When to replace the brake pads??
 

Hi.

I noticed my front pads appear to be about 1/8" thick (maybe a bit more) and the rears look to be about 3/8" thick (also maybe a bit more).

I'm thinking that the front should be done soon, but how thin it thin enough?

Also, I have never done a break pad job on any car before, but doing it on my 1997 Boxster seems like a fun, rewarding and major cost saving project. I've watched some videos and it really seems simple to do.

So, thoughts on how thin I can wear those pads down? and thoughts/guidance on doing it myself.

Any help will be great!! Thank you all.

Adam

The easiest way to know when to replace the pads is when the brake pad warning light illuminates on the dash. Each brake pad has a "sensor" that consists of an electrical loop of wire that is inserted into the brake pad and when the pad wears down far enough the loop is broken (which breaks the circuit) and the light on the dash turns on.

Alternatively, you can manually inspect the pads and replace them just before they wear down to the pad sensor hole that is molded into the edge of the brake pad. This will also save the cost of a new brake pad sensor.

Also, be sure to measure the thickness of the rotors to be sure that they are still within allowable thickness.

Brake pads are a fairly straight forward DIY and there is a lot of experience and help available here on the Forum.

Here you can see the pad sensor holes on the edge of this new set of pads...
http://i1114.photobucket.com/albums/...psszimkhdg.jpg

Here is a completely worn set of pads - don't wait this long!
http://i1114.photobucket.com/albums/...psoudktwsv.jpg

http://i1114.photobucket.com/albums/...psiwnf7hat.jpg

From new to gone in one track day
That some pretty heavy braking Tom

Rule of thumb is when the friction material is the same thickness as the backing plate, then it's time to replace.

Measuring the rotor thickness is more tricky. The ridge and grooves make it hard to get a real accurate measurement of the thickness. There is a special gauge for this:

https://images-na.ssl-images-amazon....L._SL1000_.jpg

How many miles on the car??

Ok cool.

I'm a little confused then....

When I said I have about 1/8" in the front and 3/8" in the rear, I estimated this by looking through the wheel on an angle to see what I thought are the pads.

Are you saying/showing me that in order to really see the remaining pad thickness, you need to take the wheel off and look at it face on?

I can send a picture of what I think is the pad, but not until tonight. But basically I'm looking at the part that comes in direct contact with the silver disk. I can only see the outer pad.

Assuming I have this correct, based on this statement: "Rule of thumb is when the friction material is the same thickness as the backing plate, then it's time to replace." I should replace the front pretty soon, like as in the next 1000 miles or less.

The car has 37,000 miles on it.

There are several DIY articles available on replacing pads and other common repairs. I would also recommend two books: 101 Projects and the Bentley book. Both are available on Amazon. I bought mine used.

I bought all the needed parts from Pelican. Lots and lots of choices. I buy parts from manufacturers that are OEM suppliers to Porsche, not the grossly overpriced Porsche branded parts.

Its actually quite easy. Take care that you get a long reach, low profile floor jack and decent jack stands. It is not safe to do repairs with the car held up by the scissor jack.

Anker

At 37,000 miles the rotors (silver round thing) should be fine.

Yes the backing plate is a steel piece that the friction material is bonded to. When you look in there you can see 1 side and if it's 1/8 of an inch, then replace NOW.

http://i1114.photobucket.com/albums/...psszimkhdg.jpg

Just to be perfectly clear, ( we are talking brakes here ) the backing plate is the outer yellow piece that has the silver pin in the center running thru it. OK? The friction material is also yellow but smaller and the pin does not go thru it.

Now, we are talkin about a MAJOR safety system that keep you safe but also those around you. If you do not have the knowledge, skills or tools, please ask for help or take it to a shop and watch. I have no idea where Fountain Hills is, but if I were close I would come and help you learn this simple but very important task. Please take no risks with this work!

