upgraded brake grief!!

right then…. lets see if I can explain this proper like….
I am going to be running an upgraded servo 9" I think it is which works just fine and also gm calipers (need to do a service kit change on 'em tho as the rubberboots are goosed!)
with 280mm discs but when I removed it all from the car to do the required service work I have noticed that the pads on both sides are not contacting the disc entirely and it's creating about a 4-5,, flange to the top of the pad
how do I stop this from happening? I was thinking a 285mm disc would sort the problem but cannot find a set of discs that size anywhere which have the correct center bore or the right stud placement….. anyone be able to help me out on this issue????
AAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGGGGG!!!

Have you got your calipers on the correct sides? there may be a slight offset from the mounting holes. Either that, or if you have had the spacer brackets custom made, they may not be quite right. These are just guesses as I have not experienced this before.

I have the GM calipers on 256 discs  

as far as I was aware the calipers were on the correct sides and the carriers are also GM and use shouldered bolts to attach everything seems to fit o.k. but as stated in previous post the pad wont hit the disc 100%!
this conversion was not originally done by myself so I'm not again 100% if the correct parts were used but when I searched for a refurb kit for the calipers and took the part number to a Vauxhall dealer he said that they were Vectra c calipers.
I need to get to the bottom of this before I go wasting my cash on a refurb kit for them as if I can't either find the correct size disc for em I might get G60 calipers…… don't really want too though as funds are really tight at the mo

Not sure I understand 100% but if you are saying the pads overhang the discs on the outside then in my experience this does happen with the Vectra caliper/g60 disc combination. Yeah a 285mm disc would help somewhat with that.

abfmk1 said

Not sure I understand 100% but if you are saying the pads overhang the discs on the outside then in my experience this does happen with the Vectra caliper/g60 disc combination. Yeah a 285mm disc would help somewhat with that.

the top edge of the pad doesn't contact the disc surface….. i'll take a picky of the pad later so ya can see what I am talking about, I figured a 285mm disc would be an easy fix to the problem, just can't find a 285mm disc with the correct center bore in a 4x100 fitment

Yeah I understand, normal as I said, seem to remember sometime ago (and I could be wrong) a company used to offer a large disc conversion using a 285mm disc as opposed to the more used 280 mm conversions, cannot remember who though.

Does it cause any problems this overhang? Maybe noise? Wouldn't have thought it would affect braking performance by anything noticable.

noise I think, and ain't 100% that the gasses are getting out quick enough, also fade possibly due to previous reason and uneven pad wear!
 

Have you got any old brake pads hanging about? If so, you could try trimming the overhanging pad material off with a 1mm wide grinding disc?? These things are built to handle heat so the only issue would be the brittleness. Might be worth a shot. steady as she goes…

If you have a 4-5mm overhang (assuming from your first post), then a 285mm disc wont do it for you as it is will only reduce the overhang by 2.5mm

TSR used to do a 285mm disc setup; discs were expensive though. 

are you sure you are using the right gm calipers as they did do some for for 288 discs

dik-van-dub said

are you sure you are using the right gm calipers as they did do some for for 288 discs

ain't got a clue as they were fitted already to the car…

I have no idea but is that not the point, these cars have 288 mm discs not 280.

kamikaze cabby said

as far as I was aware the calipers were on the correct sides and the carriers are also GM and use shouldered bolts to attach everything seems to fit o.k. but as stated in previous post the pad wont hit the disc 100%!
this conversion was not originally done by myself so I'm not again 100% if the correct parts were used but when I searched for a refurb kit for the calipers and took the part number to a Vauxhall dealer he said that they were Vectra c calipers.
I need to get to the bottom of this before I go wasting my cash on a refurb kit for them as if I can't either find the correct size disc for em I might get G60 calipers…… don't really want too though as funds are really tight at the mo

I fitted Cavalier GSi/Vectra on 256mm discs to my Mk1

There were two discs used by GM at that time.

256 x 24mm disc - Cavalier, Calibra, Astra, Vectra C

256 x 20mm disc - Corsa B 1.6, Tigra A

The thinner disc setup use slightly smaller calipers.

Vectra B discs are 288 and have to be re-drilled

Vectra C discs are 285 and have to be re-drilled