Bleeding the brakes

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Categories: MR2 Mk2 Articles -> Brakes

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[url=https://imoc.co.uk/app.php/kb/viewarticle?a=96&sid=bdf2d9a5b6eb92fe9067273405dd5c6f]Knowledge Base - Bleeding the brakes[/url]

How to Bleed the brakes
by Jamie Ayres

You will need...
New brake fluid
Jam jar with about two inches of fluid in the bottom
Piece of see through plastic pipe big enough to fit over the bleed nipple tightly
8mm ring spanner (open spanners are a bit risky as they easily round the nuts off... you DON\'T want to do this to your bleed nipple!)
Assistant to push down on the brake pedal

** The best method I find is to cut a hole in the top of the empty jam jar lid big enough to squeeze the tube through and make sure there is a little hole that air can escape from the jar. Also, if you have a piece of clear plastic tube with another piece of softer black rubber hose on the end you\'ll find this easier to slip over the bleed nipple. It\'s just a matter of getting the correct sized hoses to fit over each other! **

Your brake fluid reservoir will be on the left hand side of the front compartment (it\'s where the brake pedal is). Take off the cap and, if you can, use a syringe to remove as much of the fluid that is in there as possible. Replace this with the new stuff. If you don\'t do this you will end up just pumping old stuff through for the first 10 or so pumps!

Make sure that there is a good amount of fluid in there before you start... you\'ll want to check regularly when you\'re doing it as well. If that reservoir gets empty it\'ll pump air into your lines and you\'ll have to start again.

Replace the cap and find the wheels furthest from the reservoir... the rear left.

Jack the car up and remove the wheel

Find brake bleed nipple (rubber capped protrusion with a nut shaped bit. Sits on the back end of the calliper)

Remove rubber cap

Place ring spanner over bleed nipple and make sure the thing turns slightly before bothering with the next stage

Leave ring spanner over the bleed nipple and squeeze the end of the rubber tube over the nipple... making sure it\'s a good fit.

Ensure that the end of the tube in the jar is down into the fluid

Get your assistant to get into the car and start the engine (the brakes use pressure assitance so the engine running makes the job easier)

* Get the assistant to push down reasonably slowly on the pedal
* Loosen the bleed nipple with the spanner and watch the fluid flow down the clear pipe (this when you check for bubbles and is the reason for the \'clear\' pipe)
* Tighten bleed nipple
* Ask assistant to lift foot off pedal (this draws fluid back into the line from the reservoir)

** Make sure that the assistant *only* lets go of the pedal when you say so and you\'ve made sure that the bleed nipple has been closed. Otherwise it will suck air in from the calliper end... and you\'ll be starting again **

Repeat the above (*) procedure as many times as you see fit to remove all of the old fluid (probably about 12 or more times for the rears... less for the fronts)

Repeat on all corners.

Remember to check the level of that fluid! I filled up mine four times when doing the rears to ensure that the fluid didn\'t drain away too much. You can see how much you\'re using by looking in the jam jar. I used over a litre on mine to ensure that no old fluid was left.

This procedure was done on a MkI but it\'s pretty much the same for all cars which don\'t use cables for the brakes (which haven\'t been used for about 30 years!!!) Also, if you have a decent ramp that the car can fit onto or a pit you can do the whole job without jacking the car up or taking wheels off!
by Ben Formesyn

Get an Ez-bleed from Halfords - about a tenner, it clips onto the nipple and has a one way valve on the bottom which allow you to bleed the old fluid out.

I wouldn\'t mess about trying to re-use - 1 litre of DOT 5.1 fluid costs under a tenner, you could use DOT4 as well if you\'re not planning to do trackdays.

You will have to top up the brake fluid reservoir as you bleed out fluid and air - I\'ve found that after every 4 or 5 pedal pumps you need to top it up.
by Alan Head

One other thing to add to this - when bleeding the brakes use slow rhythmic pumps of the pedal. Its also a good idea not to use a full pedal stroke as this can cause the seals in the MC to blow (make contact with parts of the cylinder they don\'t normally. Stick a thin block of wood or similar under the pedal so your pumper can\'t push it to the floor. Oh, and one other thing - if you\'re doing all four bleed the one furthest from the MC first and work towards the one closest. Not sure where the MC is on a Mk2 but on a Mk1 this means NSR/OSR/NSF/OSF is the sequence...