Brakes: Front Discs, Pads Replacement - Guide

[BestGear]

Hi Folks

Having replaced the rear brakes a few weeks ago, I decided to replace the fronts too. They were not too bad, but would need doing in a few months, so doing them now, meant that they did not need doing in mid-winter!

Anyway - firstly, getting the right partnumbers for genuine or aftermarket pads and discs for the front was tricky, as several conflicting numbers appeared for the VIN... and when looking at the diameters and size of pads, they did not agree!

Anyway - I was told that all UK XC90s have the same front discs and pads - I am not sure if this holds true for the 17" wheeled vehicles (mine is 18") but suspect it is.

This is further confused by the fact Volvo seem to state 16" or 17" wheel son the boxes and listings!

Anyway - these are the discs and pads...





Have a close look at the pads - the upper pad (in the picture above) has a small rectangle cut on the pad bracket - this is the bracket that you see from the front of the caliper and it locks the caliper anti-rattle spring.



It is not obvious when you look, but you need to unclip the spring from this bracket when you start the job. The bracket you see below - at the left hand side is the pad bracket - this its easy to see how to release the spring.



And..the spring when removed...



Anyway - when I first got the car, I thought it must have 2 or 4 pot calipers, given the size of the calipers - they are huge! They are however, single pot (piston), but are substancial.

The good news is that removing them follows what has become standard practice on most modern cars.



To remove the pads, you need to remove the two caliper slides. These are similar to the rear setup on this car - remove the two plastic caps (highlighted within the red ) then under them, two hex head pins - easy to remove and no threadlock so easy peasy.

Take note - unlike the rears, these pins are of differing lengths - the longer one being fitted to the upper slide.





When the caliper is removed, remove the pads - one is clipped into the caliper front, and the other clipped into the piston. When removed, ensure that you support the caliper properly, and that the rubber brake hose is not being unduly twisted or under tension.

Next - you need to remove the caliper carrier bracket. This is two bolts to the hub - shown below. These appear tight, but in reality, its just the threadlock holding them in.




Once the bracket is off, its a simple job of removing the centre 10mm bolt and removing the disc. If the disc is tight, give it a few hits from the rear to free it off. If its really stubborn, put some release oil through the wheel bolt holes aiming between the disc and hub - that usually does it.



With the disc removed...



So - put it all back together!

When refitting the disc, ensure that there is no debris between the hub surface and disc rear.

Its usually advised these days, to loosen the bleed nipple on the caliper when pushing the piston back in to save any risk or reversing the direction of any seals within the ABS or master cylinder. Your call - just get it pushed back!

Fit the pads to the caliper - both clip in.

Refit the caliper carrier, having replaced the bolts or cleaned the threadlock out of the original bolts - remember to use threadlock when fitting (if the replacements dont already come with threadlock in the threads).



Now, get the caliper back on the disc and fit the two slide pins having cleaned them up first - remember to observe the long/short fitment.

All that remains is to refit the spring - just the reverse of removal - this time clipping it into the pad bracket.

Its sensible to put some coppaslip around the hub centre where the wheel locates, as they often corrode on.

Thats it!

David

[chb]

Excellent guide, and as a photographer can I congratulate you in the quality of the photo's....you must be using something half decent.


oh...and what gold paint are you using for the calipers?

[BestGear]

Hi

The camera is my trusty Nikon D200... a bit "old" by todays standards but a well made body. Lense is a 18-200, which equates to 28-300mm in old money. Its not always easy to get the right shots when you want to get the job done - so some shots could be much improved...

Paint? - Hamerite smooth gold - and a 1/2" brush. I have always found you dont need to get every surface or indeed the whole caliper to look good.... which perhaps appears sloppy, but the end effect is good. Worth getting a tin of brake cleaner too - just to clean them up before painting.

Smooth Gold

Brake cleaner

The brake cleaner is available from tyre typical high street car shop - usually in 300 or 500ml tins.

David

[chb]

I have the same lens on my D80. Maybe we should be upgrading to D7000's

[BestGear]

Originally Posted by chb

I have the same lens on my D80. Maybe we should be upgrading to D7000's

It would be nice... but I am happy with the D200 really... I dont need more resolution in reality... plus, being full frame, you loose the convenience of the longer lenses as I am sure the 7000 is full frame...

David

[ascender]

Thanks for this guide, its spot on.

Just for info as I was caught out, the allen/hex key you need to get the hex head pins out is a 7mm. I seemed to have every size but the 7 so had to make a quick trip to B&Q.

