Question re Brake Caliper bolts pls fellas

[Quattro-Charlie]

Changing the rear discs on my 08 C6 3.0

The pads have barely done a thousand smooth driving miles so am not bothering with changing them, a wee bit of sanding should do the trick so I've heard. Now I understand I should replace the caliper securing bolts but as these are nearly new again I'm not going to as new ones would come with pads so I believe. I've read either put new bolts that come already covered with threadlock or use bolts I already have with a bit of thread lock. I'm possibly overthinking this and trying to get hold of a threadlock (loctite 243) that has a brakeaway of 26Nm... but getting some asap nearby isnt possible...would some regular blue threadlock say loctite 248 or other blue threadlock be ok? They don't have a brakeaway force of 26Nm etc but perhaps it's not necessary...I hope.. I understand the bolts are tightened to 35Nm anyway... what do you guys reckon?.

also from caliper sliding pins....it doesn't say threadlock is needed...however I'm not certain of the torque amount to use, is it around 25Nm of something like that.... Thanks guys, I did btw check forum already for threadlock question but couldn't find an answer.

Pr code is 1ZL on front and 1KW on the back if I recall it correctly.

[zollaf]

why would you re use the old pads that have worn to the shape of the old discs, so not only will they never work properly as they wont contact the whole area of the new discs but they will also wear the new discs out where they do contact. bin them and buy new, job done.

[Quattro-Charlie]

Thanks Zollaf...why you ask...I guess it's down to reading advice on forums, some will be good and some bad so perhaps the one that I read stating that nearly new pads are ok to reuse as they'll just wear down flat again, was bad advice....they did say give them a bit of a sand if necessary.. I couldn't bin a nearly new 100 odd pound pair of pads!
Well I didn't buy new pads and am stuck with this option I guess.... can you or anybody please just answer my question reg the threadlock as that's all I really need to know...and if you'll throw me a bone, the torque amount for the front sliding pins pls.

[lynalldiscovery]

Changing the rear discs on my 08 C6 3.0

The pads have barely done a thousand smooth driving miles so am not bothering with changing them, a wee bit of sanding should do the trick so I've heard. Now I understand I should replace the caliper securing bolts but as these are nearly new again I'm not going to as new ones would come with pads so I believe. I've read either put new bolts that come already covered with threadlock or use bolts I already have with a bit of thread lock. I'm possibly overthinking this and trying to get hold of a threadlock (loctite 243) that has a brakeaway of 26Nm... but getting some asap nearby isnt possible...would some regular blue threadlock say loctite 248 or other blue threadlock be ok? They don't have a brakeaway force of 26Nm etc but perhaps it's not necessary...I hope.. I understand the bolts are tightened to 35Nm anyway... what do you guys reckon?.

also from caliper sliding pins....it doesn't say threadlock is needed...however I'm not certain of the torque amount to use, is it around 25Nm of something like that.... Thanks guys, I did btw check forum already for threadlock question but couldn't find an answer.

Pr code is 1ZL on front and 1KW on the back if I recall it correctly.

If the pads are only 1k old I assume the discs were okay when the new pads were fitted? if so why not just run them out as a set then fit new?
I would guess any old loctite will do the job, myself I have never used any, do it tight no issues.
Remember to grease the slider pins and dont use copaslip use regular grease.

[rowdy-999]

The old pads will be ok on new discs, they'll just take longer to bed in. Like you say some rough sand paper to remove any residue will help.
Ive never changed caliper retaining bolts....i'm not saying this is correct procedure , just what I've done with no issues.
I wouldn't even torque guide pin bolts because that sounds like a great way to snap a bolt. ....I do mine firmly tight with a 1/2 ratchet. If you use loctite only use a weak strength, because otherwise it'll just cause headaches in the future...

[Quattro-Charlie]

Thanks guys for both of your answers.

lynall, the discs although nicely flat with no ridges etc are really worn down with a good size lips front and back haha :confused:
...regarding sliding pins, the rear appears to be metal to metal so yeah I guess regular grease is good....currently they're sliding smoothly as the pads were only done 6 months ago, so I'm gonna leave them as is I reckon?

The front caliper sliding pins are metal to rubber. I was thinking red rubber grease but this chap on eBay sells this American molycote stuff which is super slippy and as the seller says, the best stuff for these pins therefore I'll use this.
For the parts where the pads slide on the metal part of the caliper (the edges or wings maybe..) I've bought this molyslip AS40 molybendum disulphide paste, a guy on eBay sells 500g pots for £9 which is approx 70% cheaper than usual...
I'll also use a little paste on the back of the shims where they touch the calipers.....either that or copper grease.

Im still in 2 minds whether or not to put a smear of copper grease on the face of the hub where it meets the brake disc......I think I'll go with not as some people stated that the power etc should be distributed through the friction created in that area rather then just the bolts. Ideas on this?? And also on my choices of grease etc..

