Jim bailey - 928 International

Jim G ......the 928 actually has great brakes when they are working , I have raced on the early 80 front calipers / discs and the 82-86 fronts both work very well ; they will lock up sticky DOT legal race tires very easily . Try disconnecting the vacuum to the booster and see if the effort to stop changes . The two proportioning valves only reduce braking to the rear brakes so the front brakes lock up FIRST . I suspect the booster is not boosting for one reason or another .

928FIXER

First problem is that you had the rotors turned.Thats not a good idea.It can be done if done carfully by a caring person but most people do it to fast and to deep and leave a "record groove" finish in the rotor that leaves you with a hi hard pedal and no stopping power.Some shops run a sanding disc over it make it look "pretty" but its of little help to the finish.Put on a fresh set of rotors that have been blanchard ground and you will feel the difference on the first drive and they will get even better in about 1,000 miles of bedding in.

Randy V

Have you bedded in the new pads? This is critical.

The best and easiest way is to accelerate the car up to 30 mph (no more than that) on a level road, then apply the brakes - softly at first, until the car comes to a complete stop. Repeat up to 10 times - applying firmer pressure each time. Do not lock up the brakes - you want to bring the car to a long, slow stop.

After this, your brakes may experience significant fade due to the tremendous heat generated - keep that in mind during the last couple braking times.

Let the brakes cool - either by driving for awhile, or parking the car. After cool-down, you should now notice a significant improvement in braking performance.

Jim bailey - 928 International

928 fixer ..I believe he had the problem before he did this brake work and turned the rotors and still has the same problem . In my limited experience , turned rotors once bedded in stop the car just fine the drawback is the minimum thickness stamped on the rotors gives little material for resurfacing and it is sometimes difficult to get them true which makes the pedal "pulse" under braking . Any 928 should be able to lockup the tires , make big black marks and flat spot tires ......that I have done before with the old very brown 1980 .

Weissach

I sounds like you might have a vacuum problem at the booster. Remember that even with a leak in the booster, the brakes will work. You just won't have full control of your brakes.

macreel

Jim G... Stopping distances, perf'c.:
from 60 mph = 138 ft
(in 6 succesive tries, no fade)
from 80 mph = 248 ft.

G'luck.

Jim bailey - 928 International

With no vacuum or a defective booster you have no power assist , no power brakes , just a rather bad manual brake system which requires far too much effort to stop the car .

mark kibort

Hey, i raced my 79 at Thunderhill with mintex race pads. the car was fine. a little mushy at the end of the race, but the car was awesome, especially for how small the brake pads are up front for that model year. remember, 2:10 as a time was as fast as Don hanson in his 6.5 liter for his first couple of seasons racign, so you know I was punishing the ole 79.
The brakes on the 928s are just awesome. If you are having issues on the street, it could be you took too much material off the rotors. (dont turn them, you can get rotors new for almost as much money !)
or , you blead the system wrong. (ie start with the rear passenger side, driver side rear, then passenger side front, and then driver side front) . go the old fasion way. open valve (someone else does this), push pedal down to floor, close valve, lift pedal, repeat!

Ive used a bunch of different methods , pressure, one way valves, etc. they all dont seem to work as well as the old fasion way!

MK
brakes all day till tuesday!

Evian

BUY AN ANCHOR IN CASE ALL ELSE FAILS.