Grinding/Scraping noise from rear nearside wheel.

[Albert27]

Hi guys,

Out driving today and initially during harder braking started hearing what I can only describe as a grinding/scraping noise.  Have pinpointed it to the rear nearside wheel.  It starts under braking and when brakes released carries on for a few seconds.  On my last drive it carried on for 10-15 seconds after releasing brakes and was quite loud.

I took the wheel off and had a look at the pads without removing them.  Both are ok, although they were replaced only a year ago and the outer pad is much thinner than the inner.  Whether this is related I don't know but could do with some advice on that too.  

I wondered if some rust could have got between the pad and the disc?  

Any advice on where i go next to diagnose this problem would be great.

[Micro]

Hi guys,
Out driving today and initially during harder braking started hearing what I can only describe as a grinding/scraping noise.  Have pinpointed it to the rear nearside wheel.  It starts under braking and when brakes released carries on for a few seconds.  On my last drive it carried on for 10-15 seconds after releasing brakes and was quite loud.
I took the wheel off and had a look at the pads without removing them.  Both are ok, although they were replaced only a year ago and the outer pad is much thinner than the inner.  Whether this is related I don't know but could do with some advice on that too.  
I wondered if some rust could have got between the pad and the disc?  
Any advice on where i go next to diagnose this problem would be great.

Do you have experience in dismantling brakes?

Does the wheel spin freely when the handbrake is disengaged?

[Albert27]

Just now, Micro said:

 

Do you have experience in dismantling brakes?

Does the wheel spin freely when the handbrake is disengaged?

 

No experience in dismantling brakes although I've been reading a lot so could probably take the pads out.  I haven't checked the handbrake so will look into that tomorrow.  If the wheel doesn't spin freely what would that suggest?

[Tdci-Peter]

1 hour ago, Albert27 said:

No experience in dismantling brakes although I've been reading a lot so could probably take the pads out.

The one tool you will need is a 7mm A/F Hex bit. An Allen key might do it, but a Hex bit that fits into an standard ratchet driver will be much better. That is to remove the caliper guide pins. I posted a few tips here:

(You won't need a wind-back tool to inspect the pads, but it is needed to fit new ones)

The wheel not turning freely may indicate a bit of grit or rust between pad and disk. Or it could be the caliper piston is sticking, or the guide pins are sticking. The rapid and uneven pad wear suggests sticking pins. Clean & re-fit with suitable silicon or brake rubber grease.

If you have to remove the disk, perhaps to inspect or de-rust the inside, the caliper bracket bolts will be tight and stiff (sometimes thread lock is applied). You will need a good, well fitting socket, and maybe an extension tube on the ratchet handle.

Inspect the caliper piston dust seal carefully. If intact, then sticking pistons can often be freed by winding in and pumping out a few times. If damaged, then the caliper must be serviced (new seals) or replaced.

 

[Albert27]

2 hours ago, Tdci-Peter said:

The one tool you will need is a 7mm A/F Hex bit. An Allen key might do it, but a Hex bit that fits into an standard ratchet driver will be much better. That is to remove the caliper guide pins. I posted a few tips here:

(You won't need a wind-back tool to inspect the pads, but it is needed to fit new ones)

The wheel not turning freely may indicate a bit of grit or rust between pad and disk. Or it could be the caliper piston is sticking, or the guide pins are sticking. The rapid and uneven pad wear suggests sticking pins. Clean & re-fit with suitable silicon or brake rubber grease.

If you have to remove the disk, perhaps to inspect or de-rust the inside, the caliper bracket bolts will be tight and stiff (sometimes thread lock is applied). You will need a good, well fitting socket, and maybe an extension tube on the ratchet handle.

Inspect the caliper piston dust seal carefully. If intact, then sticking pistons can often be freed by winding in and pumping out a few times. If damaged, then the caliper must be serviced (new seals) or replaced.

 

Thanks Peter. Is the car safe to drive for a while assuming the problem is sticking guide pins? Only i need a bit of time to get the right tools together and would rather tackle it next weekend.

Could you recommend a readily available grease suitable for the job?

Also, do I need to be careful with brake dust? 

 

[Proautocare]

[Tdci-Peter]

47 minutes ago, Albert27 said:

Is the car safe to drive for a while assuming the problem is sticking guide pins? Only i need a bit of time to get the right tools together and would rather tackle it next weekend.

