Dilemma: when to change brakes?
Dilemma: when to change brakes?
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Synchromesh

Original Poster:

2,428 posts

197 months

Friday 27th September 2013
quotequote all
Looking for a bit of input as I can't decide what my best move would be here...

Just had my car (E36 328i) inspected and have been told I have approx 3mm of material left on the brake pads, and have been advised to get all four pads and discs replaced soon. I had a look for myself, and the garage who did the inspection know they won't be doing the work, so I know they're not having me on.

However, I've booked a track day which is in two weeks time, more specifically, an afternoon session at Keevil airfield.

So my question is, should I change the brakes the before or after this TD. If I get them done before, I risk not having them properly bedded in in time, and destroying the pads on track. If I leave it until after the TD, I risk finishing off my pads on track and not being able to get home (don't have breakdown cover).

I'm totally prepared to drive the track day with the state of the brakes in the back of my mind, and not use their full capacity, but for 3mm of pad, which option poses the lesser financial risk?

iva cosworth

44,044 posts

194 months

Friday 27th September 2013
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Do them before the track day as 3mm won't last long on track.

I would change pads only and then do the discs after the track day.

Big Fat Fatty

3,315 posts

187 months

Friday 27th September 2013
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Will you be doing the work yourself?

I'd buy some new pads now, do the trackday and change them there afterwards for the drive home. Or get two sets, one to change now before the day and then change them again afterwards.

wolf1

3,103 posts

281 months

Friday 27th September 2013
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Change them before the trackday. That'll give them time to bed in properly and you wont be facing any potential brake fade issues.

Synchromesh

Original Poster:

2,428 posts

197 months

Friday 27th September 2013
quotequote all
Big Fat Fatty said:
Will you be doing the work yourself?

I'd buy some new pads now, do the trackday and change them there afterwards for the drive home. Or get two sets, one to change now before the day and then change them again afterwards.
I've never done brakes myself, but I'd prepared to attempt it for the first time, just not at a track day. Don't plan to get through a set of pads in an afternoon either - did 6 track events in my MR2 (not all full days) on the same brakes and they still had life in them when I sold it!

iva and wolf - thanks for the advice. Looks like I'll get them done beforehand then.

Ray Luxury-Yacht

8,918 posts

247 months

Saturday 28th September 2013
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As above, I strongly recommend you change them before your track day!

Not only because the 3mm bit of meat left won't last 5 minutes on a track day (well, assuming you drive the car like you should be on a track day!) but also that the diminished pad material means that heat will build up to a much higher degree on shallow pads, which means that the heat will then be transferred and dissipated into the pistons and ultimately the caliper itself - which means two things: you will get brake fade from overheated pads, and also you may boil up the brake fluid over and above it's working limit, and then get a squishy pedal and all the problems that will also bring!

All undesirable things on a track day, I am sure you'll agree!

With regard to breaking-in the new pads...I wouldn't worry about that...you'll be able to do that pretty quickly on a track day.


For example - ok, a slightly different scenario I grant you - but back in my racing days on motorbikes, there were occasions when we had no choice but to head out for a race with a brand-new set of pads in the calipers. Yes, the race pads we used were pretty soft...but over the combination of the out-lap and two warm-up laps, if we used the distance carefully and spent the time braking hard and accelerating / repeat / by the time we got to the start line ready to go, the pads were as near as dammit broken in.

Then we maybe had to go a wee bit careful on lap one - just bringing the braking markers forwards by maybe 5 or 10 metres. Once a full race lap was done though, the pads were totally up to speed.


HTH!


vrooom

3,763 posts

298 months

Saturday 28th September 2013
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what 3mm?? 2 weeks ? you can do them in half day if you took your time. I change mine if it goes to like 5 mmm

brillomaster

1,902 posts

201 months

Saturday 28th September 2013
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most important thing to know is, what brakes set up have you got? my e36 328i has just failed its MOT for having front brakes below 1.5mm... I run EBC yellowstuff pads all round, which were new 4 trackdays ago.

so in four trackdays the fronts have gone down to 1.5mm, and the rears have gone down to 3mm.

if you've got decent pads on the front and you've still got 3mm left, i'd say you're good to go. if they're standard pads, they'll turn to cheese and fall off at the first sign of heat (i know because mine did after a day at Hullavington)

Also, you wont be stranded, you'll just have less than perfect brakes, and a orrible grinding noise, so you'll eat the front discs also)

to be on the safe side if you're reasonably confident, take a spare set with you, and if you start having a problem, swap them for new ones.