Shuddering vibration from rear brakes

[TRTerry]

Why do I get a shuddering vibration from the rear upon forceful braking? Light braking seems OK. Brakes operate in a straight line.

I seem to recall that new brake shoes should have their leading edge filed down with a bevel as they can otherwise snatch, but am not sure if my recall is correct.Can anyone put me right about this?

I also understand it may be due to contamination, or ovality of the (new)drums. Is there anything else that could cause this vibration that was not present before the brakes change. If so are there any simple tests or visual inspection clues to help me determine the problem when I strip them down this weekend.

I have completely replaced all of the rear brake system. Including new drums, shoes, slaves and snails,and some pipe and handbrakes cables. I then had bleeding problems, overcome by replacing the wife with a Gunsons brake bleed system. Then servo problems necessitating a new servo as the old one had a gash in the diaphragm.

I have never fitted the small snail like stabilising springs as these have not been present for the last 20 years on the fronts or the back brakes, is this now the time to fit them?

Thanks in advance for any input.


Terry

[MarkyB]

I'd check the condition of the brackets on the rear axle that the springs locate on.
They can be a dirt trap which leads to RUST!
Also the rubber pads they sit on, and the bushes in the spring ends.

[bmcecosse]

I agree - it's very possible that now the brakes are actually working - the axle is 'tramping' - caused by worn bushes/axle mounts etc.......