Could you recommend a readily available grease suitable for the job?

Also, do I need to be careful with brake dust? 

Safe to use for a while: I would say yes, but I would check that the brakes are not overheating when not being used. After driving for a while without much brake use, and coming to a gentle halt, see if the disks are very hot. A little wet brush is a less painful test than fingers, in case they are hot! Sizzle means hot, in either case.

Grease: Something like: http://www.ebay.co.uk/itm/like/400344619952

(This is not for the inside of the caliper piston seal, you need the red rubber grease if you replace caliper seals, but it is fine for the sliding pins.) Copperslip or an equivalent is usually used (very sparingly) on the points of contact between pad and caliper bracket, and pad and piston. The pair is here: http://www.ebay.co.uk/itm/like/351438387186

The asbestos warnings are way out of date now, just brush it away from you. There is not usually much on a disk brake anyway, it is all blown or washed away while driving.

The Ford instructions above contain a couple of "interesting" differences:

Clamping the hose and releasing the bleed nipple is supposed to avoid "flipping the master cylinder seals". When pistons are pushed back by hand, the danger of this is virtually zero. If rapidly pushed back with a powerful tool, there may be a small danger. The merits of crushing a high pressure flexible hose flat are up for discussion. I use a wind back tool that turns the piston, but all of the inwards pressure is simply hand pressure, and so avoid any risk of damage to the hose, and the need to bleed the brakes, by allowing the fluid back to the reservoir.

They say no grease on the pad contact points. This is contrary to all advice I have heard to date, and the installation instructions provided by the pad manufacturers with their pads that I recall seeing. It is probably because some low grade spanner monkeys doing this job in low cost tyre brake & exhaust centers are prone to getting grease everywhere.

Have a look round this forum and other places, and make up you own mind, is all I can say.

 

[Albert27]

9 hours ago, Tdci-Peter said:

Safe to use for a while: I would say yes, but I would check that the brakes are not overheating when not being used. After driving for a while without much brake use, and coming to a gentle halt, see if the disks are very hot. A little wet brush is a less painful test than fingers, in case they are hot! Sizzle means hot, in either case.

Grease: Something like: http://www.ebay.co.uk/itm/like/400344619952

(This is not for the inside of the caliper piston seal, you need the red rubber grease if you replace caliper seals, but it is fine for the sliding pins.) Copperslip or an equivalent is usually used (very sparingly) on the points of contact between pad and caliper bracket, and pad and piston. The pair is here: http://www.ebay.co.uk/itm/like/351438387186

The asbestos warnings are way out of date now, just brush it away from you. There is not usually much on a disk brake anyway, it is all blown or washed away while driving.

The Ford instructions above contain a couple of "interesting" differences:

Clamping the hose and releasing the bleed nipple is supposed to avoid "flipping the master cylinder seals". When pistons are pushed back by hand, the danger of this is virtually zero. If rapidly pushed back with a powerful tool, there may be a small danger. The merits of crushing a high pressure flexible hose flat are up for discussion. I use a wind back tool that turns the piston, but all of the inwards pressure is simply hand pressure, and so avoid any risk of damage to the hose, and the need to bleed the brakes, by allowing the fluid back to the reservoir.

They say no grease on the pad contact points. This is contrary to all advice I have heard to date, and the installation instructions provided by the pad manufacturers with their pads that I recall seeing. It is probably because some low grade spanner monkeys doing this job in low cost tyre brake & exhaust centers are prone to getting grease everywhere.

Have a look round this forum and other places, and make up you own mind, is all I can say.

 

All makes sense, thank you.

One thing I'm not clear about though:

For the problem to be guide pins, and considering the rapid uneven wear, it's fair to say they've been sticking for quite a while. However, the scraping/grinding noise only started yesterday.  Why is that?  Hope I'm not missing something here......

I notice in the haynes manual regards to bleeding after working on caliper; 'If the MC has been disconnected and reconnected then the complete system (all circuits) must be bled of air. If the component of one circuit has been disturbed then only that particular circuit need be bled'.  Am i right in thinking then, that it my case i only need to bleed the rear nearside wheel as that's the caliper that will have been tampered with and this is what it means by 'one circuit'?

[Tdci-Peter]

2 hours ago, Albert27 said:

in my case i only need to bleed the rear nearside wheel as that's the caliper that will have been tampered with and this is what it means by 'one circuit'?

