Bicycle Mechanics - Shimano 600 dual-pivot brake calipers: need spring replacement?

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reducedfatoreo
10-18-11, 12:29 PM
I just scored some pretty good condition Shimano 600 brake calipers (BR-6403), but the return springs seem to be a bit worn out. Anyone know where I can find some replacement springs that I can put on when I clean and rebuild these brakes? I've been failing at Googling them so far...

bikeman715
10-18-11, 12:34 PM
Have you try contracting Shimano for the parts ? ,with most Shimano stuff there no replacement parts , once it fail you just replace the unit.
FastJake
10-18-11, 12:38 PM
What exactly is wrong with them? I'd clean them up, mount them and see if they work before looking for replacement parts.

bradtx
10-18-11, 02:05 PM
reducedfatoreo, Actually the springs on the Shimano dual pivots aren't that stiff. Unless one is noticeably weaker than the other, I wouldn't worry about it.

Brad
Drew Eckhardt
10-18-11, 02:07 PM
I just scored some pretty good condition Shimano 600 brake calipers (BR-6403), but the return springs seem to be a bit worn out. Anyone know where I can find some replacement springs that I can put on when I clean and rebuild these brakes? I've been failing at Googling them so far...

Return springs break but otherwise don't wear out.

If the brakes return without cable tension don't worry about it. Some Shimano brake levers have internal return springs; maybe they were built softer than other brakes because of that.

If that's not the case and the return spring isn't cracked you have some sort of friction issue. Maybe one of the lock nuts is loose and the pivot bolt tightened. Maybe the pivots/washers/plastic spring clip that rotate and slide against each other are dirty. Take them apart, clean, grease, and put them back together.
reducedfatoreo
10-18-11, 03:42 PM
Return springs break but otherwise don't wear out.

If the brakes return without cable tension don't worry about it.

Good to know that unless they're broken I shouldn't worry. Brad, I was indeed comparing them to other caliper brakes that have stiffer springs, hence my query as to whether I need to replace the springs or not. Thanks for the info!


Take them apart, clean, grease, and put them back together.

I'll be doing just that and will report back. Thanks for the help, all!
FastJake
10-18-11, 03:53 PM
I was indeed comparing them to other caliper brakes that have stiffer springs, hence my query as to whether I need to replace the springs or not.


The weak springs are what make the brakes feel so good, part of the SLR (Shimano Linear Response) system. They don't require much hand effort, and therefore are much easier to modulate. And the fact that they're just really well made brakes.