Big Brake Kit recommendations

[jann]

May need some rear discs for my 91 IS as they are rusted due to the car sitting still for an age....
Whats the standard size rear disc you guys do?
Would it fit the standard e30 rear calliper
Also i forgot the size of my BBS's
Could anyone tell by the pic

I would go outside and check... but its freaking boltic outside
Bit of a noob in this area.
Jann.

[Jhonno]

M3 E30 kits must fit behind 16's (315/320mm at most) as most of these cars are fitted with them.

325mm will fit as I said.. I am running 17's so will probably run bigger.

[keri-WMS]

Diameter wise 325 fits in a 16" wheel.. 17's are ideal for track use due to tyre choice, my e30 was awesome on it's 17's, not for rallying though..

M3 E30 kits must fit behind 16's (315/320mm at most) as most of these cars are fitted with them.

Re the M3, I want to get the kits in 16's, which really means 298.5 / 310 in many cases. A bigger kit might be worth it for people running 5-stud struts as a conversion, as "big wheels" seems to be part of the plan in many cases? Also 298.5 / 310 / 323 rotors are all cheap, bigger than that it starts to get painful for people.

Not sure about marks, I will have a look at the weekend to have and see.

With regards to break in procedure I just went down to a local trading estate and kept running up and down between two roundabouts slowly increasing brake pressure on the straights. Is that sufficient??

I cleaned the discs with isopropyl alcohol before use.

Any suggestions on pads with the coating??

I don't have the Ferodo bed-in stuff here, don't sound too far wrong though - and the disc were cleaned which is good.

With regards to the pads with a break-in coating I would just try some EBC Reds and see how you get on, don't push them until the bed-in layer has worn off to keep the temperatures even.

Let me know what you find with the discs!

Keri, I'm very interested in the rear kit so will be keeping an eye on the thread.

Cool - sadly it'll be a while before I stock them I expect, mainly because I'll have to get a big custom batch of the calipers made with small pistons.

[keri-WMS]

May need some rear discs for my 91 IS as they are rusted due to the car sitting still for an age....
Whats the standard size rear disc you guys do?
Would it fit the standard e30 rear calliper
Also i forgot the size of my BBS's

Std rear E30 discs are 258x10 and fit the standard rear caliper. I think that's the 15" BBS you have there?

Have a look at the bottom of page.1 of this thread, got the info there.

[Jhonno]

Keri.. There are quite a few disc option. One I have been looking at @330x30 is £36 a disc. I need to get hold of one to look at it, but I have been distracted by CSL discs, which are lighter..

[keri-WMS]

Keri.. There are quite a few disc option. One I have been looking at @330x30 is £36 a disc. I need to get hold of one to look at it, but I have been distracted by CSL discs, which are lighter..

That's for the E30 M3? I though all the bigger / later 3 series discs were deeper, and the 5 series ones deeper still?

[Jhonno]

Yeah.. I have been donated a CSL disc to see if I can work anything with.

CSL disc vs. stock M3



The 330 discs are not of BMW origin, but I believe much closer to the required offset off the bat

[Theo]

Mr Brake Disc, allow me to introduce you to Mr Track Rod End.

[Jhonno]

Fully aware of that clash..

[keri-WMS]

That's always the problem - I can find loads of discs I can use by putting a spacer between it and the hub, but that means the suspension geometry gets changed plus longer wheel bolts are needed, so not really an option for me.

[Jhonno]

Yeah it is an issue, I don't think running a sensible spacer is a huge problem though.. I used to run a 5mm just to clear my front caliper and I don't think it had a negative effect.

The 330x30 disc I was looking at has a 44mm back spacing, which is very close I think to not requiring a spacer, or only needing a small one. I haven't had one in my hand yet though. I need to see if ECP will let me buy and return..

[BadDave]

A 2 pc setup is the way forward.
Ok It's pricier, but get's you what your after.

And is that an E31,E34 M5 or E38 Brembo I spy in the pic??

[keri-WMS]

The plan is always to use a size where I can offer both discs and rotors+bells for the same caliper and bracket. The trouble is even with the "perfect" disc (or a rotor and bell) there still isn't room radially for me to get down to 300mm, or even 330mm.

This might result in a new caliper.....

[Jhonno]

That makes sense.. I was thinking about bells and rotors again, but this is a cheaper solution if I can get it to work.

