Binding front brake?

[RivieraBob]

On my last (short) drive out before winter hibernation I had a distinct steering wheel wobble. Pulled over to have a quick look over car and when got going was fine again. Last year when up on the ramp I noticed my o/s front wheel didn't turn very freely, suspecting it could be same again when I returned I checked and they spun freely by hand.  I've just put the car up on the ramp again (not driven since) and the front o/s wheel is stuck fast, can't even move with a breaker bar. Can the caliper piston continue to extend under residual pressure when not in use and then get stuck, or is it more likely just close contact of the pads so that they have fused to the disc. ie can it still be a sticky piston even though the wheel turned fine by hand when parked up in garage after last run?

Brake fluid is changed every 2 years and I had what I thought was a professional full brake refurb 4 years ago. I like to pretend I can do stuff on the car but I never touch the brakes as the consequences of my general uselessness frighten me in that area. So what's my best course of action to check? - if I buy a brake spreader will it be able to force the pads apart from the discs or will my first drive in the spring generally free it all off? - I'm sure that's hope vs reality!

Bob

[Ian Comerford]

Do you know if your flexi lines were changed during the refurb?  These can swell internally with age and reduce the backflow of fluid, preventing the pistons from retracting.  It’s strange that you tried forcing the pistons back and they didn’t move.  I would try a brake piston spreader with the pads removed to push the pistons back in and exercise them a few times, so remove pads, insert spreader and depress pistons fully, refit pads, press brake pedal, then repeat twice more.  I go through this exercise every winter and it has kept my calipers free and working well since I refurbed them in 2008. From experience driving a car with brakes that are starting to stick does not free them off. 

To add, every few months after a drive, or a break in a drive I go round the car and feel each wheel centre to see how warm it is, it can indicate whether a pistons is sticking.

This is the one I have, probably the best value tool I have bought https://www.machinemart.co.uk/p/disc-brake-piston-spreader-0---65mm/

 

[RivieraBob]

Thanks Ian! I don't believe the lines were changed during the refurb. As the wheel won't turn by hand I presume the pads are gripping the disc (potentially by stuck piston or corrosion) - won't this make the pads difficult to remove? Can you use the spreader to separate them from the disc ie push the piston back with the pads in situ, or is there a handy trick to get the pads apart if compressed? You can tell I've never done this before!

Bob

[Ian Comerford]

It’s not too difficult normally.  I remove the pins locating the pads in the caliper.  Next I use the pad to push the piston back in on each side, you can’t get the spreader in there at this moment.  So I use a screwdriver in the hole in the pad where the pin fitted and lever the pad against the piston.  You have to do this on each side.  You might be able to get some sort of small g clamp in there as well.  Hope this makes sense, but please come back if not clear

The other thing I check during my winter brake maintenance is the relative thickness of each pad as this can tell you whether any piston is ‘dragging’ and causing one pad to wear more than the others

[Mobydick]

If the pads have small holes on the edges, you can pull them out with a tool like this -

https://amzn.eu/d/2QLDbiU   - or research “ brake pad puller”. 
I would suggest that’s its unlikely it’s under pressure- it’s just got slightly stuck. I would be tempted to drive it forward to release them  

Alternatively, could it be a seized wheel bearing? 

 

[RivieraBob]

Thanks chaps... I feel such an amateur on this stuff but guess (from fear) just lack experience - there's only one way to get it though. I'll buy the brake spreader and pad puller and 'on y va!' If all comes apart well then guess it's potentially a soft brake line blockage or wheel bearing as suggested. It's winter and I have a lift so perfect timing really. Thanks again, such a helpful forum.

Bob

[mean in green]

Easy stuff first - the chances are that it’ll free off without much effort.

[RivieraBob]

Hopefully final question.....do you need to open the brake fluid reservoir cap when pushing the pistons back? 

[Type911]

Yes, put some rags around the top too just in case it overflows

[Ant7]

Same reason I ended up rebuilding all four on mine Bob, they got so bad that I initially thought my callipers would be scrap until I removed them and examined them, luckily I managed to clean and rebuild my originals, although not before asking if any of the chaps here had a few to spare just encase, I was thankful a few lads came back to me with some, however as stated I managed to sort out my own, but again I was thankful that the offers were there, just encase.

Good luck sorting them, and the comments on the flexy pipes is spot on, they can act as a one way valve when they swell up inside, stopping the fluid from flowing back, which in turn holds the brakes on.

Ant.

[SilverWT]

 

1 hour ago, Type911 said:

Yes, put some rags around the top too just in case it overflows

It will be peeing out the overflow pipe first (just behind the front valance by the inner wing on the right side as you look at the car from the front). So either need to put something there as well, or clamp the pipe at the reservoir end.

Mark

[RivieraBob]

Thanks again chaps for all the helpful advice!