AE86 VEnted disc thickness

**myt-16v** · 26-07-2007, 01:45 PM

HI all

Does any one know what the thickness of JDM front dics should be and what the minimum thickness allowed is??

Many thanks

**LeeRoy** · 26-07-2007, 01:53 PM

Get onto the DBA website and check there. Should have min and max thicknesses.

**twentyEight** · 26-07-2007, 02:17 PM

Original thickness: 12.5mm

Minimum thickness: 11.5mm

http://www.dba.com.au/2006/PDF_CATAL...Catalogue_AUST

**Mr Revhead** · 26-07-2007, 02:25 PM

thats not for the jdm ones....

17mm min and 18mm new is my info....

**twentyEight** · 26-07-2007, 02:36 PM

Feck, I missed the JDM part...

**Mr Revhead** · 26-07-2007, 02:39 PM

JDM yo.... makes all the difference

**parrot** · 26-07-2007, 02:40 PM

twentyEight and Mr revhead are both correct according to the AE86 Body manual. maximum disc runout is 0.15mm

**myt-16v** · 26-07-2007, 03:41 PM

Thanks for that guys. Much appreciated.

If discs are to thin does that make pedal feel very spongy. Coz i've checked everything else. New master cylinder etc.

**oldeskewltoy** · 27-07-2007, 03:36 PM

AE86 brakes are a touchy subject. All too often I've found a bad master cylinder... and often it isn't bad till you attempt to bleed the brakes. The easiest way of confirmng this I've found... bleed the brakes... get it operating like it should... start the car.... the pedal goes soft right after the first use of the brakes ONCE the engine is running.......

Reasoning is simple... the master cylinder has this working range it usually works in... eventually it wears a pattern into the master cylinder. The first attempt at bleeding the brakes pushes the master cylinder past its regular operating range causing small irregularities in the master cylinder seals... causing air to get in the system.

When bleeding brakes to flush the system I recommend instead of bleeding the brakes, use a basting bulb... draw out all the fluid in the master and replace with new fluid. a week later I do the same thing again... and a week after that I do it a third time. By the third time I've swapped out more than 80% of the original fluid. The system is cleaned up and the master cylinder is never pushed beyond its normal operating range....