Technical Front brake caliper guide pin removal 1.2

[vexorg]

I had to do the front brakes and discs yesterday.

All fairly sraight forward, though I wasted a lot of time trying to figure out how that top guide pin is removed. It didn't help it was caked in crap at the back, and felt like an allen headed bolt. 8mm was too loose, but did catch, though not brave enough to try if it was that loose. 10mm was way too big. Same with torx, T50 was loose, T55 was way too big.

I'm guessing it's a 9mm allen key??? Of course nowhere sells those.
How does that top guide pin come out?

Anyway, I was able to get it all done just leaving that guide bolt attached to the carrier. Normally like the carrier off to give a good clean with a wire brush on the pad guides, but managed in situ.

Seems a bad design with that guide pin at the bottom, it's very exposed to road dirt. It had stuck on the passenger's side and one pad was down to the metal, though they were all very low.
I should really have checked the new parts first. I spent time cleaning up the bottom pin, and care taking out the disc bolts (made of super soft metal), only to find new bolts in with the discs and new pins in with the pads!

 

[jackwhoo]

Hi,

The following is from memory so please be kind.

A lot of people struggle removing the upper slide pin , loctite from factory? Heat could be your friend. It may be possible to leave guide pin in place and slide caliper off pin-be careful with rubber boots.

Best wishes
Jack

 

[varesecrazy]

Old puntos were 7mm hex.. so 9mm sounds plausible

But Torx..or Ribe are still a possibility

Sounds like you found a way with the pin staying in place though

 

[varesecrazy]

I am left thinking Ive done this on a modern FIAT.. But cannot remember what I used :-(

If this warm weather holds I will revisit it

 

[jackwhoo]

The slot in the caliper that the lower pin passes through needs a good clean / de-rust so the pin is free. If not uneven pad wear will result.

 

[varesecrazy]

A helpful thread that was under this as I viewed it

Removing Front Brake Caliper Mount - Weird Star Type Nut Stuck ! | FIAT 500 (2007+)

Hi, Am trying to change the disks and pads on my wife's 2016 Fiat 500 1.2 petrol. The whole assembly on these later 500s seems more like the Abarths if you look at the YouTube videos. Anyway all is going fine until it comes to remove the bracket holding the calipers (the calipers come off with...

www.fiatforum.com

 

[vexorg]

That thread was referring to the carrier bolts, mine had standard 17mm bolt heads (M10).

Was easy enough to do with the top guide pin in place, undone the carrier, removed the disc, put the carrier back on, then the caliper hinges up enough, sojust tied the caliper up out the way

 

[jrkitching]

A lot of people struggle removing the upper slide pin , loctite from factory?

Yes, mine were. Even on a brand new car, these will be tight; after a few British winters, expect them to be challenging.

You absolutely need a decent hex key socket (8mm from memory, I'll check when I next get underneath) and probably a breaker bar. Using an allen key (and likely a hammer) will almost certainly end in tears. If you've a well used car and someone else has previously 'had a go' at this bolt/pin, it could well be rounded internally.

My own car was less than two months old when I took mine off to put this thread together.

I'm not a fan of single pivot cantilevered calipers; two slider designs are much better from an engineering perspective. I suppose the rationale is that it makes for a quick pad change if you leave the caliper in situ and just hinge it out of the way, but once corrosion has started to take hold, you'll need to get it off anyway if you want to do a proper job of cleaning the reaction frames. It's much easier once you've got them securely clamped on the bench and can safely take power tools to them.

And take care of those frames; despite being crudely engineered, replacements are neither cheap nor readily obtainable.

 

[Danoid]

does the bolt need re-greasing? I’m use too more traditional slider pins and not just the one at the top.

I assume it does but not familiar with the design

 

[jrkitching]

I’m use too more traditional slider pins and not just the one at the top.

It's basically the same, except there's one sliding pin instead of two.

I regreased mine, shorthly after taking delivery of the car from new, after first (carefully) removing the rubber gaiter and degreasing both gaiter & pin. Unless the gaiter splits or otherwise becomes damaged, this should only need doing occasionally (not so frequently as every pad change). This is in stark contrast to the exposed parts; the lower pin, the contact areas of the pads and the reaction frames, all of which benefit from being stripped, cleaned, lubricated and refitted at least every other winter (and always when changing the pads).

When either removing or reattaching the caliper from/to the reaction frame, be very careful to ensure the rubber gaiter is free to turn on the large pin as the bolt is tightened, or you'll twist the gaiter and likely rip it. I like to keep one hand on the gaiter while I'm actually turning the pin.

Keep the appropriate parts of the brakes cleaned & lubricated, and they'll both be problem free and last a long time. Assemble them dry, and they'll soon have you tearing your hair out - and posting on this forum!

