Saturday, February 18, 2017

Aston Martin Brake Change: Do-It-Yourself on the 2007 V8 Vantage

In a prior post, I laid out my 10-year ownership experience and maintenance costs on my 2007 Aston Martin V8 Vantage. I'm following up here with a Do-It-Yourself Brake Change discussion so that you can see that brake maintenance is easily done at home for a reasonable price, about $354 in parts compared to a full dealer brake service of more like $1200, or an independent shop cost of about $800. Keep in mind, I am not replacing the rotors in this case, as it wasn't necessary, I am only replacing the front and rear brake pads and any brake-wear sensors that have worn down.

So, let's say you just got a warning light on your dash, telling you "rear brake wear - see dealer" or something like that. That means your pads have worn down to the level that the brake wear sensors have come into contact with the rotors and now have worn down the plastic on the sensor face and tripped the electronic sensor. Please note that if you do your brake work before the sensor gets worn down, and you do not get a warning light, you do not need to replace the sensors. Even if the sensors had a touch of wear, they are good until they have been worn down so much that the circuit gets tripped.  After that, they're done.  You'll see more on that as we go.

Hopefully, this helps you as I try to document this process step-by-step ( not always easy to grab a camera mid-service when you've only got two hands!).

First: jack up the rear or front of the car (or the whole thing if you're lucky enough to have a lift!). I'm going to start with the rear wheels, so I first place a wheel chock in front of the front tires so I don't roll the car into something else (primarily the red car right in front of it!).

When you look under the side skirt areas of your V8 Vantage, you'll notice three areas where the composite body panels are recessed or cut away to reveal the metal frame where you can place a jack or a jack stand. The age-old problem is this: if you use a floor jack on a jack point, how do you then use that same structural point to place your jack stands? Well, not such a problem here, because of that  third (central) cut-out. Note that I used a hockey puck on my floor jack so that the contact point of the jack would not crack the surrounding plastic or composite body parts. I used a Vancouver Canuck puck because all the Canadians I know are nice people ;-).

I used the center-most cut-out area to jack the car up, which is just rear-ward of the forward jack-stand cutout (the forward cut-out is the one in the third photo below where you see the rubber grommet in the frame hole). Maybe it is hard to see here, but the puck fits nicely in the cut-out just to the rear of that forward one. You can also see where the jack is positioned just under the side mirror, to give you an idea of where to look for this cut-out.

Using that area to jack the car caused both the front and rear wheels to come off the ground enough that I could slip a jack stand under either, or both. I chose to do just the rears to start, so I didn't have to worry about the stability of the car on one side when I went to jack the other side up. I usually jack up all four on other cars (see "Cayman S Brake Update), but this time I decided be different, to show that a two-jack-stand method is just fine. I placed the jack stand longitudinally-oriented with the narrow frame cut-out closest to the rear wheels, so again it isn't touching plastic.

I then repeated this process on the other side, jacking up slowly so as not to disturb the first side's jack stand stability. When I was done, I had the two jack stands securely under the frame on both sides, ready to remove the rear wheels and start on the rear brakes.

Now we can see the simplicity of the brake pad replacement.  All you have to do is remove two retaining pins that run from the inside of the caliper across the back and through the holes in the brakes pads, and it is all held in place by a flat metal tension spring plate.  On the left of the first photo below, I start with the top pin and a metal "punch" and hammer.  I tap that pin L-to-R until it is about half way out. Then to keep the spring from flying away when the top pin is removed, I place my thumb against the brass colored spring plate (second photo below) and hold it down while I pull the top pin all the way out. Then I can remove the spring plate and move to the lower pin.

Now with both pins and the spring out, you can see where the rubber lead for the brake wear sensor comes through the caliper gap and attaches to the brake pad. In this case, I had gotten rear brake sensor lights on the dash, so I know I will be replacing the sensor devices.

This photo shows where that brake sensor leads to: the sensor device and wire is strapped along the brake line in a rubber wire harness leading to an electrical plug. The second photo shows the new sensors I purchased online ($120 via Ebay for OEM devices).