In fact, if the wind-back procedure I gave is used, none of the hydraulic unions need to be tampered with, and there is no bleeding to do at all.

Otherwise, yes, you normally only bleed the wheel where the caliper hose was disconnected or loosened. Bleeding of air that enters the M/C end can be difficult, not only all 4 wheels, but the ABS needs a special procedure using a computer to ensure all air is removed from it. Do not allow the reservoir become empty! (Unlikely in most cases)

A problem with any "tampering" with the hydraulic circuit is that caliper bleed screws are often over tightened, and corrode in place. They can be very difficult to undo, and are very easy to shear off, or to round off the flats. If it shears off, it usually means a new caliper. It would need a well equipped workshop to drill out the remains, re-tap and fit an adapter and new bleed screw. With stiff bleed screws, I remove the caliper from the car, mount it very securely in a vice at a comfortable working height, and use a very well fitting socket with a tee-bar handle to undo it. Heat and judicious tapping are also of use. Penetrating oil is actually of little use on a well corroded joint, at least until it first moves.

Before allowing air in (loosening a hose), test whether the bleed screw can be undone. If not, apply penetrating oil, and corrosion proofer like Waxoil around it, and leave it until some future time, unless removal is really essential. Pads & disks can be changed on the Focus without touching any hose connections.

2 hours ago, Albert27 said:

For the problem to be guide pins, and considering the rapid uneven wear, it's fair to say they've been sticking for quite a while. However, the scraping/grinding noise only started yesterday.

Yes, I noticed that. I think the problems may be two separate ones. Removal of the pads may give some clue. However, last time I replaced my front pads, one pad had worn very badly. By the time I had it all dismantled, there was no clue as to why. I guess a pin had been sticking, but undoing them hides this. I just cleaned everything, put new pads in, greased the pins, and it has not happened again.

 

[Tdci-Peter]

One other point I have remembered:

The pads slide on little rails on the caliper bracket. Check it can slide evenly, and there is no steps, bumps or bad dents in the rail part of the caliper bracket where the pad slides. A pad jamming in the bracket can cause uneven wear and other problems.

[mjt]

1 hour ago, Tdci-Peter said:

I guess a pin had been sticking, but undoing them hides this. I just cleaned everything, put new pads in, greased the pins, and it has not happened again

Peter, the caliper slides on the guide pins in rubber grommets so it's most unlikely they would stick. The comment in your subsequent post is more germane. The pads can, and do, stick in the carrier due to the build-up of corrosion, brake dust and dirt and it's usually necessary to clean the carrier grooves and judiciously apply some copper grease.

[Albert27]

1 hour ago, Tdci-Peter said:

One other point I have remembered:

The inner pad slides on little rails on the caliper bracket. Check it can slide evenly, and there is no steps, bumps or bad dents in the rail part of the caliper bracket where the pad slides. A pad jamming in the bracket can cause uneven wear and other problems.

 

Update:

The wheel spins but there is a grating sound - definitely more noticeable compared the other rear wheel. I've been out with the car this morning and have closely examined the brake pads on the rear nearside wheel.  My lack of experience is about to show through - I think I was wrong when i said they were OK in the original post. I am now nearly certain that what i thought was the outer pad is actually the metal backing plate and the pad is completely worn causing the noise.  The uneven wear is considerable as the inner pad and pads on the other offside rear are very thick.  I will post a picture shortly below - I'm hoping the lack of pad and my backing plate theory can be confirmed...... 

I will need to replace both the inner and outer pad on rear nearside as well as cleaning and greasing the guide pins to try and prevent the sticking as you've said.  Do I need to replace the pads on the offside rear as well? 

[Albert27]

[mjt]

You should never replace pads on one side only. This would badly affect side-to-side balance, at least until the new pads had fully bedded in. Always replace as an axle set.

[Albert27]

2 hours ago, mjt said:

Peter, the caliper slides on the guide pins in rubber grommets so it's most unlikely they would stick. The comment in your subsequent post is more germane. The pads can, and do, stick in the carrier due to the build-up of corrosion, brake dust and dirt and it's usually necessary to clean the carrier grooves and judiciously apply some copper grease.

Carrier Groves, where exactly are they on the caliper? 