If you don't have calipers with the pins, an easy el-cheapo way to measure the rotors is to use a couple of thick washers on the rotor surface, measure and then subtract the thickness of the washers
Yuo can buy a decent digital caliper from Harbor Freight for around $10. Mine look just like the ones Jon posted, but without the pins

Brake pad changes are probably one of the easiest DIY you can do.
It takes more time to jack the car and remove the wheel than to change the pads.
Once the wheel is off, it takes me maybe 90 seconds to swap out the pads

Ok here's what I'm going to do, I will post a photo of what I'm looking at and first see if it's what I think it is. I'm I'm correct, the front is about 1/8th inch remaining.

Here's the deal though, when I take the picture, the wheel will be on the car. I cannot take the same picture as shown above with the yellow pads (unless there's a way to get up under there, I guess I can try that too.

Anyway....hold this thought. I'll update this page with some pictures.

Thanks all...oh yeah Fountain Hills, Arizona. The weather is awesome this time of year!!

nice tool.
i went mcgiver, and made main from a $10 HF caliper, 2nuts and hot glue.
on a second thought, the original macgyver would probably use chewing gum instead of hot glue :D

I don't understand why you can't take the wheel off?????

You need to do that to examine the pads.

Anker

Take a look.....


http://986forum.com/forums/uploads02...1480718920.jpg



Now here is what I think is the pad.



http://986forum.com/forums/uploads02...1480720734.jpg

http://986forum.com/forums/uploads02...1480720984.jpg



Is that 1/8" thick section the brake pad? If so, I'm thinking that the brake light should be coming on pretty soon and that I should be ordering parts very soon.

Thoughts???

Yes, that is the pad material you have pointed out there. They are close to being in need of replacement as they look to be slightly thicker than the backing plate.

It's a great tool and not expensive at about $35. I don't have one BTW. I do kinda like you but used ball bearings, flats ground on the back and the same HF calipers, so I can get into the grooves and get a truer min. measurement.

Harbor Freight has one for $25. For this kind of work their stuff is great.

Anker

I develop the friction for a major brake pad manufacturer and we recommend that you change your pads when they reach 3mm of thickness left. The reason is that most companies use an "under layer" beneath the main friction material. Typically, these are 1.5 to 2mm thick in the OE pads (ours too). The under layer will have some stopping ability but do not wear too well so once you reach it it will be gone quickly.

Upshot is you should change the front pads soon. Rears are ok for a little more mileage.

Mark

It's fun to use the special gauge to determine rotor thickness, and I have one, too, but it's not really a required tool.

Your rotors are allowed to lose no more than 2 mm thickness from new.

It's pretty easy to feel for a lip at the outside edge of your rotor, and if there is one it really can't be more than 1 mm higher than the rest of the rotor surface. Remember the same lip almost certainly exists on the other side of the rotor which is of course harder to see. So, 2 mm loss is 1 mm on each side. One millimeter isn't very much, and if you have any lip at all it's likely pretty close to 1 mm and it's time for new rotors. You've got a ruler or tape measure somewhere to remind you what 1 mm looks like.

And, it is senseless to put new pads on worn rotors.

And, to replace the rotors, you have to remove the calipers first and reuse of the screws that mount the calipers is forbidden.

All that being said, I'd have to add that for someone that's not sure where their brake pads are and (I assume) not really sure whether you even have wear sensors installed, I'd advise at the minimum finding a friend that's done it before to assist. Perhaps there's a VERY basic u-tube out there that would help quite a bit, but at your novice level it's pretty doubtful that a bunch a typed words from a forum will get you through it. In any event, attempting this and about any level of DIY maintenance without reference to a repair manual is not wise, to say the least.

Full disclosure: I used to produce repair manuals as a job. Mine was of course a Military situation and you were required to have someone read the steps EVERY time.

Hi . Great info! Yes I am a novice. But I also know my limits. I posted the pictures to confirm what I knew from other cars just to be sure things were not more complicated which is what I keep expecting with this car. I think changing the pads and oil is easier on this car than on my Toyota 4Runner!!

And yes I have help too and I too have writen manuals and I am not wholly reliant on this forum for information. I'm using YouTube, manuals, books, experience, questing mentors and asking lots of question (many of which I know the answer too to test the answers I get, that's how I find the smart people).

I will order my parts tomorrow.

I think I'll follow up in this thread for a progress report.

Thx!!!

Boomer, once you have the brakes replaced and the wheel off you might also consider purging the brake fluid with new fluid.