 

[vexorg]

I usually put copper grease on the pad slider area, though only a thin coating. My worry is that the brake dust sticks to the grease and gets clogged up.

You can do a good job of cleaning with the carrier on the car, I've got a skinny wire brush for the drill and it was a nice fit in the groove. Usually it needs the bigger wire brush for the rectangular pad slides.

 

[jackwhoo]

On older vehicles or harsh climates the rust can be very thick and hard on the carrier frames. The very think hard rust can be chipped off the areas where pads mount as wire brush won't touch it.

 

[jrkitching]

I've got a skinny wire brush for the drill and it was a nice fit in the groove.

Yes, the half round contact area makes for easy cleaning with a wire brush in a drill. Most of the previous vehicles I've owned had right angle corners in the contact area, which can be awkward to derust properly.

My worry is that the brake dust sticks to the grease and gets clogged up.

It does stick somewhat, but stays sufficiently 'greasy' that it's only going to be a problem if left for a number of years. Without some form of protection, corrosion will cause them to stick within weeks.

I like to strip & clean the whole lot about once every two years; generally I see somewhere in the region of 55k-65k out of a set of pads.

 

[Pugglt Auld Jock]

When I first tackled Becky I found these top pins were solid. I tried to loosen them with a socket type Allen key - so i could get some real effort into it by using a breaker bar - but it was obvious I was just going to break it so I left them were they were and, once I'd got the bottom pins out, I just swiveled the caliper up and slid it sideways off the top pin. I've continued to do it this way whenever necessary ever since and will only try to get the top pin out, which I'm guessing will involve lots of heat, if the top pin rusts.

I've been doing a number of brake overhauls on various family vehicles this past year and I can't remember exactly what the guide construction is on the Panda. Generally this sort of pin arrangement is fairly common but some slide in a rubber bush and others slide in metal bushing - not to be confused with exterior rubber dust excluding sleeves. If the pin slides in a rubber bush, like my Ibiza, then, after cleaning the pin and bushing, it needs to be lubed with something like red rubber grease or silicon grease so as not to erode the rubber. Metal bushed assemblies I would use a non metallic ceramic brake grease on. Copa slip works too but you need to be careful not to apply it too liberally and be aware it's actually not such a good lubricant, more of an anti seize and there are questions over whether it has any place being used on modern brakes.

Personally, If the top pin is in good order and not corroded, I'd just leave it where it is and slide the caliper off it so you can clean and lube it. The bottom pin is definitely prone to rusting in place and it's only too easy to break the small lug it passes through in the caliper carrier if you get too violent. Both my local Factors can supply replacement pin kits quite cheaply off the shelf. so looks like they are readily available. If your's is a bit rusty just get a kit.

Although not dealing specifically with the troublesome top pin, this post I made shortly after we'd bought Becky may be of interest: https://www.fiatforum.com/threads/beckys-brakes-a-few-surprises.459983/

 

[Ralf S.]

Rasputin will need pads soon and I've been wondering about this infamous pin..

I'm sure it's fairly obvious when it's in front of you.. but that Jockish guide looks useful. Ta.


<Edit> Looks like the old Cinquecento setup - bash the pin out and rotate the whole caliper using the top pin. Am I missing something?

And @Pugglt Auld Jock - Amusing photos sequence... tap tap tap gently photos.. then blow torch...


Ralf S.

 

[Pugglt Auld Jock]

And @Pugglt Auld Jock - Amusing photos sequence... tap tap tap gently photos.. then blow torch...


Ralf S.

Just like real life I suppose? Gently gently does it but let the "dog" see the big stick just in case it thinks it can resist! Of course I'm joking but I've worked for a couple of blokes who have tried to control me in this way.

 

[Danoid]

Another question, is the front piston wind in or push in?

 

[John202020]

Push

Another question, is the front piston wind in or push in?

 

[vexorg]

Rewind tend to be for when the handbrake is integrated into the caliper.

For front I usually just change discs and pads at same time, and big screwdriver into the caliper and pads/disc to force the piston back.

 

[jrkitching]

Rewind tend to be for when the handbrake is integrated into the caliper.

Rear pads on the 500/Panda (on those models so equipped) need a rewind tool. Front pads are just a straight push back.

For front I usually just change discs and pads at same time

Me too, at least on the 1.2. The discs are cheap as chips, and wear almost as fast as the pads. If you reuse them, they'll likely go below minimum thickness before the second set of pads wear out.

and big screwdriver into the caliper and pads/disc to force the piston back

A 4" G clamp works well (the moving end fits neatly into the piston), and is both more controlled and less brutal.

I'd recommend clamping the flexible hose and opening the bleed screw before pushing back the pistons; it prevents any contamination being pushed back through the ABS modulator (they're frighteningly expensive, so why take the chance?), and it eliminates any risk of the master cylinder overflowing.