[mjt]

I don't know about groves  but what I meant by the grooves are the sliding faces that locate the pads in the carrier. They are what absorb the forces on the pads when braking. The caliper itself just floats and simply squeezes the pads together. It doesn't take any of the rotational forces when braking.

[Tdci-Peter]

3 hours ago, Albert27 said:

Carrier Groves, where exactly are they on the caliper? 

It did cross my mind that a pad could be worn right down, but I did not like to suggest it! In that case, use the car as little as possible until replaced. It can damage the disk with the metal to metal contact, as well as reducing brake efficiency badly.

It is hard to be sure from the photos, but if there is any pad left, it must be wafer thin.

Pics below show the Groves or Grooves that the pads fit in to. Like Mike says, these grooves take all the braking force, but must allow the pad to slide in and out, if only by a tiny amount. (From http://www.justanswer.com/uk-ford/48y1n-ford-cmax-replace-rear-caliper-pads.html)

 

[Albert27]

46 minutes ago, Tdci-Peter said:

It did cross my mind that a pad could be worn right down, but I did not like to suggest it! In that case, use the car as little as possible until replaced. It can damage the disk with the metal to metal contact, as well as reducing brake efficiency badly.

It is hard to be sure from the photos, but if there is any pad left, it must be wafer thin.

Pics below show the Groves or Grooves that the pads fit in to. Like Mike says, these grooves take all the braking force, but must allow the pad to slide in and out, if only by a tiny amount. (From http://www.justanswer.com/uk-ford/48y1n-ford-cmax-replace-rear-caliper-pads.html)

 

Thanks for all the info - this has really helped me.  I've the parts on order (including the 7mm hex bit you mentioned as my allen key wouldn't do it!) and they should be with me by Wednesday.  Working locally so will limp the car until then trying to avoid unnecessary braking!  

[mjt]

David, you might be ok. What has probably happened is that the pad has worn so thin that the backing plate has started to rub on the corroded ridges that form on thedisc outside the swept area. With luck the actual swept area will still be undamaged.

I would take a careful look at the inner surface of the disc when you take the old pads out. If the outer pad has indeed worn so thin and the inner one is still thick it is likely the inner one has stuck in the carrier so has not been contacting the disc much in which case you might find the inside surface is corroded.

[Albert27]

1 hour ago, mjt said:

David, you might be ok. What has probably happened is that the pad has worn so thin that the backing plate has started to rub on the corroded ridges that form on thedisc outside the swept area. With luck the actual swept area will still be undamaged.

I would take a careful look at the inner surface of the disc when you take the old pads out. If the outer pad has indeed worn so thin and the inner one is still thick it is likely the inner one has stuck in the carrier so has not been contacting the disc much in which case you might find the inside surface is corroded.

Ok thanks Mike.  I will have a careful look.  If it is corroded, are we talking new discs?  I also notice it's just a single disc at the rear.  Why is that?

[Tdci-Peter]

59 minutes ago, mjt said:

What has probably happened is that the pad has worn so thin

I did lose a pad altogether, once. But I knew something had happened!

I was braking from about () 70, for a roundabout. There was a Bang. The brake pedal went right down, and I lost just about all braking. Releasing the brakes, and re-applying them, I got back pretty reasonable braking, and stopped before the roundabout. But I was shaking a bit! And there was a bit of a grating noise from the brakes.

I pulled over just after the roundabout, checked my underwear (), it was ok. Then had a look at the brakes, but could not see anything. Tried the pedal a few times, all seemed ok. No puddles of fluid under the car, brake reservoir ok. So I continued the rest of the 20 odd miles back home, but rather carefully. I made sure I was not going to need any more hard braking. The grinding noise on applying them continued, but they worked ok.

I narrowed it down to one rear brake, and next day took the wheel off. One pad had lost all its liner. Basically, the pad had worn down, and also come unglued from the backing plate. The liner was thinner than the gap between caliper and disk, and it just escaped, suddenly. The piston then moved forward, causing the brake pedal drop. Once the backing plate was against the disk, then all the other brakes worked ok. New pads fixed the problem.

This was a V*****l, so I guess it serves me right! The brakes on this were the dual piston type, not the floating caliper type. I think I prefer the Ford style floating caliper type. Also on that car, rear brakes had a rigid brake pipe, so pad or disk replacement meant disconnecting the brake line, and all the bleeding operations after.

