…a sudden vibration in the car which feels like a puncture, but which, after 3 miles disappears completely?

I’ve checked the tyre pressures and they’re all fine, there’s nothing visible in the tyres…I’m at a loss.

Few things to check:

Wheel bolts
Driveshaft CV boots
Dampers (could have been a combination of tired damper and poor road for 3 miles)
Wheel weights

Well, It’s a stick piston on the front left calliper. Fine when cool and cool outside, but gradually gets worse as heat builds up.

New callipers, disc, pads, sensors, and hoses incoming…

You’re not allowed to give the correct answer so fast! I’m going to ignore your last post.

It’s that child you just ran over, hanging onto the bumper.

Sex toy going off in the boot?

Sex toy going on in the boot?

Surely you can just get the caliper rebuilt? In fact, it may just need freeing up.
I’ve had a rear caliper stick so sucessfully that the rear pads caught fire. We freed it up with the aid of a g clamp and it was fine for several years.
Good idea to replace the pads, but I doubt the sensors, hoses or the caliper will be toasted.

Wait to see if it happens again. On Monday I had a similar experience and thought I’d gotten a puncture. Pulled over to find a big lump of melted tarmac stuck to the tread complete with road chippings. Took a while for it to fling off then it was back to normal.

I’ve had a look at the hoses on the front (and the rear) and they’re badly corroded and will likely shear when I try to undo them. Sensors should be replaced with the pads should they not?

The discs and pads were budgeted for later this year anyway.

As for freeing the piston – you’re recommending removing the calliper, g-clamping the free piston and pumping the pedal to see if it move the piston?

Then what? Dot fluid the the piston and push it back?

dodgy bit of road? you’d be surprised 😉

I’ll give it a shot, but will remove the calliper this evening and see what it looks like.

“Surely you can just get the caliper rebuilt? In fact, it may just need freeing up.
I’ve had a rear caliper stick so sucessfully that the rear pads caught fire. We freed it up with the aid of a g clamp and it was fine for several years.”

the first part of your reply was promising – it went downhill fast from there.

generally a reason its stuck in the first place. i mean you can bodge it like you did but i like my cars to work properly not just be barely legal.

i rebuilt a set of brakes that were sticking and yes they worked but post rebuild they were totally different brakes – even the mot man commented on how it had “good brakes” for the type of car….

have watched folk proclaim they “unstuck” vw rear brakes before only to find their new pads and disks were banjo’d in short order as it stuck on again.

daffys doing the right thing.

Well, I removed the calliper last night, placed DOT fluid behind the dust seal and left it to soak, freed the piston with a persuader and then used a g-clamp to force it back into the calliper. After a few in/out sessions with the g-clamp, the piston freed up sufficiently to use a ratchet clamp. More soaking and movement allowed the piston to be pushed back by hand.

I’ve had the disk off and it’s not warped, the pads are okay, though now more worn on one side than the other, but still with 6-8mm of meat on them.

Pads, and runners anti-seized and the slide pins PTFEed. reassembled and tested this morning and all’s well.

Let’s see if it lasts…

Had a similar thing on my car. Freed up the callipers/pistons as described above and was fine for a few weeks, then went down some steep hills and it started sticking again due to heat building up and expansion. Whole new calliper fitted and new fluid in the end, better to be safe than sorry!

The wheel got very hot when this was going on, could barely touch it, I’m sure this could lead to a tyre blowout if it all gets too hot?