Family4x4
9th May 2014, 04:35 PM
Disclaimer: I take no responsibility for others completing this job incorrectly and injuring themselves or others. If you are not confident and competent in undertaking this task, employ a trained professional.
The tools and seal kit I used are below. I replaced seals on both rear calipers.
44345 44346
A few items not in the picture are a small piece of dowl, q tips, vice, brake cleaner and brake grease.
Firstly i put a liberal amount of WD 40 into the cylinders via the brake line bolt hole, these calipers had been sitting for a while.
Next was to undo and remove the 12mm slide pin bolt (it may be very tight), followed by pulling the caliper apart and off the 2nd slide pin.
With the caliper in two pieces I then began the process to remove the piston.
There is a metal retaining clip holding the dust boot on this can be removed with a pick.
44347 44348
You may not be able to see the retaining clip, but it is on the outside rim of the boot on the cylinder wall. Once you have located the leading edge of the clip it should come out easily.
Once the clip is off it helps to push the piston out a little then remove the dust boot.
On these calipers the pistons were quite stuck, I used a piece of dowel(wood) in the brake line bolt hole and hammered the piston out. There are other methods of removing pistons, they can be googled if required.
44350 44351
Once you have the piston out check the general condition of the piston and cylinder with a visual inspection. If there is severe pitting or any deep gouges in either they will need to be replaced.
The square cut seal can now be removed from the cylinder. I use a hooked pick. Be careful not to damage or gouge the cylinder wall. The old black seal can be seen in the picture below.
44352
I use brake cleaner and a soft toothbrush to clean the piston and cylinder. The toothbrush should do a good job of removing any remnants of the old seal from the piston. When cleaning the cylinder pay particular attention to the notch where the new seal will seat.
Also remove the bleed nipple and check, clean or replace if necessary.
Once the cylinder is clean and the piston clean/polished you are ready to fit the new square cut seal. I lay out a new clean rag to avoid getting any dirt or contaminants on the new seal. It may also pay to wash your hands.
44353
Use a small amount of Dot 3 brake fluid to coat the outside of the seal (you may want to wear gloves). Then fit the seal into the groove in the cylinder. Ensure the seal has seated properly and not rolled.
44354
You can now fit the piston. Again coat the inside of the cylinder and the out side of the piston lightly with brake fluid.
When fitting the piston pay attention to it going in straight/square. I use a clamp and impact socket to gently guide the piston in. Only seat the piston about half way, so the groove for the dust boot is still showing.
44355
Now you can fit the dust boot to the groove on the piston, the flatter side of the boot faces the cylinder. The picture below show the face of the boot that will be showing when fitted.
44356 44357
When you have the boot on use your clamp and socket to further seat the piston, stop when the boot is starting to touch the cylinder housing.
44358
Now the boot needs to be fitted inside the cylinder housing, using your fingers or small flat blade screw driver carefully feed the boot into the cylinder housing. In the photo above you can see part of the boot has started to go into the housing.
Once the boot is inside the housing it needs to be seated. I carefully used the curved back of a pick to seat the boot. In the second photo below on the right hand side outer part of the boot, you can see the boot is still not seated.
44359 44360
When you have seated the boot the retaining clip needs to be fitted. Gently squeeze the retainer clip until it it the correct size to match the outer boot. Feed it on top of the very outer of the boot. Once it is in it can also be pushed carefully into place with the back of a pick.
44361
The piston assembly is now complete. The bleeder nipple can be refitted and its new rubber cap put on.
Now the slide pins will need to be cleaned. Remove old grease from the pins, also remove the old rubber boots and clean the housings.
44362
When refitting the small boot attach it to its larger end first.
44363 44364
With a small amount of grease and some gentle persuasion the double ended boot can be refitted.
44365
With a small amount of grease the bush from the double boot pin can be pushed in to the boot.
44366
Before putting the two halves of the caliper together check that the bolt on the fixed slide pin is tight.
Then grease the fixed slide pin and push it through the boot into its housing ensure the boot seats in the groove.
When swiveling the caliper the boot should not move, the pin should turn freely inside it.
