JamesBaby wrote:RS4 B7 Caliper Refurbishment.
I set about a colour change and refurb of the front Brembo 8 Pot calipers and the rear calipers.
Before I started I checked all the bleed screws were free and found one on the front caliper, and one on the rear were seized. I figured I'd be able to get them off once the calipers were off the car but they were so badly seized that I rounded the head on them. In the end I needed the help of a professional to get them off. Jonny at
www.brakecaliperrefurbs.co.uk in Rochdale was very helpful and got the bleeders out. Jonny did my previous caliper refurb on my Daytona Avant earlier in this thread. On this occasion I decided to have a go myself.
To prevent brake fluid escape from the system I pressed the brake pedal down and wedged it with a long bar against the seat. This meant that just a small amount of fluid from the line was lost and the rest can't get past the master cylinder.
Here you can see how they looked at the start, and a picture of the rounded bleeder on one of the Brembo's.
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I tested various Red colours on an old toaster and found a colour called Brembo Red High Temperature from a company on eBay called 'xtremeautos' to be the right one. £23 delieverd. The etch primer also came with it. There is a Pillar Box red from Hycote available from shops but I found it too orange looking in certain light. On this picture there is a matt and gloss version on the long edge, and the Hycote Pillar box on the short edge.
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I started with the fronts and rubbed them down properly with Red grade Scotch pad. You have to get all the dirt and grime off and remove any shine from the original coating. Also rub he RS decal area so there is no raised lettering to spoil the finish. Here is the caliper with the pistons masked up using proper paint masking tape. I left the old bleeders in loose so as to not bung the threads with paint during painting. I will later replace them with Titanium bleed screws as they will not corrode like steel against Aluminium does. I also bunged all the screw holes with tissue paper.
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I cleaned and then soaked all the metal pins and parts in Bilt Hamber Deox-C rust remover. They came out nice as you can see. It's a great product I used earlier in this thread.
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I created a paint booth in my garden shed by stapling plastic sheet to the ceiling and walls. I hung a pole across the width and used coat hanger wire to hang the calipers. With the calipers clean and rubbed down started painting the etch primer.
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The spray painting process.
The first coat of paint or primer is not the coat that covers everything. It is merely a dusting of paint to form the base on which the full coat will sit.
Use the light coat of paint or primer to get into the nooks and crannies of the caliper first, and then continue to a light dusting all round.
Leave it to dry for 10-20 minutes depending on ambient temperature. You are simply wanting the solvent to 'flash off', and you can tell when it goes from wet to matt looking.
Then apply a fuller coat following the spray can instructions. Approx 25 cm away in cross strokes, paint or primer the caliper lightly, ensuring the nooks and crannies are covered.
Finally after that coat has flashed off, paint your final full layer. It is tempting at this stage to keep adding paint to cover everything. Don't. Just wait and apply another coat if needed otherwise you will get runs.
After your light and main primer coat, you may need 2-3 coats of colour including the first light dusting coat.
I added new decals from brakecaliperdecals.co.uk. If you are adding new decals you have a choice of sticking them on top and be done, or like me paint over them with a clear lacquer.
I carefully stuck my decals on whilst the paint was touch dry but not yet dried fully or baked. This I understand allows the vinyl adhesive to dry out with the paint.
With the caliper touch dry I sprayed it with a light coat of clear lacquer. By that I mean what feels like an insignificant dusting of lacquer. Leave to dry for stated time (15-20 mins), and then paint a slightly fuller coat. Then finally and full wet coat after that. Then leave to dry for several hours.
Here it is drying in the sun.
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I wanted the paint to have immediate resilience so I heat baked the caliper slightly. I prepped the oven to 60 degrees Celsius and baked the caliper for around 20-30 mins. Then I turned the oven up to 90 degrees and as soon as it hit 90 and turned the oven off and just let the fan spin on until cool. Here it is in the oven
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The reassembly.
I bought new Titanium bleed screws for the Brembos. The rears are steel so new steel ones are fine. You will notice the PTFE on the bleed screws. Some say this is not needed as it's the seat of the screw that's creating the fluid seal. However, it is also said that using a pressure bleeder can force some fluid up past the threads and thus risk bubbling the fresh paint off. I used the tape and figured it should be fine and well away from the seat.
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I also painted the centre pad holder nut silver, just to brake up the red colour on the Brembo's. Here is the finished article.
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And on the car
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To say I'm happy with how they came out is an understatement. Though the process was not without it's issues.
The thread where the brake line enters the caliper was cross threaded. The second time it's happened to me. I found a place in Rochdale called Lockstitch
http://www.lockstitchuk.co.uk/
They expertly hellicoiled the banjo thread on the caliper and I strongly suggest that you get this done to your Brembos. It is stronger as well.
Whilst the rear calipers were off I unscrewed the pistons and inserted new seals and lubricated them. They work great now too.
My pedal feel now is incredible too as a good clean up and regrease helps the brake system.
