[Brakes] Brakes Locking after stopping

[GarryK]

Hi.
2014 van
After stopping, occasionally the brakes have locked on, first time a week ago, happened 3 times. vehicle would not move at all, first time seemed to clear, after pumping brake. 2nd time cleared quickly, 3rd time took longer (typical in busy town traffic). Been OK for last few days.
Garage no ideas.
Any thoughts please?
TIA

[Gryffindor]

I'm no mechanic at all but it sounds like the pads are not letting go of the discs after braking, so maybe some sort of spring failure, but if it affects all the brakes together then more likely something to do with the brake servo system not 'letting go'?

[cancunia]

Handbrake cable sticking?

[GraemeT]

If it's all four brakes rather than an individual one (are they all equally hot to the touch/spit/glow in the dark) then it may be that hydraulic pressure in the system is not backing off when the pedal is released - master cylinder, servo or sticking pedal. Not sure about the mechanical connections from pedal to master cylinder/servo on these but may be worth a gander to see if anything looks rusty/sticky etc.

If it's just one wheel then it could be the caliper (disc), return spring (drums) or the flexi hose internals are collapsed/pinched so they act as a one way valve but sounds like it's more than one if the vehicle is stuck solid.

[Trevor]

Silly question, is this when you have stopped on a hill? It's not just the 'hill start' activating is it?

[jj9]

Silly question, is this when you have stopped on a hill? It's not just the 'hill start' activating is it?

That's exactly the lines I was thinking along.

Does the van have "Hill Assist" or whatever they call it?

.

[GarryK]

Thanks, wouldn't drive, didn't force it, so not hot, did release eventually, didn't think I had put the handbrake on on first occasion, but now wondering...
I did wonder about the master cylinder or servo, but garage expressed doubts.

[GarryK]

No hill start fitted

[polar]

If the garage have no idea you need to find a new garage - really!

There are so many possibilities so of the diagnostic would be asking you specific questions, Then it would be a stripp down of the brakes mechanical components, from there you may be going down the hydraulic route.

2014 is not that old but hydraulic hoses can collapse holding pressure, sticking master cylinder, why do they have doubts!?

There are so many possibilities but someone needs to start looking who knows what he or she his doing.

[cancunia]

A bit of a faff and will need some care to try, but if you have time & it's in a safe place next time it sticks, you can jack a front wheel up and see if the wheel will spin when in gear & engine running with the handbrake on. If it still sticks, try the other wheel. That will tell you if it's front or back. No need to rev, just in gear & ease the clutch out gently and see if the engine tone changes.
A safer way would be to take it to a garage with a rolling road, and like Polar says, probably a different one to the one you've tried.