172 Cup Brake Question

[Eddie.]

I know this has been covered a few times, but I'm trying to get some answers to more than just the first question.

So, I've bought this cup, and while I was under it yesterday, I noticed that the brake bias lever, was zip tied all the way up. My understanding is that there should be a spring there (instead of the arm found on a non cup 172/182), but the spring fails so a zip tie is a common "fix"?

With that in mind, my NSR caliper is sticking on, to the point you can barely turn the wheel with the handbrake off, could this be related to my lever being zip tied all the way up?

Thanks in advance.

 

[GCC]

Is the other side free rolling?? If not, possibly, if so, no... In short

 

[Eddie.]

Yeah the drivers side is fine.

Okay, so the caliper is probably the culprit.

Is a zip tied lever okay? I'd rather it just be working properly, instead of having a bodge?

 

[masekwm]

Probably been zip tied to get through an MOT where the tester didn't realise it should have poor rear effort.

 

[tomsteer]

The cups valve didn't have the link found on the standard 172 and 182. The cable ties are as @masekwm says generally used to get a CUP through an MOT as when the arm is held up maximum braking effort is given.

If you cut the cable ties you'll have a "as it left the factory" set up but be warned come MOT time the testers may fail it on "little to no effort", even after showing them the VOSA document, trying to explain it to them etc etc.

As for the caliper sticking, that's not down to the cable ties. Could either be a seized caliper, some sort of blockage in the system (including a failed bias valve) or something else. You could crack the bleed nipple and see if you can then spin the wheel, would show if pressure was somehow being held in the caliper. Most likely dust boot is damaged when someone has over enthusiastically wound the piston in following a pad change and this has allowed debris and moisture in, causing the piston to seize.

Try winding the piston in, should be relatively free moving, if it doesn't budge you'll easily pick up a replacement for about £20!

 

[McGherkin]

If you cut the cable ties you'll have a "as it left the factory" set up but be warned come MOT time the testers may fail it on "little to no effort", even after showing them the VOSA document, trying to explain it to them etc etc.

Better to have difficulty at the MOT than going to brake in an emergency, locking the rear wheels, and pirouetting into whatever it was you were trying to avoid.

 

[tomsteer]

@McDriftin I completely agree, I've only ever done it just prior to taking it for an MOT then cut them off after. I think there are a few guys on here who run like this all the time though, personally I'd leave it as per factory spec, its just difficult to get an MOT with the factory spec!

 

[masekwm]

I've never had an issue, first year time I took it in the tester suggested there was an issue but once he read the VOSA note he was happy and the following two years it's sailed through.

 

[Eddie.]

Fantastic, thanks for the info chaps.