When replacing the pads with aftermarket ones, is it worth fixing the anti-noise shims to the back of them or not?

[LiamM]

Originally Posted by BestGear

Hi Folks

Having replaced the rear brakes a few weeks ago, I decided to replace the fronts too. They were not too bad, but would need doing in a few months, so doing them now, meant that they did not need doing in mid-winter!

Anyway - firstly, getting the right partnumbers for genuine or aftermarket pads and discs for the front was tricky, as several conflicting numbers appeared for the VIN... and when looking at the diameters and size of pads, they did not agree!

Anyway - I was told that all UK XC90s have the same front discs and pads - I am not sure if this holds true for the 17" wheeled vehicles (mine is 18") but suspect it is.

This is further confused by the fact Volvo seem to state 16" or 17" wheel son the boxes and listings!

Anyway - these are the discs and pads...





Have a close look at the pads - the upper pad (in the picture above) has a small rectangle cut on the pad bracket - this is the bracket that you see from the front of the caliper and it locks the caliper anti-rattle spring.



It is not obvious when you look, but you need to unclip the spring from this bracket when you start the job. The bracket you see below - at the left hand side is the pad bracket - this its easy to see how to release the spring.



And..the spring when removed...



Anyway - when I first got the car, I thought it must have 2 or 4 pot calipers, given the size of the calipers - they are huge! They are however, single pot (piston), but are substancial.

The good news is that removing them follows what has become standard practice on most modern cars.



To remove the pads, you need to remove the two caliper slides. These are similar to the rear setup on this car - remove the two plastic caps (highlighted within the red ) then under them, two hex head pins - easy to remove and no threadlock so easy peasy.

Take note - unlike the rears, these pins are of differing lengths - the longer one being fitted to the upper slide.





When the caliper is removed, remove the pads - one is clipped into the caliper front, and the other clipped into the piston. When removed, ensure that you support the caliper properly, and that the rubber brake hose is not being unduly twisted or under tension.

Next - you need to remove the caliper carrier bracket. This is two bolts to the hub - shown below. These appear tight, but in reality, its just the threadlock holding them in.




Once the bracket is off, its a simple job of removing the centre 10mm bolt and removing the disc. If the disc is tight, give it a few hits from the rear to free it off. If its really stubborn, put some release oil through the wheel bolt holes aiming between the disc and hub - that usually does it.



With the disc removed...



So - put it all back together!

When refitting the disc, ensure that there is no debris between the hub surface and disc rear.

Its usually advised these days, to loosen the bleed nipple on the caliper when pushing the piston back in to save any risk or reversing the direction of any seals within the ABS or master cylinder. Your call - just get it pushed back!

Fit the pads to the caliper - both clip in.

Refit the caliper carrier, having replaced the bolts or cleaned the threadlock out of the original bolts - remember to use threadlock when fitting (if the replacements dont already come with threadlock in the threads).



Now, get the caliper back on the disc and fit the two slide pins having cleaned them up first - remember to observe the long/short fitment.

All that remains is to refit the spring - just the reverse of removal - this time clipping it into the pad bracket.

Its sensible to put some coppaslip around the hub centre where the wheel locates, as they often corrode on.

Thats it!

David

I know this is an old post, but it’s just what I’m looking for.

I’ll need disks front and rear, and then 4 sets of pads. Is there any other consumables that I’d need to avoid me having to make multiple trips?

[TruckbusUK]

Originally Posted by LiamM

I know this is an old post, but it’s just what I’m looking for.

I’ll need disks front and rear, and then 4 sets of pads. Is there any other consumables that I’d need to avoid me having to make multiple trips?

Take care the caliper carrier mounting bolts are stretch bolts and will not tighten properly if reused (sure its a 60 degree tighten after hitting the torque value.) Your choice, just be aware.

[dambat]

Caliper bolts are not TTY. They just have an angular torque setting, as do many other non-TTY bolts. Volvo may recommend you replace, but not due to plastic deformation.

Some TTY bolts may be reused (up to x times). Landrover 300 Tdi head bolts got 4 uses according to the factory manual.

[TruckbusUK]

Hello dambat, Volvo say they are when I enquired however personally I would never reuse any TTY bolt ... why?

The main issue is with TTY bolts is that once you reach that Yield Point and return back to the elastic region, you’ve changed the crystal properties inside the steel and it’s permanently deformed, visually depending on the fastener used it can be obvious, others its not.

However its a personal choice.