Christmas has come early... AP Brakes THEY'RE ON

[JMC 0]

However, by putting thicker discs in, some people did need to file down the pad guide pins as shown in the photo below to prevent rubbing against the disc surface. But I would have thought you'd have heard the contact if this were your problem.

 

Cheers for the pic Yalan. The pins were filed down by the previous owner of the callipers - if anything they would be a mm or so too short now. Basically he was using 24mm callipers with 28mm discs. To do this he ground down the pads :shock: , and filed down the pad guide pins to get the discs to fit. Of course none of this was mentioned until after I'd bought them. As I didn't want to grind down pads when it came to changing them, I thought I would get discs which were thin enough to get the pads to fit without modifying.

 

Spin them wheels to see if anything is binding!

It wouldn't take much - maybe even less than a mm of misalignment for the caliper to be off to one side and be permanantly rubbing on one side of the disc. If this is the case, I'd be very careful of driving it. Constant rubbing would mean lots of heat and the potential for overheating and warping! Not nice on such expensive discs!

 

How much clearance have you got between the caliper and inside of the wheel? Looks close!

 

There is a surprising amount of clearance, the pictures don't show that though (prob becasue of the angle I took it from). I've made sure there is atleast 20mm all round so there is plenty of space for cooling. Definately just need to get thing thing off the ground and spin those wheels. Even after 30miles the discs are warm (wouldn't want to put my hand on them), but definately not glowing, so I am hoping this is just a "bedding in" phase.

[Kevin Bacon 5]

Yeah that's true. It took me ages to get my AP calipers aligned dead centrally over the disc, using various shims behind the carriers. It's still not perfect but the calipers aren't binding though.

 

Brembos and AP calipers tend to have scope for thicker discs, so you should be OK. it's more than likely the rears causing the problem as they are just an ineffective, crap design full stop!!

[JMC 0]

Hmmm, checked the wheels over the weekend. The rears rotate freely, so it aint them. The fronts, when I try to spin them, stop after about a quarter of a turn. Had a quick feel around on the calliper and there is basically zero space between the back of the pad and the calliper. On the plus side it has got a little better - I am now only about 2mpg down on what I was before I had them done. Still only done about 250 miles in it since fitting them (problems with living close to work), so it seems they're just going to need some more surface wearing off them.

 

On the plus side the discs are not heating on one side preferantially, so the callipers appear to be aligned correctly which is a good thing.

[Kevin Bacon 5]

Don't forget with the front wheels you will be turning against the driveshafts and gearbox diff, so they won't freewheel like the rears.

 

OK, sounds like the thicker discs have max'd out your calipers then. You could, erm, sand the pads down :lol:

 

If you have access to a bench sander, it takes seconds 8)

 

I wouldn't normally condone such behaviour as the pad face rarely remains flat (important!) when you've finished sanding, but since the discs are essentially sanding the pads anyway, it's not as bodgey as it sounds :lol:

[JMC 0]

I could actually hear it against the pad as I spun the wheel, so I'm sure it's that. Know what you mean about the driveshaft etc though Kev, and I wasn't expecting it to be free wheeling like the rears. I was just surprised at how quickly it stopped.

 

Unfortunately I don't have a bench sander (just something about doing that is admitting defeat as well, and I have concerns about keeping it flat, as the last muppet who had done that on my previous set had the surface of it curved like the horizon :shock: ). I am back up to 1-2 mpg down on what I was before changing them, so it must at some point go back to normal. I'm off down to G-Werks on monday so that will put a few more miles on it (110 round trip), so I'll see how it feels after that, then I might have to admit defeat and take it to be done - especially with it being rolling roaded in a weeks time.

[JMC 0]

Time for a quick update - put 1000 miles on these now and any binding has ceased. All in all very good brakes (better than I will ever need) so to anyone thinking of trying something like this - yes the callipers will take discs slightly wider than the normal ones, however expect a big of rubbing for a few hundred miles while everything settles in. Oh, and BG Developments were great to deal with...

