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240 Brake squishiness - because I’m a lazy, lazy man

I’m sure I could Google this, but someone ‘round here will know without any effort from me. :)

I’ve become convinced that the brakes in the 240 are losing effectiveness as I drive ... feeling pretty squishy.
I think the brake warning light may even have flickered today (it’d gone put before I looked down, but it was either the brake failure or handbrake light).

When I think about it, it’s probably been 15-ish years since I did the fluid, so it probably needs a full flush & replacement.
But what causes squishiness & the light to come on if you’re not losing fluid; munted or blocked one-way valve? Busted booster? Everything’s getting close to 20yrs old now!

Comments

  • Depending on the model of 240 the light will be a low fluid level or an imbalance in the two brake circuits.

    The first one is easily fixed. Flush the fluid.

    The second could be a range of things, though as the fluid is so old it may be the master cylinder failing, or a range of other things.
    Flush the fluid and a good bleed will certainly assist in the longevity of the brake components.
    Rears first, then drivers front, then passenger front. For the fronts, the bleeder nearest the outside of the calliper first, then the top one, then the inside one last.
    Generally do the rears until the new fluid comes through and no air bubbles or gunk in the fluid. I use a clear plastic hose (from Clarke Rubber) into an old brake fluid bottle. Direct the hose upwards from the bleeder so any air rises away from the bleed nipple.

    Brakes are important, and the parts to replace them are costly compared to a fluid change every so often. My two cents :-)
  • DauntlessDauntless (@Dauntless) Central West NSW
    edited May 21
    I'd just bleed it all through the lines and see what comes out, and if it improves. I'd suspect any rubber components first.
  • edited May 25
    OK ... ongoing story ...

    It’s flushed & has new fluid. I painted the booster X years ago, and there’s been fluid run down the booster judging by the bubbled paint on said booster ... and I don’t recall spilling fluid in the past. But maybe I did.
    Drove for 4hrs solid this arvo, and the fluid level hasn’t changed at all.
    I do think I had some brake fade today. Brakes felt squishy and were losing bite ... what causes that?
  • How old is the master cylinder?
  • Brake fade is caused by too much heat, the friction qualities of the pad/rotor (or shoe/drum) stop working, or the fluid is boiling. The pedal will go hard and the car will not slow down very well. Pretty scary stuff.
    Two perspectives on this, you are driving outside the capabilities of the brakes, the brakes are not at a serviceable level for the driving they are doing. In short they don't work.
    Remnants of a trickle of fluid behind the master is not a big deal. Visible fluid there is a big deal.
    If the fluid level changes after a drive there is a problem! It will drop as pads wear, very slowly. No change is good :-)
    At a guess, knowing little of the car etc, it may want front pads and rotors. I use Bremtec pads from Voldat in my 200s and they are great around town and not dusty. Did you look at the pads when bleeding? Much meat on them?
  • How old is the master cylinder?
    I'd say 16-17 years.
    I'm told that symptoms of failing master cylinders is leakage, I don't recall spilling any brake fluid (which doesn't necessarily mean it didn't happen) and the paint on the booster has definitely been brake-fluided.
    However I drove it in all sorts of conditions from hilly country roads to bumper-to-bumper for that ~4hrs on Saturday (with the new fluid), and it's not lost any. I still thought it felt squishy.
    ROLL DMC wrote:
    Brake fade is caused by too much heat, the friction qualities of the pad/rotor (or shoe/drum) stop working, or the fluid is boiling. The pedal will go hard and the car will not slow down very well.
    Hmm, well maybe it's not "fade" per se, the pedal didn't go hard at all, it felt more like it had too much travel & wasn't doing as much as it usually does.
    ROLL DMC wrote:
    At a guess, knowing little of the car etc, it may want front pads and rotors. I use Bremtec pads from Voldat in my 200s and they are great around town and not dusty. Did you look at the pads when bleeding? Much meat on them?
    I'm happy to do a lot of things myself, but brakes is one of those things I prefer to pay someone who knows what they're doing to do … so no, I didn't look at the pads. It's only been a few hundred km's since I last did, though, and they had plenty of meat then. They're EBC Green Stuff (so shouldn't wear as quickly as the yellows or reds) only have maybe 10k km at a maximum on them, probably less. But it has been quite some time since I checked them, so yeah I might check them again.

    I'm starting to get a bit suspicious that I've just become used to a new car with Brembos and that the Volvo's just old ...
  • Air in the lines causes a dull feel
  • Could be master, could be air. Take it to a mechanic if you are not happy with the feel or if they have deteriorated recently. They will know straight away and any mechanic can replace a master cylinder, no need for a Volvo specialist, though a Volvo workshop will also look over the car and know what to look for elsewhere.
  • Yes flushed & bled by mechanic on Friday, he's certain they got all the air out (he worked for a Volvo dealership in the US when 240's were still common and I'm inclined to trust him), he's the one who said it doesn't feel quite right (I agree) but doesn't have the symptoms of a dead master ... unless it leaked, which he didn't think it was doing (and which it didn't do Saturday).
  • A common way that a tandem master cylinder can fail is to lose the first stage, which will gives you a squishy pedal, but no external leak.
    The brake fluid escapes around the seal and returns to the master. You will usually be able to see little bubbles in the resevoir if you get someone else to slowly press the brake pedal.
    Generally you have no effective brakes on the first inch or so of pedal travel.
  • jamesincJames (@jamesinc) Oz Volvo Ice Fortress
    It's a pretty straightforward system, if there's no air in it you're really only left with a fault in the master or failing brake hoses.
  • edited May 29
    A common way that a tandem master cylinder can fail is to lose the first stage, which will gives you a squishy pedal, but no external leak.
    The brake fluid escapes around the seal and returns to the master. You will usually be able to see little bubbles in the resevoir if you get someone else to slowly press the brake pedal.
    Generally you have no effective brakes on the first inch or so of pedal travel.
    So I've driven to work today to pick-up the replacement spare tyre, and I think the above describes what it feels like.

    @jamesinc , what's your rough estimate of your weekend movements? Any likelihood of being around at some stage? Wouldn't mind if someone who's used to the normal pedal-feel could tell me I'm not imagining it … if you think there's any chance you'll be around, I shall be in touch via telephonic communication ...
  • SpacSpac (@Spac) Canberra-ish.
    Dead booster will make the pedal rock hard, possibly accompanied by a whistling or hissing sound, and possibly a bad idle.

    Based on what you have said, you have a problem with the master cylinder (as Tim said) or the distribution block on the left hand side of the engine cross member.
  • edited June 10
    If the distribution block had a problem, would it be leaking? It’s not wet to touch, nor can I see any liquid.

    Visited Fearless Leader a coupla hours ago, he drove mine ... compared to normal, it’s definitely got the symptom Tim mentioned of there being no brakes at first. Stops fine, but the usual light prod to avoid lurching during a heel/toe results in nada.
    So I’ve decided - I’m gonna replace the master.
    jamesinc
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