new one as it's not included in the brake caliper rebuild kit.
Here are the brake calipers in halves.
Gotsta love shiny car parts!
To get the pistons out, you must first take off the dust boot, and the boot guide. The metal boot guides will be reused.
In the manual, it says to blow compressed air through the brake fluid holes to get the pistons out of the chambers. I don't own a compressor in my home, instead, I pryed the pistons out carefully with a flat head screwdriver. Just be very careful not to scratch the pistons' cylinder part, as this can cause brake fluid to leak later on or dust to get in the system and cause premature brake caliper failure.
Once you get the pistons out, take the chamber walls' rubber seals off. You can either use a screwdriver to take it out or a gasket hook tool. And again, be very careful not to scratch the chamber walls.
Wipe the chamber walls clean before installing the new rubber gasket. The rebuild kit should come with a grease pack more than enough to grease all the rubber gaskets and pistons.
Simply slide the new rubber gaskets in place by hand.
After greasing the pistons, just push it back in the chambers while making sure it goes in leveled.
Reinstall the dust boot metal guides back in place after the pistons.
I turned the dust boots inside out, like this, for an easier install.
The inner part goes in first over the pistons' grooved edge.
Then you simply turn it back right side out over the dust boot metal guide.
After you reinstall the new rubber seals, pistons, dust boot guide and dust boots, you are now ready to reassemble the brake calipers together. Position the two small rubber gaskets back in the brake fluid holes.
And lastly, bolt the two halves back together. The shorter bolts go to the outer holes, and the longer to the inner holes. It would be easier to tighten the bolts back to spec once it's on the hub.
Disclaimer: Use at your own risk. If you don't feel comfortable doing a procedure then don't do it. This information is to be used as a guide and is for illustration purposes only. By no means is my site a definitive source for the procedures listed; it is simply how I or the tutorial contributor did things. The tutorial contributor, and I are not responsible in any way for anything that happens as a result of following these guides.
Safety First: When working on your car put safety first. Use common sense and be careful. If you're doing electrical work disconnect the battery. If you need to jack up the car use jack stands and wheel blocks. Common sense is the key.