I think the recommended interval is 3 years. There are 2 nipples at each wheel, on the calipers, to bleed and many of us use a pressure bleeding system like Motiv to make it quick and easy to do.

We alternate brake fluid colors at each change to make it easy to see when the new color starts coming out the bleed line so you know when you are done.


<iframe width="560" height="315" src="https://www.youtube.com/embed/mwvJxjqMYCQ" frameborder="0" allowfullscreen></iframe>
Note: The video only shows 1 of the 2 bleeder nipples being bled. You should bleed both nipples.

If you dont want to pay for the bleeder you can DIY and make one with a pesticide sprayer and a rubber stopper to fit your brake reservoir.

You need a small pressure guage as well as you don't want to over pressure the system and blow out any seals in the reservoir.

Good video, but

Get a good shop jack. The scissor jack is a pain in the butt, and you will need the shop jack to put the car on jack stands.

Why not use the impact driver to loosen the wheel nuts after jacking up the wheel?

The tool kit has a threaded guide in it to help put the wheel on. You can see what a pain it is to get the first bolt aligned if you don't use it.

I would never use an impact driver to tighten wheel bolts. Many impact drivers will over torque the bolts, even on the lowest setting. Easy to spin them in by hand and then use a torque wrench set at the proper torque.

He isn't tightening them in the right sequence. Always skip over one bolt going in one direction.

Anker

A couple of things on changing brake fluid.

You could change it at least every 2 years, more often if you track the car.
Unfortunately the Blue fluid is no longer available due to govt regulations that brake fluid must be amber or clear

jb92563,

Great point. I'm glad you brought this up.

So I just ordered my brake pad stuff from Pelican. I ordered to standard NON-ceramic type pads made by Textar. The guy who helped be out (Bruce) set me up with all the other stuff I will need.

He too mentioned bleeding the brakes, but said I could get away with only bleeding the front brakes and not worry about the rear. Do you guys agree with that? Reason I ask is most of the stuff I've read about that say you do all 4 wheels. I know on an aircraft I used to fly we could do just one wheel at a time, but I'm not sure how much transfer there is here....

I have read/heard to do this every two years. The car came with great records of all the maintenance that's been done on it, but the problem is, these dealer mechanics can't write and I can barely read their hard writing!! I think I need to have my wife decode their writing, she used to be a teacher!

SO, let's for the moment assume I cannot read/decode or otherwise verify an actual last brake bleed date. In this case I should for sure do the job.

One final question for the moment...I have no idea what kind of pads are on the front wheel right now. The only thing I can be sure of is: they were put on by the dealer at some point and I really can't complain about the amount of dust. The wheels do get a little dirty, but whipping them clean is very easy. I just don't know if they are ceramic or not. My guess is they are NOT ceramic.

Did I make a mistake by getting non-ceramic pads? I was pretty happy with the $88.00 price of those pads. I can't say I'd be happy about $110.00 pads, but what do I know...

It wouldn't make much sense to bleed or flush the brakes if you didn't do all four.

Yaa, that video was the first time I have ever flushed the brakes. I found out about the other bleed nipple afterwards. :confused:

So that's what that other thing is in the Porsche kit an alignment tool? I'll have to give that a try next time. :D

If there's a better way to tighten the lugs I'll do that too. Didn't know direction made a difference.

"We do everything like in the German Army, by the book of instruction"
<iframe width="560" height="315" src="https://www.youtube.com/embed/McFj_vq3cwk?start=0&end=9&autoplay=1&loop=1" frameborder="0" allowfullscreen></iframe>

I guess the whole point of that video is how easy it is to do and quick too.

For the $60 I spent on the Motiv, I beat the dealers cost now and into the future 1000%

When you bleed old fluid from a caliper in any location ,the first squirt of old fluid it the bleeder jar is usually the darkest. On that basis it seems prudent to bleed all calipers from all bleed nipples. In the correct sequence. Do not screw up and need to bleed the ABS ! Instructions are useful if followed.

You can buy Hydraulic fluid dye but the UV kind is only advertised for vehicles since it does not change the color of the Brake Fluid due to the Gov rules.

