Brake Discs, to machine or not to machine?

[Disco-tastic]

Hi all,

I need new pads front and rear. I am going to go the Akebonos (part numbers 1098 front and 1099 rear - can someone please confirm this as I can't find it on their website?) and have been told that the discs on the D3/4 shouldn't be machined. My mechanic will do it anyway for me if I want (I really don't want to have to fork out for new discs too!) but also said I could just install the pads and see how they go (well, I asked if I could :angel: ), with a chance they will make noise under braking.

So I have a few questions:

Are those Akebono part numbers correct?
Why shouldn't the discs be machined?
Apart from noise, is there any problem with just installing new pads? the discs are not grooved or damaged at the moment.


I had wondered, as mine is a 2008 petrol V6, if the discs for these would be ok to machine, compared to a newer D4, as the discs were older and a different alloy used?

Thanks for the help :)

Cheers,

Dan

[BMKal]

Yes - you have the correct Akebono part numbers.

https://www.aulro.com/afvb/images/imported/2016/09/409.jpg (http://postimg.org/image/v73ymiwep/)

If your discs are still in good condition and close to original thickness, and as you say, not grooved - I wouldn't have any hesitation at all in giving them a light skim on a lathe. Basically shouldn't require much more than a touch up with wet & dry to remove any glazing and give a new surface for the pads to work on.

Many years ago, I worked as a brake mechanic, and used to very lightly skim discs all the time for exactly this reason.

When I fitted the Akebono's to my D4, I replaced all the discs as they were probably grooved beyond machining, though still had a fair bit of life left in them. But like yourself, I wanted a "new" surface for the Akebono pads to work on. I have not been sorry with that decision - the discs are still like new and the pads have shown very little sign of wear after about 70,000km. And no more brake dust.

It would probably be wise to also replace your brake pad wear sensors at the same time - they cost bugger all. You can re-use the old ones if they have not worn through and activated, but I was told that the wires can be brittle and easy to brake, particularly if your brakes have been running hot. You can get replacement sensors either from your LR dealer or from Pedders. ;)

[Disco-tastic]

Thanks BMKal!

So i could actually sand my discs back using a fine grit sand paper? If so that would be awesome! Then i don't have to take them off and have a workshop machine them, and i can hopefully do it all in one day! Could i use a fine grit (say 600) on an orbital sander or better to use wet/dry by hand?

I will need a new sensor. It activated about 4 weeks ago... :wasntme:

Cheers

Dan

[LandyAndy]

Sandpaper wont work.
Firstly you need to measure the thickness of the disc,the minimum thickness is stamped/embossed on all discs.
Are you DIY your brakes??? If so there are companies that come to your home in a spannerbus and can machine the discs without removing.
Replacing the discs isn't too hard if they are too thin.
ENJOY
Andrew

[weeds]

[QUOTE=Disco-tastic;Could i use a fine grit (say 600) on an orbital sander or better to use wet/dry by hand?

Dan[/QUOTE]



I wouldn't do either.....no way of judging if you have taken an even amount of material off.......more than likely get feedback through the pedal...

Like Andy said...get a mobile guy out to machine them.......

[Disco-tastic]

Ahh sweet i didnt know there were mobile guys. I'll have a look around my area.

Yeah i plan to DIY. Bolts and stuff are generally fine. The only thing i hate is pushing the calipers back in. Last time i did it i had fluid pouring out the reservoir, and the time before that i tried to bleed it out the nipple but got air in the lines and it needed a full bleed.

Might get a proper bleed kit and do it that way. [emoji106]

Cheers

Dan

[PerthDisco]

Mine needed only a little fluid removed when the pads were down to the warning light. The small syringes we had had home for dispensing kids medicine did the trick. Can buy cheap at pharmacy.

[Disco-tastic]

Well i didnt find a mobile guy but i found a workshop 10mins from home that will machine front and rear for $110 all up. And he works saturdays. :)

Thats a bit cheaper than new discs...

Cheers

Dan

[101RRS]

Really if the disks are not warped or have deep gouges I wouldn't bother - I never do mine and if anything the wear pattern increases area so grip must be a bit better.

Just ensure they are above the wear limit and will remain so for the life of the new pads.

[BMKal]

Well i didnt find a mobile guy but i found a workshop 10mins from home that will machine front and rear for $110 all up. And he works saturdays. :)

Thats a bit cheaper than new discs...

Cheers

Dan

Sounds like your best option - but you only need the very lightest of skims. As said before, I used to regularly do this with wet & dry paper - but I did it "on the lathe" - with the disc spinning. Really only enough to clean the surface. ;)

[Disco-tastic]

Well, i fitted the new pads on the weekend. I ended up not getting the discs machines, mainly because they were down to 28.2mm front and 18.2mm rear (min is 27mm front and 17mm rear) and i didnt want to lose too much getting them machined. I also saved $110 which is nice! [emoji106]

So far no squealing and brakes are feeling fine.

Heres a pic of old vs new pads
https://www.aulro.com/afvb/images/imported/2016/09/181.jpg (http://s57.photobucket.com/user/lawolski/media/Mobile%20Uploads/1030391_zpsyyabk4t1.jpg.html)

I think i got my moneys worth out of those old pads...

One last question - my pad wear sensors are busted. To stop the warning do i cut the wires and join them?

Thanks for all your help everyone!

Cheers

Dan