Note: If I had continued to press the brake pedal hard, the front brakes should have continued to work, as all brake systems are designed to have some degree or front / rear independence. But there is quite a big pedal movement when you lose an axle.

2 hours ago, Albert27 said:

 Working locally so will limp the car until then trying to avoid unnecessary braking!  

All the above is just an anecdote for infotainment. I have got nothing better to do. Hmmm, That is a lie, I have some urgent work, but don't want to do it!

David, your case sounds nothing like this. I do not want to alarm you!

1 hour ago, mjt said:

rub on the corroded ridges that form on the disc outside the swept area.

My car gets irregular use. Sometimes it goes almost a week just sitting and gently rusting. I tend to have a lot of problems with corroding brake disks. I now service my brakes annually, and remove any rust from those outer and inner areas on both sides. It seem to be making both the disks and pads last much longer. Once rusty ridges build up, the rust can spread into the working area of the disk. It is not always obvious, polished rust can be shiny just like metal. But fairly aggressive application of a file to the rust ridges then chips away and reveals the rust spreading in. Bad corrosion pits would mean replacing the disk, but if caught in time, it can be filed off, taking some care not to file into good metal, and always file in the rotational direction, so any file marks run round the disk.

It is a good idea to remove the worst of the ridges when replacing pads. When to replace the disks is up to the individual, as long as the thickness is within specification, and the disk is flat & sound. From Haynes (mk2 Diesel), minimum disc thickness is 9mm for rears, 23mm for fronts. Also caliper bracket bolt torque is 70nm (rear), or 120nm (front), guide pin torque is 35nm (rear) or 28nm (front). The guide pin torques are a bit weird, but that is what it says.

5 minutes ago, Albert27 said:

If it is corroded, are we talking new discs?  I also notice it's just a single disc at the rear.  Why is that?

Just seen the latest post, my view on new disks is above - It depends on the condition and how much effort you want to put in to cleaning them up. As you have to remove disks to properly see the inside, and then it is a pain to put the car back together while new ones are obtained, if they are serviceable (see above), I would clean them up and re-use them until the next brake service.

In my view, ventilated (double) disks are an utter waste of space, unsprung weight and money on a road going car. For the ventilation to work, they need to be rotating fast. But disks are hottest when you have just stopped, or are going slowly down a steep hill. Only when racing with rapid repeated braking from high speed do they have a real use. Anyone who drives like that on public roads these days is a bit of a nutter (in my opinion, anyway!).

But even with racing style use, the fronts carry 80% of the braking load, so singles for the back are almost always used.

[Albert27]

8 minutes ago, Tdci-Peter said:

I did lose a pad altogether, once. But I knew something had happened!

I was braking from about () 70, for a roundabout. There was a Bang. The brake pedal went right down, and I lost just about all braking. Releasing the brakes, and re-applying them, I got back pretty reasonable braking, and stopped before the roundabout. But I was shaking a bit! And there was a bit of a grating noise from the brakes.

I pulled over just after the roundabout, checked my underwear (), it was ok. Then had a look at the brakes, but could not see anything. Tried the pedal a few times, all seemed ok. No puddles of fluid under the car, brake reservoir ok. So I continued the rest of the 20 odd miles back home, but rather carefully. I made sure I was not going to need any more hard braking. The grinding noise on applying them continued, but they worked ok.

I narrowed it down to one rear brake, and next day took the wheel off. One pad had lost all its liner. Basically, the pad had worn down, and also come unglued from the backing plate. The liner was thinner than the gap between caliper and disk, and it just escaped, suddenly. The piston then moved forward, causing the brake pedal drop. Once the backing plate was against the disk, then all the other brakes worked ok. New pads fixed the problem.

This was a V*****l, so I guess it serves me right! The brakes on this were the dual piston type, not the floating caliper type. I think I prefer the Ford style floating caliper type. Also on that car, rear brakes had a rigid brake pipe, so pad or disk replacement meant disconnecting the brake line, and all the bleeding operations after.

Note: If I had continued to press the brake pedal hard, the front brakes should have continued to work, as all brake systems are designed to have some degree or front / rear independence. But there is quite a big pedal movement when you lose an axle.

All the above is just an anecdote for infotainment. I have got nothing better to do. Hmmm, That is a lie, I have some urgent work, but don't want to do it!

David, your case sounds nothing like this. I do not want to alarm you!