[furbster]

Sorry Theo,

Forgot to thank you for the beddding in and pad information!!

[Jhonno]

A 2 pc setup is the way forward.
Ok It's pricier, but get's you what your after.

And is that an E31,E34 M5 or E38 Brembo I spy in the pic??

E31 840i Brembo.. Bolts straight on to the e30 M3 strut..

[furbster]

I don't have the Ferodo bed-in stuff here, don't sound too far wrong though - and the disc were cleaned which is good.

With regards to the pads with a break-in coating I would just try some EBC Reds and see how you get on, don't push them until the bed-in layer has worn off to keep the temperatures even.

Let me know what you find with the discs!

Right, the snow has finaly melted so I was able to get the wheels of today to inspect the discs and the pads....

The discs are showing no signs of any uneven pad deposit marks like the pics you showed however the pads appear to be f*'#ed for want of a better word!!

The driver side pads were absolutely fine with not too much wear at all but the passenger side is a different story. One pad has worn very unevenly (on a slope) and the other is almost through to the metal. (It hasn't damaged the disc yet and its not got that far).

I have linked some pics below for you to have a look at and welcome any suggestions as to why it happened and how to avoid it. Obviously I am going to need to replace my pads before Saturdays track day!







And finally a pic of the offending sides caliper with the pads removed.



One thing I don't know if it's worth mentioning or not but there is no locating screw in the disc as the hole does not line up with the thread in the hub. (Probably not relevant but thought I'd give as much info as possible).

Which Wilwood Caliper is the same as mine as Rally Design is just down the road from me and I need to pic some pads up quickly as the only day I can fit them is Tuesday before my track day on Saturday.

Thanks

[keri-WMS]

Hi Shane, I've got EBC reds on the shelf, and can get Reds/Yellows sent to you direct from EBC (Parcel Force 24h), but to be 100% sure you get them in time, the pad you're after is the same as the split-pin Wilwood Dynalite uses (the older type, and not the bridge bolt type). Take one of your old pads with you to RD to be totally sure they are the same.

As for the tapered wear, that's normal (but a bit annoying) with 4-pot calipers, and happens because the leading edge wants to "dig in" and tries to rotate the pad, creating faster wear at the front. The way round it is to have staggered pistons (like the WMS 1.62/1.75 size T20) with the smaller piston at the front to cancel the "dig in" effect, but it's less common to do this with smaller pistons. We could break from the convention and do staggered small-piston calipers, but this will add cost to the kits and mean race teams have to carry twice as many spares.

In the case of your pads, they are nearly worn out by the look of them - a race pads (or any pad in fact) has less thermal mass as it wears, so as they get thin your brakes get hotter, and wear faster as a result, plus are more likely to fade. This means most pads get replaced before the wedge becomes an issue - normally at about 50% > 30% thickness at the thinnest part.

Could you post some photos of your discs please? There looks to be a lot of surface rust from the discs on the pads - if your discs are rusty they will of course increase the rate the pad abrasion / wedging effect occurs compared to a clean disc? This normally means the outer pad in each caliper wears faster then the inner as the inside face of the disc is protected from the elements and stays rust-free!

Get a toothbrush and brake cleaner on the exposed pistons to get most of the dust off, then give them a LIGHT rub with something like fine scotchbright to clean them up before you push them back in the bores and fit the new pads.

By the way, the 1mm "lip" you can see on the pads is because Ferodo make their pads 1mm "taller" than the EBC ones (and most other makes I've seen), all WMS kits are based on EBC pads. Of course the lip isn't a problem, just looks nasty!

The reason for the lack of locating screw-hole in the disc is exactly the same as the same-size pistons: cost for the customer.....most people would rather pay less and not bother with the screw!

If the general consensus on the piston sizes and screw hole is people would like them (and are happy with the extra cost) then we are more than happy to look at it!

[furbster]

Hi Keri,

Thanks for the quick reply as normal..... That is exactly the reason I bought the kit from you and not a Wilwood setup from Rally Design in the first place!

I will post some pics of the discs in the week I get back out there to fit the new pads, that all makes perfect sense to me but I was just a bit surpised at how quickly the pads wore (Theo did say he had the same problem with Ferodos so I'll just stay away from them from now on).

