(Disc brake service, part 2)
Here's the same washer, removed, showing the bent part. This could be from where it had been pried out before. I don't know...
I set each part on a clean piece of paper, in order, so I could re-assemble it the correct way. There is no real rocket science here, but never having done this before I didn't want to take any chances that I'd get the order wrong:
Note that once you have the thing disassembled like this, it is a good opportunity to perform other service such as installing new bearings and performing Jeephammer's water-proofing steps
. Thanks to Mvigo for pointing this out!
Here's the spindle with the hub and everything else removed. The scond bearing comes out when you pull off the hub-
Here is the back of the hub/rotor assembly. You can see the groves worn into the rotor.
At first I was not sure how the hub and rotor were attached togethger. I read one post stating that they can get rusted together and can be difficult to separate.
My CJ isn't too rusty so I didn't know if this would be a problem or not. After tinkering with it for 15 minutes, I figured out the trick:
Turn the assemly so that the studs are pointing up, and pound them out with a hammer. You could also use a punch to be sure to avoid damaging the threads, although the studs are rounded at the ends so the threads aren't really exposed to the head of the hammer.
Here we see the rotor separated from the hub, and the 5 studs standing up:
Stud removal with hammer:
After separating the rotor (which I wasn't going to reuse), I had the hub to deal with. What I REALLY needed was a blasting cabinet so I could get the thing pristine again. You all know how I like to refinish metal things. But that wasn't in the cards. So I wire-wheeled the hub and used auto degreaser/cleaner to help loosen the buildup of grime. I also used a scraper to get the heavy stuff off. Also, I left the bearing inside the hub and put clean paper towels balled up in each open end of the rotor so prevent crap from getting in there. I know a professional would have cleaned all of the grease out, installed new bearings and seals and all that, but I did not take that step. Some of you may consider this a shortcut.
It pained me to disassemble all this stuff but leave some parts still dirty...
Believe me, I'd love to have taken the time and expense to replace all that stuff, but now I know it's not to difficult to do in the future.
When I did the passenger side, I noticed the hub/rotor assembly had some real play in it: like 1/8" inch. It seemed wrong. When I was disassembling the parts from the spindle, one of the nuts was not tight. It was about 1 turn from being finger tight!
When I reassembled that side, the final product was rock solid: no more play It's one of those things that was lurking that I might never have known about, but an experienced Jeep mechanic (or any mechanic) would perhaps take the time to inspect before putting any real miles on the vehicle.
Here we see the cleaned hub on the new rotor. I show it from this angle so you can understand how they fit together. It's easy to lose track of which way the rotor goes. This is one of many times when you can look at the other side to see how it's supposed to look.
Here we see hub in the rotor with the studs pounded back in:
I was not able to pound the wheel studs in 100% of the way. The only way to get them all the way in (short of using a press), is to mount the wheel on the hub: When you tighten the lug nuts down, it will pull the studs to be fully seated. Because of this, I would reccomend that you re-tighten the lug nuts after 50 or 100 miles of driving, just to be sure everything is tight.
And finally we have the whole thing mounted back on the axle. Note there is no brake caliper yet.
Now, if you've never done disc brakes before, it's difficult to know how the pads relate to the caliper and the disc and the mounting bracket. Here we see the new pads sitting on the mounting bracket. All the caliper does is squeeze the pads against the disc. It's that simple. The wire pieces are the
ant-rattle clips, but they hook onto the caliper.
I can't really explain how the pads sit on the bracket. It's another one of those small puzzles you just have to figure out. Look at the other side if you need help. It's not complicated but like anything else, it takes longer the first time.
Here's the caliper on the pads. Note you can barely see the shiny metal bleeder valve toward the top. THE BLEEDER VALVE MUST GO TOWARD THE TOP, NOT THE BOTTOM. If it's on the bottom, then you have the wrong caliper on.
Here's the broken anti-rattle clip. Because the caliper slides on its mounting bolts (that's how it's designed to work), it is designed to move around and it could rattle. The anti-rattle clip is designed to prevent that.
And finally, a bonus shot of the CJ on 4 jack stands:
That's it for the photos.
After I got the front brakes done, I had to bleed the whole system, in part because I wanted to putge out the old fluid which was of unknown age.
If you're new to brakes, here's the bottom line on bleeding: The brake hydraulic system must be free of air. Air compresses, but fluid does not. If you have air in the lines, then the brake pedal will feel spongy and you won't have the same breaking ability. So when you bleed the brake system, you're simply getting out the air.
It sounds simple, but it can be a pain.
I started bleeding with the MityVac so I could do the work without needing a helper to operate the brake pedal. The mityvac did a good job of pulling out the old fluid while I refilled the master cylinder with new fluid. The problem was I could never get to the point where I wasn't seeing air bubbles coming out of the line. Ultimately I think this was mostly because the bleeder hose didn't fit air-tight on the bleeder valves.
After going literally around and around the Jeep with the Mityvac, bleeding each corner over and over, I stopped and then got a helper to start working the brake pedal. That's when I finally started seeing some results. That purged out some air, some additional old fluid, and ultimately the brakes were made to work well again.
Don't hesitate to get a bleeder valve wrench. This was the best $5 I spent for the project. It fits precicely on the valves, it doesn't fall off, and it is offset so that it stands slightly away from the calipers.
In the end, I ran about 1 1/2 quarts of nre brake fluid through the system. Some posts here claimed to use a lot more than that to get a good, air-free system.
I still need to service the rear drums. One is leaking fluid pretty fast and just looks like a mess inside. The other one looks to have been serviced but I will still probably replace the shoes in it. Drum brakes are a bit more complicated than disc, so it will be a learning curve for me. New drums are not cheap, so I intend to re-use mine. The initial inspection didn't reveal any major flaws that I could see.
After doing the brakes today and taking a couple of test drives, I can honestly say the brakes are imrpoved. They aren't as dramatically better as I had hoped, but I am pleased for a first time brake job. There may still be some air in the system. Plus, my drum brakes are probably totally gone so I think I'll get some more stopping power once those are properly done.
During the process I started to question the viability of the master cylinder but I think it's OK at this point. I have do doubt that it will also need replacement at some point in the future. The posts here are full of warnings about the poor quality of the reman MCs. J.E.E.P...