AP Brakes users - Opinions please

[rlk500]

I have just had fitted AP 4 pots to my E30 M3. Ran the car at Outloon on Saturday and to say the least I am not a happy camper.

I am using Ferodo DS2500 pads and have proper ducting to back plates.

Either with the ducts fully open or closed I found the braking very inconsistent. You get an initial bite (but not a throw you out of the seat bite) followed by a period of very little retardation and then a big stop when at very low speed. Surely this isn't right. I was at times thinking I was going to hit people in front of me, I didn't as the car pulled up, but it wasn't confidence inspiring.

It would be interesting to hear other people's experiences, I have no reason to doubt that the hardware is good and can be made to work properly, or am I expecting too much.

One final point, with the engine off I have a firm pedal but it will slowly sink down under pressure, is this normal ?

[rlk500]

Thanks. Gdr, do you get a consistent stop when hitting the brakes, also do you have any ducting to the brakes ?

TIA

[rlk500]

Thanks guys. I have spoken to the guys who fitted the kit, who were most apologetic that all did not appear to be well and we discussed what to do. As I am a fair distance from them, I have been supplied with a list of items to check, but ultimately as most have implied, it seems most likely that there is a problem with the master cyclinder or I have a leak somewhere.

[rlk500]

Thanks fro the comments, gives me a good idea that all is definatley not well. I have recieved a set of Pagid pads to try, which are slightly better, but the car doesn't really pull up any better than the stock brakes did. I have spoken to the guys who fitted them and they are dead keen to have the car back to get it sorted, so it will be going back in early December.

[rlk500]

Just a quick update on the brake issues. I returned the car at the weekend and the proprieter drove the car. There I am thinking "what if he comes back and says they are fine.....". I need not have worried. His first comment was something along the lines of "mmmmmm...the're interesting" and then "you drove it here like that, and all they offered you was tea, should have been a large whisky...." So it does appear there is a problem. They are fairly sure that the brakes are working but one of the other systems is failing, either Servo, M/cylinder, ABS control unit etc etc. I await further news.

[rlk500]

Got the brakes sorted. It appears that the bias valve has developed a fault. They now work perfectly, and I am well pleased with them. Even with the Pagid blues which accordingly need lots of heat, they work excently from cold. Can't wait for a thorough track test.

[rlk500]

I spoke too soon.........bl**dy problems are back. Initial bite then very little, then they come back strong again as the car is almost stationary.

The appear to detoriorate over time, which would imply a leak, but then I would have thought it would be mushy all the time.

I have a new master cylinder on ordere to go in, fitters would like to replace the bias valve again as this fixed it last time. So It's MC first, then another bias valve if that doesn't sort it.