Brake discs and pad depositing.

Simon · 24 Aug 2012 at 09:26

Dogbreath said:
A friend of mine has a Civic VTi tarmac rally car which is currently running the standard size (tiny) front discs with DS2500. The car regularly comes into service with the discs visibly glowing, yet he has never experienced fade with these pads. The only only bad thing that happens is they start crumbling around the edges if you abuse them that badly. DS3000 are better but he had a hard time sourcing any.

He tried a set of Mintex race pads and they felt spongey and chewed through a set of discs in short order - not great for £150 worth of pads.

DS3000 are rubbish when cold, amazing when hot so perfect for track work. They will ruin your wheels though.

Liampope · 24 Aug 2012 at 09:35

Upgraded fluid/pads/discs will all be good for sure, but that sounds like a spectacularly quick time to boiling fluid, so are you sure you have the basics right first? You definately did a good job of the bleed and got out all old fluid/air/moisture, and all your calipers are in good order - no seized up pistons?

InvaderGIR · 24 Aug 2012 at 09:42

Will said:
I think Greens and halfords brake fluid will just never be quite the job with an E36 on track, I wouldnt be blaming the discs. 285mm discs on a relatively heavy car doesnt sound ideal either, any easy bolt on upgrade from another model elsewhere in the BMW range (ala the 300mm upgrade for my car which was cheap as chips)?

285mm is fine on the E36, some people upgrade it to the 300mm or whatever from the E46 as a precaution but generally there are minimal problems. Most people that I've spoken to with track E36s run stock sized discs, generic vented ones (E36 328i doesn't have solid) and some decent pads. Along with braided lines and DOT 5.1.

I'm surprised Clarkey is running DOT 4 though to be honest, I'm fairly sure I ran DOT 5.1 in my 318iS (same brake setup as a 328i), but can't remember.

As I said in the first reply though, read THIS thread (needs login) about PF pads as they are a decent price (even without the 10% discount) and a very good product.

318is boy said:
im running the z rated pads on genuine floating discs - took it out on track (Full weight road car m3) worked very well. felt like they got to a point where you though hmm they are getting a bit hot, maybe i should come in but then stayed at the level and behaved impecabbly. wear rate is quite high on discs and pads though. 10k and they nearly half gone..... (1 trackday)

Captain Vimes said:
As above, I put a set of these on my full fat M3 and was running 20-30 minutes sessions at bedford without issue. They did lose a little bit of bite after a while, but I could still trigger the ABS if I pushed the pedal hard enough.

I used rbf600 fluid on my set up and would reccomend them for occasional track days + road work.

There is mention of Yellow Stuffs being good/better but then also mention of them only lasting under 1k with track and road use.

I never had any issue in the 328i when it came to braking with these pads on the car, although I have no first hand track experience only fast road.

Berger · 24 Aug 2012 at 10:14

Gaygle said:
Wouldn't grooved and drilled discs help with the fade also?

Not noticeably the discs will be vented all round.

I would replace the lines/fluid and throw the greenstuffs as far as you can.

Replace with DS2500, ensure you bed them in properly and job done.

Probably end up cheaper to buy new discs than have them machined to remove the glazing/crud.

Firestar_3x · 24 Aug 2012 at 10:16

Dogbreath said:
You could fit Yellowstuff, or you could fit some decent pads like DS2500. Greenstuff is barely a fast road pad, it has no place on a track unless fitted to a very light car.

Oh so true, Greens turned out to be great on the 5 due to the weight, wouldn't fit them to anything larger, i found reds pants, cold bite is beyond a joke.

Simon · 24 Aug 2012 at 10:26

Yeah Yellows are better than reds when cold.

I hate Red, they ruin disks and are no better than yellows.

DS2500s seem to cause disk judder on S2000s with the Bremtech disks so maybe they dont suit certain pad materal / disk pairings.

Im still a bit perplexed as to why only DOT4 was used

HummuH1 · 24 Aug 2012 at 11:22

Simon said:
Im still a bit perplexed as to why only DOT4 was used

Why? A lot of high temp racing fluids are DOT 4. ATE Superblue is DOT 4.

Having tracked quite a few BMW's, if you plan to track it regularly there is only really one option to consider IMO, get a 4+ piston BBK. There's some decent kits for c. 300mm sizes for not a huge amount of money (compared to AP, Brembo etc).

BMW brakes have always been their achillies heel. You can upgrade the disc's, pads, hoses and fluid and it will make a substantial difference, to fade rather than stopping power. All that really ends up doing though is delaying the fade i.e. it takes longer for the brakes to overheat, so if you track it a lot, I'd seriously suggest a BBK is a better long term solution. They have decent 2nd hand value as well if you sell the car on.

Matt82 · 24 Aug 2012 at 11:27

brake fluid you get over the counter from VW, which is the same as what they use in the R8 and Lambos etc is just dot 4

Simon · 24 Aug 2012 at 11:35

And? That will overheat on a track too then. The R8 and lambos may use it but this for a car with proper cooling and much much bigger brakes, designed from the start to be driven hard.

DOT 5.1 is only a few quid more than DOT4 and if your already driving outside the cars design parameters then why not get an extra 40C on the dry boiling point?

Firestar_3x · 24 Aug 2012 at 11:36

Simon said:
Yeah Yellows are better than reds when cold.

