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front hub knock

Posted: Fri Aug 13, 2010 2:58 pm
by Suede Ed
Got a knocking sound when applying the front brake, on inspection i've noticed the peg on the fork link seems loose in the slot on the hub back plate. With the brake pulled on i can move the hub forwards and back a couple of mill making the knocking sound. (Although i'm sure the answer is 'new hub' :( ) Does this matter? will it pass an MOT? Could I shim it out some how?.

Cheers

Re: front hub knock

Posted: Fri Aug 13, 2010 3:16 pm
by Supereibar
Suede Ed wrote:Got a knocking sound when applying the front brake, on inspection i've noticed the peg on the fork link seems loose in the slot on the hub back plate. With the brake pulled on i can move the hub forwards and back a couple of mill making the knocking sound. (Although i'm sure the answer is 'new hub' :( ) Does this matter? will it pass an MOT? Could I shim it out some how?.

Cheers
Hello mate, thats a very common problem. I've had that happened with several hubs. It is mostly due to vibration hitting up and down, undoing the left or right nut then creating play in there. This causes a groove on the "U" shaped female side of the backplate.

There is a bodge you can do just to pass the MOT, which is "adding". Meaning, you need to either put a piece of cardboard or something in the U to create a good "cushin". This will not last very long but you should be fine just to pass the test. After that, yes I am afraid you need a new backplate.. Unless someone has a better suggetion :?

Re: front hub knock

Posted: Fri Aug 13, 2010 6:20 pm
by Suede Ed
thanks Super, i'll try a thin piece of nylon glued in for the MOT,then new back plate £15 from SR.

Re: front hub knock

Posted: Fri Aug 13, 2010 8:27 pm
by leehuggy72
Evening,

sorry to highjack thread was just wondering...

my hydraulic inboard disc brake has an annoying knock, when i pull the brake lever it works fine no problems nice and quick.. its just when i hold the lever in and rock the scoot back and forth i get a little knock.. like it has slop or something..

firstly is this normal in inboard brakes and am i being a bit critical. :?

secondly if not, does anyone know what could be the problem.. :roll:

Re: front hub knock

Posted: Tue Aug 17, 2010 5:36 pm
by shocky
Suede Ed wrote:Got a knocking sound when applying the front brake, on inspection i've noticed the peg on the fork link seems loose in the slot on the hub back plate. With the brake pulled on i can move the hub forwards and back a couple of mill making the knocking sound. (Although i'm sure the answer is 'new hub' :( ) Does this matter? will it pass an MOT? Could I shim it out some how?.

Cheers
its a safety critical area so new back plate ......... but a bodge could be a steel food or drink can cut into a thin strip and made into a circle and fitted over the peg so its a tight fit i have used a special shim material (various thickness of thin metel going up in 0.1mm increments ) when shimming hydrilkic shafts some have been perfect even after 2 yrs hard use maybe a TEMP solution

Re: front hub knock

Posted: Fri Aug 20, 2010 3:50 pm
by dirtyhandslopez
Suede Ed wrote:Got a knocking sound when applying the front brake, on inspection i've noticed the peg on the fork link seems loose in the slot on the hub back plate. With the brake pulled on i can move the hub forwards and back a couple of mill making the knocking sound. (Although i'm sure the answer is 'new hub' :( ) Does this matter? will it pass an MOT? Could I shim it out some how?.

Cheers
Beer can shim, some beer cans are thicker than others ;) I have had a shim in my front hub slot for years now. As long as you can get a perfect tight fit with the shim, nothing can really go bad. Unless it falls out when changing a flat and you don't notice :ninja:
Or get the shim stock that Shocky suggested.

Re: front hub knock

Posted: Sun Aug 22, 2010 9:40 pm
by rakki
leehuggy:
Is the anti-rattle circlip installed?