Thread: Brake Fluid

Use a syringe or similar to remove the old fluid from the master cylinder. Dot 4 is Ok becuase you will be replacing all the fluid. As you bleed each corner you will see the new fluid coming thru so just bleed till you get clean fliud at each corner.

However if you bleed the system this is the danger zone for failure of Master cylinders, Your brake Master will have operated in a paticular area for some time, there tends to be a build up that occurs either side of the normal operating area of the cylinder. when you bleed the the system the rubbers will stoke past this build up and sometimes will cause a leak, so just be aware of this.

Most vehicle manufacturers recomend brake fluid replaceemnt at 12 month or 2 year intervals.

glen

I'm well over that period then Glen, It hasn't been replaced for at least 3 years, maybe more. Master cylinder looks relatively new, but uf ut goes, it goes. Hopefully all is ok though. I'll have to find a syringe or similar to remove the fluid from the master cylinder though. Bursoms or somebody should have something that I can use.

I have in the past when helping a friend at his house used a damp sponge stuffed in the top to get most of the fluid out. Brake fluid is water based.

Just go easy when you bleed it should be ok.

glen

I made a brake bleeder a few years ago to flush systems using a common garden pressure spray (the type that uses a 4 litre or so container, with a sealed lid and a pump in the lid), grabbed a lid off a vitamin jar that uses the same thread as the master cylinder (truly !) drilled a hole and used a screw in barb fitting the same size as the hose, fitted an O ring in the lid and voila ! a pressure brake bleeder/flusher.

Works a treat and no stuffing any brake seals by working them past where they normaly sit.

What a clever little fridgie. Good idea, Rick.

Dot 4 is better than dot 3 in terms of boiling point and preformance, but it degrades faster. If your existing brake fluid is that bad, Id suggest my normal brake fluid changing process, Yes I know I advocate brakes are over rated, use the gear box to slow down and anticipate the traffic but nothing beats both feet mashed on a good firm brake pedal for those "where did that big truck suddenly come from" panic stops.

From the same supplier get at least 2l of 2 different dyed brake fluids that are the same spec. Ie 2l of green mobile dot 3 brake fluid and 2l of blue mobile dot 3.

Doing the normal brake bleed procedure change your first batch of fluid say to the blue fluid.

Now repeat with the green.

It sounds excessive at first but it does guarentee you'll get good fluid in the system and you'll be stunned at the amount of gunk that comes out with the first change.

Im not sure how much I trust this next bit but it might bare thinking about.

Ive been told you can blend brake fluid upwards, as in you can add dot 4 fluid to dot 3 but not the otherway around. Given that, you might want to consider going dot 3 fluid incase you get into trouble in the backwaters.

Personally I carry enough brake fluid to flush and refill the brake system. (amongst, and as SWMBO will testify, enough gear to fabricate a new Landie from the dirt up.)

if he is doing a brake flush....then there will be no mixing......
i think that 4 litres of brake fluid is overkill......1 litre is more than enough.....



the best way to do the flush is to empty or suck out the fluid from the reservoir....
then refill with the new fluid......
then starting at the brake furthest from the master cylinder....usually the passenger side rear.......
start to bleed the fluid till it comes out clean.....ie...the new fluid......
keep an eye on the reservoir to make sure you dont run out in the process.....
then you do the drivers side rear.....then passenger side front.....then drivers side front......

have a look here......this is one of the better ones......


http://www.justtools.com.au/prod3560.htm