Technical 500 brake issues - urgent if possible please

[Dervdrain]

Hi guys, picked up this 500 recently and just got the wheels off to investigate some noises - not surprising when you see the pics.

However, some monkey has been in here before - no R clips on the pins.

OS outer pad completely worn but other pad fine, piston moves OK in calliper with hand pressure.

Any ideas - seems to float OK...

NS pads all good, obviously I'll replace the four all round.

BUT - having not had one before - the caliper is free on the sliding bush but actually comes right off - this can't be right surely?
There seems to be a hex key bolt but the caliper can slide right off past it.

Also no screws securing the disc to the hub - missing I presume?

 

[bugsymike]

As you say replace pads both sides.
Not a problem caliper sliding off pin as it cannot do that when in situ all assembled with both pins etc.
Main thing is check they all slide freely and are lubricated with suitable brake grease.
More to the point is the cause of one pad worn down, if you are sure calipers sliding freely on pins then you only have a sticking brake piston , which must be addressed. Either freed off or replaced.
After assembly and road test , jack up and check both wheels turn easily (very slight drag due to disc not drum brakes) but also check brakes not getting hot through undue dragging.
I suspect piston on worn side has got rusty inside causing the problem.

 

[Dervdrain]

Thanks Mike - that was my thought and the usual thing as you say - I'll check it over now. Do you know the standard/min brake thickness on these - it's a 2014 1.2.

EDIT: appears to be here, mine are around 10.5 at present. https://www.halfords.com/motoring/car-parts/brakes/brake-discs/bosch-front/rear-brake-disc-775342.html

Presuming there should be a disc securing bolt - anyone know the size?

 

[varesecrazy]

Thanks Mike -

10.2 min. Thickness

Do you know the standard/min brake thickness on these - it's a 2014 1.2.

EDIT: appears to be here, mine are around 10.5 at present. https://www.halfords.com/motoring/car-parts/brakes/brake-discs/bosch-front/rear-brake-disc-775342.html

Presuming there should be a disc securing bolt - anyone know the size?

It's the same as the rear.. Maybe "borrow one"

 

[Dervdrain]

Can't easily access the rear - seems to be between M6 and M8??

 

[Dervdrain]

Putting in new discs and pads today - will have to wait on the disc bolts...

 

[bugsymike]

Putting in new discs and pads today - will have to wait on the disc bolts...

I have often come across discs with no retaining screw, they can't come loose with the wheel bolts holding it all on.
The only time it is a noticeable problem is where the screw has been broken off and is slightly raised, this can mean if the disc is aligned to different wheel bolts then the brake disc can be slightly proud, which will cause a brake shudder.
Some makes of vehicles come from new with no retaining screws.

 

[The Panda Nut]

As you say replace pads both sides.
Not a problem caliper sliding off pin as it cannot do that when in situ all assembled with both pins etc.
Main thing is check they all slide freely and are lubricated with suitable brake grease.
More to the point is the cause of one pad worn down, if you are sure calipers sliding freely on pins then you only have a sticking brake piston , which must be addressed. Either freed off or replaced.
After assembly and road test , jack up and check both wheels turn easily (very slight drag due to disc not drum brakes) but also check brakes not getting hot through undue dragging.
I suspect piston on worn side has got rusty inside causing the problem.

I suggest a new slider pin kit with rubber bushes as these seem critical to ensuring the calper remains straigt as it slides. If you dont change the bushes takthen out and turn them 90 degrees to even the wear. Fiat prices are ludicrous so buy else where. Kits can be had for £15 to 30. The discs look good just showing the signs of pads being worn out and thus not getting pull pressure squeeze to really shine up. One worn pad suggests tardy caliper sliding, but this could have been in the past at the other end when the pads were newer. I am treating slider pin bushes as service items from now on. Check the piston is smooth over the full range and doesnt have a sticky spot. Keep your eye on pad wear as you go so if you do get a problem you can free it off. My neighbours Astra wore one pad out in 3K miles. I replaced them as he wanted to do a long run on the day. They appeared free but started sticking as the pads got to 25% worn. fettling them again sorted it for a while but a new caliper was eventially fitted. They dont make them like they used to. Personally I hate sliding single pot brakes for this very reason.

 

[vexorg]

The 1.2 is a real cheap and nasty setup. Just clean it all up, new pads, and it'll be back the low crappy standard fiat wanted.

 

[portland_bill]

Make sure the pad carrier is clean. If the pads are tight in the carrier, they may resist moving, which may be the case here. The thicker pad has stuck in the housing, causing all the pressure to act upon the now thin pad. Pads should be snug in the carrier, but not tight. Often it is necessary to run a file around the ends, mostly to take off the paint, but sometimes the backplate casting is poor. Don't make them too loose.

 

[The Panda Nut]

The 1.2 is a real cheap and nasty setup. Just clean it all up, new pads, and it'll be back the low crappy standard fiat wanted.

Yep 169 brakes are not well thought through. They really shouldnt need the level of TLC required. Brakes need to work, all the time, and indefinitely. Not need constant fettling. The 319 brakes are more conventional and dont have the smae demands than heaven.

 

[Dervdrain]

Thanks guys, cleaned it all as best I could and everything 'appeared' to be moving as it should - braking OK pending proper bedding in but I'll keep and eye and inspect again after a few miles.

 

[portland_bill]

Thanks guys, cleaned it all as best I could and everything 'appeared' to be moving as it should - braking OK pending proper bedding in but I'll keep and eye and inspect again after a few miles.

Make it an annual event, strip, clean, and reassemble.