My 2005 1.2 4x4 has started making an odd noise which I believe comes from the front brake calipers.

It started early in the year and I put down to rust on the discs, or from worn pads contacting the 'lip' that forms on the disc. I replaced the (ventilated) discs and pads recently though and the noise is still there. Can be heard when driving slowly, especially after having used the brakes and then pulling away. Sounds like a metal to metal noise -- its a rattle, not a squeak (or, maybe like a dimpled golf ball rolling round a metal bowl), and alters with road speed. Very lightly pressing the brakes (so taking up 'slack' between pads and disc, but not enough to slow the car) stops the sound. Also replaced rear brakes, partly because they needed doing, and partly just in case the noise was from there.

With the wheels off there seems to be a degree of 'rock' in the sliding part of the calipers. The bolts holding the sliding section of the caliper are tight, as are those holding the fixed part to the hub casting. On the 4x4 (and maybe 100HP?) the calipers are secured by 12 or 13mm bolts (can't recall which), not allen screws as on the other Pandas. These bolt into a metal rod that provides the 'slide' for the caliper. These rods move freely in and out (inside rubber bellows) of the fixed part) -- but it is as if these rods have too much slack, maybe as if they have worn to be too small a diameter? The brakes all work fine but the noise is slowly getting worse. After driving for a while it goes away, as the pads back off. But comes back after braking to stop the car. Anyone got any suggestions? Are those guide rods replaceable?

Thanks

Pete

The only time I have ever experienced this noise was when I fitted some pattern brake pads to the front brakes of a Volvo 740. The backing plates of the pads were marginally smaller than the OEM ones allowing the pads to rattle within the calipers until stabilised by applying the brakes.
I don't think this applies in your case. Although you describe the caliper mechanism sliding on its pins, it is in fact more correctly described as a floating caliper. This, however, is a technicality. If there is wear in the pins then they could cause a rattling noise as described. You might also see wedge-shaped wear on the brake pad on the floating side of the caliper.
I do not know if the pin mechanism is replaceable, you should ask your Fiat dealer or a reputable motor factor. I suspect that a replacement caliper would be needed which is expensive for the Panda. It would be worth getting a garage to give an opinion before incurring the expense of replacement calipers.

P.S. I think that worn wheel bearings can also produce a rattle as you describe.

...Thanks Chris. I was wondering if bearings might be the issue, but not too easy test (as you well know) since you cannot just jack and spin one wheel on the 4x4. No obvious looseness when wheel jacked and attempts to rock it top to bottom, but a bearing has to be pretty well shot before play can be felt that way.

Still have suspicions that it's the floating caliper. But I will take it to my friendly local mechanic shortly and see what he can tell me

Pete

Herts Hillhopper said:

...These rods move freely in and out (inside rubber bellows) of the fixed part) -- but it is as if these rods have too much slack, maybe as if they have worn to be too small a diameter? The brakes all work fine but the noise is slowly getting worse. After driving for a while it goes away, as the pads back off. But comes back after braking to stop the car. Anyone got any suggestions? Are those guide rods replaceable?

Thanks

Pete

Click to expand...

I know you have, but....pack the bellows and back of the pads with copper slip? I don't know whether the Pandas have anti rattle shims/clips, but if they do, replacing with new might help.

My money goes on Pad Rattle too. I have an aftermarket kit on my Audi and one side had no anti-rattle shims fitted, which I'd not noticed. Rattle, Rattle, Rattle over bumps and divots that only disappeared when the brakes were on. Removed Pads, fitted shims and now all peace and quiet. Shims (if fitted) can wear over time or CooperSlip can rub away. Either way, that's my suspicion anyway.

Phil G

I've resurrected this old thread, because I have finally solved the problem (3 years later!) Previously I've commented that the car made an odd noise, which I thought was from the front brakes, and that it didn't go away even after replacing discs and pads. Both my previous 2 sets of discs and pads have come from my local motor factor, and seemed to be fine as replacements -- certainly the last set of pads has lasted really well, and actually the discs weren't too bad.

But over the weekend I've replaced them again, this time with parts from Shop4Parts. The discs were genuine Fiat parts, and the pads were boxed as Bendix and labelled specfically for Fiat. Each of the new pads had a plastic/rubber backing pad on the back -- the non-Fiat ones previously used were just painted metal. And, bingo, the noise has completely gone!

So, there it is: the non-Fiat pads seem to make a noise... Not (thankfully) a wheel bearing, CV joint or driveshaft, just pads without a silencing backing pad on them.