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240 Critique my proposed brake-master replacement plan

edited July 2 in General
OK so I've decided that, given I've got the parts, it's not worth a 5hr round-trip to the mechanic just for a brake-master replacement. I've checked YouTube for how-to videos, and I think I have a plan.

Can anyone tell me if I'm missing something?
Standard 240 brakes.
Doing it by myself.

  1. Since I've got the wheels off, check the pads before starting the process, and do a rush-panic last-minute shop-around looking for EBC Green Stuffs when I find they need replacing.
  2. Buy one of those sucky-pump things to draw fluid out at the caliper end.
  3. Use a siphon-thingy to (neatly & hopefully without mess) empty the reservoir.
  4. Undo the brake lines at the master, catching drips.
  5. Undo the bolts that attach the master to the booster, remove master, replace with new master (has own reservoir bottle).
  6. Fill reservoir with new fluid.
  7. Start at the corner furthest from the brake-distribution block (driver's rear).
  8. Attach tube, undo bleed nipple, pump until air-bubbles start coming through & keep going until the bubbles stop. Watch the reservoir doesn't get empty during the process! Tighten bleed nipple. Make sure no bubbles get sucked back in, use a cable-tie tight around the clear PVC tubing I'm using at the bleed-nipple just to be sure it's properly tight/sealed.
  9. Rinse-repeat on other wheels, working closer to distribution-block (passenger-rear, driver's front, passenger-front).
  10. Drive around block, scream in fear when brakes don't work, book tow-truck & mechanic to do it properly, crack open beer.

A question - what diameter PVC tubing should I be using for a 240?


  • List looks good only thing i would add is its best practice to "bench bleed" the new master before fitting it. You fill the reservoir, remove the rubber bungs from outlets,push and hold the piston down, then hold your fingers over the outlets while you let the piston return. Repeat 2/3 times and on the last time refit the tubber bungs.
    Makes bleeding on the car much quicker and reduces the amount of excess air you are adding to the system.
  • +1 for bench bleeding.

    If you for some reason forget to bench bleed and have a helper, I found bleeding the master cylinder in situ quite simple too:

    *tighten brake lines to master cylinder
    *fill with brake fluid
    *Get helper to press and hold the brake pedal to the floor.
    *crack open brake lines at master cylinder and use a rag or container to catch any brake fluid (don't release brake pedal).
    *tighten nuts to brake lines
    * release brake pedal

    -repeat until no air comes out of the master cylinder.

    I had to repeat 4x before only fluid came out. Took 2 minutes.

  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.
    What's wrong with you!?
    Just think,when at 2.35am after a day chasing the bolt that fell into the engine bay you get it together you then spill the fluid all over the front th guard and your left trouser leg and still don't get it finished,need to call for help or have it flat topped to a shop!
    Just take it to the shop, 5 hours pleasant drive compared to the aforementioned? .......you know this will end in tears!
  • jamesincJames (@jamesinc) Oz Volvo Ice Fortress
    @Forg hit me up if you need a second person, happy to help and I've rebuilt all the parts of a 240 brake system before so have a vague understanding of what to do
  • SpacSpac (@Spac) Canberra-ish.
    You forgot the manicure at the end.
    And the pedicure just to treat yourself.

    Seriously, I wouldn't bother with trying to syringe the fluid out of the caliper end. Just pump the fluid out with the brake pedal.

    Otherwise, your plan is fine, with Tim's additions.
  • edited July 3
    Just take it to the shop, 5 hours pleasant drive compared to the aforementioned? .......you know this will end in tears!
    The 5 hours is in peak hour, which is why it takes 5 hours and not 2.5 … if it were a nice trip up the Hunter Valley it would be different. :)
    Besides it's too late, Rock Auto had this swanky sucky-bleedy thing that comes in it's own little carry-case for the same price delivered as you pay here for a plastic sprayer-bottle attached to a bit of garden-hose with chewing-gum, so how could I not buy it? So I'm now officially committed! Plus once the wheels come off to check the pads, I'm not going to put them back on again to get to a mechanic, that sounds like way too much effort!!!!one!!oneone!!

    Ta for the offer James, I may take you up on it (although I sorta want to DIY myself now I've psyched myself up, I rebuilt everything way-back-when but I don't remember doing the filling/bleeding myself so I must have asked the mechanic I was living 'round the corner from to do that bit … and I've kinda committed to doing it myself now, with the vacuum bleeder doohickey & the brake fluid that Spac recommended even being on special at SuperCheap last weekend :D).

