I removed the pin which flushing my ABS brakes this weekend. I used a 1/4" drift pin and light hammer until the pin was flush with the caliper, and then a smaller drift pin perhaps 3/16 to drive the pin through the caliper.
The pin has a squeezable 'olive' on it that locks the pin into the caliper. It takes a bit of a tap to get it to move. It won't move far before it's free, but you've probably figured that out already. Use a large nail with the pointy end ground/filed flat, or a proper drift. The 'c' clip is a safety retainer. I very much doubt that the pin can fall out, but replace the clip anyway. Any engineering hardware shop should carry a similar item. If you can't get one, just use some stainless-steel lockwire to hold the pin in place. Wrap it tightly in the pin groove, and twist it tight against the pin. It will be fine until you can get a replacement external circlip (which is what the retainer clip is).
I ride an R1150GS Adventure with sidecar. IBA #39193
The e-clip is easy enough to lose. I lost mine doing a similar job a year ago and after initially thinking that my life depended on the fitting of a wafer thin circle of aluminium but then considering how difficult the pin had been to get out once the e-clip had been removed decided to throw caution to the wind and ride without it. If you decide to ride without it make sure that the retaining pin has been fully driven home from the gear change side. You can tell it has if you can put your finger nail in the e-clip retaining groove on the end of the retaining pin
For complete peace of mind though I would suggest visiting the engineering shop or using wire as suggested above. If you buy the part from BMW you have to buy a kit complete with retaining pin at a ridiculous price when all you want is the e-clip.
60% of the art of conversation is knowing when to say nothing
Thanks for all of the advice. I finally got the pin out with the help of a phillips screwdriver and expert use of a hammer.
Now I discover that to move the brake pistons back enough to get the new pads in, I apparently will have to remove the brake fluid. Tell me if I am wrong, but right now the pistons prevent me from fitting the pads.
I also had the spring clip fall out, but I think I know how it goes back in.
So golly, now I get to learn how to flush the brakes. This would almost be fun if the garage wasn't 110 degrees and I had all the time in the world. Oh well,...
If you don't have a pad-spreader, then try a set of flat-lipped vice grips in reverse. If you don't have them, then do what I do.
Grab the biggest flat-blade screw driver you have and wrap a couple of windings of tape (Masking or insulation or cloth - It's just to cover the sharp edge and provide cushioning against the pad material) around the blade end.
You have to gently 'lever' the pads back into the caliper against the push of the piston. Slow and steady will do it, unless you have run out of reservoir space. Now - This bit is critical.
If you have topped off the brake reservoir with worn pads, you are likely to run out of 'space' for the extra fluid being forced back because the new pads are thicker than the old ones. If you haven't topped off the fluid, there should be space left and the pads will be able to move (gently with force) and the fluid level will be ok. When they are spread apart, quickly get them started over the disk and 'wiggle' the caliper back into position. Do the mounts up BEFORE you try the brakes! Ensure the wheel is free and the pads 'relax'.
CHECK THE LEVEL CAREFULLY AS AN OVER-FULL RESERVOIR MAY EITHER LOCK THE BRAKES ON OR RESULT IN A LEAK.
Follow your maintenance guide for checking the fluid level on your particular bike. Draw off any excess with a syringe, or better still, do a bleed and fluid refresh whenever you replace the pads as the timing is usually good for that sort of task.
Also check that the pads are free to 'move' on the slide pin. Sometimes they stick and one pad wears many times faster than the other.
I ride an R1150GS Adventure with sidecar. IBA #39193
