Knackered discs ?

[DannyVTS]

Now I know my front discs need replacing, but upon checking the condtition of my rears today they are in a much worse physical Condition

Do they need replacing too ?

Front:


Rear:

[catman]

Yes, they look very worn. I would replace the discs (and pads) all round.

Tim

[WeirdNeville]

Fronts look ok to me, but I can't tell how much of a lip they've got on them. Can you find the specs for how "thin" they should be? Most workshop manuals specify a minimum thickness.

The rears look a bit pitted but again, I've seen worse. I'd check the function of that caliper, or see if they clean up with some harder use. Again, if they're coming down to minimum thickness, change them.

[HellDiver]

Look fine to me. If it's your french crisp-bag on wheels, don't waste any money on it.

[Nuttah]

rears apear to have been ran with very low pads for quite some time, my rear discs where in a simular condition but after fitting new pads and a few thousand miles they smoothed out and looked much better!

[DannyVTS]

With regard to the front they are warped I think getting bad shaking on heavy braking although I'm yet to clarify this

With regard to giving them heavy use I do 300 miles a week and they perform quite well except squeaking and shaking

[supersingle]

DannyVTS said:

With regard to the front they are warped I think getting bad shaking on heavy braking although I'm yet to clarify this

With regard to giving them heavy use I do 300 miles a week and they perform quite well except squeaking and shaking

Try letting your brakes off as you stop. It stops pad deposits sticking to the discs. That's usually what causes the vibration rather than warped discs. Hth.

[DannyVTS]

HellDiver said:

Look fine to me. If it's your french crisp-bag on wheels, don't waste any money on it.

Cheers, as you say, it's my french crisp bag

[DannyVTS]

supersingle said:

Try letting your brakes off as you stop. It stops pad deposits sticking to the discs. That's usually what causes the vibration rather than warped discs. Hth.

Thanks, I read that in another thread

Is there a way to remove these deposits?

[supersingle]

Do two or three really hard applications of the brakes i.e 60 to 10 mph to get the discs and pads really hot. That should renew the surfaces of both discs and pads.

Once you've got deposits on your discs they tend to get worse unless you do the above. The deposits are slightly raised and keep collecting more material unless they are cleaned off with hard applications of the brakes.

Obviously take care when trying this technique!

[DannyVTS]

I'll try it out, thanks
Danny

[YoungOne]

Just borrow some calipers and measure the thickness, think the minimum on my swift is 18mm

[deveng]

YoungOne said:

Just borrow some calipers and measure the thickness, think the minimum on my swift is 18mm

So? Minimum thickess on my A3 is 25mm which is fk all help!

[HellDiver]

Minimum thickness is usually stamped on the disc, or there's a wee cutout on the edge of the disc at the minimum thickness.

[anonymous-user]

Take the discs off and use a fairly coarse grit paper on a flat surface to remove built up deposits. A flap wheel in a drill is effective in cleaning the edges and will remove corrossion quickly. As for the wear limits it depends on usage, the manufacturers will twll you replace at 2-3mm, which is unecessary IMO. I would be more concerned about stress cracks than thickness.

[vrooom]

fk sake, change the brakes, it needed new discs and pads all around.

[FesterNath]

Badly pitted discs can wear through pads in a very short time

[FesterNath]

Badly pitted discs can wear through pads in a very short time

[TheLurker]

HellDiver said:

Minimum thickness is usually stamped on the disc, or there's a wee cutout on the edge of the disc at the minimum thickness.

By the time you need to read the information they usually have about 3mm of rust over it though!

[Dave Brand]

The fronts look OK to me. The rears need replacing - with that amount of corrosion they will probably still work satisfactorily but will tend to be noisy (rumble) & aren't going to get any better.

If you haven't got a dial gauge a simple way of checking the fronts for runout is to use feeler gauges between the disc & the pad. If you want to clean pad deposits off them, try brake cleaner & wire wool - personally, I'd never use an abrasive on the working surface of a disc.