So I got some new seals for my brake calipers as I had a couple of issues,
A. I either had no brakes, or full lock.
B. I had pressure to the Master Cylinder, then it would just go soft.
My Trouble shooting to date:
1. Re-bleed the entire system - No Change.
2. Re-bleed with a vacuum bleeder - No Change.
3. Re-Bleed from every bolt, nook and cranny - No Change.
4. Replaced the Front Master Cylinder after my one gave up the go, and repeated step 3. - This was the point where I had pressure after I pumped the lever 2 or 3 times, then it would just soften up.
5. Pulled apart the calipers (front and rear) to inspect for stuck pistons etc, Decided to clean them at this stage but didnt reseal. - No change.
Which leads me to this Post, I have brought some new seals for my calipers and have decided to repeat step 5.,
Just a note right now, This isn't a 100% correct guide, and I take no responsibility if you make a boo boo,
This is just a step by step of how I done it.
I started with my rear caliper as I dont have a garage and the weather was looking average, so I decided I would have enough time to do the one.
I have cleaned and resealed the caliper and bleed the system, and I can say I have fantastic pressure, but absolutely no brakes, However it would appear I am in need of new pads, they look a bit thin but I cant find a wear mark to show the min. wear.
Right Lets get into it!
(Sorry if I get a bit vague, let me know if you have Questions and ill fix things up)
Step 1. Identify the Caliper!
Step 2. Remove the two bolts holding the caliper to the brake bracket, At this point it is a good idea to crack the banjo bolt before the two bolts are removed, making it easier when the caliper is off.
Step 3. Move the caliper away from the bike and undo the banjo bolt, be careful not to drop the two copper washer, if your cheap like me you will need these for later, Make sure you quickly cover up and seal the end of the brake hose, Brake fluid is incredibly corrosive and will mess up your paint.
I used a plastic freezer bag and some tape to seal it up.
Step 4. You need to remove the two grub screws holding the pins in.
Step 5. Remove the pins (go figure), once the pins are out inspect them to make sure they aren't bent or scored.
Step 6. Remove the pads, and inspect them for wear.
Step 7. Remove the Anchor plate, this just pulls out of two rubber boots.
At this point I found I had a stuck piston, and you can see why when you see the amount of rust around it,
I Should at this stage replace the piston, but I decided not to for now.
Step 8. Once you have the bare calliper in your hands you need to remove the pistons,
There are a few ways to do this but I find a pair of pliers and alot of care is all that is needed, you must make sure you DO NOT score the piston.
Step 9. Remove the bleed nipple (you dont need to, but I prefer to when im cleaning it down)
Step 10. Removing the seals, I have seal picks so this was an easy task, however you can use anything from a scribe, small flat head screw driver or a sharp knife, Again DO NOT SCORE ANYTHING.
(Sorry I thought I had a photo for this but I dont)
The Fun part! Cleaning! This is self explanatory so ill just toss in some pictures so you can see,
I used a small container and made a Kerosene bath and put all the caliper parts into it, I used an old tooth brush to scrub all the grease and grime off of everything, as for the rust on the piston and inside of the caliper I used a scotch pad and Kero, didnt remove all of it, but it removed enough for me to be happy, After the Kero bath I sprayed all the parts down with brake cleaner to ensure they are clean and dry quickly, it is important to mention DO NOT USE WATER, you want all parts to be completely clean and dry.
You want to put the new seals into their correct places, simple enough.
The rest is just repeat all of above and work from step 10 to step 1.
You will need to grease the pistons, I also greased the pins,
To do this you want clean hands and you dont want to go over kill with the grease either.
Also back to the copper washers from earlier, Im a bit cheap and didnt get new ones, Its recommended you do,
However if you are feeling tight, you can hang them on a screw driver and heat them up with a lighter, this helps them expand back.
Hope this is somewhat helpful!
If there is anything you think I have missed please let me know and I can maybe add it when I do the next lot of calipers etc, feel free to add questions and ill try and Answer them and please add any tips and hints or corrections.