Brakes poor after changing pads

StarCruiser May 8, 2019

  1. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    my front pads had begun to squeal so I ordered another set from Milners as the ones fitted had been so good.

    I also ordered some tears but didn’t change these as there was plenty left on the Ferodo ones in there. I just gave them a bit of Copper Ease around the slidey bits and put them back.

    The new ones came with a serious chamfer each end (pic to follow) and brake feel is now pretty spongy with a need to press pretty hard for any real stopping power.
    I was careful not to push the brake pedal too far down when pumping it all back tight again.

    My question is are they going to improve, bed in, or do I need to be looking elsewhere? Or is it simply the reduced pad area (my suspicion) that means reduced braking?

    Does anybody have some older Milners known good pads to compare, @Chris ?

    I cannot imagine air has got in because I haven’t opened the system. I cannot understand the sponginess though.

    Any thoughts appreciated.
     
  2. Josh Tagg

    Josh Tagg Well-Known Member I am in uk

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    Most pads usually take a few days use to bed in to the old discs
     
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  3. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    This is what I’m thinking but it seems far more noticible this time.

    Anyway, the question is somewhat answered by me opening the second set of fronts that I ordered to find that they aren’t chamfered at all.
    The chamfered pic is of the rear ones.
    F308AB02-40E0-4D57-9DAE-19BA1A4C3900.jpeg 4C092AA6-6E95-4A42-87C2-4E9ECBD99D8D.jpeg

    Clearly some change has taken place.
     
  4. frank rabbets

    frank rabbets Well-Known Member

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    I suspect they will bed in Rich. I've had your problem before especially if there is a wear lip on the edge of the disc which obviously bites into the pad. Or the disc is wear grooved. What I do is drive with my left foot on the brake and foot hard on the throttle in 2 or 3 gear. You can feel the brake pedal drop as the pads take up the profile of the disc. (not in the manual lol).
     
  5. clivehorridge

    clivehorridge Well-Known Member Supporter Guru I am in romania

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    I’ve been caught out in the past when new pads fitted, forgetting they’ll be less effective just at that moment when you need them!
    They should bed in soon enough, but I can’t think why they should feel spongy...
    Unless you’ve changed the anti-squeal shins or put a bit too much line between pad and shim (if any)...
    I’ve just had new pads fitted on mine and after 100 km, they’re as sharp as ever.
     
  6. AndyCook

    AndyCook Well-Known Member I am in scotland

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    Didn’t you bleed the brakes after fitting ? I have found that has helped even when just changing pads.
    When you pushed pistons in to fit new pads, did you open bleed valve to expel the cruddy old fluid behind pistons ?
    I aways do that too, makes retraction pistons easier and gets rid of the old fluid in calliper
     
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  7. Higgy

    Higgy Well-Known Member Supporter I am in denmark

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    When i did the pads on the 120, It was the same as you described. So i bled em up to find the fluid was not that brilliant, so i flushed old out and put new fluid in.... Massive difference... By the end of the day once they had bed in Stops on a penny... Iv had those chamfered edge ones, Never noticed any difference Really..Give em time Mate or as Andy says, Just bleed em up....
     
  8. Charlie

    Charlie Well-Known Member I am in indonesia

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    I just did a brake upgrade on my Troopy, first impression....... why did I bother, but 200 miles later things improved.
     
  9. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    Errr, no, and,umm, err no. :shifty:
    Duly noted but never done this before. I’ve probably bled most of the fluid out during a refurb last year so it shouldn't be bad but who knows.

    They do seem to be improving slightly. Progressive would be the optimistic description.
     
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  10. Beau

    Beau Well-Known Member I am in guyana

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    Aren't you supposed to break in all break pads? I've always braked hard from about 50 mph a to a slight roll a few times until they get hot/start to fade and then drive around for 10 minutes for them to cool down. After that they should be 100% bedded. I've done this on all my cars. The procedure is sometimes printed on instruction sheets that come with pads too...
     
