OK, so the front calipers were refurb'd as described at the start of this thread 6 years ago. Over the last few months I havent been using the car that much but there was a hint of judder which, on my last motorway/fast outing recently started to get noticeable at high speed. So, as i had some new Brembo pads sitting on the shelf, I thought i would investigate whether the pistons/pads were sticking and renew the pads whilst i was at it. I did have real trouble getting the pads/ pistons retracted and then getting the pads out of the guides required considerable force. After removing the pads I was able to get the pistons fully depressed albeit with the aid of clamps but they did, eventually, move under finger pressure. It seemed to me that the pads sticking in the guides was the main issue. So, after some filing, i got the new pads to fit in the guides with just sufficient movement. Result - so i thought. Test drive employing a bedding technique involving a number of stops from 60 to 0 soon revealed alarming judder.
I should add that when the calipers were off the discs and pads removed I did carefully try the brake pedal without the engine running to see if the pistons would move out. (I used a chunk of wood of suitable thickness to ensure the pistons wouldn't pop out completely). There was very little movement 3-5mm at most and what there was different for each piston.
I don't subscribe to the "warped discs" theory after reading an authoritative article by some brake specialist and the suspension arms are all pretty recent so there should be no play there. The car had an alignment check 2 years ago. If it is sticky pistons why should this happen after 6 years?
I'm now thinking about getting them refurbed - again - though this time at BCS as they give a lifetime warrant as well as on the paint. (The previous powder coating has peeled off from 50 percent of the caliper's surfaces
). The alternative is a D3 upgrade but the lack of uprights is an issue and, besides, that's not a job i can do at home. Is there anything else i should try before sending the calipers off?