However the other colors are available and are under $10 for a bottle that will last even a racer a lifetime as you only use a couple drops every other time you flush.


God forbid that some kid see my can of Blue Brake fluid and think that its blueberry CoolAid, Oh, but wait, my gold brake fluid looks like Apple Juice.
So just as Bureaucrats come to dumb conclusions so must I, hence it must be true that kids prefer Blueberry over Apple Brake Fluid, and naturally it has been verified by special interest group's scientists by testing that on actual children.

You should bleed all the brakes, not just the fronts.
That is really poor advise

A bleed and a flush are different when you bleed you pull out a couple of onces. A flush requires a liter and it replaces all the fluid

When I get a chance I'll find my list of volume for each caliper Iirc it's 350 for rr 300 Rl
250 RF and 150 or close to that

The clutch bleed is an additional 150 ml if iremeber correctly

To save time when flushing, grab the turkey baster from the Missus cooking tools drawer and quickly sprint to the garage/driveway. Do not look furtively around you will give it away. Take the top off the MC and suck out all the crappy black-ish fluid in there and wipe out the gunk on the bottom. Squirt that junk into a container for later disposal. Wrap the baster in a paper towel and stick it in your pocket. Slink back into the kitchen and work your way over to the sink. Pretend to wash your hands and deftly sneak the baster from your pocket and into the sink. Give it a quick rinse and put it back into drawer. If she happens to see you with a big bulge in your pants, well that could be an issue but not our problem :-)

Well I've got everything ordered for the brake pads and brake bleed/flush jobs.

I've got my Saturday blocked off. I'm hopeful I'll only need half of it for the job!!

Thank you all for the help thus far.

LMAO!!

I have a spar one for my aquarium. I went down that road before. I got caught! And the bulge was NOT in my pants!! Dang...

Hold the phone a second...I have a question for you guys about bleeding the brakes.

Initially, I will remove say 90% of the old brake fluid out of the reservoir and then connect up the pressure tank with the new fluid. I understand the bleed process fine, but my question is at the back end of the process.

Once I'm done with the bleed, I'd expect to have some fluid remaining in the pressure tank and the lines between it and the reservoir cap (I'll start with 1 liter in the pressure tank on new fluid). As I release the pressure on the tank slowly, I'd expect the fluid to start filling the reservoir a bit, not a lot, but some. Then, when the pressure is off and I remove the pressure cap, I should (I BETTER) have some fluid in the reservoir. At this point do I simply refill the reservoir?

Now here is a technical point. I will be changing ONLY the front pads on this job, the rear pads are ok for now. If I understand this stuff correctly, I SHOULD NOT refill the reservoir back to the MAX line, but more closely to what the system started at, level wise, before I started anything.

Is that correct?

A good alternate method with a power bleeder is to do it dry.
Don t put fluid in the bleeder, fill the reservoir with fluid and use the bleeder only for pressure
Just be sure to check to make sure there is still fluid in the reservoir.

Bleed the rear brakes even if you are not changing the pads

bleeding only uses a few ounces of fluid. Bleeding is only removing the fluid in the caliper and maybe a little more as well as looking for air bubbles

If you are removing most of the fluid in the reservoir, and replacing it and more with fresh fluid you are flushing the system, not bleeding it.

As to as how much fluid should be in the reservoir after you are done.

First change the pads, then bleed or flush the system.
When you are done with that, fill it to the MAX line

bleeding/flushing is the last thing you do

JayG,

This is interesting to me. I have not heard a distinction between bleeding and flushing. It seems like a lot of people (at least on YouTube) use the term interchangeably. But what you have said makes a lot of sense to me.

Also, as a tad bit of more important information...I went back through the records I got from the previous owner. He had it dealer maintained. In October of 2015 (14 months ago), he had the brakes flushed...$160.00...:barf:

So, given that new bit of info, I think a bleed would be most appropriate here. Agree?

In doing so, I should follow your instructions then. To do this, would you suggest:

1. Remove old fluid from reservoir (not 100% drain)
2. Fill reservoir with new fluid (3/4-7/8 full)
3. Bleed all 4 brakes (until any air bubbles are gone)
4. Remove the pressure tank
5. Top off the fluid in the reservoir to MAX

In doing this, I would not put any fluid in the pressure tank and as you suggested, and use it to apply pressure to the system.

