Ever since my little play in the dirt, my 4x4 TA has had noisy, gritty brakes.

I could feel/hear a gritty, gentle grinding when applying the brakes and in reverse, the N/S front and both rear brakes hooted like a demented owl, quite loudly, particularly when a little steering input was applied (parallel parking).

As per usual, the dealer booked me in to look at it sometime in 2214 after stating the usual "never heard of that before", so I decided to have a look myself as the hooting and grinding was effecting my fillings!

Seems the factory have saved a little and built up the brakes completely dry, not a spot of brake grease or copperslip in sight.

I stripped them down and noticed on the front, the top locating lug on the pads has been slapping on the caliper carrier at the top (obvious it's slapping up the top as it drags the pads upwards as it goes back in reverse) and started to wear a dint in the carrier.
I cleaned it all up with some brake cleaner, wire wool and some fine grit paper to smooth the edges of the dints off the carrier and liberally copperslipped up the contact points between pad and carrier. (both on the pads lugs and carrier).

The front caliper is held on to the carrier with some 7mm Allen key pins under a couple of plastic covers that pop off, these are the pins the caliper floats on and were bone dry, these just unscrew and got some copper slip too, as did the contact points of the spring clip that acts as an "anti rattle" on the outside of the front calipers that are a bugger to get back in the little holes.


At the rear the pads locating lugs are shimmed with some sort of "anti rattle" pieces top and bottom, springy metal shims coloured gold.
When cleaned off, I could make out where the pads contact the shims and rub/vibrate as the gold coating has worn off.

Both sides of the shims have this coating worn due to the different contact points whether going forwards and backwards, so it's easy to identify where the problem is and where to apply the copperslip.

Again, copperslip on both sides of the shims (and carrier) after cleaning well saw them clipped back in with a dab of the stuff on the contact points of the pad's lugs to shims.
The pins on the rears under the rubber covers that the caliper "floats" on did have evidence that as some point in the build they may have "smelt" a little brake grease, so more copperslip when on those and the lot built back up.

On neither front or back did I remove the carriers from the hubs as I had good access underneath via a lift to get at and clean both sides of the carriers well enough.
I was careful when applying the grease as not to contaminate the discs and pads friction material, though the backs of the pads did get a good coating, even though the pad backs have a anti rattle coating adhered to them.

All in all an hour and a half job that cost me less than the fuel and time to the dealer and back.
At just over a fiver for a can of brake cleaner and a 20g tube of copperslip (enough to do them twice) was a good result.

Now the brakes are super smooth, the gritty feeling has gone as have my demented owls and it should stay like that for a lot longer that the 1800 miles I've done so far.

All good stuff, except, the caliper pins should have proper brake grease, not copper grease.
Copper grease is not a lubricant. It is called grease only because of its consistency, not its properties. It is an anti-seize compound, aimed at bolt threads to prevent corrosion and allow easier removal. It is good for preventing brake squeal as it is resistant to heat, but does attract dust.

On the pins it will obviously be better than the nothing that Fiat put there, but sometime it would be good to replace it with proper stuff.

I will now add checking these to my list of things to do when the rain stops.

Fair point, but copperslip has worked for me for forty years.

More importantly, the use of something heat resistant is essential as normal grease tends to burn easily and brakes generate massive temps.

Searching online is not very productive. Opinions vary between different substances.
Dow Corning actually make a specific grease for this application, Molykote G3407, but their website suggests it comes in a large tub, looks like 20 litres. A bit excessive if you just need a thimbleful once every 5 years or so.
General Motors have the Molykote stuff under part number 93165631, (Opel number 19 48 003) available here, to order, but will cost £10.30 with carriage.
http://www.vauxhallworldparts.com/v...uxhall Parts&cheaper=true&partnumber=93165631
Presumably available from your Vauxhall dealer.

Otherwise, red brake grease seems the best alternative.

The brake squeal seems like a problem for most/all 4x4.
When I complained at my dealer, they said there was a technical bulletin from Fiat. It read along these line"fit new rear pads, at owners expense even if the pads are only barely worn"
I told them to fook right off and bought a nissan leaf!

My dealer too a different view and replaced the pads foc

I think the issue with the rear brakes on the 4x4 is the performance of the floating calipers. I replaced the pads on my 2009 Panda Cross 4x4 last April, just four months ago, and suffered from squeaking on the n/s rear. On investigating this weekend the outer pad on the n/s rear was virtually worn away completely whilst the inner pad wear was normal.

I've now stripped the brakes completely replacing the discs and pads. One of the guide pins for the floating caliper on the n/s slides was in poor condition. These pins seem to provide two functions: (i) they guide and allow the caliper to float, and (ii) they provide a degree of suction or return force such that when pressure on the brake cylinder is released the caliper returns to it's original position with equal pressure on both pads.

If the guide pins are in poor condition, or lack lubrication then when pressure on the master cylinder is released the caliper does not return to it's neutral position and so there is residual pressure on the outer pad. This leads to excess friction, overheating of the brake, squeaks, squeals and excessive and uneven wear on the outer pad and outer surface of the disc.

It is easy to test the operation of the pins when the floating caliper is removed. Simply pull the pin out a cm or so. It should move smoothly and with a degree of resistance. On release it should return to it's original position. Any stickiness, lack of return, or 'gritty' operation would indicate problems.

I don't know if it is possible to buy replacement pins. On taking the pins out I notice that the upper and lower pins have a slightly different design. The upper pin has a plastic end piece that is full of grease. I suspect this is some form of dash-pot that provides the return suction to the caliper assembly. The lower pin is a steel pin with four flats milled along the length of the pin. These may be to aid grease flow.

I have cleaned the pins and re-greased with a high temperature grease whilst I investigate if it is possible to make a more complete service of the brakes.

I'll keep updating here as I find out more about he availability or not of spare parts for the calipers.

Updated information on 4x4 brakes.

The guide pins, rubber seals etc. are available as a brake calliper fitting kit from brakeparts.co.uk.

The kit costs £16.31 including VAT and contains 2 x guide pins, 2 x bolts to secure calliper to guide pins, 2 x rubber seals and 1 sachet of silicone grease.