Rebuild time....
Okay, correct seal and piston kit this time! Caliper paint all dry and looking good so on with the rebuild
General notes -
make sure everything is clean, really clean!
If it moves, slides or rotates, grease it
rubber seals are fragile, don't rush or use the sharp edge of the screwdriver to force anything in - it will go back together with patience
Step 1. Check the kit! Per caliper there are 4 seals for the caliper, 2 dust boots for the carrier, some grease and a piston, as shown below
Step 2. Handbrake lever seal - Before you mount the seal, check and grease the bearing. You can see that there is a break in the needle rollers, this is for the handbrake pin. Make sure you rotate the bearing so the hole into the caliper is open for the pin you'll fit later will drop through to the lever. THIS IS IMPORTANT!
Step 3. Grease and fit the seal. You must also grease the pin and groove for the handbrake pin. Remember what was said before - note the orientation of the pin. On the top there is a flat edge and a rounded edge. Make sure the pin is all the way in and the seal sits in the groove in the pin
Step 4. Refit the arm, lock washer and nut. Tighten nut. The small arm should be one side of the spring pin, the longer arm the other side
Step 5. Refit the spring. Note that the short arm of the spring goes against the pin first, then with the pliers you fit the hook end in to the arm
Step 6. Rebuild the internals - Now you have to swap out the seals on the internal mechanism. There are only 2 seals, but it is important to note the direction they go in
Small "Square" seal goes to the spindle - Note here that there is a groove in the seal, when taking the old one off note the direction and refit the new one the same way
"Round" seal goes to the inner mechanism
Remove the seal, grease and fit new one. Also fill the hole in the back end with grease to hold the pin
Swap out the square seal on the spindle
Step 7. Reassemble the internal mechanism
Step 8. Insert into caliper. Okay, if you look into the barrel of the caliper you will see there are 2 drilled location holes, that match up to the pins on the mechanism above.
I couldn't get a good shot inside the barrel but you can see one of the holes in the shot below
Lower the mechanism into the barrel. The grease will hold the pin. Turn the mechanism until the pins line up and it drops the last step into place. Once it's in place you'll be able to see the cir clip groove at the bottom of the barrel
Step 9. Insert the internal spring, bearing cir clip - be prepared to scream at the whole thing during this step....
Grease the thrust race and washer. Place the parts over the spindle in the following order - Bearing, Washer, Spring (narrow end first), top hat
Okay, lower in the cir clip. I got it to the bottom of the barrel, then using 2 thin screw drivers I pushed it either side until the snapped into place. I couldn't photograph this but if you've got step 8 right you won't need a lot of force to do this.
Step 11. Fit the piston seal - grease it!
The caliper is now ready for the piston and dust seal
Step 12. Depending on what kit you've bought, you either have a new piston with internals or without. Mine was without so I had to swap over the spring and mechanism. With circlip pliers, remove the internal cir clip and remove the parts
Step 13. Re-build the piston. Replace the shaft, locating it in the bottom of the piston, then the spring and washer. Lastly, replace the cir clip. This spring is a hell of a lot more powerful so to get the cir clip into the grove, I used a 17mm socket and a vice.
Place the socket inside the piston (as above) and compress everything in the vice slowly until you hear the cir clip click. Then slowly unwind the vice. To be safe I checked the cir clip was seated correctly and gave it a few taps with the socket and a hammer for good measure!
Step 14. Dust seal and piston. This will either go right f!rst time or be thrown across the garage! What worked in the end was as follows:
Grease the seal and piston, lots of grease!
Put the dust seal onto the piston, pushing the seal up the piston (not down over the top). Push it all the way upto the groove in the piston so you have what's shown below
Now pull the seal back down the piston
Until it's about to come off the piston. Now the seal is essentially unraveled/inverted
Now, put the seal into the caliper, holding the piston. The part of the seal that sits in the barrel is off the end of the piston while still on the piston. This is important as if you try and fit the seal to the caliper first, the piston will not fit the seal. Not easy to explain
It takes a bit of time to get the seal into position. I used a piece of blunt plastic to push the seal into place. Once it is, you push and turn the piston back into place on the spindle with the large screwdriver. If it's tight or won't go easily, chances are you've not seated the dust seal correctly
The seal will drop into the groove on the piston
Job done! Repeat the above for the other side and you'll have 2 rebuilt calipers (or be stressed out that it wouldn't go back together properly!)
Check the handbrake lever works correctly (turn by hand), refit and bleed the brakes properly. I'd also recommend spinning the wheel and making sure both the handbrake and foot brake works on each wheel before driving off.