Porsche Brake Caliper Pins

I am servicing the brakes on my 924s and for those that care the brakes are the type where you remove a string clip that goes through the two pins. You then pull two pins, remove a rattle plate and then you can slide the pucks out. This makes for very fast pad changes at the track. HOWEVER for normal street use up here where we have snow the pins will rust / corrode and weld themselves to the caliper bracket making removal possible but it results in the destruction of the pin. You end up crushing the hole in the pin that the clip goes through.

I can get a new set for $65 plus shipping (probably end up being closer to $80). This includes four pins two spring clips and two rattle clips enough to do one axle. My thinking is that this is nuts!!!! So I have been looking at this and broke out my dial calipers and have come to the conclusion that all I need is two feet of 6mm stainless steel rod. More than enough to make 4 pins.

My question is should I be looking for any particular type of stainless. I want the one that is most resistant to rusting but I know from past experience that as you get harder they will tend to rust a little. Doing some searching on the web I have found 6mm rod in 303, 316 and 440C. I am assuming that I should go with the 303.

No one? Dang some seriously loud crickets on this one.

I went ahead and ordered a meter of 6mm 303 highly polished stainless steel rod with a tolerance of .00001mm.

Delivered to my door overnight mail for less than $20!!! Enough to make several setts. I am going to make up several setts both front and rears. I wonder if anyone else out there would want some?

I will post up PIX when I make them up and install them. See what you all think.

My Pops is a metallurgist and the most resilient stainless to rust will have high percentage of chrome and nickel and low carbon content. I guess my Pops told me they will do a surface treatment of some stainless that etches out the iron atoms in the stainless, which is the point of corrosion. I don't know what the process is called. There is a an alloy called inconel which is a very high nickel alloy and I'm pretty damn sure it will never rust.

303 stainless is terrible in saltwater, so if your roads are salted in the winter, the pins will go away pretty quickly. The good news is that 303 is very easy to machine. 440C is so-so for corrosion resistance.

316 SS is much, much better for corrosion resistance. 17-4 PH is even better, but significantly more expensive and a pain in the butt to machine. Nitronic 60 is perhaps the ultimate in corrosion resistance, but it is a real screaming bitch to work with.

You can buy short lengths of any of these at mcmaster.com.

My concern with this is the heat transfer the pins would get. I would think the heat might affect the corrosion resistance of stainless. But then I'm not a metalurgist and since I probably misspelled it that proves I'm not.

benzbaron wrote: There is a an alloy called inconel which is a very high nickel alloy and I'm pretty damn sure it will never rust.

Have not checked the pricing but I would assume that a 6mm rod in that length of would be ungodly expensive.

I had to make some nuts out of inconel once and I must have gone through more carbide taps than I made nuts. So have fun working with that stuff, if you can find it :).

OK the process of taking the iron atom off the surface is called passivizing. My pops said a ostenetic 300-series stainless should be good. Another idea is see what the marine guys use. Good luck.

benzbaron wrote: OK the process of taking the iron atom off the surface is called passivizing. My pops said an austenitic 300-series stainless should be good. Another idea is see what the marine guys use. Good luck.

fixed that for ya.

Well here is what I have for the moment we will see how these hold up. This is after a couple of days driving around and there is no rust visible so far. I also learned that Cobalt drills are NOT the ticket for drilling stainless. Good old cheap steel bits were much better.

Whoa on the inconel. It has some really cool properties regarding heat tolerance, but it's way too expensive as a result for something this inane. 316SS sounds like a pretty good bet. Keep in mind that stainless rusts too, just not very quickly. If you want to spend, get some mild steel versions coated through Praxair, their tungsten coating rocks the house. A regular old chrome coating (not the shiny bumper chrome) will work very well for preventing corrosion as well.

Ti wouldn't corrode....and it's not as expensive in that quantity as people might think.

The reason I went with 303 was that it maintains its properties up to 1,500 deg. I probably should have gone with the 304 as it also goes to 1,500 and has better resistance to corrosion than the 303 but machinability gets harder and since I am doing this with a basic drill press and a clamp the 303 seemed the better choice. 316 only can Handel up to 800 deg.

I think I am going to go get some 6mm 304 and make up another set and swap out one set in the car. I will then drive it through the winter (yes I drive the car though the winter) and see if there is an appreciable difference.

did you cotter pin the inside ends as well, or mushroom it? just curious..

having the same brake set up on both of my 924's, and several others ive owned, i've never really had an issue with them rusting over, or at least not extensive enough to worry about. I ll have to check mine again, not something ive really thought of before...