oval drums - not?

[davidjoyner]

Hi all you foondies can you help? I have Mr Speets front TLS brakes with new shadow drums. Done about 10 K miles on them. Brakes have been v.good. I stacked the bike into a curb edge but it was all repaired fine apart from bits falling off afterwards. Recently the f/ brakes felt as if they were starting to go oval. Had a fiddle about last night and while checking the headrace bearings I noticed the front axle was loose! good grief just been up the bypass at a ton! Tightened it up while holding the front brake on to centralise the plates. Now there is a terrible oval feeling - the lever actually pumps in your hand when applied.
Took the wheel out. Rigged up a dial gauge on the axle and reading off the inside of the drum about halfway along it - nipped up any play on the bearings with some lashed up spacers etc.
As I rotate gauge:- set 0 at lowest point and it reads 15 thou at the highest point 180 deg away.
Both drums read exactly the same and the high point is at the same location in relation to the rim.
Are the drums oval?
Can they move off centre somehow?
What the heck am I doing wong?
Cheers Dave

 

[ossie]

can you put the gauge on the ally bit of the hub that the drums locate on to see if that is true to the bearings.
strange if it was ok before your kerb clip.
OSSIE

 

[roy the mechanic]

Try mark the wheel rim at the point of maximum run-out, slacken wheel spindle, rotate wheel 180 degrees, apply brake+tighten spindle, you now have 2 chances, none + a dogs. Be lucky, Roy.

 

[clevtrev]

Try mark the wheel rim at the point of maximum run-out, slacken wheel spindle, rotate wheel 180 degrees, apply brake+tighten spindle, you now have 2 chances, none + a dogs. Be lucky, Roy.

What`s all this `apply brake and tighten spindle` ?

 

[roy the mechanic]

As the enquirer has non standard brakes, they may require a different approach to rectify the problem, that the average vin owner is unable to understand. I learned this trick from Mr Warr of London.

 

[david bowen]

when you fitted new drums did you check they run out on the front edge of the drums if there was a burr on the back of the drums this can cause this problem

 

[clevtrev]

As the enquirer has non standard brakes, they may require a different approach to rectify the problem, that the average vin owner is unable to understand. I learned this trick from Mr Warr of London.

So tell me what this `trick` achieves, when you have a 1/2" spindle going through a 1/2" hole, and a 3/4" shaft going through a 3/4" hole.

 

[davidjoyner]

Thanks Ossie I'll report back

 

[davidjoyner]

Mnr. Speet did it for me and it was perfect. Must be something to do with shunt - I think my memory has been shunted as well! I cant rememnber when i first noticed it!

 

[roy the mechanic]

The trick centralises the shoes/backplate with the drum, it certainly works on H-D's, as mentioned this bike has aftermarket brakes so alternative "fixes" MUST be worth a shot.