Tuesday, April 10, 2018

mini love - part 43

I waited for the winter to be over to install the Wilwood big brake kit for the front wheels on the Mini. Last summer I wanted to try out the stock brake as a baseline driving on tracks. I wanted to experience each step of change, from all stock brake, then to racing front brake pads with the stock calipers. I also wanted to use up the stock brake so I feel better they are not going to waste.

HPDE days are coming up fast and furious. I left myself very little time to install the Wilwood brakes. With projects like this there can be unanticipated surprise and it would be a real drag if after installing the new brakes then realized some is wrong and having to revert back to the stock brakes.

Wilwood BBK assembly diagram and parts list

wrong way to compress the caliper piston; it has been so long that I forgot

a pair of Channellock make it really easy for these floating calipers

the dust shield comes off as it is no longer compatible with the bigger disc diameter of the Wilwood as well as the calipers

seemingly a simple brake swap ended up requiring a lot of tools

the two main bolts fasten the caliper mounting bracket; I first use 3 pieces of 0.016" shims but it turns out 2 pieces after checking the centering of the caliper WRT the disc

just snug tight for now

next is to place the disc onto the hub and held by one countersink Torx bolt

this view scared me for a moment but the protruding ends of the main bolts are actually in the recess of the hub

here shows the part pieces for the caliper studs; I use 3 pieces of 0.016" spacers which is perfect

this strange looking nut got me really worry; I first tried Torx socket and realize it need twice number of points; I would realize it just need a 7/16" 12-point socket

the Wilwood braided brake lines does not have the rubber grommet made into the line so it is a sloppy fit since it has to slip over the fitting at the end

the hydraulic fluid port of the Wilwood caliper requires a 90-degree elbow

the elbow fitted

the smaller grommet does not fit into the bracket the factory brake uses; fortunately the Koni damper provisioned a smaller slot for it

these nuts and washers are for securing the caliper to the caliper bracket

the brake pads has not been fitted yet

The Wilwood braided lines where it mate to the Mini's hard lines gave me the most fit. It does not fit into the bracket as the hole of the bracket is slotted to prevent the line from rotate as you tighten the compressing fitting. I have to slightly round out the slotted hole of the bracket, which is quite hard in the confine space and dripping brake fluid. It is also very hard to tell how the slide in retainer work. After a lot of cussing and file and grind to fit I figured out it need to be slide in this way as in the photo below. A Channellock pliers make it easy.

Next is to address now defunct brake pad wear sensor. If I simply remove it, the brake wear indicator will illuminate. I decide to just tie it neatly away onto the bracket of the Koni damper.

the outer CV boot is in good shape

instead of leaving the 4 brake dust shield bolt holes expose to the elements I decided to replace the 4 Torx bolts to protect the threads from corrosion

the brake pads are semi-metalic

As I test fitted the brake pads I realized the calipers are not center WRT the disc rotor; it was a pain to subtract one 0.016" shim from the two main bolts holding the caliper bracket to the steering knuckle at this point. That a time consuming step I could have avoided have I found my feeler gauge earlier.

installing the anti-squeal shims onto the brake pads

the caliper is now center WRT the rotor when using only two shims

Next I check what it take to install the ECS braided brake lines for the rear brakes, since I will be flushing the brake fluid.

the ECS braided brake lines appears to be nicer than the Wilwood; it has made in the line grommet, and slotted end fitting where it mates to the hard line; it is also cheaper than the Wilwood ones

here is where the hard line connects to the stock rubber line

this is the other end of the brake line connecting to the caliper

the right side has the brake pad wear sensor so is more congested

I decided to postpone installing the braided brake line for the rear brakes, in case the Wilwood front brake turns out to be too much for the rear brakes and I have to increase the rear brake rotors.

Triple checking all the fasteners of the new brakes are properly torqued, including the brake lines the last step is to bleed the brakes. I broke out the brand new Schwaben pressure bleeder.

I also found a bottle to capture the waste brake fluid

I chose this for the narrow opening which will keep the hose end at the bottom; the snap on cap is also a bonus

I had to work between many periodic rain periods and it suck when you work with brake fluid

I actually had buyer's remorse after buying the pressure bleeder. This is because brake fluid is hygroscopic. With expensive racing fluid the last thing you want to do is pour a big quantity of fluid into the pressure bleeder and expose the unused fluid to air in storage. I also would realize the use of a pressure bleeder can make a big mess with unintended fluid spillage.

I then realize I can use it differently than intended. I would use it without putting brake fluid into the bleeder but just use it to pressure the brake fluid reservoir. To this the Schwaben shines over the competitions.

The bleeding fittings on the Wilwood calipers are tiny. It requires a 1/4" box end wrench. I also don't have hose of this small diameter so a trip to Home Depot for 1/4" OD PVC hose.

it has a quick disconnect fitting that is valved; it also has a pressure release

I switched to the plastic as for some reason the billet aluminum one has a small leak - I didn't want to apply too much torque to the cap so I switched to the plastic cap

The Schwaben bleeder make it really easy to bleed the brakes without putting the fluid into the bleeder. It is quite easy to remove the cap and check the reservoir level and resume.

I only pressurize to 10 PSI; I rather be safe than sorry

this is all the waste fluid collected

I had a major scare just when I refitting the wheels after satisfied the brakes are all properly installed and bled. After installing 2 wheel bolts just hand snug, I turned the wheel to make sure for one last time there is no interference. Clunk! WTF? I was sure last summer I did a very thorough job of clearance check and the SSR wheel has plenty of clearance. I look for wheel balance weight and there is none that come close to the calipers. Then I realized it is the home made wheel hangers that I screwed in deep and one hits the two main bolts for the caliper bracket. It would be a disaster to only find interference after all this work, and having to revert back to the stock brakes.
next I went for a drive to perform brake check, and first step of bedding in the brake pads

the surface rust of the rotor face from the rain is nicely polished away with just a short drive

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