Right had the 312's fitted ages ago along with grooved discs all round, and to my horror after a bit of reasearch the mechanic stuck em on backwards

How hard is it to swap them so they run the other way? i have done the rear setup on a Polo gti and have the caliper rewind tool etc.

Is the front much the same? i know you dont need the rewind tool! Also can you leave the carriers in place as the same as the back ones? also any bleeding of the system needed as i cant do that :(

Also while im at it going to replace the rear pads as the brake pedal has become hard and the brakes are pretty poor to be honest. Front pads have loads on them would the rears being low cause the poor braking??

Oh and heres a pic of what im up against :thumbdwn:

The groves will make very little difference regardless of which way they run. Piece of cake to swap around though, just unbolt the caliper from the main 18mm bolts. Slide the caplier and carrier off complete. Remove disc screw if you have one, remove disc, swap over and refit. No bleeding, No pistons to worry about.

The groves will make very little difference regardless of which way they run. Piece of cake to swap around though, just unbolt the caliper from the main 18mm bolts. Slide the caplier and carrier off complete. Remove disc screw if you have one, remove disc, swap over and refit. No bleeding, No pistons to worry about.

Ahh brilliant, nice and straight forward then, its just a minor detail that bugs me, i know they should in theory be running the other way so i'll have to fix it.

The rear pads will be getting changed so might as well do them all

Would low rear pads cause stiff brake pedal and all round aweful brakes? the pic shows front pad depth... im assuming this looks okay :confused:

It shouldnt do no, how low are the rear pads?

It shouldnt do no, how low are the rear pads?

Pretty low! need changed asap, not wearing on the metal just yet

Car is 4 years and 53k miles old, planned on getting the brake fluid changed at next service at 57k. Might as well change pads myself and see if this alleviates the problem :confused:

I'm sure this is like trying to teach a granny to suck eggs but ... the direction of the grooves doesn't matter *nearly* as much as the direction of the vents. Make sure the discs are on so that the vents work right!

I'm sure this is like trying to teach a granny to suck eggs but ... the direction of the grooves doesn't matter *nearly* as much as the direction of the vents. Make sure the discs are on so that the vents work right!

I've just recently fitted 312's and gave no thought to the disc rotation. Thought you could fit to either side regardless. Now that you've raised this: can you advise how to check which is correct? Thanks.

Glad to see you've finally decided to turn them around!

I've just recently fitted 312's and gave no thought to the disc rotation. Thought you could fit to either side regardless. Now that you've raised this: can you advise how to check which is correct? Thanks.

unless yours are grooved then it will make no difference as all 'plain' discs are made the same way and fit either side.

This will help:Brake pad and rotor replacement - Passat World Forums

unless yours are grooved then it will make no difference as all 'plain' discs are made the same way and fit either side.

i think mine were OEM discs that were grooved

Are you absolutely-dootley sure they're on the wrong way? Mine look like this, and they're definitely correct!

Are you absolutely-dootley sure they're on the wrong way? Mine look like this, and they're definitely correct!

Well evertime i see them on a car fabia or not there always the other way round? and numerous people have commented before there on the wrong way as the groove should hit the inside of the pad first :confused:

Dont tell me this as i have just changed the fronts they were OEM discs with grooves in im guessing as they could run either way

heres my handy work, please say i dont have to change it again, think i'll cry

have you noticed any diference then

Still on drive lol! not driven it yet... needs new rear pads so i'll change the rears next weekend lol

unless yours are grooved then it will make no difference as all 'plain' discs are made the same way and fit either side.

Appreciate your response. Thanks.

Mine are grooved and like this

There's no problem what so ever having the grooves on the disc the other way round! All it does is mean its slighty more aggressive on the pad. That is all. I've been fitting discs both ways round for years and noticed no difference what so ever to the braking performance.

Infact I believe some manufactures specify the disc to be mounted that way round! I wouldn't go to the hassle of changing it for essentially no gain.

Here we go. Problem solved.... The grooves DO NOT dictate the direction of rotation... the internal Vanes do.

Ventilation gap

It is a popular misconception that the slots or drillings in a disc determinate the direction of rotation. In truth, for an internally vented disc, the geometry of the vanes dictates the direction of rotation.

There are 3 different ventilation types in use:

· Straight vanes

· Curved vanes

· Pillars

The straight vanes and the pillars are non-directional, and can be used on either side of the vehicle. The curved vane disc, however, is directional. A curved vane disc must be installed with the vanes running back from the inside to the outside diameters in the direction of rotation. Orienting the disc in this manner, creates a centrifugal pump. The rotation of the disc causes air to be pumped from the center of the disc, through the vanes, and out through the outside diameter of the disc. This enhances the disc’s ability to dissipate heat. On some OEM applications, this standard is not satisfied: the use of directional discs means to manage two codes (left and right) per axle with some extra cost therefore it happens that a car manufacturer can use the same disc with curved vanes on both sides, losing part of the benefit in balance with lower costs.

This was taken from the brembo brake info page Brembo Brake Information Page

Hope this helps.

Neil

Infact I believe some manufactures specify the disc to be mounted that way round! I wouldn't go to the hassle of changing it for essentially no gain.

Changed the rear today along with new pads

Found my brake problem. one of the pads on the inside of the disc had 'popped out' of place and only half the pad was on the disc :confused: