Brake upgrade question.

[Leeroy87]

Maybe it was the brake fluid not being changed in awhile. Yesterday I went and picked up some nearly new full set  s3 calipers, carriers, hoses with new discs and pads for £400  . Just waiting on Daveb to send out new braided lines and my blue brake fluid to arrive 

P.s The s3 setup weighs a ton 

[flashp]

I wonder if by doing this you will have by default fixed a previously inexpensive fault to rectify.
You may notice the extra weight but the brakes are good. 

[r5gtt]

unsprung weight or was it sprung weigh

[Leeroy87]

Haha hopefully mate. Decided on this option as I'm going stage 2+ the end of January anyway. Yeah from what I've read they seem to be a good upgrade 

I wonder if by doing this you will have by default fixed a previously inexpensive fault to rectify.
You may notice the extra weight but the brakes are good. 

[pudding]

/\  Same.  Running stage2 ED30 with standard brakes and not found them lacking for road use.

Braking from 100ish on a downhill dual-carriageway exit is about the only time I've felt they were a little lacking, but that accounts for about 1% of my daily driving.

My only gripe about the brakes is the inconsistent pedal feel.  Sometimes they feel super grabby and other times they need a firmer push.  Vacuum pump on it's way out maybe?

What pads are they? If they are other than OE and have a specific bedding in procedure as performance pads often do, repeat the procedure and see what happens.
How old is your fluid? Has it always been changed on time?
Have you done a track day on them? You may have boiled the fluid and introduced bubbles.

I'd bet on one or more of the above before a brake servo.

The brakes were recently overhauled with OEM pads and discs all round, following complete seizure of both rear calipers.   

The previous owner fitted Mintex pads and aftermarket discs and the OEM stuff feels a lot better, so I think I'll stick with that from now on.   Yeah fluid done recently as part of a full service at my local dealer.  No track days done as yet.

I do actually have a leaky servo (can hear it hissing in the cabin) but there's also a vacuum pump on the side of the engine isn't there?  Not sure what that feeds but I've heard they can go.

[flashp]

Both rear calipers seizing is mightily unfortunate.
A lack of fluid changes is the biggest culprit for this, but not the only cause granted but definitely the most common.

I think you're being sensible in pursuing an OE parts fix and also properly diagnosing problems.

Maybe prudent and possibly cheaper given the accuracy of good diagnostics to give the car to a good independent garage for completing the rectification.

Maybe it's just a leaking hose/pipe or fitting?

[pudding]

Both rear calipers seizing in mightily unfortunate.
A lack of fluid changes is the biggest culprit for this, but not the only cause granted but definitely the most common.

I think you're being sensible in pursuing an OE parts fix and also properly diagnosing problems.

Maybe prudent and possibly cheaper given the accuracy of good diagnostics to give the car to a good independent garage for completing the rectification.

Maybe it's just a leaking hose/pipe or fitting?

Yeah my local dealer did the work.  I normally steer clear of them but this one is actually very good, and 5 min walk from my work!  They emailed me a video of their diagnosis, showing the rear wheel being hard to rotate by hand and both the calipers being beyond strip down and repair, so I know they weren't ripping me. 

Oddly enough the brakes have been very consistent this week, so I'll leave it for a while and see what happens.  Maybe it was just the new discs/pads bedding or something.