Do you think we would be able to get some Yellows to me on a "Pre 10am delivery" for Tuesday and if so what would the additional cost be?

Failing that Rally Design only seem to stock EBC Greens as well as Willwood pads, I know the Greens won't be up to the job but am not sure which Willwood compound to go for.... Could you advise based on the specs below???

GATOR GREEN High friction at low temperatures, high torque - low pedal effort, excellent qualifying pad. 0 - 800°F OVAL RACE PAD - (short distance events)

POLY 'B' High friction over wide temperature range, consistant pedal, minimal pre bed required. 700 - 1500°F MEDIUM / HARD RACE APPLICATIONS, HARD RALLY, EURO CAR, GROUP A

TAN Ideal very low temperature pad, high torque - very low pedal effort. 0 - 700°F MOTORCYCLES, DRAG RACING, AUTOCROSS, AUTOTEST, SPRINTS

POLY 'D' High cold friction, low wear rate and easy on discs. Good fast road pad with no bedding in required. Consistent pedal feel hot or cold. 0 - 800°F FAST STREET, LIGHT RALLY, LIGHT RACE

POLY 'A' Severe duty race brake pad, long life, high friction, easily bedded and reasonable cold performance with extended rotor life. 450 - 1300°F HARD RACE, ENDURANCE RACING,
INTERNATIONAL RALLY

POLY 'E' Low wear rate, extended rotor life, very high friction from cold, ideal for high performance road vehicles, Cosworth's, Subaru's, etc. 0 - 900°F FAST ROAD, LIGHT RALLY, LIGHT RACE

POLY 'Q' A ceramic enhanced formula offering quieter stopping, low dust, long life, quick recovery and high fade resistance - the ultimate road car pad. 0 - 900°F FAST ROAD, LIGHT RALLY

I'm not bothered by the locating screw by the way, just thought I'd mention it incase it was relevant.

Thanks again

[e301988325i]

The uneven pad wear on one caliper would indicate sticky pistons not retracting to me.

When using new brake pads of a different compound, scrub the surface of the disc with emery cloth to remove deposits fom the previous brake pad material, otherwise from experience you will suffer horrible vibration. I use wilwoods and wilwood pads.

[keri-WMS]

No problem at all - happy to help!

EBC Yellows can only be PF24h as I have no control over them, £7.50+vat rings a bell?

EBC Reds I have here so can book a courier for the morning on those, it looks like £5.00+vat for 48h (often really next-day), £10.00+vat for 24h, £12.50+vat for by 12:00, £15.00+vat for by 10:00, £23.75+vat for by 9:00!

The law of diminishing returns I think it's called!

In terms of Wilwood pads, the Gator Green looks ok, I don't think it's the same as EBC Green is it? Better ask them? Poly A or Poly D look sensible though, best to pick one that works from cold.

e301988325i is right about scrubbing the discs clean, and made a good point about the pistons - I would get out there tonight (sorry!!) to clean the pistons and push them back in. They should go back in by hand or "very easily" if you use a clamp, if one of them is sticking let me know tonight so I have time to get some seals to you.

Just to be clear, the "wedging" is a seperate issue and happens with all similar 4-pots even if the calipers are perfect.

[furbster]

Thanks Guys,

Keri - I'll pop into Rally Design first thing in the morning just to be on the safe side as I don't really want EBC Reds and the Yellows won't get to me in time.

If they haven't got anything suitable in stock then I'll come back to you for those Reds as a backup plan.

I'm pretty sure I've got your contact details but could you either PM or post them on here just in case?

Thanks

[keri-WMS]

Thanks Guys,

Keri - I'll pop into Rally Design first thing in the morning just to be on the safe side as I don't really want EBC Reds and the Yellows won't get to me in time.

If they haven't got anything suitable in stock then I'll come back to you for those Reds as a backup plan.

I'm pretty sure I've got your contact details but could you either PM or post them on here just in case?

Thanks

Sounds like a plan, I'll PM you my mobile!

[e301988325i]

Just to be clear, the "wedging" is a seperate issue and happens with all similar 4-pots even if the calipers are perfect.

I had problems with this and found the caliper not sitting perfectly to the disc. I checked this by mounting a magnetic dti (clock) on the wheel bearing and rotating it (the wheel bearing and clock) along the caliper.

