LEWIS LH4 Brake Service Kit G1 for Lever and Caliper, No Lever Mark

Unmarked LH4 levers are the ones this G1 service kit is written for, so look at the lever first. The kit covers both the caliper and the lever body.

Checking your LH4 lever for a mark

Look over the lever for a mark such as X, a, a1 or X0. If you find none, G1 is the kit named for your brake, and if one of those marks is there, the G2 version is the one to order instead. If the surface is too worn to read, ask first.

Two O-ring groups inside the LH4 caliper

The caliper side lists two piston O-ring references, Caliper #5 and Caliper #4, with two of each, plus one O-ring for the joint between the clamshells. Keep those groups apart on the bench, and compare each old seal against its replacement as it comes out.

Lever parts that come in the kit

On the lever side you get a new piston, a modified piston sleeve made for LHT and LH4 only, front and rear piston O-rings, sleeve O-rings, a circlip, a spring and a diaphragm. Two oil port O-rings are in there too.

What to have ready beyond the kit

The parts list names no brake fluid and no bleed tools. A lever and caliper service normally ends with a bleed, so sort those out first, and use the fluid your LH4 brake calls for, since this kit does not state one.

• Confirm the brake is an LH4, then confirm the lever has no mark
• Caliper reference #14 is the clamshell O-ring
• Lever reference #15 is the piston
• Lever references #16 and #17 are the front and rear piston O-rings
• Lever reference #7 is the diaphragm and #14 is the spring

Work in a clean area and keep the old set until the rebuilt LH4 brake holds pressure.