Viewing 21 posts - 1 through 21 (of 21 total)
  • Annoying squeak/squeal from car but stops when brakes are applied.
  • blader1611
    Free Member

    Its a 6 yr old merc b class and it squeals all the time until you touch the brakes. Garage has checked the pistons and wheel bearings and said they were fine. So i suspected that the piston was rubbing on the brake backing plate so i took the brakes apart and applied copper grease and cleaned the piston. Took it for a test drive and all was well but about 15 mins in the squeal has returned. Loads of brake pad left by the way, any other ideas?

    bails
    Full Member

    Mouse in the glovebox?

    spooky_b329
    Full Member

    Handbrake sticking on slightly?

    milky1980
    Free Member

    Stone stuck between the disc and backplate? Had similar on my old Fiesta and there was a small ridge chippings could settle on, go over a bump and it would squeal against the disc. Pressing the brake pedal would cause the pads to dampen the noise.

    bencooper
    Free Member

    Sticky pistons so not retracting properly? My car does it a bit if it’s been driven for awhile without braking – on a motorway for instance. I assume it’s everything warming up and binding as it’s not being lubricated.

    simmy
    Free Member

    My Fiesta does it sometimes but the Brake Discs are getting worn and have quite a lip on them so my mechanic says it’s catching on the disc occasionally.

    It’s having new discs and pads next service.

    bikebouy
    Free Member

    Those small alloy plates the pads sit in, are they fixed to the calliper properly? If not they will “hum” due to vibration. Merc do a paste that they use when refitting pads, and almost “glue” these alloy seat plates. It’s a sort of rubbery paste that sets, but doesn’t go hard. You can get it in most auto parts places, I’d try that.

    It happened on my 59′ b class until I complained about the squeal, Merc took the calliper apart and replaced these plates and fixed them in. It’s not just a b class issue, most Mercs of that age do the same to some extent due to them using the same type of arrangement.

    Don’t have the car now, but it cured my squeal.

    HTH.

    And I’ve just looked on YouTube and plenty of vids explaining “how to” and also look on Merc forums, there’s a few folks on there moaning about the same thing.

    Blazin-saddles
    Free Member

    my brand new van does this too. very annoying. mainly when it’s hot or on a long motorway drive so I suspect a sticky piston too. All fine according to supplying dealer who diagnosed without taking a wheel off. it’ll be going back again and again until they sort it!

    nosedive
    Free Member

    My vito did this, apparently slight lip on the disc was causing it, my garage slightly filed the top corner of the pad and it stopped (was told to budget for new discs at next pad change).

    blader1611
    Free Member

    Bikebouy – cheers for the advice i will try and look for a youtube vid about that as ours is a 10 plate so could very well be that issue. We have only just got this merc so its a bit annoying. The rear end of the merc seems noisy as well but more like road noise but slightly amplified (i would have said a rumbling bearing) but yet again Merc dealer said bearings are fine. May be we are not used to it yet and its just a noisy car compared to what we have had before.

    blader1611
    Free Member

    Does the foot brake operate the front brakes only or do they operate all four? I only greased up the front pads.

    spooky_b329
    Full Member

    It does all four. Every wheel has to be braked to be road legal.

    tron
    Free Member

    The in board pads are usually clipped to the caliper piston. The outer caliper is usually placed on the carrier and held in place by the caliper (most car brakes are single piston, and the entire caliper can slide on pins to give clamping force on both sides of the disk).

    Because the outboard pads are basically loose, they can vibrate and whistle or hum. Some pads have anti vibration stuff stuck to the back of the pad, or you can get greases (copper slip, mintex cera-tec etc) that add some damping to stop the vibration making a noise.

    This link (not embedded the image as it’s on someone else’s forum) shows where I’d be greasing on a typical car caliper set up.

    The pad can stick in the carrier, in which case you need to attack it with a file and grease the pad to carrier contact points.

    And the caliper can stick on its sliders – in which case you can either play about cleaning and regreasing the pins and rubbers you have, or you can just put new ones in. There’s a firm called “brake parts” who do the refurb bits or whole replacement calipers for most cars. They’re cheaper than the likes of Euro car parts most of the time, and sometimes they’re cheaper than their own website on eBay…

    blader1611
    Free Member

    Tron – thanks for that info, that is really useful indeed and now makes a lot of sense. I guess i need to do the back brakes as well. I will check all the sliders as they were a bit grubby.

    stevemuzzy
    Free Member

    Spooky.. the hand brake on a merc is a foot brake. Only does rear wheels…

    spooky_b329
    Full Member

    Stupid Mercs 🙂 Blader, if you mean the handbrake, call it a handbrake or E brake to avoid confusion with the service/foot brakes 🙂

    bikebouy
    Free Member

    There’s a lot of space in the rear/boot area in the b class, road noise does come through into the boot and sort of gets amplified a little, unless there’s something wrong with the wheel bearings it’ll just be road noise. One thing I did encounter was flat spots on the rear tyres. It was quite odd really because it as driven as a spare car with use only about once a week and on the original tyres (less than 20k) but it got flat spots and I had to get them changed (did all four at the same time) that noise did “reverberate” through the boot and I did notice it as I didn’t drive the car very much, but took it one day and noticed it.. Took it to Merc for a service and they pointed it out whilst I was there, and I got them changed.
    I liked the car, loads of space and very comfortable, drive really nicely and a great place to spend your time going to the shops.

    bigyinn
    Free Member

    blader1611 – Member

    Does the foot brake operate the front brakes only or do they operate all four? I only greased up the front pads.
    Im not trying to be a dick, but if you’re asking that sort of question, should you be fiddling with something critical like brakes?

    thisisnotaspoon
    Free Member

    It’s not a daft question, the ‘hand’ brake usually operates the rear, but not always.

    And in that car the handbrake is opperated by your foot.

    bigyinn
    Free Member

    I read his question as referring to the main brakes, not the parking brake. If he meant parking brake then fine.

    craigxxl
    Free Member

    Probably just dirt build up on the callipers not allowing the pads to return properly. Clean up with a wire brush and copper grease the pads sliders. Also remove and clean the slider pins and lightly grease.

Viewing 21 posts - 1 through 21 (of 21 total)

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