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[Cliffo B]

Don't think so,my 2003 Elite estate has them on as OE. And although super progresive brakes their just a load of trouble as regards spares. The calipers are now a non serviced part. I waited 3 weeks for some new replacements from Germany, only in the end to be told the GM policy was to provide Re-manufactured Units,exchanged for the old units on a surcharge system. These came as de-rusted, with a lot of vital casting relief that supports the pads rotted away, then passivated they even used the original pistons that were so rusty you could hardly define the cut outs that have to be off set 20deg. The reason I wanted to replace mine was they were also badly corroded so someone else will finish up with my scrapped caliper.The outcome after a lot of searching was I managed to source a new one, which was obviously old UK stock for the passenger side.The drivers side is a remanufactured unit. I travelled to a firm at Rochdale called Brakes International to see over the counter before I accepted the unit on offer he told me it was remanufactured in Denmark by a firm called Budweg. The standard was acceptable the casting showed minor rust damage but was well plated and both pistons were brand new replacements. The unit cost £129.25,I didn't return my old unit for a £20.00 + vat refund not really viable mileage wise. It's badly corroded anyway. So there it is all you with late model Elite's take note. I think its a scandal and irresponsible that things as vital as brake calipers cannot be purchased at any price new to OE spec. >:(In future I'll make it a part of my regular serviceing to hose off with water inside the calipers when the council start to grit the roads its obvious the vented disks are creating a turbine effect with the anti freezing chemicals and destroying the internals of the caliper castings.Sorry to have to impart such news but if you know these things then at least you can take precautions.    

[Andy B]

.....
I travelled to a firm at Rochdale called Brakes International to  ......   

Which is where my pattern discs came from for the front of my Senator. They lasted about 3/4000 miles before I had problems with warping. Needless to say that Brakes International were not interested. 

[Cliffo B]

I would never use aftermarket parts unless forced in this case I was forced. And they had the best option available by far.

[Elite Pete]

I thought the vented rears used a different caliper :-?

mah its all the same unless you are up grading the standard size of the disc .

A :yNDY

They do, its wider. I replaced the solid discs on my old mini facelift to vented and had to get the calipers aswell

Old disc/caliper



Vented disc/caliper

[2woody]

there's a few things here....


the vented rear set-up is the same diameter, but thicker discs. The caliper is of course different because the disc-spacing aperture is wider, BUT the caliper pistons are also 42mm as opposed to 40 of the early cars.

I'm reasonably sure that the very late cars had what's called EBD, or "electeronic brake distribution", which is probably the reason for the larger piston - this mod alone increases the rear bias by some considerable amount, but is needed for EBD.

As far as I know, there are three basic different brake setups on the faster Omega B vehicles :-

( figures are disc dia/piston dia and primary/secondary master cylinder bore )

296/57 vented front, 286/40 solid rear with 25/20 master cylinder.

296/57 vented front, 286/40 solid rear with 25/25 master cylinder

296/57 vented front, 286/42 vented rear with 25/25 master cylinder and EBD

regarding "upgrades", I wouldn't advise unless you really know what you're doing. And by that I mean at least 10 years in a vehicle design capacity, with testing thrown in to boot. Brake bias is a very complex subject - even the confirmatory test costs upwards of £20K and takes a week to do. If you can't display absolute mastery of the subject, how good are you going to be in court when the judge asks you how come you've just mown down a bus-queue full of nuns ?

Of the things that could be changed, by far the most effective is the disc diameter and the piston diameter - larger diameter of both = more effective brakes, or to put it more correctly, more tractive effort for a given pedal force input.

Fitting the vented setup to a car with no other changes will raise the efficiency of the rear brakes, but will also result in them locking earlier - hence bringing the ABS on earlier and also unfortunately lengthening the overall stopping distance - what is needed is a balanced approach, where rear improvements are matched by front improvements.

As an example, I do actually have the late Omega B discs on the back of one of my cars, but it's got 350mm discs on the front, which makes the balance about right.

just for reference ( as I've said before ) grooved and vented is only of benefit when your pad life is at most two hours or less - think endurance racing. This is because the holes and grooves are there to dissipate gases and bits of dead pad - they perform no other tasks. They may even lead to premature wear and disc cracking.