[DrDomer]

Hoping someone can help me with checking on brake pads. I'm a complete idiot when it comes to car mechanics and maintenance. In the past if something needed fixed the dealer or shop just fixed it. I never wanted to mess with it.

Well, now I hope to take the car to the track a couple of times a year. One of the things they talk about is brake pads. How do you check to see if they're sufficient to get out on the track? Do our cars need upgraded break pads for track days? Thanks for any pointers.

[S4to335]

If you are a relative noob to track driving...I would not worry about any brake pad change at this point. The stock brakes are fine for newbies. If you do anything..I would change to some Motul RBF600 brake fluid with a higher boiling point. I did get stock brake pad overflow (since it got hot and expanded) when I tracked my car with stock brake fluid. Cost varies by whom you get to do the job. Should be more than about an hours labor at a shop..and bring them the fluid or be prepared to be raped on the price of it.

[DrDomer]

F\U question. How do you determine the remaining brake pad life? Is there a way to look at them directly and know? Sorry for a very basic question.

[S4to335]

new, brake pads are about 3/8 to 7/16" deep....as they wear down...they decrease that number. Normal conservative thought it if your brake pads are less than 1/2 their original depth, that you should consider changing them for a track event...or at least bring a spare pair of pads with you to the event. Trust me on this...being unprepared for brake pad wear...I had to drive 178 miles home one day...from a track event...only using my emergency (rear) brake. I could not touch my regular brake pedal or you would hear the brake pad backing plate directly against the rotor with a very nasty metal-to-metal sound. My brake pad on one side was totally gone.

[DrDomer]

Thanks. This was why I was asking. By the time I have my track event I'll have roughly 12-13K miles on the car, and the track is 3 hrs from home. I read the pad replacement DIY on e90post. Is the only way to really measure pad depth to swing out the caliper? I really don't feel like bringing pads to the track that might need replaced. How would you handle it? Just bring the extra pads or have them replaced ahead of the event or should I be ok? I think I need a local mechanic outside of my BMW dealership that I can trust...

Originally Posted by S4to335

new, brake pads are about 3/8 to 7/16" deep....as they wear down...they decrease that number. Normal conservative thought it if your brake pads are less than 1/2 their original depth, that you should consider changing them for a track event...or at least bring a spare pair of pads with you to the event. Trust me on this...being unprepared for brake pad wear...I had to drive 178 miles home one day...from a track event...only using my emergency (rear) brake. I could not touch my regular brake pedal or you would hear the brake pad backing plate directly against the rotor with a very nasty metal-to-metal sound. My brake pad on one side was totally gone.

[2e9x's]

Personally I would replace them. My philosophy with track events is that you want to go and just enjoy your car. An ounce of prevention...

I had a track car for a while. Before each and every event I changed pads and rotors...I just didn't want to worry about them during the event. To me, the price was worth it.

[DrDomer]

Originally Posted by White05X3

I had a track car for a while. Before each and every event I changed pads and rotors...I just didn't want to worry about them during the event. To me, the price was worth it.

[S4to335]

Originally Posted by White05X3

Personally I would replace them. My philosophy with track events is that you want to go and just enjoy your car. An ounce of prevention...

I had a track car for a while. Before each and every event I changed pads and rotors...I just didn't want to worry about them during the event. To me, the price was worth it.

Wow...$$$$

[shimshimhada]

I would do what S4to335 said and swap out the brake fluid, although my stock fluid was fine for my first few events, granted it was extremely cold.

You should learn how to flush and bleed brake fluid anyway, it's an imperative skill for the track. Don't worry, it's very simple.

[JoeyG]

Originally Posted by shimshimhada

You should learn how to flush and bleed brake fluid anyway, it's an imperative skill for the track. Don't worry, it's very simple.

I'm in the same boat as the OP. Any chance you can do a quick write-up regarding the flush/bleed process?

[Dascamel]

Go to Midas or some random brake shop and just ask them show you how they do it. If its your first few times, I wouldn't worry about it too much.

[2e9x's]

Originally Posted by S4to335

Wow...$$$$

Nah...it was a 1989 MR2. The rotors were cheap ebay drilled rotors and the pads were fairly cheap Porterfield R4's. It was nice not to need to worry about my brakes.

[sg335]

Do a quick visual check of the pads through the caliper. The the pad material is equal to or less than the backing plate, change your pads as you have worn them down about 80%. New pad thickness is more than double the plate thickness.

