rear brake pad replacement and pedal 'wobble'

[Guest thomas]

Hi folks

I've been 'stalking' this forum for a couple of months but now this is my first post, a bit cheeky really as its a request for advice, but here goes….

 

I am the proud owner of a new nc750s, as of January this year. Bearing in mind its 'deficiencies' ( to me, cheap suspension, crude brakes and downright bizzare seat) I am really pleased with it, such a 'benign' friendly, easy bike, I call it my 'little donkey', (and my 'old' bike is a 1050 Triumph….)

 

The brakes, however, I never really got on with. Wooden, is the word that springs to my mind. Maybe I'm just old school. Anyhow, after 1200 miles, I decided to try different pads, some EBC organic ones, which I duly fitted last week. Aha, much better for me, I thought, more 'feel' and 'progressive' than Honda's sintered 'wooden blocks'!

However, since fitting the rears I have noticed a curious 'wobble' feel through the rear brake pedal on light braking that I didn't notice before. Almost as if the abs is kicking in slightly (it isn't). I don't notice it when I give the pedal some welly. I'm pretty sure I put the pads in properly, after all, they only fit in one way don't they?! I'm guessing the new pads must be subtly different, perhaps slightly too large 'pin holes' or something.

……So… my question is, should this be something I should be concerned about, or will they 'bed in'?

Thanks in advance, and thank you for running this most informative forum.

Thomas

[trisaki 2,029]

Are the floating pins greased and free moving , the pad furthest away from the piston needs to be hard up against the caliper body when pushing the pins in , otherwise it snags on the anti rattle plate , everything clean ?, worth bleeding , did both my two NCs to find quite a lot of air

[Guest robin]

Make sure the pads are correctly in the little springs at both ends, then as trisaki said.

[Guest machinman]

May be worth running a dial gauge across the disc to check for warping.

[Guest thomas]

Hi again

 

Thanks for your suggestions, now I have chucked the car out of the garage I shall have another good look and check things over, in the warm….

[CFB 4,601]

+1 for a warped disc

[RussB644 379]

Welcome to the forum Thomas Let us know how you got in with that will you, would be interested to hear how those brake pads settle in.....

[Guest thomas]

Well I had a look and like all the best engineering solutions left things alone for a few more days, and I think the 'wobble through the pedal' has settled a bit.

I have a theory…...

Firstly I checked for run out by the highly technical means of placing a metal waste bin next to the rear disc so it just 'kissed' it, then turned the wheel (bike on centre stand, obviously!) and sure enough there was one patch which rubbed a hint more, so there is indeed some run out in the disc, but I'm not convinced it is significant. My experiences of warped discs on cars (I've had plenty of 'em) is that they feed wobble back to the pedal on hard braking at speed, not the opposite as here.

Then I gave the pads a little jiggle in the caliper and they do rock a bit in there. They do seem to be correctly fitted btw. They have a thick coating of red paint on their backsides (missus). 

I reckon they might not be perfectly flat against the piston/ housing, and that it takes a few days for the paint on them to get cut into slightly to stop any rocking on first pressure. Or something.

I could take them out and try lying them on glass and testing for rocking, but as I said they seem to be feeling 'better' after about 7 days use.

I'll keep an eye on things….

Thanks for your suggestions, all.

Cheers.

Edited March 13, 2016 by thomas

[michael 324]

This may be a complete flyer, and I fully expect to be advised so, yet I have found in some circumstances a careful re-torquing of the disc mounting bolts can alleviate *some* run out of the disc.

 

It's merely something else to consider in amongst all the other things to look at.

 

And i do admit, it's more likely something that was disassembled then reassembled than something that wasn't touched in your maintenance procedure.

 

Oh! and welcome. fear not your first post was an inquiry. During my brief time here i've found a plethora of helpful folks

Edited March 13, 2016 by michael