1958 G11 - Front Brake Judder

starfield181 · Post by **starfield181** » Fri Sep 14, 2012 10:18 pm

AS a change from wet sumping, can I seek some advice about front end judder which I experienced whilst doing a road test today. Anything above very mild use of the front brake produces the judder and the harder you pull the lever the worse it seems to be.

I have checked the steering head bearings and can detect no play. Similarly there is no detectable play in the wheel bearings (which were replaced during a recent rebuild) nor in either fork leg.

The only other thing I can think of is ovality in the brake drum - assuming this can cause judder? The front wheel has been rebuilt with s/s spokes and new rim if that is significant. Have I overlooked any other possible cause.

Thanks

Peter

Stuoyb · Post by **Stuoyb** » Fri Sep 14, 2012 10:58 pm

When you have a wheel rebuilt the tension on the hub & drum changes resulting in judder.
After having the wheel rebuilt you should always have the drum skimmmed.

Rob Harknett · Post by **Rob Harknett** » Fri Sep 14, 2012 11:11 pm

I had this on a 55 G3LS brought only 9 months old. All I did was what an old boy told me to do, I was only 16 at the time. he said brake shoes are picking up, bevel off the leading edge of the brake linings.

Duncan · Post by **Duncan** » Fri Sep 14, 2012 11:12 pm

Peter, start with the low cost option first, there may be dust in the hub or the leading edge of the shoes may not have a chamfer. Dismantle check and clean then reassemble and centralise the brakes.

wilko · Post by **wilko** » Sat Sep 15, 2012 12:41 am

Had the same problem on my single sided brake. Luckily the drum is screwed on, so i took it off and had it machined and now perfect. It only had about 5 thou runout so it doesn't take much.

paul knapp · Post by **paul knapp** » Sat Sep 15, 2012 9:44 am

Worn slider bushes will aggravate the situation.

iandusud · Post by **iandusud** » Sat Sep 15, 2012 10:55 am

If the drum has been pulled out of round by the spokes when the wheel was rebuilt it can be rectified in the same way. If you can set your wheel up in a jig with a dial guage on the inside of the drum you'll be able to see where the drum is out of true and adjust the spokes accordingly. However I would recommend that you slacken off all of the spokes a bit first, get the drum and rim round and then work on getting the tension up. If your drum was true before the rebuild and is out of true now I would suggest that whoever rebuilt it didn't do a good job of evenly tensioning the spokes. I have built and rebuilt many wheels, including the full width hub AMC variety and these hubs are very solid and don't pull out of round easily, unlike some. The problem is that it is perfectly possible to tension a wheel so that the rim is perfectly true and have very uneven tension on the spokes. Good luck in sorting it out.

Ian

Tolly · Post by **Tolly** » Sat Sep 15, 2012 9:45 pm

I had the same problem with mine when I first bought it, it had been standing for 12 years (with a flat Tyre). It was the drum out of true so I had it skimmed, perfect ever since.

starfield181 · Post by **starfield181** » Sun Sep 16, 2012 4:50 pm

quote:
When you have a wheel rebuilt the tension on the hub & drum changes resulting in judder.
After having the wheel rebuilt you should always have the drum skimmmed.

I totally agree, unfortunately the wheel had already been rebuilt when I bought the bike. Normally I re-build my own wheels for that very reason.
However, as yet I don't know for sure if uneven tension is the cause.

starfield181 · Post by **starfield181** » Sun Sep 16, 2012 4:52 pm

quote:
Peter, start with the low cost option first, there may be dust in the hub or the leading edge of the shoes may not have a chamfer. Dismantle check and clean then reassemble and centralise the brakes.

My thoughts as well. The bike had been largely unused for 12 months or more and it does squeak a bit so may well have a good dose of rust on the drum which won't help. However, while its out I will be able to check for ovailty.Edited by - starfield181 on 16 Sep 2012 3:53:56 PM