Board logo

How to bleed brakes
JoelP - 28/4/04 at 08:31 PM

my final task before a test drive, so i thought i'd check that i had the right end of the stick. I've got a mate coming round to pump the pedal tommorow, do you just undo one nipple, press the pedal, tighten the nipple, and release the pedal, over and over again and working from the nearest wheel to the furthest? thats as much as i know unfortunately...

any help appreciated!


NS Dev - 28/4/04 at 08:36 PM

that's the way I do it!!

Just watch out for any air getting drawn in around the threads of the bleed screw. It shouldn't if the screw is closed at each pedal release but sometimes your shouts get out of synch!!


locoboy - 28/4/04 at 08:39 PM

easy bleed kit is the dogs balls, well IMHO


NS Dev - 28/4/04 at 08:41 PM

It is if you are stuck on your own!

With 2 it is probably as quick to do without it but I have one for when I am on my own!


splitrivet - 28/4/04 at 09:18 PM

Im with you col definately the bit of kit to have.
Cheers,
Bob


Doc - 28/4/04 at 09:41 PM

I have always bled from the cylinder furthest away from the master cylinder first and the only Haynes manual I can reach from my chair without putting my beer down says the same.


jonti - 28/4/04 at 09:50 PM

I've always done it starting furthest away and hold pedal down whilst you tighten the nipple.
Works for me
Easybleed is good though


Peteff - 28/4/04 at 11:13 PM

Furthest first nearest to M/C last. I put a tube on the nipple into a jar of fluid in case you get out of sync so you draw fluid back in and you can see bubbles coming out.


britishtrident - 29/4/04 at 06:45 AM

A lot depends on the type of mastercylinder you have some mastercylinders of ATE and DBA origin can draw air in past the seal on the return stroke, these require bleeding under slight posative pressure from the mastercylinder resevoir to keep the seal fully expanded against the bore.

For an normal Lucas/Girling/Locheed system I usuallly prime the system first by opening a pipe union a couple of turns on the mastercylinder and getting the assistant to push the pedal down and hold it down catching any fluid spray by holding a cloth round the connection then tighening the connecton and releasing the pedal.

It is usual to start bleeding the longest pipe run but this isn't vital as with a new system it is best go round all the nipples at least twice.

The key to getting the air out is slow steady strokes going down with very slow return strokes --- The slow down stroke reduces the pressure in the sysyem making any air bubbles large and less likely to get trapped. The very slow return stroke minimises any negative pressure in the system and reduces the ammount of air and expelled fluid sucked back into the system.

When bleeding the rear brakes handbrake should be off and the manual or self adjuster should be adjusted to give the shoes a normal running clearance.

If you have difficulty getting all the air out of brakes a good trick is to pump the front caliper piston out a bit, then clamp the brake hose, open the bleed nipple and push the piston back.

Remember also the air in the brakes is not the sole cause of a spongey pedal so once you get the air out get an assistant to bang the brake pedal on an off hard while you check that the pedal box and mountings are stiff enough and that the caliper pistons are free and the caliper brackets aren't bent.

[Edited on 29/4/04 by britishtrident]


NS Dev - 29/4/04 at 06:54 AM

All very good advice from BritishTrident


JoelP - 29/4/04 at 12:16 PM

thanks everyone, i shall do as advised!