Hi all, something has gone awry with my 11 plate superb.

Visiting my folks in Yorkshire and from the living room I heard my alarm, I looked out the window to see the motor trundling off down the hill towards the main road, much excitement ensued as I'm sure you can imagine.

The car was parked in 1st with the handbrake on....

So I can only conclude the handbrake needs adjusting.

It's never been that good but in previous discussions I've simply been told that it's self adjusting and there's not much that can be done, that's surely not right?

It can't be normal for a car to run off down a hill by itself!

Are the calipers known for wearing in some peculiar way, the service brakes are absolutely fine, no spongeyness or anything, I actually replaced the rear pads yesterday, I didnt spot anything untoward and I have since driven 3-400 miles with no issues, so everything should be well bedded in.

Any thought would be greatfully received, I'd quite like to get this sorted ASAP.

1 hour ago, Woosh said:

I've simply been told that it's self adjusting and there's not much that can be done

Well, my usual technique is to apply the footbrake as hard as I can, then pull the handbrake on hard 2 or 3 times. After this, the handbrake travel should be shorter.

 

The other possibility is that the rear brake pads need replaced.

Often I find the calipers have long ceased to slide as corrosion and baked on crud on the pad/caliper parts that are meant to slide have effectively seized them. So you end up with only one side of the disc braking. Add to that a tendency for the pads to only work in a restricted, grooved part of the disc

Example

 

Also the brake lever on the caliper can seize, needs freeing up, and the brake cables can rust internally near the cable ends, which doesn't help.

 

Assuming you have a manual handbrake check the T bar adjuster located behind the internal handbrake, when you pull the handbrake on that both cables move equally, and one side isn't seized or having trouble.

 

In short, strip, clean, renew bits, lubricate and check all parts are moving as they should.

 

Remember hot discs contract when they cool so a tight handbrake can become loose when it cools down. If your brakes are dragging, they will get stinking hot. 

 

Must have been quite an incline if the car still moved while in 1st gear. Remember to turn front wheels such as the car will move to a safe position e.g. kerb, if brakes fail to hold.

 

Edited 6 August, 20214 yr by xman

16 hours ago, Woosh said:

I've simply been told that it's self adjusting and there's not much that can be done, that's surely not right?

 

I actually replaced the rear pads yesterday, I didnt spot anything untoward

 

 

As part of replacing the rear pads you will have wound back the caliper hydraulic piston with a special tool  - this mechanism is the self adjustment. Usually if you have to adjust handbrake cables then something isn't quite right. This has been the case with almost every brake system for decades with various adjustment mechanisms - some better that others! I remember the one on the mkII Cortina, hopeless. The ones on VAG cars usually ok but handbrake lever can seize somewhat if neglected.

 

As mentioned further up the thread the condition of all the brake components is really important. Are the calipers free to slide and what condition are the discs?

 

• If caliper sliders are stiff then handbrake may be only acting on one pad - which when it does slide may release somewhat
• If disks are corroded/scored/worn then it's less than ideal and new pads will take 1000's of miles to bed in

As it's a major safety component I'd suggest a qualified mechanic checks it over.

 

With rear disks don't forget as it cools and contracts the action of the handbrake will reduce (with drum brakes it's the opposite)

 

Edited 7 August, 20214 yr by bigjohn

17 hours ago, Woosh said:

The car was parked in 1st with the handbrake on....

 

 

Not this time it wasn't unless the hill was very very steep.

Edited 7 August, 20214 yr by J.R.

Hi all thanks for the replies. To answer a few bits, the calipers slide with no issue, I checked this when I changed the pads, condition of the disks is good, they were changed last time the pads were renewed.

I will go ahead and check the cables and lever end adjustment.

While I'm  ot strictly speaking a qualified motor mechanic.

By trade im a mechanical engineer currently working on the railway but have in the past worked on agricultural machinery, my dad was a self employed motor mechanic and I spent my childhood working alongside him. So I'm very confident that I'm able to safely do the job.

