Technical Front brake caliper guide pin removal 1.2

[Danoid]

What I do when it’s pushback is keep a pad in then use my brake rewind kit.

This will be a job in the summer as I’ve not changed brake parts on a Fiat and too cold.

We’re only the 2nd owner and the cars only do 28k, the front brake pads are a little low despite being changed at 18k by previous owner. The car does pull to the left when breaking so I suspect the sliders could be a little seized. So this will be a nice little job in the summer but I’ll change discs and pads as it’s cheap enough

 

[John202020]

We’re only the 2nd owner and the cars only do 28k, the front brake pads are a little low despite being changed at 18k by previous owner.

Not really related, bought the Mazda 10 years ago still on the front discs and pads 60k later, 3 sets of discs and pads on the rear

 

[Danoid]

Not really related, bought the Mazda 10 years ago still on the front discs and pads 60k later, 3 sets of discs and pads on the rear

That’s done good innings, I must admit I tend to drive like it’s on a constant Italian tune up, which isn’t going to help

 

[Pugglt Auld Jock]

The car does pull to the left when breaking so I suspect the sliders could be a little seized. So this will be a nice little job in the summer but I’ll change discs and pads as it’s cheap enough

It's much more likely that the pad has rusted to the caliper carrier in my experience. Not that it couldn't be the slide pin or that small bottom pin being seized.

 

[Pugglt Auld Jock]

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.

I have a push back tool but actually find a joiner's G clamp works just as well on front calipers.

Pinching off the brake hose and opening the bleed nipple so the old fluid is expelled as the piston is pushed back is a great idea not only for the reason you mention regarding contamination of the ABS unit but also you will then be adding new fluid to the reservoir which can only be good. The problem comes with older cars, like many of ours are, where there is a very real risk of snapping off the pesky nipple due to it being corroded in place. At least, if it snaps off, you'll not be stranded because the system will still be sealed but it's annoying to know you've snapped the nipple off.

It might interest folks to know I asked around several of the small garages around me (where I'm well known) and all said they would only slacked bleed nipples on older - over about 5 years - vehicles if specifically bleeding the system. for pad renewals they would just allow the fluid to return to the reservoir. All said that, as far as they were aware, this wasn't causing any problems. Anyone doing more than just the occasional pad change might like to look into a tool I've talked about before. Vibroshock it's called



You'll need to be seriously into your cars and have a compressor and air hammer though. It's sold under many brand names but seems to be the same tool regardless of brand. It really does work but you need to remember to let the tool hammer away at the fixing until it undoes with only moderate force applied to the handle. It's still very possible to snap the nipple/stud or whatever if you don't let it hammer for long enough and just heave on the side handle - just needs a wee bit of intelligent use.

 

[vexorg]

I have a fear of broken bleed nipples, has happened too many times on older cars. Why cant they make then a decent size!!

I'be never had any issue with just pushing the pads back in and no other precaution, and I've done a lot of brakes, at least once on every car I've had

 

[jrkitching]

I have a fear of broken bleed nipples

Me too.

Which is why I always put some sort of antiseize on the exposed part of the thread before retightening them. Fitting protective covers like these helps too, and both is even better.

I'be never had any issue with just pushing the pads back in and no other precaution, and I've done a lot of brakes, at least once on every car I've had

Aah, the old 'I've always done it this way and never had a problem' argument. This breaks down in any 'low risk, high consequence' situation. Sure, you'll get away with it almost all the time, but on that rare occasion when you don't, you'll have a major problem on your hands.

If you want a good example of what can happen when risk assessment is done on the 'what have we always got away with in the past' principle, look at the Shoreham air crash.

 

[Ralf S.]

I've had a few troubles with nipples... but after I snapped my second or third one I invested in a set of those drill-out extractors. The nipple already has a hole drilled in it, so the Easy-Out has a pre-made hole for it to wind into. Having said that, since I bought the extractors, I've never had another snapped nipple..

Anyhow, these days I undo the nipple whenever I'm fitting new pads. Exercising the nipple keeps it from seizing in the first place and I like to bleed the brakes every so often anyway, rather than waiting for pad change time.

You can help the nipple by sticking some copper (or any) grease on the threads, while you have the hose clamped and the nipple loosened... and if the "nut"/ flats start to become rounded off (since they rust, regardless of the thread sticking or not) then I just put a new nipple in there. There are stainless steel ones for sale, if you hunt about on fleabay. I have some on the Stilo and they still look like new..


Ralf S.

 

[Pugglt Auld Jock]

Me too.

Which is why I always put some sort of antiseize on the exposed part of the thread before retightening them. Fitting protective covers like these helps too, and both is even better.



Aah, the old 'I've always done it this way and never had a problem' argument. This breaks down in any 'low risk, high consequence' situation. Sure, you'll get away with it almost all the time, but on that rare occasion when you don't, you'll have a major problem on your hands.

If you want a good example of what can happen when risk assessment is done on the 'what have we always got away with in the past' principle, look at the Shoreham air crash.

One of the first things I do on any vehicle when it joins "the family fleet" is to get my hands on it and give it a top to toe check over. I'm due to do exactly that with the new Mazda within the next week or so. One of the first things I like to do is comprehensively check brakes and suspension/steering. Removing the nipples, giving them a wee dod of copaslip/alumslip or similar and reinstalling them is a priority and it also allows a brake fluid change if needed.

I like your "I've always done it this way and never had a problem" argument - How very true. Probably with a well maintained system where the fluid is changed properly and regularly the risk is very low indeed. But for the average, not very much cared for, family car? It's a bit of a game of Russian Roulette I think.

Talking about Russian Roulette, I have to admit that I don't bleed out the ABS unit when doing a fluid change. Mostly this is because I don't have the gear to drive the module on anything except the Fiats and VAG stuff. Asking around again it would seem that this, ignoring the ABS module, is typical.

 

[vexorg]

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.

Well based on that, it got a bit of extra copper grease on the guides this morning