Brake judder above 50mph

[winger300]

I'm getting some brake judder when braking at higher speeds, it judders quite badly from 60mph-50mph but below 50mph it is very smooth.

I replaced the front tyres, balanced, tracking was done.. I've replaced all the bushes for poly, new front drums, new front cylinders but kept the old brake shoes (plenty material left).

It's odd that they only judder at higher speeds, could this be caused by the old shoes?

What else is there to check?

[MoggyTech]

This can be caused by a shoe 'snatching' which sometimes only happens at higher speeds. First things first.

1: Jack up front end and check wheel bearings for any play

2: Remove Drums and use some 80 grit glass paper to deglaze the drums. And the same paper to clean the old shoes, and make sure each show has a trailing edge sanded into the lining. (Or just fit new linings.)
Have drums checked for ovality, as that is a common cause of this condition.

3: Check all brake return springs are in correct location and not broken/loose or worn out

4: Swap front and back wheels over, just incase it is a balance issue.

[winger300]

I'm using new drums, I've sanded the inside of the drum and shoes, but you may be correct about them snatching.

No play in the hub bearings

I'll try the wheel swap, but I think they are fine since the car feels very smooth at high speed, only judders while braking.

[MoggyTech]

I'm using new drums, .

In that case, check them for ovality. Some of these 'New' parts seem to be a little lacking in the quality department.

Not really a great idea to use old shoes with new drums. The shoes profile will take a while to bed into the new drums.

FWIW I get this for a few hundred miles after replacing discs and pads on the traveller, but it always clears up on it's own

[DanRodd]

have you filed a chamfer onto the front and rear edged of the shoes?

[winger300]

That's one thing i haven't done, I'll try tomorrow and post the result.

[DanRodd]

just a thought,a lot of old manuals advise this as it stops the shoes from snatching,ive got all new brakes on mine but havent done any motorway yet but will find out tomorrow on the way to the Midland rally if i have the same probs!

[winger300]

I haven't done anything with the shoes, but its actually getting better the more I use it, so I'm sure the problem is as you describe, and the edges are being worn down.

Thanks again for the advice.

[DanRodd]

good good,after about 100 miles they will be so much better,mine certainly were,and i really dont know what people keep moaning about,ive got a bog standard Minor set up with no servo,and the brakes are brilliant!just remember to take the drums off and clean out the dust,and readjust them after a few hundred miles.

[Orkney]

i really dont know what people keep moaning about

couldnt agree more !

the shaving a chamfer on teh leading edges is worth doing - could just be that they need slight bedding in but also 'centralising' (if there be such a word) in that they can slide left to right on the snails a bit until set in the right place.
Think i read somewhere a few emergency stops will help - but then you dont want to overheat or gum up new shoes.

[bmcecosse]

These brakes can be fine with good old shoes - but some of the replacement shoes sold now are hopeless - useless for stopping, fade almost immediately and seem to go hard and craze all over the surface. If the old shoes are working - don't discard them lightly!

[DanRodd]

the whole system needed replacing on mine when i brought it back to the road after 5 yrs idle,the old shoes had glazed over,and it wasnt untill i took it for its mot i realised how bad they were,i had fited new on the front but not the rear,and it failed on the rear brakes,there was almost ZERO movement on the brake test gauges!After fitting new drums and shoes they were excellent.Possibly the worst job ive had to do on it was changing the Handbrake cables!why did they have to put the mounting bolt right in the corner of the footwell/tunnel!so awkward and typically siezed.