Sticking front brake

[softscoop]

A couple of months ago I noticed the front wheel was warm to the touch , after just driving straight roads without any real braking. My car is 2005 with 165,000 miles so it wasn't a surprise that it's started doing it.

 

A few weeks ago I took the pads and carrier off, wire brushed off all the crud, regreased the sliders and carrier where the pads sit and put all back together.

 

That seemed to solve it at the time, but yesterday there was a burning smell when I got home, sure enough the wheel was red hot.

 

The sliders were free when I put it back together so I'm assuming the piston is siezing inside.

 

Getting quotes from garages to fit a replacement caliper as at this time of year I don't have time to do it myself.

 

One garage threw me off saying there was a high chance that it was actually the flexible hose collapsing inside, and that can cause the same symptoms.

 

Is this even likely? It's not something that I'd even considered at all.

 

Actual braking is fine. The pedal feels normal. I tried a few hard stops this morning and it stopped no problem from 60 etc.

[J.R.]

A sticking piston would cause an imbalance when braking, the vehicle would veer to the opposite side if you brake moderately with your hands off the wheel.

 

If it does not do that and if the other disc is not getting warm then the garages suggestion is plausible, you can brake correctly but the fluid pressure is being maintained on that one caliper, I would try and replicate it with the wheel jacked up when the brake drags open the bleed nipple to be 100% sure.

 

Just off to do my front brakes now, I will do the same test!

[softscoop]

That is a really good quick test.

 

I'll be giving it a try before replacing the caliper.

 

Now the next question is what hose do I need to replace it with...

[CWARD]

If you've got 13 years out of the original pipes you're doing well. It is possible the pipe is beginning to collapse and reducing flow back out of the caliper but most likely the  piston will be sticking. If you plan on keeping the car then change the piston and seals if you can do it yourself otherwise get a reconditioned one fitted and new pipes at the same time as they pretty cheap anyway, then you're only paying for the fluid bleeding the once.

[Guest]

Personally I never put any belief in the garage tall stories of hydraulic pipes collapsing internally.

 

They are always positive pressure so how an internal conduit can collapse is beyond me, swell and burst yes but not collapse.

 

I've cut and autopsied plenty of hoses in my time and have never seen the internals breaking in such a way.

[J.R.]

I have experienced them swell inwards at the crimped ends reducing the ID, also aggravated by the steel outer corroding, it was a clutch line and the fault was characterised by the clutch being very heavy to operate but still light if you depressed it very slowly.

 

But for a flap of detached rubber to become a one way valve would be a very rare and unlucky occurence.

[Doofy]

Got the same problem with mine, Replaced both front discs, pads and offside front caliper but the problem persists. Driver side front disc is always a lot hotter than the other side, Never thought of the hydraulic hose being at fault.. 

[PipH]

Garages have a habit of clamping off rubber hydraulic pipes to prevent loss of fluid while working on calipers as it saves time.

 

Also think it could damage pipes internally & weaken them.

 

So possibly could result in creating an inefficient valve in the pipe, enough to just hold the piston dragging the pad.

 

 

[xman]

In my experience its either

 

Pad plates and/or caliper sticking on the corroded carrier, strip off, and clean the carrier where the pad backing plates and caliper slide over. The carrier surfaces are often heavily corroded and need a file to clean off the corrosion back to metal. High temp brake grease (ceratec) applied to these surfaces lightly. Sometimes the pad backing plates are tight on the carrier so a light filing in appropriate places to keep them loose.

 

Clean the slide pins back to shiny with steel wool and very lightly grease.

 

After reassembly check the caliper slides back and forth freely. 

 

Do not go mad with the grease, including on the slide pins.

 

And/or the piston is full of debris stopping it moving back easily. Undo nipple and push piston fully back, so pushing out the crud laden fluid. Close nipple and pump piston out taking great care not to push it out completely. Undo nipple and repeat drain of piston by pushing back. Keep an eye on fluid level. If piston is still not moving back easily and smoothly, repeat.

 

Works for me for sticking overheating pads/pistons. 

 

An annual brush/clean down of caliper/pads with a manual push back of piston/pad to check free sliding helps stop this developing in the first place (rear discs would need to wind back pistons)

[AGFalco]

2 hours ago, xman said:

An annual brush/clean down of caliper/pads with a manual push back of piston/pad to check free sliding helps stop this developing in the first place (rear discs would need to wind back pistons)

 

Did mine today along with two new front tyres. ( only got 27 K miles out of the fronts  )

Worth doing if you ask me.

 

Thanks AG Falco

[SuperbTWM]

On 13/12/2018 at 12:04, softscoop said:

A few weeks ago I took the pads and carrier off, wire brushed off all the crud, regreased the sliders and carrier where the pads sit and put all back together.

 

 

 

Did you try pushing the piston in?

[softscoop]

I did, but only with a plastic clamp. I thought I had a rewind tool when I started the job but remembered it was one of the tools stolen from my garage when it was broken into 

[xman]

You don't need a wind back tool for the front calipers, the pistons can be pushed back with your thumbs. Although I would strongly recommend opening the brake bleed nipple (after attaching a simple bleed kit - pipe/container) to stop crud being pushed back into the abs control system.

Edited 15 December, 2018 by xman

[tyreman1]

sticking front calipers is a regular occurrence on my Octavia,probably twice a year I'll take the pads out of the fronts and lubricate and pump the pistons in and out a few times ,doesn't take long. On the brake hose idea I've know plenty of collapsed hoses in my time holding pressure on, at the garage where I work we always factor in the price of a new flexi hose when changing calipers, for what they cost it's not worth taking a chance.

 

[softscoop]

When I did look at it, the piston felt very stiff to push back in. I could barely get it back in enough to get the existing pads back in.

 

At this time of year I really struggle to find time to get any work done on the car as it's dark when I leave in the mornings and get back at night. Not having a drive doesn't help either.

 

I've bought a new caliper, slide pins and hose to be fitted by a garage next week.

 

The caliper could be fine but for the sake of £60 for a new one, when I'm already paying for the labor it's worth just changing the lot.

 

Just what you need before Christmas but hey ho. 

 

Thanks for the help folks. No doubt the passenger side will follow shortly.

 

[spartacus68]

Sticking pistons are usually terminal. You can eek a few more miles out of them by extending brake piston with pads and disc off and clean, then lightly grease with Lockheed red grease. Wire brush carriers and use Copperease lightly on back of pads and edges.

 

Bigg Red are great for rebuild kits, but if you can be bothered, just opt for a rebuild caliper from Bosch, especially at 165k miles.

 

Lastly, do a brake fluid change. Should be done every 2 years as DOT 4 fluid absorbs moisture.