So just an observation and a few questions from one successful E4 complete rebuild and one (to date) less successful rebuild. Although both brakes are E4s they weren't bought at the same time, maybe a year apart, and the rear has seen quite a bit more use than the front.
Observation- what Hope called a "Seal Kit Complete" in 2003 and the allegedly same "Seal Kit Complete" in 2013 are not in fact the same, despite having the same part #. The 2003 kit had all the caliper seals, caliper O-ring, lever piston spring, circlip, brass washer, lever adjust screw, lever dust boot, bleed nipple cover and a small aluminium tube the utility of which I'm yet to ascertain. The 2013 kit had all of the rubber bits but none of the metal bits which I actually needed as the allen head on the lever adjust screw had rounded and wouldn't budge until I got a clamp on the bastard and gave it no chioce but to move or completely destroy the village in the process. It moved. Anyway more on that later.
The front went easy and smoothly but took me ages as it was my first disco. After a few practice bleeds I got it feeling pretty nice. Need new brake pads but everything is moving smoothly, no shims needed and even the Hope screech I came to love has all but gone, just a few muted protest squeals, a bit of fade but more than happy with it. 1-0 VB.
The rear has been a bit more problematic. Caliper rebuild went to plan, always fun getting those 4 pistons out, but eventually I made them yield to my will (and my young fella with some serious pumping on the track pump helped). Made sure I cleaned the pistons as well as I could before putting them back and bathed in Dot 4 (not me, the pistons, though I do quite like the smell of Dot 4 it's just a bit rough on the old plums). The lever rebuild was a serious pain in the arse. No new lever adjust screw was the first fly in the ointment but no problem I thought I'll just use the old one out of the front. Except they were different sizes, at least the round head that pushes the piston is, which made the brass washer a different size and the piston spring assembly where the round head of the lever adjust screw pushes against it a different size as well. You can see the parts I'm talking about in this pic. Parts from the front lever. Smaller than the parts from the rear lever.
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As you can see the brass washer is almost rissoled but a few belts from the hammer made it seaworthy but obviously I'd like shiny new bits, new bits that I thought I'd already paid for but obviously haven't. So to question one: I know I can get these small parts from Hope but is the lever adjust screw replacement part the small size or the larger size? If it's the large size I think I can get away with re-using the brass washer and piston spring that came from the rear lever as they are in better nick than the parts shown above.
Despite this I could reassemble everything and got some new fluid through the system. Problem is, despite the new pistons seals and my cleaning efforts the pistons on one side of the caliper are not moving freely and consequently braking power is virtually non existent. 1-1 VB. The pistons do move just not as far as the pistons on the other side, causing the rotor to flex. Also notice that the caliper halves visibly flex when the lever is squeezed. Think my first port of call might be new bolts for the caliper halves. Then new pads. Then, if all else fails, new pistons. So question 2: I know Hope sells pistons for the M4 calipers, phenolic black ones different from the pistons in mine but function trumps form. Will these pistons fit in my E4s? I know the M4 has different sized pistons but one of them is the same size as the E4. Big one or small one?
I know a quick phone call to Hope will answer all my questions but thought asking here might help create a bit of a reference base to help others. Sorry for the wall of text. It was theraputic for me though and now I'll have a ciggy.