The Mongoose Menace is a sturdy little entry level BMX. Unlike some cheapie BMXs it has closely spoked wheels with heavy duty oversized axles and a decent – if weighty – component quality. The steering head is an Aheadset type where the stem clamps on to the fork tube “steerer” There is a threaded top cap with a hole in the centre to allow the front brake cable to run through the centre of the fork steerer. The elaborate rear brake arrangement uses split balanced cables and a rotating cable joiner/bearing assembly that allows the bars to be spun round and round without snagging the cables on the steering head. It’s made this way to allow for stunts when riding. Although the rotating brake arrangement isn’t relevant to non-BMX bikes the typical so-called “threadless” headstem is in principle similar to those used on most modern bikes.
Here are some more views of this sad case of a bike as it was, to show the assembled steering head and brake arrangement :
Once the brake components, bar stem and bars are removed the steerer needed a good whack directly on the top with the hammer shown, with a rubber protector fitted. I also left the steerer cap on to avoid thread damage to the steerer while hitting it .
Now dismantled, top row L —> R are brake spinner bearing & spacer, bracket for split cable, spacer, bar stem, spring washer and top cap with hole for front cable
Bottom row L —-> R lower bearing race cover/seal, 2 caged bearings, head race, top race cover/seal and a plastic sealing wedge.
The lower fork crown race will be cleaned and left on the fork for reassembly and the bearing cups left in the frame and cleaned.
I’ve left out the cables to avoid confusion.
Started to de-grease the bearings with kerosene and de-rust the other parts with rust converter — The latter is a magic liquid based on Phosphoric Acid that converts red iron oxide rust to a stable black iron phosphate. There are many different brands of this available from hardware and auto stores. It’s a must have …..
This last component is the bearing for the rear brake cable transfer – it contains many small ball bearings and doesn’t appear to easily dismantle. I’ll flush it as best I can with kero and re-oil it . It’s not a highly stressed bearing, it just has to run freely, so that should be OK.
I hope this isn’t too boring for non-mechanically inclined cyclists, I will try to split these posts up a bit …