C5 REAR BRAKE CALIPER PROBLEM

[Robert]

Hi

My rear brakes suddenly started grinding. On investigation I found the rear caliper appeared to be out of line and is scraping against the inside of the wheel - metal against metal.

Are the bolts likely to have bent - is it best to fit a new caliper with new bolts.

[myglaren]

This is a very common problem caused by corrosion on the interface between the aluminium calliper and steel trailing arm it is mounted on.

There are several thread devoted to this problem but essentially you need to remove the calliper and scrape/file/sandpaper the corrosion from the surfaces then fabricate a thin gasket from polythene or similar, or grease the mating surfaces to hinder the formation of more corrosion.

The bolts can be very difficult to remove as they are threadlocked the full length, are very tight and worse, with the calliper being forced away from the mounting point - always the upper edge more than the lower, the bolts are under stress.

You will need to proceed with caution to avoid shearing them off.
A good soaking with Plus-Gas will soften the threadlock and help with any corrosion on the bolts. Repeated application of Plus-Gas over 48 hours will be beneficial, then some heat applied to the bolts will further ease removal.

[citronut]

i juest did the rear arm bearings on both sides of a C5 for a car sales,

the bolts were completly stuck solid in the N/S calliper even after they had unwound from the arm,

i ended up purchaseing 4 new bolts from citroen and driftted the old ones out of the calliper,

when i collected the new bolts the parts manager told me they dont bother trying to salvage C5 rear callipers at all, they just lop them off and fit new callipetrs and bolts,


the one i did i didnt bother removeing the O/S calliper, i just removed the arm with disc and calliper attatch,

regards malcolm

[Robert]

Hi Guy's

Thanks for your advice. The car is back on the road and working now.

Got a new exchange caliper for £85. My local small garage fitted it for £50 cash so not bad.

The mechanic said the bolts were completely siezed on, he had to heat them up until they were glowing in order to get them out.

Thanks again.

[myglaren]

Pleased you have got it sorted.

It is worth removing them every second year and cleaning off any corrosion then re-greasing them to hold it back.

[andybsmith]

Just done mine, what i found is that if the bolts will turn, take your time because the threadlock heats up and grabs the bolt, so a few turns until it gets tight then leave it for 2 mins, come back and hey presto its easier to turn again. That being said it still took 20 mins per bolt.

[Kowalski]

Just done mine, what i found is that if the bolts will turn, take your time because the threadlock heats up and grabs the bolt, so a few turns until it gets tight then leave it for 2 mins, come back and hey presto its easier to turn again. That being said it still took 20 mins per bolt.

I cleaned up the rear calipers on my C5, the car is an 05 so the corrosion behind the caliper wasn't bad enough to bend the bolts. I'd read that spraying brake disc cleaner and pentrating oil into the holes in the caliper softened the threadlock, so I tried that and the threadlock was soft when it came out. The bolts unscrewed relatively easilly but the problem I had was actually withdrawing them from the caliper, although they rotated fairly easilly they wouldn't just pull out by hand. The Haynes manual recommended removing the caliper and using a press to remove the bolts, I managed to work them free by getting hold of the boltheads with locking pliers and turning back and forth while pulling them out.

After cleaning up the calipers, I coated the mating face with wire rope grease. Wire rope grease is a black sticky grease used to lubricate wire ropes amongst other things, I tried waterproof grease (Duckhams Keenol) and copper grease (Copaslip) but the wire rope grease was the only thing that stopped the corrosion from returning on both of my Xantias, hopefully it'll do the same on the C5.

[HDI Dave]

After cleaning up the calipers, I coated the mating face with wire rope grease. Wire rope grease is a black sticky grease used to lubricate wire ropes amongst other things, I tried waterproof grease (Duckhams Keenol) and copper grease (Copaslip) but the wire rope grease was the only thing that stopped the corrosion from returning on both of my Xantias, hopefully it'll do the same on the C5.

Interesting,never heard of it before(wire rope grease).

I usually use a range of greases,normal,heavy duty,high melting point stuff etc, and the old 'copaslip',(although the 'magic/fantastic' copaslip does tend to dry out..)

2 questions,

Is it high temperature? I'm guessing it is, as it works on calipers,ie,hot,without going runny..for want of a better word

Where do you find it? Sure I've never noticed it at the local factors..

Cheers, Dave.

[myglaren]

Lawson's
Expensive!

I might be able to obtain small quantities but will have to investigate - I know a man who knows a man, like

[HDI Dave]

Lawson's
Expensive!

Flippin eck, (am from Yorkshire tha knows,tight.. ) - that IS expensive.

In your link,does fluid mean the actual grease? as it can't be the spray?!

and,you can't beat a man who knows a mans brother in laws sisters best wokfriend etc

[myglaren]

Flippin eck, (am from Yorkshire tha knows,tight.. ) - that IS expensive.

Me too, Dave. Me too

In your link,does fluid mean the actual grease? as it can't be the spray?!

From what I can see, it is the dressing that is the thick gloopy stuff that we used to hate when traversing bridges in places they were never intended to be traversed.
The fluid seems to be a water dispersant/lubricant of much lower viscosity and the spray a lighter version of that.

Axle grease from rolling stock would be similar but when do you ever see a train these days.

[Kowalski]

Flippin eck, (am from Yorkshire tha knows,tight.. ) - that IS expensive.

Me too, Dave. Me too

In your link,does fluid mean the actual grease? as it can't be the spray?!

From what I can see, it is the dressing that is the thick gloopy stuff that we used to hate when traversing bridges in places they were never intended to be traversed.
The fluid seems to be a water dispersant/lubricant of much lower viscosity and the spray a lighter version of that.

Axle grease from rolling stock would be similar but when do you ever see a train these days.

Anti climb paint is probably similar stuff to the wire rope grease, the other thing I've got a tin of which is similar in colour and consistency is underseal although it is a bit less thick and sticky and probably easier to apply.

There are a few types of wire rope lubricant / dressing, the spray ones are generally dissolved in some sort of light solvent that evapourates leaving behind the grease, they're designed to penetrate to the core of the rope and carry the grease inside. The other type is what I've been using which is something that resembles bitumin but is a bit more sticky.

The product I've been referring to as "wire rope grease" is called "Pinion Grease", it's made by Ovoline and wire ropes are only one of its applications, its number 352 on the pdf linked to below.

http://www.ovoline.co.uk/ovoline/pdf/offh.pdf

It came in a 12.5kg bucket which may be more grease than you'll want / need.

Rocol does a similar sounding product, called TufGear Universal. The PDF describes it as "Smooth, black, adhesive grease" which sounds like the Ovoline 352.

http://www.rocol.com/tsds/live/tds/engl ... %20TDS.pdf

You can get a 400g tube of the Rocol Tufgear for about £10, might be worth somebody buying a tube to try it out.

[addo]

I dunno; you could have a lot more fun with 25 pounds of sticky black grease, some rollers/poles and a list of barryboy driveways.

[john alexander]

And if the worst comes just swop the calipers side to side

[Gazzaman22]

Bolts for the back calipers 2007 Citroen c5 ii
anyone know of a replacement part number or where to get a couple of pairs before i tackle the replacement?