To remove the pads, I first squeezed the pads outward so that the pistons worked a bit back into the calipers, so that extra room would be made for the new, thicker pads to get re-installed (you can also compress those pistons later). As you remove the pads, you can see how the brake sensor fits snugly in the slot on the inside pad. I also used this opportunity to measure the thickness of the rotors with a micrometer, and they were still above spec for replacement (I have about .7mm left to go before replacing the rotors, so that suggests to me I have worn off maybe 1.3mm from the 28mm starting point. I don't track this car hard, so these rotors are ok for now, but will likely get worn by my new brake pads, so in another 10K miles or so, I'll likely do new rotors and pads again).

After removing the old brake sensor from the pad, you can see the worn spot compared to the raised bump that exists on the new sensor.

Next, you have to remove three snug-tabs that keep the old sensor wire strapped to the brake line. Then, you have to remove the electrical plug end as it is attached to the frame with a small ratcheted post. You use a screwdriver to pop the plug end off the frame, and then you have to use screwdriver to pull up the tab that keep the old plug attached to the wires leading to the dashboard. It looks like this before you pop the tab on the black part (the whole plastic is part of the replacement part, the black portion stays on the car).

Now that I have popped the two apart by prying up a bit on the black tab while pulling the white plastic away, you can see the two retaining posts on the white section that I had to pop off the frame to get to the point above. On the bottom right you see the guide pin that goes in one hole, and on the left bottom you see the ratcheted pin that secures it in the other hole.

There is a slight extra degree of difficulty on the driver's (left) side of the car, as the brake sensor harness goes under an additional brake line that has to be popped out of it's rubber retaining housing so that you can squeeze the white plastic piece under to remove and replace.  See how my blue-gloved finger below is pulling the brake line up a bit to create clearance for the left side brake sensor plug.

Now with the new sensor in place, we are ready to attach the sensor-end to the new brake pads. I've also cleaned off some of that nasty brake dust from the red calipers and you can sort of see inside where the pistons are recessed back into the calipers for the install of the new pads.

I chose to go with replacement pads that were not the OEM pads from Aston Martin. I had read that the aftermarket pads were grippier, but that might also mean they are more likely to wear my rotors down faster. The non-OEM pads were less expensive as well. I got EBC Redstuff ceramic low dust brake pads (DP91308C for front and DP91309C for rear). These are ceramic compound pads that work with steel brake rotors, not to be confused with pads for carbon-ceramic brakes. Cost was $122 for the front set and $112 for the back set. The rear set came with the anti-squeal plates attached, while the fronts had them in the box so the buyer could use them or not.

The EBC's fit great, no problem. Although on one pad, I had a struggle to fit the brake wear sensor head into the slot. A little filing to shave down the slotted area was all it needed. Then I just slid the pads in and tapped in the pins while holding in the tension spring.

Once they were all back in place, I replaced the wheels and checked the torque on the lug nuts (factory setting for the 22M nuts is 135lbs on the 19-inch wheels, or 100lbs if you have the 21MM lug nuts).

Shout out at this point to Bosch for one of the most dependable power tools I've ever owned. The lithium ion batteries on this impact gun last for months without losing charge. This is a great tool for the garage and the track, if you're taking wheels on and off reasonably often. In addition to this, I use a clicker-style torque wrench, 1/2' drive from Craftsman, with a  max setting of 150lbs, to set final torque on the wheels nuts once the car is back on its tires.

After it is all back down and torqued properly, I just crank her up and get ready to take it out to bed in the brakes with a  little spirited braking, according to the brake pad manufacturer's instructions. Before you head out, make sure you pump the brakes a number of times to get the pressure back in the calipers and get the caliper pistons fully re-engaged with the new pads. After 5-7 pumps, your brake pedal pressure should feel solid again. I had used the opportunity while the wheels were off to wash the inside of the wheels where all that nasty brake dust settles! She is ready and roadworthy again. Total cost: $354. Time: a few hours, including beer breaks.

No comments:

Post a Comment