Lastly lightly grease the last slide pin bolt and fit it.
Done.
Thanks to the bloke who made this rebuild possible!
The tools and seal kit I used are below. I replaced seals on both rear calipers.
44345 44346
A few items not in the picture are a small piece of dowl, q tips, vice, brake cleaner and brake grease.
Firstly i put a liberal amount of WD 40 into the cylinders via the brake line bolt hole, these calipers had been sitting for a while.
Next was to undo and remove the 12mm slide pin bolt (it may be very tight), followed by pulling the caliper apart and off the 2nd slide pin.
With the caliper in two pieces I then began the process to remove the piston.
There is a metal retaining clip holding the dust boot on this can be removed with a pick.
44347 44348
You may not be able to see the retaining clip, but it is on the outside rim of the boot on the cylinder wall. Once you have located the leading edge of the clip it should come out easily.
Once the clip is off it helps to push the piston out a little then remove the dust boot.
On these calipers the pistons were quite stuck, I used a piece of dowel(wood) in the brake line bolt hole and hammered the piston out. There are other methods of removing pistons, they can be googled if required.
44350 44351
Once you have the piston out check the general condition of the piston and cylinder with a visual inspection. If there is severe pitting or any deep gouges in either they will need to be replaced.
The square cut seal can now be removed from the cylinder. I use a hooked pick. Be careful not to damage or gouge the cylinder wall. The old black seal can be seen in the picture below.
44352
I use brake cleaner and a soft toothbrush to clean the piston and cylinder. The toothbrush should do a good job of removing any remnants of the old seal from the piston. When cleaning the cylinder pay particular attention to the notch where the new seal will seat.
Also remove the bleed nipple and check, clean or replace if necessary.
Once the cylinder is clean and the piston clean/polished you are ready to fit the new square cut seal. I lay out a new clean rag to avoid getting any dirt or contaminants on the new seal. It may also pay to wash your hands.
44353
Use a small amount of Dot 3 brake fluid to coat the outside of the seal (you may want to wear gloves). Then fit the seal into the groove in the cylinder. Ensure the seal has seated properly and not rolled.
44354
You can now fit the piston. Again coat the inside of the cylinder and the out side of the piston lightly with brake fluid.
When fitting the piston pay attention to it going in straight/square. I use a clamp and impact socket to gently guide the piston in. Only seat the piston about half way, so the groove for the dust boot is still showing.
44355
Now you can fit the dust boot to the groove on the piston, the flatter side of the boot faces the cylinder. The picture below show the face of the boot that will be showing when fitted.
44356 44357
When you have the boot on use your clamp and socket to further seat the piston, stop when the boot is starting to touch the cylinder housing.
44358
Now the boot needs to be fitted inside the cylinder housing, using your fingers or small flat blade screw driver carefully feed the boot into the cylinder housing. In the photo above you can see part of the boot has started to go into the housing.
Once the boot is inside the housing it needs to be seated. I carefully used the curved back of a pick to seat the boot. In the second photo below on the right hand side outer part of the boot, you can see the boot is still not seated.
44359 44360
When you have seated the boot the retaining clip needs to be fitted. Gently squeeze the retainer clip until it it the correct size to match the outer boot. Feed it on top of the very outer of the boot. Once it is in it can also be pushed carefully into place with the back of a pick.
44361
The piston assembly is now complete. The bleeder nipple can be refitted and its new rubber cap put on.
Now the slide pins will need to be cleaned. Remove old grease from the pins, also remove the old rubber boots and clean the housings.
44362
When refitting the small boot attach it to its larger end first.
44363 44364
With a small amount of grease and some gentle persuasion the double ended boot can be refitted.
44365
With a small amount of grease the bush from the double boot pin can be pushed in to the boot.
44366
Before putting the two halves of the caliper together check that the bolt on the fixed slide pin is tight.
Then grease the fixed slide pin and push it through the boot into its housing ensure the boot seats in the groove.
When swiveling the caliper the boot should not move, the pin should turn freely inside it.
Lastly lightly grease the last slide pin bolt and fit it.
Done.
Thanks to the bloke who made this rebuild possible!