No pictures for now
As the DC5 caliper swap it is a popular mod this might be helpful for some people.
I would like to point out that this is the process I have followed for several calipers and for now it has worked fine for me.
Use this document just as a reference and follow it at your own risk.
Brakes are a delicate system of your car which might compromise your safety if anything goes wrong.
Here I had a set of DC5 Brembo calipers, I have to admit they came in pretty good shape but I decided to go for a full refurb just for... fun?
Bleeder nipple check.
For every set of used calipers playing the lottery of seized bleeder nipples is the first thing to do. Doing anything before knowing these are stuck or no is pointless IMHO.
Normally using a normal spanner might work but I have had bad experiences with these screws. The last thing you want to have is a damaged screw head.
My advice is to use a tube wrench or a long socket ALWAYS. Spanners might have some play and you might end up damaging the nipple's head and getting into trouble.
Use hexagonal wrenches/sockets only. Those "star" (12 sided) wrenches will probably damage the head too.
Apply a single and hard knock using a long bar or even an impact pistol, you might end up damaging the head if you pull soft and constantly.
Once the screws start to be loose, GET AN AIR GUN!! Put the bleeder caps on and thoroughly clean the screw's thread. Use brake cleaner spray if any dirt remains around the thread.
You don't want any dirt inside and probably some particles have dropped off when loosening the screw.
At this point the bleeder nipples should be confirmed not to be seized and it is worth to proceed to refurb the calipers, if not, there are plenty of videos on youtube about releasing these screws.
Make sure the banjo bolt and bleeder nipples are completely tight before proceeding to clean the calipers so no particles get inside.
Spray loads of brake cleaner and try to get rid of as much dirt as you can using this product, as it might not be enough wash the calipers using degreaser or KH7 for instance.
The calipers must be extremely clean before proceeding to manipulate them
I like checking how the pistons move BEFORE stripping the caliper. As the caliper should be clean now, get a tube that fits in the rotor's housing and wrap it around with a cloth rag.
Some people use wooden blocks or even the brake pads themselves. I like to use a tube because it remains centred so all the pistons come out by the same amount.
Anyways, remove the banjo bolt and using an air gun blow some air into the caliper. Make sure the inlet bore is CLEAN, yet again, you dont want any dirt to go inside the calipers.
The right tooling width the pistons should let the pistons come out at their maximum stroke without overpassing the seals.
Apply low pressure/flow so you can see how each of the pistons actuate.
Notice if any of the pistons moves with any difficulties, they might need to be checked later.
You should to feel with your own hands the smoothness of the movement of the pistons, remove the tube placed for stopping the pistons and release the bleeder screws, this is helpful specially for pushing the "last" piston in the circuit.
As the pistons are communicated in line it has happened to me that the piston furthest to the inlet slides harder than the others because of the air flow being restricted by the caliper itself. Having the bleeders open will help evacuate the air.
Push the pistons by hand and experience yourself how each of them slides.
At this point you could skip replacing the seals/rubbers/scraper rings if you feel comfortable with the functionality results. It is advisable to replace the bleeder screws or at least take them off and thoroughly clean the thread and using an air gun ensure they are not stuck.
In case removing the lacquer or sanding the calipers is needed I prefer to paint the calipers before taking out the pistons. Some others prefer painting the calipers after replacing the seals as the brake fluid might dissolve the fresh paint.
To me the reason is simple, dirt entry, I'd rather have to retouch the paint at the end and avoid having particles produced by the sanding mesisng up with the new seals.
Not much to say here, some will powdercoat the calipers, some others will use regular paint and a brush, heat proof spray paint, whatever works for you.
Before doing anything (specially if the calipers are freshly painted) cover the calipers with masking tape, this will allow you to protect the paint and handle the calipers with ease.
Cleanliness is key at this point, I like placing a cloth rag over the table so the spilled brake fluid is absorbed.
Pop out the pistons, I normally do it in two steps, first placing a wide tube and making the pistons come out as much as I can without surpassing the seals.
At this point I normally free the dust boots from the pistons and take the dust boots apart.
Whenever a dust boot/scraper ring is removed, blow away any particles around it. The less dirt is is exposed to the piston housing the better.
After, using a thin wooden block or something soft pop the pistons out using an air gun.
Keep it safe and do not place your hands between the pistons... and also, always place something SOFT between the pistons, you dont want any of the pistons to pop out violently and crashing against the others (damage...)
If any of the pistons gets stuck you could use a long flat screwdriver with it's tip covered by a piece of cloth and push it, be gentle, dont scratch it.
There are also special tools for this purpose, probably used just by specialist.
Put a cloth rag in the middle of the caliper (between the pistons) so the dirt particles are stopped by the rag and blow some air from the inlet bore.
Wipe with your thumbs the inner housing of each piston and make sure there are no particles inside. To me it is key to do this with your own hands (not a rag or so) so you can feel what the condition of the piston housing is.
Find your way to identify the pistons, meaning you want to place the same piston in the same housing it came out from. Myself, I place the pistons beside the caliper in the same position layout as they came out.
If you noticed that any of the pistons was not sliding smoothly it is time to check it now.
After cleaning the pistons check for the surface's condition, they should feel silky smooth even when showing some wear marks.
I have had successful results for "worn" pistons by using a 800/400 grit sanding paper and "polishing" them. Do it whatever you want, I normally place the sanding paper over the work table and sand the pistons with a linear motion over the paper while rolling them.
I am referring to some sort of polishing above, if your pistons are too worn just get some spare ones, they are quite inexpensive.
Make sure the pistons are spotless, clean them twice ^^
To remove the seal just follow one rule, do not damage the piston housing. Push/pinch the seal gently, avoid scratching the caliper's body. I have successfully used a guitar pick for this purpose
Yet again, wipe the housing with your fingers.
Lube the seal with assembly fluid. Most of the people use brake fluid and it is fine but I'd rather follow the manufacturer's advice and use the proper fluid.
Be gentle with the fluid, the outer face of the seal might not be exposed to much lubrication during its service life.
Place the seal in its housing, you'd better use two fingers and push it over the groove in opposite directions.
The seal should feel slightly tapered when fitted to the caliper. If you find the outer surface of the seal or the taper is not even, have it checked.
Lube every piston, at this point I use to fit the dust boot also.
Pay special attention to how the dust boot fits on the piston, pull the dust boot as much as you can as shown in the picture.
Slide each piston gently, they should slide silky smooth.
Before proceeding to test the calipers I'd rather flush the inner conduits by doing it this way:
Remove the bleeder screw closest to the inlet bore, blow some air (low pressure, the first piston might come out if the pressure is to high).
Put the bleeder screw back and remove the one furthest to the inlet. Proceed to flush the conduits. Do not put the bleeder screw back.
Place a tube/pipe/block between the pistons so that they can come out but don't pop out.
Using an air gun pump some air in and begin regulating the outlet flow with your thumb (last bleeder screw bore), restrict the outlet flow gently so you can see the pistons slide slowly, this is key to ensure there are no hardinesses that restrict the pistons movement.
Push the pistons back with your hands and ensure the motion is smooth.
It has happened to me once that one of the pistons did not move smoothly, just had to pop it out, "polish", clean, lube and put it back. Silky smooth right after that.
Ensure the dust boots are correctly fitted when they come out.
You should be finished at this point