Brake bleed

Hi Justin,

I’ve always found it pretty straightforward – usual risk of bleed nipples snapping or rounding off – splash some WD40 around a day or two before and use a good fitting wrench is advice I have wished I had followed.

I have never had a problem getting a decently firm pedal so I don’t think there’s a special knack required.

As for the fluid – DOT 4 is fine assuming you have not already got silicon (DOT 5) fluid in the system. Both fluids look the same when new.  They don’t feel the same on your fingers but that’s not a great way to distinguish them. The two don’t mix well so, if you don’t know what you’ve got in there, whichever one you choose, you should probably plan to flush the whole system through – which probably means doing it twice.

That’s just my view.

Chris

Remember and  bear in mind that DOT4 falling/splashing onto Cellulose paint  is a particularly bad thing. Basically DOT4 will permanently damage cellulose paint. Guess how I know this !! Do not be cavalier in sloshing the  DOT 4 about.

As Chris says above,   the trick is to be particularly gentle with the bleed nipple. A bleed nipple that has sheared off in the back of a cylinder can be a  challenging experience.  A  ring spanner is the best way to undo or do up the bleed nipple.  “Shifting spanners”  or adjustable spanners are not good.

For the bleeding process  the Traction is remarkably tolerant. Choose your wheel. Convention says you start at the wheel furthermost from the master cylinder and work towards the wheel nearest the master cylinder.  Back off the chosen  bleed nipple. Fit a CLEAR plastic tube from it to something like a jam jar.

Position a  human being (whatever they may currently identify as is irrelevant)  in the drivers seat. On the word of command they press the brake pedal down  steadily (not fast and not slow) and hold. Oil squirts into the jar. Lightly tighten the nipple. On the word of command they lift the brake pedal  and await your next instruction.  Release the nipple. Shout out “down”. Watch the stream of oil going down the pipe. Repeat until such time as the  stream of oil is clear of  air bubbles the job is done. It should require only a few strokes of the pedal to get a bubbles clear flow. Check nipple is tight. Check brake pedal is firm, top up the master cylinder  and move onto the next wheel. By the end of the process you will have flushed all the old oil through  and out of the system.

If the shoes are up close to the drums there should be very little movement of the brake pedal and a rock solid feel to the pedal as the brakes are applied.

MdeL