The strut mounting mount points don't have to be perfect, sliding calipers will accomodate some misalignment. I found a good trick was to use stainless washers instead of steel ones as they are about 0.2mm thicker when compared size for size. And this gives some fine adjustment. After this my tapered pad issues improved significantly,

To the OP, I think your pistons sticking have caused tapered wear as bad as you have shown in your pics.

[keri-WMS]

to the OP, I think your pistons sticking have caused tapered wear as bad as you have shown in your pics.

It's possible, but wedging is honestly very common/normal with non-staggered calipers. I guess Shane will find out when he pushes the pistons home. Here's what Wilwood have to say:

www.wilwood.com/TechTip/TechCaliperTip.aspx

"The caliper should be mounted so that the smaller piston end is closest to the rotor entrance, and the larger piston end toward the rotor exit. The larger piston end provides slightly greater clamping force to compensate for pad taper that can occur under extended severe use applications."

[DanThe]

I had exactly the same pad wear after a session at Oulton Park, ran the brake setup for about 3,000 miles of normal road use with perfectly even wear, then with only one days hard use they turned into door stops! These were EBC reds that seemed to disintegrate very quickly on track

[BadDave]

I run the Poly B's in my 6 pots and they seem to wear well under normal conditions.
You do get pad squeal under light application but some back road blasting soon cures that though.

No sign of tapered pad wear with differential bore pistons

[furbster]

e301988325i is right about scrubbing the discs clean, and made a good point about the pistons - I would get out there tonight (sorry!!) to clean the pistons and push them back in. They should go back in by hand or "very easily" if you use a clamp, if one of them is sticking let me know tonight so I have time to get some seals to you.

Keri - Thanks for the PM. Sorry, must have missed that bit as I was rushing to get out earlier and it's a bit dark to check now!

If one is sticking a bit I suppose I'll have to pop back to RD as I beleive they are the same as the Wilwood ones?

Would it matter too much if I didn't get the seals done until after the track day?

DanThe - I must admit Oulton is probably the hardest circuit for me on the brakes, well second to Lydden Hill which is normally a free for all so you end up trying to stuff the car up the inside on the brakes just to get past - track etiquate does not exist at that one!

BadDave - Do you use your car on the road as well or do you trailer it to circuits?

[BadDave]

BadDave - Do you use your car on the road as well or do you trailer it to circuits?

It mainly has road use, but on most of the roads I tend to play on, decent brakes are a must,along with a well sorted chassis.

The Poly B's came with the calipers as part of the deal and they're capable of hauling the old barge to a standstill PDQ to the point that,should fellow spirited drivers behind absent mindedly forget just how capable the brakes are, they find themselves having much less of a braking margin than they had anticipated.

[furbster]

BadDave - Do you use your car on the road as well or do you trailer it to circuits?

It mainly has road use, but on most of the roads I tend to play on, decent brakes are a must,along with a well sorted chassis

And the pads work okay from cold? The DS3000's weren't great when cold but the Poly B's you're using state they work between 700-1500 Degrees - I don't wanna crash into the services when pulling off the motorway for a pee break and a stretch!

[BadDave]

I've found they work fine from cold,others may have a different opinion

I haven't as yet found them to offer insufficient braking,but you do have to factor in that the pad I use is 6" in length compared to the 4" ones found in the WMS/Wilwood Dynalites with much larger disks(335mm dia)
I have upgraded to the E30 M3 master cylinder as well

[keri-WMS]

If one is sticking a bit I suppose I'll have to pop back to RD as I beleive they are the same as the Wilwood ones?

Would it matter too much if I didn't get the seals done until after the track day?

You only need to replace the seals if the pistons are sticking or leaking....I wouldn't think they are doing either, but you should clean the stuff off the pistons before pushing them back inside.

Edit: The WMS seals should also be the same as the Dynalite if you need them, but again take an old one along to check!

[DanThe]

I thought your pistons were a different diameter Keri

[keri-WMS]

I thought your pistons were a different diameter Keri

There are a few different piston sizes Wilwood use, but I think both 1.38" and 1.25" seals are available - from memory some of the staggered / 6 piston calipers had 1.25" as one of the pistons.

[keri-WMS]

After loads of hints.....here's the WMS T30x caliper at long last! It uses a mono-bridge design which makes it very very stiff, giving really good pedal feel.

Just need to get it in a kit....