Assembly Tips for D.I.Y. Kits - Mechanical Disc Brakes


These instructions assume some basic mechanical knowledge and the ability to weld to an acceptable standard. if in doubt please refer the job to qualified personnel.

1. Pack bearings with grease and fit large inner bearings to hubs and hubdiscs.

2. Fit grease seals to rear of hubs and hubdiscs.

3. Fit hubs to lazy axle. Fit small outer bearings and tighten down castle nut firmly. This ensures bearing cups are pressed firmly into hubs. Back off castle nut until hub is loose, then re-tension until free-play in hub is gone but bearings are under no pre-load. (over tightening shortens bearing life)

4. Fit split pin and dust cap. Lazy axle is now assembled.

5. Fit Hubdiscs to braked axle with same procedure as steps (3) and (4).

6. Fit disc brake shoes to mechanical disc brakes assemblies.

7. Fit disc brake flanges to inner side of disc assemblies using bolts and stainless steel sleeves supplied.

8. Slide disc assembly over hubdisc and locate disc flange to axle with entire assembly facing what will be the front of the trailer.

9. Using pad adjusting bolt, clamp disc assembly to hubdisc (this ensures axle flange will be welded square to assembly and hubdiscs)

10. Position entire disc assembly on stainless steel sleeve so a gap of approx 3mm exists between disc mounting flange and disc assembly. (as brake pads wear, assembly will slide along stainless steel sleeve).

11. Apply liberal amounts of anti-splatter to hubdisc and cover grease seal with wet rag or PVC tape to protect.

12. Before welding disc flange to axle, ensure assembly is lifted as high as it can move on 40mm or 45mm square axle to ensure mechanical lever arm will not foul on spring when fitting under trailer. (not an issue if fitting to 2-1/2" drop axle)

13. Tack weld flange and unbolt disc assembly. Weld disc flange to axle all around from outside edge and top and bottom end, using mig or low hydrogen electrodes. It is not necessary to weld inner side of flange closets to hubdisc.

14. Clean antisplatter from hubdiscs using methylated spirits and then refit mechanical disc assembly to hubdisc and rebolt to disc flange. Back off pad adjustment nut to allow approx 12mm movement at end of lever arm before brakes engage. Tighten pad adjustment bolt lock nut.

15. Mechanical disc brake axle is now assemblied.

Final Assembly

1. Fit 2.0 Mechanical brake coupling and actuator to drawbar.

2. Fit cable adjuster to actuator lever on coupling and set for maximum adjustment

3. Loop 4mm winching cable through actuator lever on mechanical disc brake assemblies and fit 2 off cable clips.

4. Pull cable through cable adjuster and back to opposite mechanical disc lever checking that cable doesn't foul on spring components etc. Weld half chain links to underside of drawbar and chassis if required for cable routing. Fit cable clips and tension with cable adjuster as required.

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