brake piston

R

Rusky

Senior member
 Cambridgeshire
Had my upgraded brakes off an e46 330ci fitted today. Mechanic thinks tge piston fitted to the refurbed calipers are too long. Spoke to the brake refurb company and they say they are 57 dia by 53mm height. Anyone know what size piston they should be ? :?
 
Just found a site that answers my question and they are the right height at 53mm :thumbsup:
 
With the pads fitted he said he couldnt get them over the disc so he sanded some off the pads. :o
 
My replacement is 53. So agree it’s 53!

So? He shaved off 4mm? That’s like half a pad? :o
 
I changed discs and pads a few weeks ago and when I did the first corner I was surprised just how far back the pistons had to be pushed - in fact I had to push them back so they were almost flush with the inner face of the calliper with the dust boot spread out so the 'bellows' were in concentric circles. Not much room to spare but didn't need to work the faces of the pads :o
 
Well they are fitted and working. Will see what happens when they need changing next. :cry:
 
Rusky said:
With the pads fitted he said he couldnt get them over the disc so he sanded some off the pads. :o
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:cry: I'd be getting another mechanic..

If they are used calipers, which I am assuming they are, and have been stood for a while, it can sometimes take a fair bit of force to fully retract the pistons. I tend to use a big G clamp, and the pistons should be pushed back until they stop moving completely. There is a small possibility that the pads were the wrong thickness, but TBH, I've never had that and must have fitted hundreds of sets over the years.

My E46 330D upgrade was a straight bolt on, with no problems, using new discs.

Mike
 
Crazy Harry said:
I changed discs and pads a few weeks ago and when I did the first corner I was surprised just how far back the pistons had to be pushed - in fact I had to push them back so they were almost flush with the inner face of the calliper with the dust boot spread out so the 'bellows' were in concentric circles. Not much room to spare but didn't need to work the faces of the pads :o
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THAT is how far back they should go on most cars, as this is also the position when it's easy to change/replace the rubber dust boot due to the fact it's inverted.

Mike
 
Mike the cakipers were refurbished looked brand new, i am thinking that he just thought that the piston was fully back when actually what he needed to use was a bit more force. Oh well its done now so all is good :thumbsup:
 
Ducklakeview said:
Crazy Harry said:
I changed discs and pads a few weeks ago and when I did the first corner I was surprised just how far back the pistons had to be pushed - in fact I had to push them back so they were almost flush with the inner face of the calliper with the dust boot spread out so the 'bellows' were in concentric circles. Not much room to spare but didn't need to work the faces of the pads :o
Click to expand...


THAT is how far back they should go on most cars, as this is also the position when it's easy to change/replace the rubber dust boot due to the fact it's inverted.

Mike
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Don't doubt that Mike - I just think that my 60's and 70's stuff isn't quite as tight on tolerances as the Zed - at that amount of wind back I could have thrown the pads into the callipers of my old ford from a couple of paces :rofl:
 
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