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  11. frank rabbets

    frank rabbets Well-Known Member

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    Pushing the pistons up inside the caliper to give clearance for the new pads will not cause air to get in. Brakes can feel spongy after a pad change because the pads bend under pressure (then return) until bedded in. That's unless one puts in new pads and new discs.
     
  12. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    I’ll try this, thanks Beau. It’s just never been so noticible. It’s the perfect storm I guess, bigger wheels, new pads on not new discs and reduced pad surface. I haven’t done many miles so yes they probably do need a bit of help bedding in.

    Most helpful replies all. :thumbup: Thanks.
     
    Last edited: May 9, 2019
  13. Chris

    Chris Super Moderator Supporter I am in europe

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    They do look different. I'll ask Carl. I tend to bleed my brakes every time I replace the pads simply because that fluid has been in the cylinders for the life of the pad and rather then push it back up the pipe, I suck it out first. It's been heated and cooled etc and makes sense to spit it out rather than swallow.
     
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  14. Dave 2000

    Dave 2000 Well-Known Member Supporter I am in spain

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    Bigger wheels reduce brake effectiveness for a given pressure, and bedding in just takes a little longer with scored discs. A good way to get rid of a bad wear ridges if finances don't allow for new, is to let the engine idle in gear, with just one wheel without traction it will turn without moving the vehicle, hold a small angle grinder against the wear ridge and it will be removed and leave a neat job, check your drive config befote you try this.

    Careful with more modern vehicles as the traction control/stability programs can get confused and may need resetting with an OBD controller.

    The bedding in procedure is generally drive normally with a little extra care however, it is normally higher performance pads that require certain bedding in procedures as per @Beau post. Some pads have a coating sprayed on that is very rough like 80 grit sandpaper, this coating will flatten out most disc scoring, but you drive normally with these coatings for best results.

    Regards

    Dave
     
    Last edited: Jun 6, 2019
  15. Shayne

    Shayne Well-Known Member Guru

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    I'm with Beau , and we both use genuine mrT pads i believe so maybe its written on the box ?

    2 or 3 emergency stops at stupid o'clock in the morning - leave yourself plenty of stopping distance .

    Oh and give it time to cool , you may recall me trying to bed in new disks and pads during 5pm rush hour around town and the pads welded themselves to the disk :doh:

    I can't find the thread .
     
    Last edited: Jun 6, 2019
  16. frank rabbets

    frank rabbets Well-Known Member

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    The rear brakes on my 89 audi coupe used to gradually fail as the design had little rear brake force for safety reasons I guess. The calipers used to seize and discs go rusty. So after the first rebuild I used to drive with the handbrake on for a few miles every 6 months or so. This used to get the calipers really hot (smoke) and scour the disc clean. You could feel the car slowing as the rear brakes started to work. Never had a problem again. Original pads fell off after 100k miles but after I employed my method pads needed changing every 50 k or so. Sold it at 245k miles. Wish I'd kept it.
     
  17. goodoldboy

    goodoldboy Well-Known Member

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    As for the fluid it should be changed every 4 years IIRC as it's hygroscopic .
     
  18. Dave 2000

    Dave 2000 Well-Known Member Supporter I am in spain

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  19. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    A bit of an update on this, after having done some heavy braking things have certainly improved but I’m pretty sure they aren’t performing as well as the set I pulled out. I’m tempted to pull these and try the set without the bevels on them as they’re clearly different.

    The sponginess has gone but I’m still having to stand on the pedal harder since the change which should have settled down by now.

    I was impressed with the original Milner ones I fitted but these are a different type with the bevels on them.
     
  20. Jake the Peg

    Jake the Peg Member I am in scotland

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    Are all the caliper pistons free, if you have some sticking after being pushed all the way in then you will have reduced braking effort, can be worthwhile carefully lifting the dust seals and giving the pistons a spray and blow out to remove any crap caught in them

    Cheers
     
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