Octavia MKII Replace Rear Brake Pads using Laser 1314

[funklet]

Hi,

I have done about 60,000 miles and the rear brakes are wearing thin. I have not had to change them on this car before but I have changed them on a Vauxhall Nova many years ago. The front pads are still about 4mm but they are a fair bit bigger with double vented discs. The rears are smaller with only single discs.

I was informed on the last service that the rear pads were <10% so I have changed them and below is some hopefully useful information.

I was quoted aboubt £140 to change the rear and £140 to change the front by the main dealer.

I ordered some pads from http://www.ebcbrakesdirect.com by putting in my Registration but unfortunately they were the incorrect type.

I had not removed them at the time I ordered so I didn't know this until I had removed a pad.

For future reference I will not trust the sites that ask for my reg!

Edit: It is important to be careful when using your reg to order parts. VAG cars can have different parts in them from the lists that must relate to the reg. This is perfectly understandable but the websites selling you parts do not inform you of this when you are ordering. You will have to do cross checking from other websites or check the images carefully to ensure you will get the correct parts. In the service book and under the mat in the boot there is the big list of all the three figure codes of the bits in your car, amongst other things in the codes are the brakes. There is a forum post somewhere which links to an explanation if you type in the codes.

After removing a pad I took it to Halfords who could order me some in at about £45 so I went to Unipart who initially brought me the incorrect pads based on my model (these were the same as the incorrect pads I got from EBC) then they found the correct pads, I am not sure how they got the correct pad part number.

Wrong pads from EBC = DP1497 = £28 - I'll have to return these.. :(

Edit: I returned them to EBC which cost me £5.60. After a lengthy email exchange with much complaining they agreed to credit me the original purchase amount plus the carriage. I had to wait three weeks (they said 14 business days, disappointing they can charge immediately and take 3 weeks to refund when it was their mistake) for the credit which was sent minus the return carriage. I had to contact them again and the reason given was that the credit could only be the same as the original purchase. They did refund the £5.60 three days later so I am not out of pocket except for the wasted time. I am not saying that you should not use EBC as if I had taken more care to ignore their reg system and find the parts myself the initial delivery was swift and I have no reason to doubt the product quality.

Correct pads from Unipart = GBP1568 = £25.66 including Mintex Cera Tec Brake Lubricant (Apparently we don't use Copper Grease any more..)

Laser 1314 Brake Caliper Piston Re-Wind Tool = £15.50 from Amazon - vital!

When the caliper is pushed back there will be fluid returning to the reservoir.

It was only serviced recently and the reservoir is already on maximum.

I removed several childrens Nurofen syringes of brake fluid from the reservoir into a Nutella glass:

Very important to have the vehicle on completely flat ground as we will need the handbrake off while it is jacked up.

Take the handbrake off and make sure the car does not roll forwards / backwards.

Loosen the wheel nuts while the wheel is still on the ground.

Jack the car and remove the wheel completely.

The caliper is held onto the wheel by 2 x 13mm bolts locked on with 15mm nuts.

These are behind the caliper and you'll need a big spanner or socket set.

Loosen the 15mm nut and hold it still while undoing the 13mm bolt.

Tools

This picture is taken looking backwards towards the wheel inside the wheel arch.

Unhitch the hand brake cable from the caliper

The caliper will be tight on the disc so I used a screwdriver to lever the pads back far enough to be able to lever the caliper off the disc.

The pads are not held in the caliper they should be left on the disc and should be easy to lever off.

img_3875 - Not much pad left here!

Wind the piston in using the tool.

You need to engage the pins on the end with the sockets on the caliper piston and tighten the plate against the other side of the caliper.

You have to hold the knurled bit still while winding the tool in. After a bit of winding the tool will be loose and you need to wind in the knurled bit some.

If you tighten the knurled bit too much then the winding bit can become too difficult to turn so just loosen the knurled bit off a bit.

You need to carry on and on until the piston will go back no further and the boot is compressed right up.

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Put the new pads on and apply the Cera Tec liberally to the rear of the pad and the face of the piston.

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Slide the caliper back on and lock the 13mm bolts and 15mm tightly back onto the caliper.