I hate Red, they ruin disks and are no better than yellows.

Going to try some yellows next, just on generic Pagids at the moment and they suck when warm.

Also first time i've seen this:

http://www.halfords.com/webapp/wcs/..._productId_238257_langId_-1_categoryId_255218

Dot 4 for cars with ESP, interesting, i'm running 5.1 atm.

Simon · 24 Aug 2012 at 11:46

Matt82 said:
brake fluid you get over the counter from VW, which is the same as what they use in the R8 and Lambos etc is just dot 4

Just checked on the VW stuff.

This needs to meet the TL766 and all the products I can see are 'Dot 4 low viscosity' with a 265-270C dry boiling point versus the 240C min of DOT4, so its closer to a 5.1 than a 4 for dry boiling point.

HummuH1 · 24 Aug 2012 at 11:49

Simon said:
And? That will overheat on a track too then. The R8 and lambos may use it but this for a car with proper cooling and much much bigger brakes, designed from the start to be driven hard.

DOT 5.1 is only a few quid more than DOT4 and if your already driving outside the cars design parameters then why not get an extra 40C on the dry boiling point?

Boiling points on a lot of DOT 4 fluids exceed DOT 5.1 boiling points. Not all fluids no matter what the DOT standards (i.e. all DOT 4 or all DOT 5.1) have the same boiling point.

Gaijin · 24 Aug 2012 at 11:51

DOT4 is 'only' a set standard.

Motul RBF 600 (which I use) is DOT4 because it fails on one of the relatively unimportant DOT 5.1 specifications (think it was a low temperature threshold or something) - however it far exceeds 5.1 specification on practically everything else and pretty much is one of the highest regarded fluids if you can't/won't pay the megabucks for Castrol SRF.

Simon · 24 Aug 2012 at 11:51

HummuH1 said:
Boiling points on a lot of DOT 4 fluids exceed DOT 5.1 boiling points. Not all fluids no matter what the DOT standards (i.e. all DOT 4 or all DOT 5.1) have the same boiling point.

No they don't, anyway not sure why this is getting so derailed. My point was maybe a better fluid than Halfords DOT4 generic stuff may help.

Especially if the pedal is going to floor, althought this could be due to the pads i guess.

Gaijin · 24 Aug 2012 at 11:55

Here you go:

Motul RBF600 Factory Line brake fluid is a 100% synthetic brake fluid particularly suitable for the demands of racing and for those requiring a high performance brake fluid. This high performance DOT 4 brake fluid is particularly suitable for race applications and exceeds the DOT 5.1 and DOT 3 standards, except for viscosity at - 40°C (-40°F)

HummuH1 · 24 Aug 2012 at 12:03

Simon said:
No they don't, anyway not sure why this is getting so derailed. My point was maybe a better fluid than Halfords DOT4 generic stuff may help.

Especially if the pedal is going to floor, althought this could be due to the pads i guess.

Mate, they do.

Here's a DOT 4: http://www.demon-tweeks.co.uk/performance/brake-fluid/motul-rbf-600-high-performance-brake-fluid-2. Dry boiling point 312 celsius.

Here's a DOT 5.1: http://www.demon-tweeks.co.uk/performance/brake-fluid/a-p-racing-formula-brake-fluid-2. Dry boiling point 275 celcius.

Point is, DOT 4 can be perfectly suitable for this application. Depends on the spec of the Halfords stuff but I know others who use it in fast road/track applications. Not saying its best suited in this case, but it's not so much of an OMFG choice as it may appear.

Ev0 · 24 Aug 2012 at 12:17

As said I used castrol super dot 4 previously and found it fine. Looking up the numbers it's dry boiling point is 280.

I forget the pros and cons of using 4 over 5.1 and vice versa now.

Simon · 24 Aug 2012 at 14:04

HummuH1 said:
Mate, they do.

Here's a DOT 4: http://www.demon-tweeks.co.uk/performance/brake-fluid/motul-rbf-600-high-performance-brake-fluid-2. Dry boiling point 312 celsius.

Here's a DOT 5.1: http://www.demon-tweeks.co.uk/performance/brake-fluid/a-p-racing-formula-brake-fluid-2. Dry boiling point 275 celcius.

Point is, DOT 4 can be perfectly suitable for this application. Depends on the spec of the Halfords stuff but I know others who use it in fast road/track applications. Not saying its best suited in this case, but it's not so much of an OMFG choice as it may appear.

Fair enough I guess you did say some and not all

, it would be nice if the Halfords product had details on dry boiling point.

bledd · 24 Aug 2012 at 14:17

Gayjin said:
DOT4 is 'only' a set standard.

Motul RBF 600 (which I use) is DOT4 because it fails on one of the relatively unimportant DOT 5.1 specifications (think it was a low temperature threshold or something) - however it far exceeds 5.1 specification on practically everything else and pretty much is one of the highest regarded fluids if you can't/won't pay the megabucks for Castrol SRF.

This is what I use.

Moved to this + braided lines from stock 'honda' brake fluid and old lines.

Nice solid pedal feel

Simon · 24 Aug 2012 at 14:24

Biggest difference on mine was a master cylinder brace, the bulkhead flexs a few mm without one which makes a big difference to pedal feel.