ST165 Master Brake Cylinder Rebuild
Not sure how many of you have done this, but I didn't find any info on it, and after a search I saw a few other people who had replaced their master cylinders. Not sure how different it is for a 185 but I'm guessing it's fairly similar. I had actually bought another master cylinder off of someone because I didn't want to screw this up, but since I already had the kit and my old MC, thought I may as well give it a shot.
Reason for doing this:
165 brake cylinder from Conicelli: $237.61
Piston kit from Conicelli: $47.29
I got the part number for this kit from a local Toyota dealer, though I see Conicelli also has a Master Cylinder Repair Kit for $55.31 also, not sure what's included in that (maybe the piston kit + reservoir?). The part # I ordered was 04493-20170.
Here's the brake cylinder laid out, along with the piston kit.
This is what's contained in the kit. On top is the #2 piston, then the spring for it, then the #1 piston and spring. Then a few misc. parts (for the life of me, I could not find anywhere to put that hairpin or the two larger copper washers. Whoops!). It also came with a (not pictured) screwdriver condom, to protect the inner "sarface" of the cylinder. Believe it or not, those were the only instructions included with this kit.
Step one is to remove this screw and pull off the reservoir
This one's kinda tricky. I didn't have all my tools with me and ended up using a pair of pliers and a bent paperclip to get this guy off, but a pair of needlenose pliers should do the job just fine. Be careful, though, because if it's not fully drained (even though I thought mine was), you'll end up with your hands covered in brake fluid. If I were doing it again, I would put something through the hole on top, where the reservoir mounts, to hold piston #1 in place while I removed the screw. Especially since once I did get the clip off, it went flying about 3 feet away.
Piston #1 should pull right out now.
Next, you need to remove the (10mm) bolt that's on the bottom. Under this bolt is that small metal rod that was in the kit, and that's holding piston #2 in.
What you'll do here is hold the entire thing upright (the way it would be mounted in the car) and push in on the end of piston #2 with a screwdriver. The pin that was hiding under the bolt should fall out once there's no pressure on it.
Don't forget to use your screwdriver condom!
After that, the second piston should come right out relatively easily.
Here is the old stuff (top) and the new stuff (bottom). Honestly I'm not 100% sure that this brake cylinder needed a rebuild (replacing it didn't end up fixing my problem anyway) but it's good experience at least
This is also a really good time to give everything a good cleaning. I try to clean every part I take off/work on with the AllTrac. With a car this old, it's a losing battle, but at least some of it will look decent.
Now, reassembly is a snap. Slide Piston #2 back into the cylinder (spring end first), while it's set upside-down. Then, as you push in with the screwdriver (plus protective tubing), you should be able to put the pin into the hole and, it should fall right into place. You'll probably need to turn the screwdriver to line up the holes for it. Once it's in, put the new bottom bolt and copper washer on to keep the rod in place
Now piston #1 goes back in, and I used the same technique as before, inserting something into the hole on top (be sure it's not something that would scrape the interior walls of the cylinder) to hold the compressed piston in place, while I put the clip back in. Then just pop the reservoir back on, replace the screw (for some reason you don't get a new one of those) and you're back in business.
All in all, it's a pretty easy job, so if you're planning to replace your master cylinder, this shouldn't add much time onto the project and would save you a lot of money.