has anyone here done a brake job yet? is it ok to change just the pads the first time or no? im at 50000 kilometers.. i just wanna know if i gotta replace the rotors.. it feels ok when i brake and no pulsing.. the discs look smooth and i feel no grooves..

 

If the rotors are not scored or glazed then it is perfectly acceptable to simply replace the pads. If you have to open the master cylinder cover make sure to bleed the brakes and once complete be sure you "bed in" the new pads properly.
Have fun!

 

I've changed pads before on my older car. Should be the same process right? I usually don't open the master cylinder do I need to do that? Are crossed drilled rotors good or do they really make a mess of brake dust? How can u tell if they are glazed of scorned? Bed in? U mean break them in properly? Thanks

 

Steve -
Nothing special about replacing pads on the G - same process as any disc brake pad job. Typically, you need to open the master cylinder to allow for the pressure release when you push the calipers full open to release the spent pads and to install the new.

As for rotors, some people swear by vented or even cross drilled however, it is my observation that unless you are doing some serious track time, these simply eat up your pads more quickly & as you noted, make a mess! (flame suit on - bring the nay sayers).

When you remove your wheels, if the rotors are even slightly ridged, grooved or have uneven color (glazing/scoring) across the face then they need to be serviced/replaced so that when you instal your pads so they function properly and wear evenly.

Lastly, as for "bedding in" - this is the specific process to ensure that new pads are mated to the rotors correctly. It involves several successive full-brake stops followed by a cool down period and then a repeat. This process is a race proven exercise that will ultimately provide better performance and longer life of the pads. (I am likely to take some heat here too since very few people actually perform this vital function - flame suit enabled )

Oh - and if you replace your rotors do make sure that you take the time and index them - don't simply slap them on like 99% of people (including mechanics) do.

 

What does this involve? I'll be replacing my rotors in a little bit and want to do it right.

 

Basically you are eliminating the runout or variance in the effective flatness of the rotors. Believe it or not, there is some variation (and typically .002" is acceptable) across the rotor face but when you install new rotors, depending upon which position they are mounted in, this variation could become greater and thus reduce effective braking and/or contribute to excessive wear and/or noise. Indexing rotors is not difficult all you need is a dial indicator and a little patience.

I found a quick video on youtube that does a fair job of explaining the process in less than 2 minutes -->
A few salient points that the video doesn't show include a proper cleaning of the hub before replacing the rotor so the new rotors are truly flush. Also, the video doesn't explain (or show) that the best results are only achieved when all lug nuts are installed and torqued to the proper spec (80 ft lb for the G37)
Good luck!