boxsey911

So I'm in the process of refurbing some brake calipers and just like most of them, there is corrosion under the spring plates so these need to come out.

The plate screws are at an awkward angle so getting a torx bit in there to undo them was a no go but I managed to find a set of torx keys at the local motor parts store . Soaked the screws in releasing oil but of course they won't budge .

So I wrapped the calipers in aluminum foil and set about heating up them up with a butane blow lamp until they were cherry red. Well after about 10 minutes heating they don't glow in the slightest and therefore still can't be budged with the torx key .

So now it's time to have a go with the other recommendation of the cold chisel (you can see by now that I've done a bit of searching ). But before I make a mess (I'm not an engineer) I would be grateful if you folks could give me some tips of how I should set about them with a chisel. Surely I don't want to chisel the heads right off?

TIA

LouZ

Steve

I tried your method of heating also to no avail. Butane, propane, even MAPP were not hot enough. The heat just got absorbed by the surrounding metal. I finally ended up heating the screw with an Acetylene torch until it was cherry red. I then removed the flame, waited about 30 seconds, then hit it again with the torch till it was cherry red again (to the point where it looked like the screw would melt). Took off the heat, and got the Torx bit on it. It then broke free with little effort, to the point where I could remove it with my fingers.

The trick is that the tip of the screw has Loctite and it must be heated above 500 F (minimum), while not transferring the heat to the caliper. By applying the heat, removing the flame, then reheating, I believe that it allows the heat to penetrate to the tip of the screw, thus releasing the bond.

Good luck, new spring plates worked wonders!

Ag02M5

Just did this. Lots of cursing.

Finally dremmel-ed the head off. Hit it with some acetylene and then channel locks to turn the stub.

Took forever but finally off. Whew. Good luck.

pete000

I attempted to remove mine and just gave up. I can't believe how tight that lock tight makes them !

The only other thing as tight is the rear caliper mounting bolts and the lower rear shock bolts !

boxsey911

So I guess you live with it Pete and file the pads down? I've already done that with the last set of pads but decided with the new (used) calipers that I want to get rid of that issue before I fit them to the car. I've already had calipers off the car so know it's a tough job and have the modified tools to do them again .

I'm sure Louz and AG are right that the butane torch is too cold. The heat was definitely conducting to the caliper but I don't have access to acetylene to try instead.

My current thoughts are to dremmel a small wedge tin the screw head and then work them loose with a cold chisel. I'm aiming to give this a go at the weekend .

Sten

Steve,

Here's my method:-

MIG weld a nut on to the top of the screw. The localised heat from the welding melts the Loctite, and you can get a decent sized socket on to wind them out. Replace with stainless button head Allen screws (4mm IIRC). If you've got the calipers off and are still stuck, take them along to John Holland at Unit 11 in Warrington, he does this all the time.

boxsey911

Thanks Barry, taking the calipers to an expert with all the gear is a good idea if I find I can't make progress myself. That will be easy to do in this case because, a] the orginal fully functioning 2 pots are still on my car so using it is not affected, b] these are 4 pots of a 928 S4 which I've just purchased to do up to replace the 2 pots and c] John is just down the road .

boxsey911

For anyone following this thread, here's another thread with information about removing the torx screws (includind the cold chisel option):

https://rennlist.com/forums/showthre...ghlight=chisel

Pesty

I had to chissel/Center punch mine off. Just using patience a vice and a big hammer. Took me ages!

Tried heateing them but could not get enough heat into them with what I had(hand held blow torch)

so just battered them into submission. They were too corroded to get a torx in them anyway.

Oracle

Could someone please post a picture or two about this??
I just bought new (used) calipers and I'm interested to know if I have to do any of this...

What's wrong and what's the condition besides rust? Why do I want to do this?
Where can I read more about this spring plates, torx, etc.

Thanks..

boxsey911

Some good pictures and information about caliper corrosion in this thread:

https://rennlist.com/forums/showthre...=spring+plates

The reason you want to do it is that the corrosion behind the plates means they get pushed outwards and new pads can't be fitted without filing down the edges of the backing plates of the new pads. I'll post some pics of mine to show the corrosion behind the plates once I finally get them off.

warmfuzzies

I would do this as a matter of course, how do you know what is behind the plates etc, better to start from a known point iMHO......thats what I did, means you won't have to play around for a few years then, and nothing like a good piece of mind to boot.

Takes a couple of hours per caliper to strip, replace seals and paint.

Kevin.


Owner of bright yellow calipers......

boxsey911

Success!

It probably took the best part of an hour to get the first screw out . But once I'd worked out the best places on the screwhead to dremel the slots for the chisel, it got easier and easier. The screws broke free with a couple of firm blows with the hammer and chisel and then it was a simple case of keeping turning the caliper over, so that I could work the screws free using downward taps. Once the scew had been tapped round through 360, the torx key could be used to unscrew it. The second caliper took less than 30 minutes to get the 4 screws and plates out.

Here's a few pics as promised:

Tools used (hammer, 10 mm cold chisel, No 25 torx key, torch and dremmel with tungsten carbide cutting bit) and the removed plates and mangled screws.



Close of caliper after removing the plates which shows the corrosion behind them:



Caliper after cleaning the corrosion away with a tapered dremmel polishing stone. I'll clean up the calipers and put some paint on the bare metal before putting in the new plates and screws.

LouZ

Congrats! Looked like mine with all of that corrosion!