If I have this all correct, the only item I'd question above is #1. I'm not certain I really need to remove the old fluid in this case, but at the same time, I'm not sure it really hurts me either. Just curious what you think.

As always, thank you for the comments!

Adam

Ok, I need some more help....

I spoke to my mechanic today and told him I wanted to do my own brake job. He encoraged me and gave me some pointers. The kicker was that he said to fully expect to replace the rotors as they will likely be out of spec. He told me to check mine and see how deep the lip is at the very edge of the disk. Anything at or near 1mm will be too much and require replacement. Furthermore, if it happens to be ok, I need to be sure to use the same exact pads as on there now, otherwise it will squeal a lot.

I checked mine and I'm just under 1mm deep at the disc edge, but the brake light still has not come on. He suggested waiting for the light to come on and when it does, order the rotors and do the job first chance.

This all sounds like honest advice. What do you think? Should I just put this off as he suggested and do it when the light comes on?

Thanks all.

That sounds like good advice. Why change the pads and rotors before you need to.
I expect by the time your pads wear down and the light comes on, the rotors will be ready for replacement too.

I wish I saw this earlier.
Let's view the bigger picture for a moment.

I get the sense Boomer has not done a ton of auto DIY, but has got an itch to explore.
This is an opportunity to learn something new, work with your hands, and feel a sense of accomplishment.

Do the brakes need to be changed? Nope. Tons of pad left in the photo.
Should he change the brakes? HELL YES.
I don't care if the pads are brand new!
You want to learn how to change em? THEN CHANGE EM.

Let's not get him overwhelmed.
First, get comfortable jacking the car with jackstands.

Do the pads.
Yes, they are easier than a Toyota since they are exposed.
It's like changing bread in a toaster!

The most important thing here is to not ruin the experience by overloading this.
This is a hobby, not an optimized business transaction.
I'd have told him to ignore the bleeding for now, but fine.
Do it while you're there, but you don't want to scare him off.

Let's take baby steps, and build some confidence.

Forget the rotors. You can do them another time.
Don't let the rotor stuff hurt your momentum.
Once you're done, you can research rotors as a follow up project to get excited about.
This will allow you a 2nd day for jacking the car and removing the wheels.
The more you do it, the easier it becomes.

He knows how to research and how to ask questions.
Boomer, YOU CAN DO THIS.
You are very smart to block out a day to do this.
Expect to spend a few hours on this, ignore what people say, that's how long it will take you.

Do you have all the right tools?
You should get yourself a 4 lb hammer and a set of punch pins.
http://www.ebay.com/itm/Grip-9-Pc-Forged-Steel-Roll-Pin-Punch-Set-in-Roll-Up-Case-Rifle-Gunsmithing-9pc-/351839318815?hash=item51eb41f31f:g:~VoAAOSwzaJX9~n x

"If it ain't broke, don't fix it." :rolleyes:

Your brakes are fine. I'm sure you can find something that actually needs fixing. ;)
These cars are fun to work on and when you do get to the pads, it's maybe a 2-3 hour job, and that's if you take your time and bleed the calipers. :)

Spectacular photo of the down to the metal brake pads, by the way!

Sugarwood and all those who have helped me.

Thank you VERY much. You are spot on although I did decide to hold off and get the rotors done at the same time. The brakes don't need to be bled. I have a guy at work who is very experienced look at the fluid and the pads and said the same. I'm good for a while.

The oil change will actually happen next.

I think I might do the brakes on my Toyota before long.

And yes I do have those punch tools. The ones I have may not be as long, but there';s tricks for that!

Yeah I have to say its a little weird to be looking FORWARD to needing to do maintenance!!

:)

Read into the tools needed for a rotor job on your car.
You might need a breaker bar for any big caliper bolts.
Extension pipe over a wrench can also work.
Bungee cords to hang the caliper.
C-clamps to push the pads back in.
4 lb hammer to bang off the rotor.

Looking forward to the results.
Don't flake out!!