New discs and pads - correct break-in procedure

G

glastoveteran

Active member
 Bristol
Hi all,

Dealer is fitting new front (not sure about rear) discs and pads to my Z4MC after they supplied it to me with the brakes in a terrible state.

What is the correct way to break them in to get the best from them? CJ recently posted this excellent article which describes a series of ten increasingly hard stops from 60mph to 5 mph:

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

Is that what I should be doing? I'm guessing the dealer isn't going to be doing that as part of the fitting process but I may be wrong?

Thanks all,

Alex
 
The following recommendations came from Nick Adams (Lotus development engineer)

With new pads and discs, or just new pads fitted run the car around for 10/20 miles using the brakes gently as normal to bed the two surfaces together. Once this has been done, check the surfaces of the discs and make sure there are no signs of any scoring or damage. Assuming all looks well take the car to an appropriate piece of quiet and straight, well sighted road and perform half a dozen medium pressure stops from 50 mph down to 20 mph to warm the brakes up. Avoid more than a minute between each stop so that the temperatures do not get a chance to deteriorate too much. Once the brakes are warm and the coast is clear, perform 2 or 3 hard stops from 70mph (where local laws allow!) to 20 mph, braking as hard as you can without locking up. Do not come to a halt between each stop, do them as fast as you can to get the brakes really hot. On the third stop come to a halt and, keeping your foot on the brake, press the brake pedal down as hard as you can and hold it there for at least a couple of minutes, don't apply the handbrake. This hurts if you are doing it right! This will bed the pistons, shims and pads together and will compress the pad material, giving a hard and repeatable pedal. Once the 2 minutes have passed, release the pedal and go for a short drive, using the brakes as normal to let everything return to normal temperatures. The brakes are now fully bedded in and ready for use in anger. Recompressing the pads once every few thousand miles to the above procedure will help keep the pedal firm, especially if you don't normally use the brakes hard.

BUT I'm sure CJs advice will do just as well :thumbsup:
 
I know that post is from a lotus engineer and that he's probably forgotten more about brakes that i will ever know... but still... that sounds like a recipe for making sure you end up with pad deposits on the discs and get vibration through the brakes later.

i've always done the increasingly hard stops from higher and higher speeds but NEVER come to a complete stop and definitely dont sit there with your foot on the pedal...
 
As posted on the other thread I do this sort of process, but def not the stopping piece. A HAmza says I'd be worried about bonding and depositing he pads on th erotor and causing all sorts of hot spot issues on the rotor.

I also like to warm the disks up a little before I start so reduce the thermal shock and drive a bit with no brakes at all after to cool everything down.

Always had respect for mmm-five on the track as he cools his disks with a full lap before stopping :thumbsup:
 
I followed these which is pretty much as above:

http://www.zeckhausen.com/bedding_in_brakes.htm

Note the below though:

At the end of each slowdown, immediately accelerate back to 60mph and then apply the brakes again. DO NOT COME TO A COMPLETE STOP! If you stop completely and sit there with your foot on the brake pedal, you will imprint pad material onto the hot rotors, which could lead to vibration, uneven braking, and even ruin the rotors.

I agree with the others concerns and would be worried about holding the pedal down.

Mine smoked like crazy when doing the hard stops :evil:
 
gannet said:
daveg said:
Mine smoked like crazy when doing the hard stops :evil:
Click to expand...

yep so did mine :o
Click to expand...

Apparently, so did mine... according to my Dad, who was following me when I did mine.
I just did a series of partial stops, like 60 - 10, then up to 80 - 20 ish... nothing really measured, but fairly hard and indeed making sure I didn't come to a stop
 
daveg said:
I followed these which is pretty much as above:

http://www.zeckhausen.com/bedding_in_brakes.htm

Note the below though:

At the end of each slowdown, immediately accelerate back to 60mph and then apply the brakes again. DO NOT COME TO A COMPLETE STOP! If you stop completely and sit there with your foot on the brake pedal, you will imprint pad material onto the hot rotors, which could lead to vibration, uneven braking, and even ruin the rotors.

I agree with the others concerns and would be worried about holding the pedal down.

Mine smoked like crazy when doing the hard stops :evil:
Click to expand...

I did this with my new disc and pads as I was going to Anglesey the following week and I wanted to make sure they were done right. As has been said gentle break in for the first 20 miles or so and then follow the procedure described. Do not stop your runs when it starts to smoke or smell do a few more and then take time to cool the whole shooting match down.

When did the day at anglesey I did start to get quite a bit of vibration early on but I just broke throw it and it stopped after a few more laps.

This is another good article well worth the time http://www.essexparts.com/learning-center/cat/brake-rotors/post/Bed-in

P
 
Thanks for all the knowledgeable responses guys - picked the car up yesterday so will have a go at one of these techniques today.
 
You must log in or register to reply here.
Back
Top Bottom