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Fit all the wheel bolts back in and screw in hand tight.

Lower the jack and apply the handbrake and torque the wheel nuts or tighten them soundly.

Go for a test drive!

Edited 27 October, 2011 by funklet

[vwcabriolet1971]

There are a number of schools of thought on the need to bleed each caliper when changing pads.

First is don't. Don't open caliper bleed nipple when pushing back piston and don't bleed after mechanical operations are complete.

Second is open caliper bleed nipple when pushing piston back and then bleed by pumping with brake foot pedal and using one way valve easy bleed kit.

Third is to open caliper bleed nipple when pushing piston back and bleed with pressure kit.

The potential problem with the first method is that the master cyl. seal lips may be reversed because of the reverse oil flow pressure when pushing the caliper piston(s) back. This will result in a new master cylinder being required. You may be lucky and this doesn't happen to you, but it can happen.

In the second method there is no reverse flow through the master cylinder so the seals can't reverse but when foot pumping the master cyl. piston may be pushed into an area where the master cyl. seals don't normally travel as far, in normal braking. This can cause seal damage when the seals pass from the highly polished normal area braking cyl. area to the un-polished un-used part of the master cyl.

The third method obviously doesn't have the risk of the seals reversing or the seal damage from the excess travel of the master cyl piston.

A lot of garages use the first method as it is quick and if in the event of the master cyl. seal reversal can always charge the customer for a new master cyl.The likelihood of the seals being reversed depends on the age/wear/condition of the master cylinder.It happended to me once so I use method 3.

Your choice !

[funklet]

It would be interesting to see what the OEM Service Document says regarding winding back brake cylinders. Maybe a main dealer could check and comment.

From a technical standpoint it does not seem likely that a perfectly working master cylinder seal will flip over by applying pressure from the slave cylinder.

This rewind pressure would occur in exactly the place where pressure is designed to occur normally when braking.

The pressure applied to one cylinder from a rewinding tool would be of a considerably lower pressure than when the footbrake applies pressure to four cylinders under normal braking.

It is possible that a master cylinder could fail when cylinders are wound back, but only if the master cylinder was already likely to fail for other reasons. This would be coincidence rather than cause and effect.

There could be situations in which cylinder pistons could travel further than desired and cause issues. This is not one of those situations as the cylinder was wound back within normal limits.

It is very important that dirty brake fluid is not pushed back into the braking system, dirty fluid can also cause failure of components.

If there is any doubt as to the cleanliness of the fluid then it should be changed anyway, along with a full braking system inspection, and then the pads can be changed.

In the service book for the Octavia II it states the brake fluid should be changed every 40,000 miles.

This is regardless of the service interval which in this case is variable...

The brake fluid was changed at 42,000 so it has only done 20,000 miles since last changed.

This puts me in the first school.

Edited 21 August, 2011 by funklet

[vwcabriolet1971]

If the master cyl. was designed to allow reverse flow then the master cylinder seal would collapse under normal braking. If you think about it, forcing reverse flow hyd. oil past the seals is exactly what you don't want to happen when braking. Without knowing the detail construction of the master cyl (port positions etc) it is difficult to know for sure what is acceptable practice and what is not . It is better to eliminate some possibile failure modes rather than trust to luck. Changing the hyd. brake oil at the same time as the pads eliminates doing some of the operations separately and ensures the whole hyd. system is serviced.

There are commercial brake instruments that can measure/sample the boiling point of the brake hyd.oil. The normal 2 year hyd. oil change interval rule is only a general guide which has to cover all sorts of climate. e.g. the water absorption in a high humidity environment ( say in the monsoon season in the far east) would be a lot higher than the absorption in a dry desert region. The mileage brake fluid interval spec is completely meaningless. The water absorption rate is time dependant not mileage related. Adopting the 40K mile interval could result in some 4K/year drivers not changing the oil for 10 years by which time the oil would have absorbed that much water that the boiling point would be dangerously low, so low in fact that the oil would boil under any heavy prolonged braking.

Where brakes are concerned ( especially mine or the families' !) , I would always adopt the safest way.

