replacing brake fluid

[Pascal]

Hi,

I've discovered with horror that one of my front drums was filled with brake fluid! Having inspected the other wheels it's time for an overhaul so I'm replacing wheel cylinders, shoes, drums all around and draining the old brake fluid which is quite murky.

Any tips on replacing the brake fluid? I'd like as far as possible to flush the old one out and minimise mixing the old fluid with the new fluid. I have a vacuum hand pump to help with this.
- Will I need to keep the brake pedal pressed whilst sucking the fluid with the pump?
- Is it better to let the old fluid run out completely from the master cylinder before pouring the new fluid?
- Is is better to prime the new wheel cylinders with brake fluid before attaching the hoses?

What is the best way of cleaning the back plates? What solvent would you use? I have some wheel cleaner left that is very effective that I'm thinking of using.

Regards

[Redmoggy]

As for cleaning anything that doesnt leave a greasy residue.
You relly want to be replacing the fluid as you draw it to save chasing a big bolt of air round the system. If the brake fluid is that mucky it may be time for a shiny new master cylinder as well. You shouldnt need to prime the wheel cylinders.

Rod

[eastona]

to replace all the fluid, I just do the same as I do when bleeding, but repeat until shiny new fluid comes out. And remember to top up the M/C regularly.

Andrew

[MGFmad]

Yes definitely leave the old fluid in and add new until it comes out of the bleed nipples. I have fitted a new system completely so had to fill with fresh fluid then bleed out the air - been at it for ages and its still not right yet!

[jaekl]

Changing fluid is definitely worth getting a spare master cylinder plug so that an air fitting can be added. No you can blow the old fluid out with compressed air. With pressure bleed it would take no time to flush out the system and have all fresh fluid and no air.

[Luxobarge]

Changing fluid is definitely worth getting a spare master cylinder plug so that an air fitting can be added. No you can blow the old fluid out with compressed air. With pressure bleed it would take no time to flush out the system and have all fresh fluid and no air.

IMHO that's a very good idea, especially as with systems such as Ezibleed (which is what I use) you don't have to keep topping up the master cylinder, it does that for you out of the main bottle, and when you have to top that up, it's a lot easier.

Just a personal opinion.....

Note to self: get a spare M/C cap......

[polo2k]

I have done just that but never had any joy getting mona to bleed apart from the usual press, lock, release, open method.

For a pressurised bleed to work does it need a seal taking out of the M/C like when fitting discs?

[alex_holden]

For a pressurised bleed to work does it need a seal taking out of the M/C like when fitting discs?

No, my Eezibleed has worked very well on both my drum-braked Minors.

[bmcecosse]

And gravity does it for me!
To clean away all the mess - start off with 'engine degreaser' spray and finish with 'disc brake cleaner' spray - both from Poundland. Both are flammable - the disc brake stuff highly so! It leaves everything perfectly oil/grease free!