[Phil K 0]

Glad it's worked out for you matey... was worried after reading about the initial outlay! 8)

[JMC 0]

Cheers Phil. Yes, the intial outlay was (for something that is designed to wear out) scary to say the least. Thankfully it all seems to be fine now. Yay

[Kevin Bacon 5]

As with everything in life, you get what you pay for.

 

Enjoy the brakes mate. You'll probably find you'll start braking later and later and enjoy that nearly as much as accelerating :-)

[junkie 0]

Think i need to get into that scary game some more, braking later and later lol.

 

I bet doing that scares the passengers more than accelerating at full boost and throttle, ie: doing a ton then stomping on the brakes at the last moment with cars in front of you.

[Kevin Bacon 5]

Yeah it's good fun but WAGs don't appreciate it much :lol:

 

I need to beef up the rear brakes too. People often say you don't need to on FWD but that's a myth imo. To see for yourself, the next time you brake hard, yank the handbrake up hard at the same time and feel the difference the rears actually doing something makes!

 

I wouldn't try it mid bend obviously as the ABS can't unlock a disc clamped by the handbrake :lol:

[junkie 0]

Its great how you blow all the myths up kev, but still best not to go more power on the rear still.

 

Well i dont have ABS so i will try mid bend and post my findings.

[Paulr1980 0]

Just wanted to say that set up is the tits!!!!

 

Well done dude. I'm not sure I can justify going to that extent (much as I'd like to) but i'll certainly be brembo'ing up in the next couple of months.

[junkie 0]

Just going to the brembos you will notice a massive difference.

[JMC 0]

Just wanted to say that set up is the tits!!!!

 

Well done dude. I'm not sure I can justify going to that extent (much as I'd like to) but i'll certainly be brembo'ing up in the next couple of months.

 

Thanks Paul, As Junkie says, you'll notice a big difference just with the brembos, nd to be honest it will be easier and cheaper to do. The reason I didn't is that I didn't want to buy yet another set of brake callipers, so I decided wo work with what I had.

[pete_griff 0]

Yeah it's good fun but WAGs don't appreciate it much :lol:

 

I need to beef up the rear brakes too. People often say you don't need to on FWD but that's a myth imo. To see for yourself, the next time you brake hard, yank the handbrake up hard at the same time and feel the difference the rears actually doing something makes!

 

I wouldn't try it mid bend obviously as the ABS can't unlock a disc clamped by the handbrake :lol:

 

it's a bit of a bodgers fix really - but if the rears really aren't performing, could you not adjust the bias valve - it has that nice long slot in it so you can put the bolt where you want it - you could try adjusting the bolt so you have it on pretty much max the whole time and see if that helps - once its sorted gonna take my car to a friend who is an MOT tester and put it on his rollers to get my bias just how i want it - you may well have already thought of this, but just a suggestion... (also rollers and lsd's dont mix, so you might be a bit stuck there!)

[Kevin Bacon 5]

Its great how you blow all the myths up kev, but still best not to go more power on the rear still.

 

Neither would I on a standard car but I'm not in the same mindset as a standard car owner when considering mods. The stock brakes barely cope with the VR6's standard power and weight, but mine has twice the output and has a battery and a 3 gallon water tank in the boot. It also has much lower and stiffer suspension than standard, so doesn't lift a wheel mid bend or dive under hard braking, so I therefore consider it responsible and essential to make the brakes as good as I can.

 

BahnBrenner's 280mm rear conversion kit makes perfect sense on my car and that kit wouldn't exist if there wasn't a need for it. Consider also the fact the MK5 GTI weighs the same as my car and has almost half the power, but has 280mm rear brakes.

 

A lot of the pedal feel comes from the rear calipers working properly, and this time of year they often get crusted in salt and grime, which has always been an achilles heel of the MK2 system.

 

For once I'd like to MOT my car and not get an advisory on the rear brake performance!!