Besides, a qualified mechanic was stood beside me as I did the work 🤣

I had considered disk contraction, as has been stated several times, its just not something I personally have ever come across with this car.

If it is disk contraction, can anyone suggest a way of dealing with it, I dont imagine the cable really has the spring in it to accommodate the movement and I dont really want to risk stretching/snapping cables by wrenching the handbrake up.

Should it be something like the cables should have a level of spring in them but they have stretched over time and lost that?

I could go through theories all day, there are people here far more experienced with superb than I am though  hence my asking.

Thank you again for all those that have replied.

 

30 minutes ago, J.R. said:

 

Not this time it wasn't unless the hill was very very steep.

I assure you it was, its the only thing that stopped it before the main road..

I actually went and checked, driving down the hill,  I stopped on the footbrake turned off the ignition, let the clutch up in first as I let off the brake and the first rotation of the engine felt a bit like hitting a kerb, it thumped into it, but had enough to just about overcome the compression and once it was away the car just kept rolling. I had to stop it again with the footbrake.

It is a fair old slope this road, and I cabt imagine it helps that its a small engine in a sizeable car (1.6) and its probably fairly well worn internally.

Something else I considered but don't honestly know,

Pistons are designed to seal against very high pressures for a very short time, but I cant imagine they are actually that air tight, I mean piston rings are split, the ends only butt up against each other, so in my mind, with a constant Weight sat against an engine, the pressure against the pistons could bleed off over time allowing it to spin, then it's own momentum can carry it as I proved, in theory anyway.

Edited 7 August, 20214 yr by Woosh

1 hour ago, Woosh said:

 

If it is disk contraction, can anyone suggest a way of dealing with it,

 

 

Usually the only way is to pull the handbrake on a bit harder. The new pads still might need a bit more bedding in as well it can take a few thousand miles especially when fitting to old disks. Also new pads may or may not have a taper on the friction material to help this bedding in process - this can mean slightly less friction material in contact for a while. Must have been a really steep hill!

 

What engine does it have out of interest?

 

 

Edited 7 August, 20214 yr by bigjohn

Does the superb have a similar silly handbrake console cover arrangement to a mk2 octavia? That has a sliding ribbon cover that easily jams in its track and impedes handbrake movement. Check and lubricate with silicon spray. There is a repair guide in the Octavia mk2 if its jamming.

 

How many clicks? IME dealers make them too tight at 2 clicks and its difficult to pull hard when the handbrake is virtually horizontal.

 

To access and see the T bar cable puller I referred to earlier, remove the rear ashtray and its holder in the centre console. Check both cables move equally and the t bar doesn't skew. Adjust with a small 10mm open ended spanner. I think its best at 4-5 clicks, the higher the handbrake setting makes it easier to apply more tension to the cables which are in effect tension springs that will accomodate small changes in disc thickness when they cool? It also ensures the pads release fully when you put the handbrake down, which ime in the Octavia is not always a positive action due to that silly sliding ribbon.

Edited 7 August, 20214 yr by xman

8 hours ago, Woosh said:

I assure you it was, its the only thing that stopped it before the main road..

I actually went and checked, driving down the hill,  I stopped on the footbrake turned off the ignition, let the clutch up in first as I let off the brake and the first rotation of the engine felt a bit like hitting a kerb, it thumped into it, but had enough to just about overcome the compression and once it was away the car just kept rolling. I had to stop it again with the footbrake.

It is a fair old slope this road, and I cabt imagine it helps that its a small engine in a sizeable car (1.6) and its probably fairly well worn internally.

Something else I considered but don't honestly know,

Pistons are designed to seal against very high pressures for a very short time, but I cant imagine they are actually that air tight, I mean piston rings are split, the ends only butt up against each other, so in my mind, with a constant Weight sat against an engine, the pressure against the pistons could bleed off over time allowing it to spin, then it's own momentum can carry it as I proved, in theory anyway.

