Last time I changed the pads in this car, I noticed some fluid leaking from the piston boot of the drivers side caliper. It's nothing big. We didn't even notice the depletion in the reservoir, but Leaking break fluid is no good. Rebuilding a caliper looks like a pain, and they aren't that expensive, so I just bought a new one.
Here we go. Jack up the car and take off the wheel.
Spray the whole thing in brake cleaner.
Make sure there is enough fluid in the reservoir. Here is the prime directive: Don't let the master cylinder run dry. If I was qualified, I would have had someone watching the reservoir, constantly filling it. If I was qualified, I would not have this blog.
Compress the cylinder with a C-clamp enough to get the caliper off. Just like if you were changing pads.
This is where I thought I was smart. I figured: Take the caliper off and hang it from the strut with a coat hanger, get the new one on, then move the hose from one to the other quickly to minimize the lost fluid. This won't work. You won't be able to put enough torque on the banjo bolt to loosen it unless its installed. Unless you're He-Man. If you are He-Man, please try it... Also, please post a comment. I would like to know if He-Man reads my blog.
Anyway, the Haynes manual says to remove the banjo bolt and then use a spare piece of hose to plug the brake line. It does not say what the hell size hose is required, so you cannot buy it. As it is, I emptied a good deal of fluid onto the pavement.
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| This was a dumb idea |
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| You can see the leaking fluid |
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Banjo bolt doesn't come off if
you take the caliper off the car |
If I was to do it again, and I still did not know the proper hose size, I would probably take the NEW caliper, hang it from the strut, take the banjo bolt off and move the line to the new caliper while it is hanging, and tighten it as much as I could. Oh well.
The caliper I bought at AutoZone came with new pad glides, pin bolts, pins, and pin boots, so I replaced all that stuff too.
After the old caliper is off, pull the brake pads and old glides. Put in new glides.
Below, you can see the new hardware vs the old hardware. Let me tell you how thankful I am that the boots on the Sentra aren't like the boots on the Corolla. I had to replace those once. They are glued to an aluminum ring which gets press fit into the caliper bracket. Press fit! I destroyed so many of those trying to press fit them... and no one carries them. You have to order them. My car was laid up for a week because I couldn't get pin boots. Anyway. the ones on the Sentra come right off.
Now, you have to put a little grease on the pins before you put them in the bracket. Make sure you get the boot over the appropriate rings, and then push the pins all the way in to eliminate any air.
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| Grease on the pin |
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| Boot on the pin |
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| Pins in the bracket |
I always put a little grease on the pads where they touch the glides because they would always bind on the corolla. Probably not necessary and dear god, only use a little and don't get it on the pad surface or the rotor
Put the caliper on and torque to the appropriate spec.
If you haven't already moved the brake line, now would be the time. Of note, when you buy your caliper, make sure you can locate the two copper washers that are the gasket on the banjo bolt. Mine were on the plug that they had in the new caliper. Do not lose these. One washer goes between the bolt head and the brake line and the other goes between the brake line and the caliper. Torque the banjo bolt to spec.
Finally, you need to bleed the brakes. You need another person. Here is my setup.
There are lots of posts on how to bleed breaks. It's pretty much the same in every car. You need another person and they press on the brakes while you open the valve. Don't let them come off the brake with the valve open, and don't let the reservoir run dry.
Even though this was pretty successful, I did dump a lot of brake fluid as I was messing with the line. The breaks are a little mushy, but they have always been mushy. I may just replace the Master cylinder for the sake of doing it. But that is another post.
