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how thick should front brake pads be?

Discussion in 'VR - VS Holden Commodore (1993 - 1997)' started by RWD4ever, Oct 25, 2019.

  1. RWD4ever

    RWD4ever Member

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    I saw a major retailer had slotted rotors for $75 - clearance sale, so I grabbed some. I happened to have some pads lying in workshop: the cheapo SUPERSTOP brand. They were very difficult to fit. I pushed back the piston, and removed the bit of tinplate (with ISO number) that clips on. But there is only a Rizla paper clearance to get it on the new rotor. The sliding pins aren't seized, as is common with such old cars. Rotor seems to be correct thickness. The pads thickness varies from 12.5 to 12.8 mm among the four of them.So looks like some sloppy manufacturing there.
    This is just the standard VS V6 brakes, not HSV, VT, VE or some other upgrade.
     
  2. _R_J_K_

    _R_J_K_ Well-Known Member

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    What did you use to push the piston back in? Was it fouling on the thick side or just everywhere? The single piston slide calipers are sometimes a bit weird when you're trying to push the two halves apart, they're a bit counter-intuitive it's hard to explain. The tin plate (the shims) are for anti-rattle/vibration (?), so if it's making some strange noise that's probably why.
     
  3. shane_3800

    shane_3800 Active Member

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    As long as the rotor spins freely they should be fine. If you force the caliper on being a lazy .... you end up having to go back on the hoist and pulling it apart again just to push the pistons back 5mm.
     
  4. greenacc

    greenacc Searching for the billion

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    Usually about 11mm at a guess but I have never actually measured them.
    If you were really desperate you could rub them on flat concrete to remove some material but make sure you do it evenly.
     
  5. vs-lover

    vs-lover Well-Known Member

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    The metal plates are called "Anti Squeal Shims"
     
  6. losh1971

    losh1971 Well-Known Member

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    I never use the shims and never have any squealing. I think if you fit VE calipers they are needed though or you get problems.
     
  7. shane_3800

    shane_3800 Active Member

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    The shims do reduce noise. New brake pad thickness varies max thickness can be changed not by concrete but buy some 80 grit on a piece of glass or a good bench. The dust they make resizing nakes it worth just going to a good mechanic of you value your health.
     
  8. losh1971

    losh1971 Well-Known Member

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    Shims must come with cheap pads, the last 5 sets of pads I bought never came with shims. I've seen hi-temp RTV used on the back of pads too but I've never used this either.
     
  9. shane_3800

    shane_3800 Active Member

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    Any stuff smeared or sprayed on the pads is BS but the shims help and come on most decent pads.
     
  10. losh1971

    losh1971 Well-Known Member

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    Hmmm interesting my last three sets of QFM's and last two sets of Bendix 4WD pads never came with shims. First pad change on the ute it had shims from previous owner. But I chucked them away as I haven't used shims in well over 10 years and never had a noise problem. That's why I thought it must have been something cheap pads come with.
     
  11. shane_3800

    shane_3800 Active Member

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    All bendix pads have backing shims these days. Gee it's probably back when I was an apprentice when they didn't have them.
    Backing shims are used by the OEM's because they work and OEM pads are better than any aftermarket crap you'll buy.
     
  12. vs-lover

    vs-lover Well-Known Member

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    Just to add to the story with the use of bonding materials used between the pads and piston, that was done purely for assembly line ease.

    This way the donkey's on the line could simply slap the calliper straight over the rotor without the pads moving around and requiring any corrective attention in the process.
     
  13. losh1971

    losh1971 Well-Known Member

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    Previous owner used orange RTV and the shims on mine. Not sure what he was thinking. Like I said never used either on my last three or four cars and never had squealing. Had groaning once but that was because I thought it would be a good idea to use loctite in the slide pin bolts. I read somewhere it was a good idea, almost stupidist idea I have ever tried. Had to wire wheel the bolts and slide pins to fix the issue, groaned like a bastard until I fixed it.
     
  14. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    Brake thickness comes down to brand and compound they use and quality control I suppose, around 11-12.5 be common sizes. Simple is google the brand and compare them to another brand. Never used baking shims only anti rattle plates.
     
  15. losh1971

    losh1971 Well-Known Member

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    Getting technical with names now are we? The manual calls them anti-chatter shims not plates. So stick that in your pipe and smoke it. ;) If you like I can even quote the manual "do not omit anti-chatter shims".
     
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  16. greenacc

    greenacc Searching for the billion

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    Several brands of pads now have a rubber backing as well. It's all there too absorb any tiny little vibrations of the pad when the piston retracts after braking creating this little gap between pass and piston. The vibration causes squeal and dealers don't want you coming back with complaints about it so add the shims as a preventive measure. I'd guess they also help his the pad perfectly square to the rotor surface which will give you that little bit better response and brake feel when you touch the brake pedal. So I keep using the original Holden shims on whatever pads I fit.
     
  17. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    Brake shims work much the same way to adjust otherwise normal brakes. On the most basic level, for many new vehicles with new brake parts, brake shims function as anti-rattle pads. They keep the pads and rotors from banging against each other or squealing.

    Not all brake pads come with shims as they aren't required and function perfectly without needing them. … This doesn't require the use of disc brake lube, but you can still apply a thin coating on top of the brake backing plate. Lastly, there are also titanium brake pad shims which act as an improved thermal barrier.

    An anti-rattle clip, also called a brake abutment clip. Anti-rattle clip shown in land of brake calliper bracket. is used to prevent brake pad looseness and noise when mounted in a brake calliper or brake calliper bracket.
     
  18. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    Sorry for not putting the shim in front of plate as I thought as I already placed shim prior you would of worked out that I was referring to shim plate. Oh you can call them a biscuit all I care. Didn't know they could talk, lol what do they say to you, rattle is a better word as chatter can mean 50 things.:)
     
  19. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    When you quote from another website you should add a link.
     
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  20. vs-lover

    vs-lover Well-Known Member

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    TLH.................OMG !
     

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