brake sizes

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hampton
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Post Thu Feb 21, 2013 11:02 am

ive currently got the standard 320 front calipers, discs and pads and rear shoes and drum setup. without converting the rear to disc is there any difference in the 320 front setup and the 325 setup (caliper, disc and pad size?) as quite frankly the 320 setup is just pants
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gromgsxr
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Post Thu Feb 21, 2013 11:23 am

If they are vented I think they same size
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Post Thu Feb 21, 2013 11:32 am

All front discs are 260mm, it's just the thickness that differs between vented and non vented.
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Post Thu Feb 21, 2013 11:48 am

320i and 325i share the same front bakes.

I would suggest a careful rebuild with new discs and good quality pads.
Adding stainless steel braided flexi hoses and good quality brake fluid will also help.

Bear in mind that these cars were designed 30+ years ago,compared to a current car the brakes will need a lot more 'shove' to work properly.
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hampton
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Post Thu Feb 21, 2013 5:03 pm

ive gave them a lot of shove last week, they just fade really quickly, can anyone recommend a drilled and grooved disc for better cooling? my only other option if i cant improve the front stoppers is to convert the rear which i didnt want to do
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Post Thu Feb 21, 2013 5:23 pm

capnmchl
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Post Thu Feb 21, 2013 6:59 pm

Drilling and grooving discs has very little to do with cooling them.

You want to convert to a vented setup if yours are solid (I'm lead to believe some 2 door 2 litres came with solid discs?) which requires new calipers, discs and pads.

Read the Wiki which grrrmachine has posted to get an idea on the possibilitys in the zoniverse.
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gromgsxr
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Post Thu Feb 21, 2013 8:01 pm

Cross drilled discs are more prone to cracking around the dril holes
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Brianmoooore
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Post Thu Feb 21, 2013 8:20 pm

hampton wrote:ive currently got the standard 320 front calipers, discs and pads and rear shoes and drum setup. without converting the rear to disc is there any difference in the 320 front setup and the 325 setup (caliper, disc and pad size?) as quite frankly the 320 setup is just pants
Have you checked the thickness of your current discs? I regularly come across E30 discs that are worn way below their minimum thickness, are also usually riddled with cracks, and know from experience that these can fade badly if worked hard.
Standard vented front brakes and solid disc rears on an E30 are well up to hard road use if in good condition, and aren't ridiculously over assisted like some more modern cars.
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hampton
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Post Fri Feb 22, 2013 8:29 am

the discs and pads are fine that are on, i think they just your cheap motor factors rubbish though, i've have the same problems before with veco discs and pads. i pick my 3 sons up every sunday in the car and it will be just piece of mind for me if i could upgrade from standard brakes. Been looking at ebc drilled and grooved and green stuff pads. i used that setup on a mk2 astra gte but it took a while for the pads get up to good operating temperature
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Brianmoooore
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Post Fri Feb 22, 2013 10:01 am

Drilling and grooving has next to nothing to do with cooling the brakes. Years ago, some brake pad compounds, especially high performance ones, would emit gasses if they were over heated. These gasses caused a 'hovercraft effect' between the friction surface and the disc, reducing brake performance, so the holes and grooves were introduced as an escape path for these gasses.
Nowadays, no road pad, no 'pretend' competition pad, and very few 'real' competition pads suffer from gassing, so these days grooves and holes are for show only.
For road use, steer away from any pad that doesn't give full performance from stone cold. There is a world of difference between competition use and road use, and only in a very few cases is any component suitable for both.
I regularly tow dubiously heavy loads with my E30s, and there are seriously steep hills around here, yet I've never suffered fade with standard E30 brakes (usually Pagid discs and pads) in good order.
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Post Fri Feb 22, 2013 1:44 pm

I would agree about not bothering with anything other than standard (vented) discs in your case, and I would also avoid EBC Greens. If you are having brake fade then I would suggest EBC Reds (appear to be better from cold than Greens in the real world, and can take a load aof abuse) - plus check that any brake cooling ducts etc are there if your car had them.

Pagid stuff has a pretty good general rep too so not a bad bet for "normal" pads.
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