    Spac … manicure? Pedicure? I don't know why anyone would subject themselves to that!
    Maybe it's the norm to be served cheese while being -cured? If so, that would explain it, and OK I'm happy to be -cured …
    Now you've reminded me though, I should get some decent rubber gloves to do this. I've been using disposables for doing car stuff that involve lots of fluids (eg. an oil-change), but with those fiddly small nuts they'd probably rip in seconds. Because we have a newish water-heater with the stupid water-temp limitation legalities I don't need gloves to wash up these days ...
  • SpacSpac (@Spac) Canberra-ish.
    Good disposable gloves won't tear. I use the blue ones from Woolies at home and they should survive a process like this.
    The ones at work are really tough - if you tear them, you would have torn yourself open...

    Depending on what sort of hot water system your have, you can probably turn the temperature up.
  • Ex850RSnoopy (@Ex850R) Somewhere Over the Rainbow. Melbourne.
    Forg wrote...."Maybe it's the norm to be served cheese while being -cured?"

    My first time getting it done the Thai lady says..."Mr Les, it like stinky cheese here" my big toe ingrown....

    She fixed it for a while. Podiatrist is a good thing though.
  • edited July 3
    Depending on what sort of hot water system your have, you can probably turn the temperature up.
    No, it's at the max, already had that checked. Had the same problem with the new system in the old house, too. Modern NSW-spec hot water is really just luke warm water (I mean it's hot enough to need cold mixed-in for showering, but IMHO water needs to be hot enough to need gloves to wash-up properly!).

    There's a Woollies down the road from work, I'll have a squiz at their disposable glove selection. The ones I've been using are those very see-through multicoloured ones, they're pretty lightweight. I'd get wifey to nick some of the fancy purple nitrile ones from her work but I know how exxy they are & would feel bad … :)
  • edited July 13

    So ... big fat fail.

    After bench-bleeding & fitting the master & my 8mm spanner being too bulky to turn the bleed-nipples & hurriedly borrowing one from a mate & realising (when he pointed it out) that I had the wrong bleed order ... I tried actually doing the bleeding.

    Big fat fail.

    No fitting in the bleeder kit will seal on the bleed nipple. The best I could manage to pull into the bleeder hose was foam.

    Rage quit, stopped myself putting the vice through the wall, returned the borrowed spanner (which meant driving through Eastwood which didn’t help the mood).

    Whether I get a mobile mechanic to do it before even trying anything else entirely depends on how soon one could turn up ... meanwhile, beer. Beer. Much beer.

  • jamesincJames (@jamesinc) Oz Volvo Ice Fortress

    @Forg just go back to basics and pump the pedal and push fluid through.

  • Was thinking about that ... because it had a full fluid flush that didn’t fix the problem & now has new master, the existing fluid is clean & the way to tell the changeover with the new (higher quality) stuff is when the bubbles from the replacement master start coming through. If I’m running the pedal, how do I know when the bubbles are coming through? I don’t see how to do it that way with only me.

  • SpacSpac (@Spac) Canberra-ish.

    Sometimes you really me me worry, Forg.

  • PaddlerEdPaddler Ed (@PaddlerEd) New England Region, NSW

    Only sometimes? I've read his posts for many years, and I think I'm beyond worrying...

    On the otherhand, I've had the mission of bleeding the brakes on the Land Cruiser - 8(!) brake cylinders on that to do, so I do have sympathy. My recommendation is to get someone to help you, it's much easier to do it with someone pumping the pedal up.

  • jamesincJames (@jamesinc) Oz Volvo Ice Fortress

    @Forg brake fluid is sold in a few different colours (yellow, green, blue, at least), if you need to know, you switch to a different colour and watch for the change at the bleed nipple.

  • edited July 14

    I bought the fluid based on quality not colour; I don’t even know that colour is an option once you decide a particular product is the best for your money?

    This doesn’t make any sense, and also doesn’t help.

    If I’m in the car pushing the brake pedal, how am I seeing what’s happening in the hose hanging off the caliper?

  • carnut222Greg S (@carnut222) Daylesford VIC
    edited July 14

    IMHO it is much easier to come up with a cap for the master cylinder reservoir with a hose on it that you can pressurise with about 10PSI, then run around and bleed the bleeder nipples in sequence while carefully watching the level in the master cylinder and topping up as necessary. You can either make up a cap using some fittings and an old cap, then tie it to a low pressure source (I use my air compressor regulated down to about 10 PSI) or you can buy a purpose-build pressure bleeder system for less than $100 on eBay. I have never ever had any luck with vacuum bleeding as it seems to draw air in from around the threads. AFAIK they pressure bleed from the master cylinder at the factory, and it pushes the air bubbles out instead of trying to suck them out. Otherwise, if you use the pump pedal method, you have to have one person in the car pumping while you’re outside opening and closing the bleeder...yelling “DOWN” when you open bleeder and “UP” when you close it...repeating on each bleeder in sequence until no air comes out then go around again for good measure...while watching master cylinder level closely!

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