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** Wear Safety Glasses **
This is a guide for a complete overhaul/seal change on a Hope hydraulic disc brake lever. Hope refer to this as the ‘Mini’ lever, it is used on all ‘open’ systems; the silver two-piece Mini/M4′s and the black/gold Mono calipers (Mini/M4/M6) and also the silver/black levers supplied with the ’07 and later Mini and M4 calipers.. The addition of the BPC adjust on the ’07 and later M6 and V2 lever changes the procedure slightly, the details are included in the necessary part of the guide.
The lever in the pictures was serviced as part of a complete system overhaul, so it was drained of fluid when I came to remove it; hence the lack of top-cap. If you’re only doing the lever, leave the reservoir cap fitted until the lever is removed from the hose. Before you loosen the lever clamp bolts, use an 8mm spanner (10mm for the older Mini) to loosen the hose fitting from the lever (1). Remove the two lever clamp bolts and the clamp, then wrap some tissue around the hose/lever joint and remove the lever fro the fitting (2) (note the copper washer (3)). If appropriate, remove the reservoir cap and drain the fluid.
Use an 8mm spanner/socket and a 3mm allen key to remove the lever pivot bolt/nut (4), and a 2mm allen to remove the lever piston pin (5). NB Turn CLOCKWISE to remove the pin from the brass barrel (6). The piston seal is held in place with a retaining clip. This can be carefully prised out with a small jewellers screwdriver (7) or use the circlip pliers. Once the lever blade is removed, the Moto (V2 & M6) lever procedure is different, so stages 7 through to 10 do not apply. Scroll down past the next two blocks of pictures below for the necessary instructions.
The piston assembly is sprung, and held in place with a brass washer and a circlip (8). You will need a set of circlip pliers to remove/replace this circlip (9). With the circlip removed the pin and washer can be pulled out (10)(remember it’s under a small spring load!). Use a soft/round tipped tool to poke the piston assembly through and out of the lever body. Do not use a screwdriver. A 3mm ball-end allen key is ideal (11)
The adjuster pin and piston are held in place by the BPC dial (a) on the Moto lever, so there’s no brass washer and circlip. To prevent the BPC dial from being screwed too far in or, more importantly, too far out, there is a retaining plate bolted into the MC body. The T-shirt shaped pate is in turn held in by a T10 bolt (b), the same interface as the reservoir cap bolts on the MC. With the lever blade out of the way, the T10 bolt can be removed, followed by the retaining plate (c). If you’re finding the plate a little stubborn, make sure that the BPC dial isn’t screwed too far in or out. With the plate removed the BPC dial can be threaded from the MC body. The adjuster is can now simply be removed from the BPC and the adjuster seal lifted out using a point (d). Make sure when you refit or replace the seal that the lip is pressed fully into the corresponding recess otherwise it may inhibit the movement of the lever in operation. To instal the BPC, hold the MC body firmly in one hand and use your thumb to depress the adjuster/piston far enough to allow the BPC thread to mate easily with the MC thread (e). I can’t stress enough the importance of ensuring that the BPC threads are aligned correctly before you use a tool to turn the dial. The worst case scenario of cross-threading the BPC dial is that you’ll need to replace the BPC dial and the MC body. Not cheap.
Picture (12) shows the full lever assembly (non-Moto). Take note when you remove the piston which way the two piston seals sit. I they are fitted the wrong way around they will not function.
Thoroughly clean all parts to be re-used, with alcohol if necessary – NOT the seals, though, as alcohol will dry them out. Prior to refitting the piston, pour a little DOT fluid into the piston barrel and run a thin layer around both piston seals. Insert the piston/spring into the barrel and carefully push it all the way in (13). Insert the piston pin and brass washer. Whilst compressing the piston, use the circlip pliers to refit the circlip over the brass washer (14). This is a bit fiddly, and may take a few attampts to get it all straight, so take your time. The piston seal and clip can now be replaced and the lever refitted. Refitting the lever to the hose is the opposite of removal, remember to fit the copper washer.
Once the hose is reconnected and tightened up, the lever can be refitted to the handlebars. The system will require a bleed; follow this link for instructions.