Mountain Bike Maintenance

(click on pictures and links to open a larger image in a new window)

** 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.

You’ll find caliper overhaul guides for the two-piece Mini/M4 here; and the Mono (Mini/M4/V2/M6/Trials) here.

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.

For Moto (M6 & V2) levers, remove the small bolt from the lever body (T10 torx), then carefully remove the small retaining plate with a point or small screwdriver. If it’s refusing to budge, make sure that the BPC adjuster isn’t dialled all the way on or out. With the retainer removed, the BPC adjuster can be threaded all the way out of the lever body. Points 7 to 10 of this guide are not applicable to the Moto lever. Pictures to follow…

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)

Picture (12) shows the full lever assembly. 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.

Clean all parts with alcohol. 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.