2009 Nissan 370Z: DIY Brake Pad and Rotor Change, Part 1
August 08, 2009
We've already hinted that we changed the front brakes and rotors on our 2009 Nissan 370Z. The following shows you what we did. But why did we do it ourselves? a) it's easy, b) we like the whole DIY thing, and; c) it saves money.
We're using factory parts because this isn't a project car, and generally we want to test our long-term cars in their as-built condition. But the process is much the same with any other pads you choose to use.
Did I mention it's easy? It is. If you have the tools, it almost takes more time to read this than to actually do it.
Don't have a 2009 NIssan 370Z? Not to worry. A lot of this will apply, in general terms at least, to other brands of cars that have 4-piston fixed calipers and hat-style rotors.
There are too many pictures for one post, so I'm breaking this into a pad change (part 1) and a rotor change (part 2). In reality, the rotor change happens in the middle of the whole process, but I'll call that out when we get there.
Our story starts just after we've jacked the car, put the front end on jack stands, chocked the rear wheels and removed the front wheels.
Step one consists picking a side to start on and turning the steering as far as it will go in the direction that makes the caliper face out.
The 370Z is particulary simple because of the open design of its fixed-piston calipers. There are no bolts to remove, and at no time do you get close to any hydraulic fittings.
I'm pointing to a little cotter clip that keeps the pad retaining pins in place. The pin isn't threaded in -- the screwdriver is simply there to rotate the pin so the clip faces our where I can grab it.
There isn't much tension on the clip, so I can easily pull it out with the point of my screwdriver. Needle nose pliers work well if the clips are tighter.
Once the clip is removed, the pin pushes stright out with a little help from my screwdriver. I'm also using my thumb to relieve tension on the broad anti-rattle spring by pressing on its central finger. Don't push hard enough to permanently bend it, however, because this part is re-used.
The two slender pad pins are the only things holding the spring in place, so it will fall out as soon as the last pin is clear.
With the pins gone, the only thing holding the pads in place is the tight clearance between the rotor, pad and pistons. The clearance opens up as the pistons retract when I pull the pad ears away from the rotor with my thumbs. It takes a few seconds of steady pressure because I'm essentially pushing hydraulic fluid backwards through the system, but I only have to move it the thickness of two or three business cards to create enough space for the pads to come out.
Both pads are out. But don't throw them away just yet. They still have a role to play.
NOTE: This is the point where those who want to do a rotor change should skip to Part 2 . Come back when you're done to see how the pads go back in. We'll still be here.
Meanwhile, if a pad change is all you want, read on...
If it looks like I've backed-up a half step, you're right. I don't have (and have never yet needed) a specialized brake pad retraction tool, but I don't do 6 or 8 of these a day, either. On the 370Z, at least, careful use of the old worn pads themselves does the trick.
On the left I've re-inserted the old pad just far enough to keep the pistons on that side form moving out as I compress the ones on the side I'm working. On the right, I've turned the other old pad 90 degrees and I'm using it to gently pry the two pistons on that side back into the caliper.
I have to be careful that the piston's rubber gaskets don't get pinched or torn in the process as I pry them back home. And I have to make sure I'm pushing both pistons in unison. Pushing one by itself will simply pop the other one out -- a disaster. I keep an eye on things and go slowly. .
In doing this, brake fluid is being pushed back into the master cylinder. If it's full already, it will overflow if you don't keep an eye on it. One benefit of doing one side at a time like this is that only half the caliper's volume of fluid goes into the resevoir at a time, and everything happens more slowly.
The difference between the thickness of the new and old pads is the amount of clearance I have to create when retracting the pistons.
I need to keep an eye peeled here as I retract each pair of pistons because this is where that surplus fluid goes. Our dealer refilled this reservior during our last visit, so it started out full and we ended up having to suck some out a couple of times during the process. An old turkey baster works fine.
Always keep the cap on the reservoir as much as possible between checks, because brake fluid absorbs moisture.
I'm doing one pad at a time, so the other old pad is still in the caliper while I change the first one. The new pads came with a graphite silencing/lubricating compound, and it goes between the backing plate (the hard steel backing of the new pad) and the shim. There's just enough lube to do a full set of 4 front brake pads, but a little goes a long way. This isn't your kids peanut butter sandwich.
Doing a single pad at a time also makes it easier to match up the shims correctly as I transfer them from old to new, and it also makes it easier to ensure the pad wear indicator (gold clip) gets put in on the correct side. Just match everything up and you're good.
Don't forget a dab of grease on the pad ends. The four corners of the backing plate do make contact with the inside of the caliper body the whole time they're in there.
New pad 1 is going in and old pad 2 is still functioning as a spacer on the other side. As soon as new pad 1 is seated, it becomes the spacer and I repeat the whole process with old pad 2. That includes retraction, watching the fluid lever (and sucking some out, etc.) and the shim and lubricant steps.
I've skipped ahead to the point where both new pads are in. The broad anti-rattle spring goes back in place as I push the first pin back through it to the hole on the other side.
Just like the diasassembly phase, I need to push the tab right here (yellow) to temporarily relieve the tension as I push the second pin through. I musn't push hard enough to permanently bend it because the tension needs to be there for the anti-rattle spring to do its job.
The phillips head on the 370Z's pad pins serves no other purpose than to allow easy positioning of the retaining clip hole. It should face straight out, like this.
The retaining clips (new ones came with the new pads) go in easily when things are properly aligned.
And that's pretty much it. One down, one to go. I repeat the whole process on the other side of the car, put the wheels back on (and torque them) and take it out for some break-in driving.
I live in an area where I can get away from traffic, and I do several firm 60 to 20 mph "stops" on an open stretch, allowing a minute or two of cool-down time in between. After a half-dozen of these, I begin driving normally up and down the hills in my neighborhood. The brakes feel as good as they ever have and there's no noise or vibration. I call it good.
Bed-in procedures vary greatly depending on the type of pad (factory or track), whether or not you replaced or refaced rotors at the same time, and with the type of driving you'll be doing (street or track). Generally speaking, the procedure is more critical and specific when exotic pads and track driving is in your future and it's less critical with factory pads and regular street use. Many new cars roll off the assembly line with no bed-in whatsoever, in fact.
If you bought a high-performance pad that's intended for track use, make sure you read and follow the specific bed-procedure the pad-maker recommends.
Dan Edmunds, Director of Vehicle Testing @ 10,001 miles