Rowdy..... you confirm what I'd read about reusing pads that are still in good condition..... though after getting the earlier advice criticising my intention to reuse the pads....instead of just directly answering my question (all too common on this site I'm afraid) I looked around and decided to go with new pads anyway.....I guess one way or another zollafs comment did serve a purpose and wasn't a total waste of time after all..
I think I'll keep hold of the pads I already have and just give them to whoever I sell the A6 to in the future...they can always use them or bin them.

[rowdy-999]

Zollaf has his own garage, so will always offer best/safest advice, and won't cut corners.
A smear of copper grease on the hub where the disc mounts stops it seizing, nothing else. Its more important to give the area a scrub with a wire brush first to remove any rust/debris, so the disc mounts true.

[zollaf]

see, a disc thats lipped will not be truly flat, it will be ridged and if you measure it will be thicker on the inside braking surface than the outside. the pad, even one thats 1000 miles old will be worn to fit this discs. put it on a new disc and it wont be a good flush fit. its false economy to re use a pad. better to wear the pads out and fit both together, which then raises the question as to why new pads were fitted to worn out discs 1000 miles ago, but thats none of my business.

[M1tchy]

I once nearly disagreed with zollaf - but re-read his post and he was right!!

As for the bolts, I recently removed my wife's to stop a squeak, on putting it back, I snapped it! I'd get new ones each time.


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[Quattro-Charlie]

Hey no I wouldn't disagree with zollaf...having read dozens and dozens of his posts I know he's very knowledgeable and runs his own place..so being his bread and butter so doing things absolutely safely and by the book is a must...but we home mechanics sometimes have to cut a couple of corners...and nobody can sue us for braking our own car!

I should add.....these rear pads are about 600 odd miles on them but it's mostly city miles and I'm a very slow smooth driver that doesn't ever use my brakes hard....driving a recovery truck often with passengers puts me in the habit of driving courteously. Maybe this is a good or a bad thing for the pads I don't know...but they're almost new to me!

Tbh I'm still in two minds about picking up new pads tomorrow or reusing these..gotta save ££ to spend elsewhere on the car... what were your guys opinion re the greases that I'm using?

zollaf whilst I still have your ear.....can you confirm the torque amount for front caliper sliding pins?..I know some say not to worry about it but I like to tighten to specified torque...I did actually study as a mechanic :biglaugh:

btw I agree...when the previous owner put the pads on he should have renewed the discs also.....but he cut corners....is a right dodgy fuqqer... he only owned the car for 2/3 months, I think that he used the car....I don't know if there's a term for it but to get people to crash into him for insurance claims... I'm pretty certain that he even somehow wound back the "clock" to a much lower mileage to maximise on the insurance payout. When he sold it to me the clocks were back to approx what they should have been, going on previous service history and mots. He is an Asian used car trader in Peterborough.

[zollaf]

not got the torques to hand but they are m8 threads so 25 nm is safe.

[Crasher]

The guide pins are 30Nm. The carrier to hub bolts vary slightly from 190Nm to 196Nm depending on which type of front brakes you have but the typical PR-1LD with 321mm discs is 196Nm. Interestingly, and I don't agree with doing this, the VAG manual Elsa says for the bolt to "clean ribs if using again" but as M1tchy says I have known them snap so we always replace them IF we can get them, if we are stuck we re-use but re-book the car. Fior the rear bolts the manual says always renew and even if it is brand new, a torqued TTY bolt is one only BUT the spec doesn't imply it is TTY, very confusing. The bolt bolt is a sod, we made our own version of the VAG special tool for this which you set at 115Nm due to the toque arm extension factor but the top bolt is 140Nm.

[Quattro-Charlie]

Thanks guys for the torque info. Luckily I've been able to circumnavigate the whole carrier bracket removal by having the A6 that the discs slide out without needing to remove the carrier brackets....I'd read many many posts so was pretty confident of this before I started otherwise I wouldn't have attempted the rear discs especially......either I'd hash up a tool something like gupsterg did or just get an Indy to do it.

I thought M1tchy was referring to the bolts that secure the rear caliper to the carrier (38Nm either new or reused with threadlocker) not carrier to hub 196 Nm ones... The 38Nm ones aren't particularly tight so I can't see how they'd snap....but any things possible.

Gonna mull over getting new pads tonight and decide in the morning.

[lynalldiscovery]

At work on the trucks we are now using a castrol anti fretting grease for the metal pin rubbered bushes set ups, slides very smoothly and seems to last well so far!
Std chassis grease on the rubber bushes doent end well!

This stuff https://www.silmid.com/lubricants/mineral-oils/castrol-molub-alloy-paste-white-t-100gm/

[Quattro-Charlie]

Yep.....went with new pads and the inc bolts in the end...now just having ARB c link problems if anyone's interested?....

[Crasher]

having ARB c link problems if anyone's interested?....

New thread?

[Quattro-Charlie]

Yes Steve it's up there on the board thingy.....I'd appreciate a little help re my links if your upto it?