Brake caliper spring failure (?)

[roubaixtuesday]

My commuter has long drop rim calipers, I *think* these

https://www.sjscycles.co.uk/brakes/front-shimano-brr451-deep-drop-caliper-brake-silver/

The rear is no longer returning, it's free to move without any spring back or resistance between the extremes of it's travel on one side (the other still springs back):

I'm guessing a spring has snapped.

Any advice? Is that likely the right diagnosis? Can you get spares for this sort of thing, or is it new caliper time?

 

[bikingdad90]

Have you taken it off and soaked it to remove all the crud and dirt and then lubricated it?
I am also assuming that the bolt isn’t over tightened as that can cause spring back issues.

 

[roubaixtuesday]

Have you taken it off and soaked it to remove all the crud and dirt and then lubricated it?
I am also assuming that the bolt isn’t over tightened as that can cause spring back issues.

Not done anything yet, but it's not remotely seized, it moves freely but without any spring back.

 

[Big John]

I'm not saying it's impossible to break one of those springs but it would be highly unlikely it's physically broken. It's more than likely become unhinged at the back.

 

[roubaixtuesday]

become unhinged at the back

Sounds like me!

Is it an easy job to disassemble and pop it back in? I've never attempted it and I suspect it might go "SPROING" and fire bits all over the garage...

 

[Big John]

I'll be amazed if you manage to break one but I suppose it could be done with enough brute force and the help of a crow bar. Usually the use of a sturdy screwdriver will re-seat the spring. First, though, I'd take a look to see if it has, in fact, become unseated.

 

[Paulus]

Firstly as @bikingdad90 says, give it a good clean up and oil the pivot points. It does look a bit mucky. Then check that the retaining bolt is not too tight, that would stop the calipers springing back.

 

[Dogtrousers]

Sounds like me!

Is it an easy job to disassemble and pop it back in? I've never attempted it and I suspect it might go "SPROING" and fire bits all over the garage...

I've disassembled, cleaned and re-assembled caliper brakes before and it wasn't a problem. However these were olde fangled Weinmann ones so who knows what booby traps they have added to modern ones.

 

[Paulus]

As an after thought, is the cable crudded up, so it's not returning properly.

 

[roubaixtuesday]

As an after thought, is the cable crudded up, so it's not returning properly.

No, everything is free

 

[roubaixtuesday]

Firstly as @bikingdad90 says, give it a good clean up and oil the pivot points. It does look a bit mucky. Then check that the retaining bolt is not too tight, that would stop the calipers springing back.

I know it looks cruddy, it's a commuter!

But to reiterate, everything is free, caliper moves with no effort, cable is free, just no return force from the spring.

 

[Paulus]

I know it looks cruddy, it's a commuter!

But to reiterate, everything is free, caliper moves with no effort, cable is free, just no return force from the spring.

Have you tried centreing the calipers?

 

[Shearwater Missile]

I think that if you unbolt the calliper from the frame you`ll see what the problem is. I would say that it is unlikely that the spring is broken but the spring does run in a rubber guide, it slides up and down. What I had once with a similar issue was that the spring needed a good clean where it slides in the guide. see the picture item 6. If that is clear then perhaps the spring is no longer being retained. Good luck.

 

[roubaixtuesday]

So...

Took the arm off the caliper and the front one for comparison. Rear one definitely different, so completely disassembled.

First, there's a nameplate and it's actually a BR-R650 caliper FWIW.

Second, what looks like a washer inside is actually a weird bearing with *tiny* balls. And yes, they do come out and roll all over the place.

Greased everything generously and put it back together again. Was better, but not quite right. Much faffing with bolt tightness later realised that using the centering adjustment made the problem much worse. Hmm. The cable run for this brake is problematic, butting up against the rack strut:

It's always worked, but obviously not ideal. Lubed the cable, which further improved things, now just about OK, but can't fine tune the centering.

So I think it was a combination of crudded caliper, cable friction, poor cable routing. I'd need to bend the rack strut to sort the route, and its alu, so I don't really fancy that.

 

[bikingdad90]

Yes can see how the rack struts are stopping the cable centering.
Might work to extend the run with an L bend from a v brake depending on where it comes from on the frame?