[DrDomer]

That was helpful... Thanks.

Originally Posted by sg335

Do a quick visual check of the pads through the
caliper. The the pad material is equal to or less than the backing plate, change your pads as you have worn them down about 80%. New pad thickness is more than double the plate thickness.

[sg335]

I have a new set of race pads, so I measured them for this thread.

Front pads are approximately 14mm thick with a 4.5mm backing plate.
Rear pads are approximately 12mm thick with a 4.5mm backing plate.

I will correct my previous statement. Replace pads when fronts are 70% worn and rears 65% worn. These percentages will leave approximately the thickness of the backing plate left. These are for Raybestos fronts and Porterfield rears. Of course you can run them until there is nothing left, but this is never a good idea as you will ruin your rotors, and at less than 4mm left in the pad, heat transfer to the caliper and brake fluid will substantially increase resulting in quicker brake fade. I agree with S4to335; change them especially for a track day at around 50% remaining. In my previous car I had a little more than the backing plate thickness showing and before the end of the day, I had to change the front pads as one side worn down to the plate attachment anchors. You can also take your pads out to take an exact measurement with calipers. Replace if both are 6mm or less for a track event.

[shimshimhada]

Originally Posted by JoeyG

I'm in the same boat as the OP. Any chance you can do a quick write-up regarding the flush/bleed process?

Super Concise DIY:

Stuff:

-Brake bleeder bottle, buy one and save time, I like the CDOC one:
http://store.cdoc.com/detail.asp?id=...e=Brake+Fluids

There's also a cheaper one at Sears.

-Brake fluid obviously, I use ATE Super Blue or Typ 200 (same stuff, different colors), there are better fluids (Motul RBF/Castrol SRFballer), ATE is good enough for me.

-Floor jack, jack stands, combination wrench for the bleeder screw (dunno which size E90/92s use, use the box-end side), crossbar or impact wrench, torque wrench

-One intelligent friend, two is better.

Steps:
1. Jack up the car, place car on jack stands, and remove the wheels. Break the lugbolts on the ground first, if you lack an impact wrench.

2. Start with the caliper furthest away from the brake fluid reservoir, on my E46, that would be the rear right caliper. So do, RR, RL, FR, RL.

3. You'll see a bleeder nipple screw on back-top side of the caliper covered by its rubber valve cap. Some cars and aftermarket BBKs have two of these.

4. Remove the rubber cap, fit the proper box-end wrench over the screw, then plug your hose on well.

5. Get your friend to pump the brake pedal until it's firm.

6. When your friend shouts FIRM: Open the screw until the fluid starts to come out, close it when your friend says FLOOR (pedal to the floor).

7. BLEEDING: repeat 5-6 until no air bubbles come out.

FLUSHING: repeat 5-6 until you see the color of the fluid change completely.

*If you're using same color gold bf as stock, use a syringe tool to get most of the old bf out first, then fill with new bf.

**Have one of your friends make sure the bf fluid level is good after every time you open and close the screw.

8. Do the other calipers.

9. Fill the reservoir to max, close cap, close hood.

10. Wheels back on and off the jacks.

11. Torque wheels to 88ft/lbs.

Done.

[JoeyG]

Excellent, thanks Shim.

[DrDomer]

Originally Posted by sg335

These are for Raybestos fronts and Porterfield rears.

How are these for day-to-day driving? Where did you buy them? Cost? Does it void any warranty? Are they lots better than the OEM pads?

[leftcoastman]

I believe sg335 is running race pads on the track. If so, race pads are horrible for the street.

Noisy, harsh on rotors, dusty, ineffective when cold, etc.

[DrDomer]

That's what I was kinda wondering. No first hand experience obviously, but everyone mentions those brands when talking about racing. Just didn't know if they had pads that could be used for both.

Originally Posted by leftcoastman

I believe sg335 is running race pads on the track. If so, race pads are horrible for the street.

Noisy, harsh on rotors, dusty, ineffective when cold, etc.

[Vickyy]

sorry if this is a noob question too.. if u do get new brake pads before an event, should you brake it in a little bit before you go tracking? or it doesnt really matter??

[khoda355]

Originally Posted by Miss vicky

sorry if this is a noob question too.. if u do get new brake pads before an event, should you brake it in a little bit before you go tracking? or it doesnt really matter??

ooo yahh i dnt think thats a noob question, if so im a noob! ha