Edited 21 August, 2011 by vwcabriolet1971

[hatchy]

Jesus H, you took some risk doing all that off the 'emergency' jack.

[Mikek3111]

I've worked at main dealerships as a qualified mechanic for 9 years plus a 4 year modern apprenticeship and I can assure you that never once have I or any mechanics I've worked with bled the braking system because of changing pads or winding calipers, and I have never had a master cylinder break on me whilst doing it.

Tbh. No disrespect, I understand your reasoning but.... I've never heard of anyone bleeding the system or opening bleed nipples in order to wind the calipers pistons back.

Jesus H, you took some risk doing all that off the 'emergency' jack. http://www.briskoda.net/forums/public/style_emoticons/#EMO_DIR#/emoticon-0104-surprised.gif

Your correct, really should of had an axle stand under there.

Edited 25 April, 2014 by Mikek3111

[brad1.8T]

Agree with above on both points. 

 

1) No need to rebleed or break into the hydraulics if you are just pushing pistons back.

 

2) Absolute lunacy to use the emergency "widow maker" jack as a work jack (they are even rubbish for changing tyres).  Totally not designed for the job.  At a minimum, slide the removed wheel under the sill or stack some timber blocks under there.

 

Small trolley jacks are available from the local auto-parts store and they work well for jobs like this.  You can often buy them bundled with a couple of jack stands for less than AUD100 (GBP70?)

[blackspaven]

Just a quicky seeing as there's pictures on this thread.

 

I've always avoided changing the rear brakes cos you generally get nightmare stories about some part of it (can't remember which) being a b1tch to get off, but looking at the pics, would I be right in saying literally the only difference between doing the front and back (apart from unclipping the handbrake cable and reconnecting on the reassembly;another thing that looks ridiculously simple unless I'm missing something??) is that you need a rewind tool for the caliper whereas the front ones can pretty much be done with some sort of leverage?!

 

If so, I feel VERY silly all of a sudden!!

[mikey vrs]

Yeah your correct in what your saying,on the octavia vrs the only tricky bit is undoing the caliper carrier bolts as access isnt great,other than that its just the caliper that needs a wind back tool.

[blackspaven]

Thanks. Was just about to ask was it the carrier bolts that are a pig cos I read that VAG use those bolts that have locking teeth at the base of the head, which I think are those type that have the little lines going out from the centre on the bolt on the flat underside of the bolt head, so I guess they must sort of lock in to the metal once you torque them up, and over time they must REALLY lock in!

[hatchy]

As far as I know it's only a ballache doing the rear discs if you have the VRs. Because of them being larger than the 'normal' discs the rear caliper carrier has to come off and the spline bolts aren't that easy to do on if working on the ground.

[zzonyx]

My two bits on the rear pad change - the widow maker apart, I'd suggest wearing gloves for this kind of work.

The pad renewal procedure requires also new shims AND new caliper bolts, both included in the pad kits supplied by serious manufacturers (mine were FERODO, but BREMBO, VAG, ATE, BOSCH, JURID and TEXTAR all supply those).

From the pictures it seems that old shims were reused, can't say for the bolts.

Caliper pins and bellows should also be thoroughly cleaned and lubricated using silicone grease which is water repellent, temperature resistant and doesn't dry over time. Together with the shim and corresponding pad surface lubrication, this provides uniform pad wear on both sides of the disc, otherwise the primary pad (the one pushed by the piston) wears more than the outer one, meaning less than 100-percent braking effect. So when you look at the secondary/outer pad to assess wear, the truth may be worse than it appears - you should check the inner pads instead. That's why wear indication typically monitors inner pads.

Applying the standard 1/2" torque wrench and socket on LUCAS-TRW rear caliper bolts (30 Nm) is impossible due to available space. The way to go is a smaller (3/8") torque wrench and a matching 13 mm crowfoot (open-end) socket.

My Octavia has almost 151,000 km, changed the rear pads last week (had about 1.5 mm left), the front (outer) ones still have around 4 mm, so will proceed shortly.

Cheers from Italy.

Edited 11 July, 2015 by zzonyx