You are correct in all your observations, the dynamic compression once it was moving will have retarded it and thankfully stopped it reaching the main road, junctions have to be less than a certain incline if not level which helps.

 

initially its just the valve springs creating any resistance, the compression comes when the crank starts turning, those of us with diesels have the advantage. You never get a release of pressure when removing a spark plug even at TDC on the firing stroke 30 seconds after stopping the engine.

 

Its a shame that so many of the old habits from days when they were really needed have been lost, like parking with the front wheels on an angle against the kerb on hills.

Edited 7 August, 20214 yr by J.R.

Some VAG models have had problems with the handbrake pawl not properly engaging on the lever resulting in the lever releasing and the car rolling away. It happened to my father's Octavia 3 when he stopped at the top of the driveway for a moment to get out and check something. - he heard a click and the car rolled down the driveway and into a wall across the road. Skoda dealer didn't want to know about it!

Thank you all for the replies,

10 hours ago, bigjohn said:

 

Usually the only way is to pull the handbrake on a bit harder. The new pads still might need a bit more bedding in as well it can take a few thousand miles especially when fitting to old disks. Also new pads may or may not have a taper on the friction material to help this bedding in process - this can mean slightly less friction material in contact for a while. Must have been a really steep hill!

 

What engine does it have out of interest?

 

 

It's a 1.6Tdi, I honestly didn't realise they took as long as that to bed in, the disks are relatively new and are clean so therefore braking in my mind across the full braking surface.

 

10 hours ago, xman said:

Does the superb have a similar silly handbrake console cover arrangement to a mk2 octavia? That has a sliding ribbon cover that easily jams in its track and impedes handbrake movement. Check and lubricate with silicon spray. There is a repair guide in the Octavia mk2 if its jamming.

 

How many clicks? IME dealers make them too tight at 2 clicks and its difficult to pull hard when the handbrake is virtually horizontal.

 

To access and see the T bar cable puller I referred to earlier, remove the rear ashtray and its holder in the centre console. Check both cables move equally and the t bar doesn't skew. Adjust with a small 10mm open ended spanner. I think its best at 4-5 clicks, the higher the handbrake setting makes it easier to apply more tension to the cables which are in effect tension springs that will accomodate small changes in disc thickness when they cool? It also ensures the pads release fully when you put the handbrake down, which ime in the Octavia is not always a positive action due to that silly sliding ribbon.

It is indeed that same design, I will make sure to grease it, ive never noted any resistance in the lever however, I will have to check for many clicks bit I feel like it's more than the 4-5 with a good pull

 

3 hours ago, J.R. said:

You are correct in all your observations, the dynamic compression once it was moving will have retarded it and thankfully stopped it reaching the main road, junctions have to be less than a certain incline if not level which helps.

 

initially its just the valve springs creating any resistance, the compression comes when the crank starts turning, those of us with diesels have the advantage. You never get a release of pressure when removing a spark plug even at TDC on the firing stroke 30 seconds after stopping the engine.

 

Its a shame that so many of the old habits from days when they were really needed have been lost, like parking with the front wheels on an angle against the kerb on hills.

Thanks for confirming my thoughts matey. it certainly is, thankfully my old man was of the same mind, hence parking in gear and so on, unfortunately I missed the fact that it was a dropped kerb (nose overhanging my parents drive) so it just ran up the kerb and around the corner down the hill.

 

3 hours ago, chimaera said:

Some VAG models have had problems with the handbrake pawl not properly engaging on the lever resulting in the lever releasing and the car rolling away. It happened to my father's Octavia 3 when he stopped at the top of the driveway for a moment to get out and check something. - he heard a click and the car rolled down the driveway and into a wall across the road. Skoda dealer didn't want to know about it!

I will certainly check that, however the handbrake was still in a raised position when I went to retrieve the car.