C5 rear banging

boristhespie · Post by **boristhespie** » 11 Jun 2011, 23:16

The rear driverside is banging on braking. Easpecially when breaking hard getting to junction.

The knocking could it just be the abs and a worn pad. Tad worried re corroded calipers.

Post by **myglaren** » 11 Jun 2011, 23:44

I doubt it is corroded calipers - drag a pad out and check it for uneven wear to verify.
Mine are corroded and in need of attention but still operate smoothly and silently.
It could be a damaged pad shifting in the carrier, which needs looking at before it gets to be a real problem.
Rear pads should come out easily unless like mine some numpty has fitted the retaining bolt the wrong way round, can't extract the pads without first removing the caliper

boristhespie · Post by **boristhespie** » 13 Jun 2011, 19:13

I didn't know you could do that? So can you change pads without taking calipers apart?

All I know is that the dealer when replacing pads pulled corroded calipers apart trying to losen the long screw thingies holding them together.

Post by **myglaren** » 13 Jun 2011, 19:32

Yes, no need to split the callipers to change brake pads.

You don't even need to split the callipers to remove them.
Undo the pad retaining bolt, force the pads away from the disc -carefully so as not to damage the disc, replace the bolt to keep the calliper halves together then remove the calliper retaining bolts (much easier said than done).

Swapping pads is a lot easier but you should ideally put a tube on the bleed nipple and crack it before pressing the pads away from the disc and consequently the piston back in it's bore. Lead the tube into a suitable container (jam jar) to collect the fluid forced out. This allows brake fluid to flow out of the bleed nipple instead of being pushed back into the ABS system, which can give rise to problems.
The loss of brake fluid is minimal.

I prefer to use a six sided socket on the bleed nipples. Less chance of rounding them off.

Give them a soaking in Plus-Gas the day before you intend to work on the brakes - just on the nipple seat, not all over the place.

Slightly tighten the nipple first then undo slightly, re tighten and undo a bit more.

You should feel from the resistance if it is corroded into the bore. Proceed with care particularly if it resists, work it gently back and forth to release the corrosion rather than just unwinding it in one go.

Sounds a faff but isn't. It doesn't take long but a sheared off bleed nipple is something to avoid at all costs.

If the nipples look to be in a bad way, renew them and smear a trace of Coppaslip or similar on the threads to prevent them corroding into place for the next time you want them releasing.

It's even simpler on a Xantia

Edit to add:

I've pinched one of SteelCity UK's photo's here - it is from an XM but the principle is the same - you can see the calliper sans retaining bolts but held together with the pad retaining bolt - here Steve has removed the calliper to get the disc and hub off.

boristhespie · Post by **boristhespie** » 13 Jun 2011, 19:54

(-expletive removed-) sake a French froggie git dealer charged me 1500 euros of which new rear calipers were the bulk when they said the bolt holes broke cause of corrosion when they tried to seperate them to fit new pads. Aaaaaaaargh!

I can pick em.

Post by **myglaren** » 13 Jun 2011, 20:02

The callipers can break when removing them - as they said, due to corrosion.

If they are corroded then they should be removed and the corrosion cleaned off before replacing the pads but technically there is no need to remove the callipers to replace the pads.

I was warned that this could happen when I had mine done first and the guy said that he would confirm that there were new callipers available if mine were damaged on removal.

As it happened they were fine and he cleaned them up, replaced the pads and fitted new bolts but even if the callipers had needed replacing the cost would have been less than £250 all in.

boristhespie · Post by **boristhespie** » 13 Jun 2011, 20:28

I put the car in for service. They sai needed new pads. Was normal basic service. Filters oil etc. Then the calipers crumbled and it cost more than that per each caliper. 1500 quidish

johnway · Post by **johnway** » 13 Jun 2011, 20:35

Hi,
Sorry to alarm you but judging by the condition of my rear calipers after I had inspected them during my C5 rear end job (see earlier posting) there is the possibility that the corrosion has eaten away the disc pad retaining bolt eyes !!! The results of this are not for the faint hearted. I have replaced calipers, bolts and pads and sealed the mating surfaces with anaerobic sealant - just as per Mr. Haynes. I do not expect to revisit the rear end again for another 50K.

Hope this helps : take the rear whhells off and have a close look - it is not hard to spot the problem you are experiencing.

All the best,
John.

john alexander · Post by **john alexander** » 14 Jun 2011, 20:06

Hi Did you know the calipers can be swapped to the other side of the car if the inner face corrosion is too bad. and forget the sealant use copperslip . Can anyone explain the reason behind the sealed bolts ???

Post by **myglaren** » 14 Jun 2011, 23:13

john alexander wrote:Hi Did you know the calipers can be swapped to the other side of the car if the inner face corrosion is too bad. and forget the sealant use copperslip . Can anyone explain the reason behind the sealed bolts ???

Dumnity!

I have never seen this done before, that I can recall.
Never done it and never noticed the callipers falling off either.

boristhespie · Post by **boristhespie** » 16 Jun 2011, 17:31

Okay as said bump bump bump coming up to junction braking in wet.

Just got outta garage.

I need NEW REAR CALIPERS as they are corroded in the usually stupid way.

Plus PADS and DISKS.

Athat's on top of the new calipers and pad n disks on front wheels two or so months ago.

WHAT'S THE LIKELY DAMAGE FOR THAT?

Post by **myglaren** » 16 Jun 2011, 17:53

boristhespie wrote:Okay as said bump bump bump coming up to junction braking in wet.

Just got outta garage.

I need NEW REAR CALIPERS as they are corroded in the usually stupid way.

Plus PADS and DISKS.

Athat's on top of the new calipers and pad n disks on front wheels two or so months ago.

WHAT'S THE LIKELY DAMAGE FOR THAT?

The callipers do not need replacing on account of the corrosion, this can be removed although it is a bit of a job and most workshops just replace with new.
There could be other damage to them caused by them being distorted of course.

boristhespie · Post by **boristhespie** » 16 Jun 2011, 18:04

I think i was 250 for front each.

boristhespie · Post by **boristhespie** » 17 Jun 2011, 20:28

Edit: not gonna be as expensive as feared. Just over what myglaren said HOWEVER the guy said that recently he's quoted prices only for the supplier to say the parts have doubled in price. That's his get out clause I guess.

Post by **myglaren** » 17 Jun 2011, 22:22

A bit of good news at last.

French Car Forum

C5 rear banging

C5 rear banging

rear brakes banging