My car gets irregular use. Sometimes it goes almost a week just sitting and gently rusting. I tend to have a lot of problems with corroding brake disks. I now service my brakes annually, and remove any rust from those outer and inner areas on both sides. It seem to be making both the disks and pads last much longer. Once rusty ridges build up, the rust can spread into the working area of the disk. It is not always obvious, polished rust can be shiny just like metal. But fairly aggressive application of a file to the rust ridges then chips away and reveals the rust spreading in. Bad corrosion pits would mean replacing the disk, but if caught in time, it can be filed off, taking some care not to file into good metal, and always file in the rotational direction, so any file marks run round the disk.

It is a good idea to remove the worst of the ridges when replacing pads. When to replace the disks is up to the individual, as long as the thickness is within specification, and the disk is flat & sound. From Haynes (mk2 Diesel), minimum disc thickness is 9mm for rears, 23mm for fronts. Also caliper bracket bolt torque is 70nm (rear), or 120nm (front), guide pin torque is 35nm (rear) or 28nm (front). The guide pin torques are a bit weird, but that is what it says.

Just seen the latest post, my view on new disks is above - It depends on the condition and how much effort you want to put in to cleaning them up. As you have to remove disks to properly see the inside, and then it is a pain to put the car back together while new ones are obtained, if they are serviceable (see above), I would clean them up and re-use them until the next brake service.

In my view, ventilated (double) disks are an utter waste of space, unsprung weight and money on a road going car. For the ventilation to work, they need to be rotating fast. But disks are hottest when you have just stopped, or are going slowly down a steep hill. Only when racing with rapid repeated braking from high speed do they have a real use. Anyone who drives like that on public roads these days is a bit of a nutter (in my opinion, anyway!).

But even with racing style use, the fronts carry 80% of the braking load, so singles for the back are almost always used.

Heck guys, I've had some quality information overload today!  I'm learning fast.  I'll probably be dreaming about floating caliper clouds whilst looking for a lost brake pad on a roundabout  

There's so much to take in on that post but one question that arises as you mention minimum brake thickness.  I used a micrometer today to measure the front disc thickness as it's been on my to do list for a while.  They came in at 22.90 & 23mm.  Pads are 60% worn.  MOT due in May.  Should i run the pads down a bit more and change discs before MOT, assuming that would be an MOT failure?

Secondly, I was going to measure the rear disc thickness but there's a guard in the way so couldn't get my micrometer on them and couldn't be bothered to figure out if/how it comes off - was busy looking at the pads!!  How do i get it out the way to measure up the single disk at the rear?

[Tdci-Peter]

17 minutes ago, Albert27 said:

 I'll probably be dreaming about floating caliper clouds whilst looking for a lost brake pad on a roundabout

Sorry

The Haynes figure of 23mm does apply to the 1.6TDCI, 2005 to 2009, so it looks like you are marginal there (Haynes is not always 100% reliable, but in matters like this it is usually pretty good). I would wait for better weather (unless you have a heated garage), just before the MoT. 0.1 or 0.2 of a mm is not going to suddenly cause a catastrophic failure.

For the rears, you probably need to remove the caliper & pads. Then the disk should pivot out enough to get a mike on without removing the caliper bracket. You really need to see what you are measuring, to avoid measuring the outer ridge. The mud shield (backplate) is likely to be very difficult to remove, maybe impossible with the disk in situ.

[williamweb]

The splash guard if like on the MK1 is riveted to the rear hub carrier,buddy.


Sent from my iPad using Ford OC

[Albert27]

Update & some further advice needed:

So went out to the car today and did the rear pads.  Got to the point where i needed to use the piston wind back tool i had (a 'laser' one) and it didn't fit. Thankfully a neighbour helped me out with his wind back set.  Can anyone tell me the adaptor i need or the size of the fit for the rear piston? I greased up the guide pins with silicone.  Have to say they didn't look too bad with dirt but hopefuly that will cure the uneven wear!

Secondly, since doing the pads the handbrake has gone quite high.  Why is this and how do i adjust it?

Also the retaining clip on the outside of the caliper i managed to snap as it was completely jammed in the caliper.  What is this clip for and does it matter that I've snapped it?

And finally, I'll post an up close picture of the disc just for opinions on replacement.  My neighbour who helped me out reckons the discs needs doing too. They are scored but let me know your thoughts. Picture below.....