Thread: Drum brakes - binding in one spot

G'day Gav,

Have you swapped the brake shoes? Also check the shoes for alignment and size in drum.

Just a thought.

Chris

Thanks - no, haven't swapped the shoes - bit of a ***** to do the bottom spring, but yeah, will give that a go in the morning. Will help narrow it down. And no - haven't checked the drums in the shoes - assumed (rightly or wrongly) that these would be matched as it was a complete set - good thought.

Were the drums & shoes checked for matching ovality (???) with a guage?

Originally Posted by 4bee

Were the drums & shoes checked for matching ovality (???) with a guage?

No. Normally when I do brakes on a series Land Rover I’d bed the shoes into the drums. Didn’t do that here but maybe I should - given that they were a full ‘bolt on’ set - and being Alko, not the Chinese copies, thought I’d be safe from that but apparently not.

I’m still failing to understand why it is binding though - when I radius shoes for a vehicle it’s usually to do with braking efficiency and pedal travel, etc rather than actually making them not bind. While I’ll try the suggestions tomorrow I’m still no wiser to why a shoe will grab like this just in one spot when I would have thought this would have to do with the run out of the drum, which I’ve eliminated.

Gav, one would almost think that the plate that was welded may have warped with weld heat maybe? Seems so odd that swapping the left that was the problem to the right and is now free would cancel out drum or shoes to me anyway and have me checking the mounting hardware and plate.

Originally Posted by RobMichelle

Gav, one would almost think that the plate that was welded may have warped with weld heat maybe? Seems so odd that swapping the left that was the problem to the right and is now free would cancel out drum or shoes to me anyway and have me checking the mounting hardware and plate.

Yeah, was my first thought but I’ve redone it and have the same issue. The alignment on ‘factory fitted’ axles doesn’t appear to be any better than what I’ve done - even checked with a local fabrication shop that specialise in trailer fab and they’ve said they only need to be close. They had about 20 axle sets on the ground and my welding to be honest is probably better than what they buy mass produced. My measurements and rework today shows I’m pretty much spot on - as close as I am on the side that runs fine. I’m comfortable with fabrication, welding and the stresses these cause so I back myself to have this part correct - the plates are thick, we’re laser cut so an exact fit over the axles - just needed to be square and welded on. Not saying you’re wrong mind you, but I’m struggling to see where I went wrong here today - when I first did then while on the van, yes but on the bench with the gear I have not so much but something sure is, so not counting this out - Thanks. 👍

Originally Posted by Homestar

I’m still failing to understand why it is binding though - when I radius shoes for a vehicle it’s usually to do with braking efficiency and pedal travel, etc rather than actually making them not bind. While I’ll try the suggestions tomorrow I’m still no wiser to why a shoe will grab like this just in one spot when I would have thought this would have to do with the run out of the drum, which I’ve eliminated.

Could be anything at the end of the day. I would have thought though, that an out of round set of shoes &/or drum would give you a high spot at the outside of the radius, hence a binding/heating effect as the part rotates.

Interesting.