Handbrake MOT fail ?

[J4CKO]

Rarely use the handbrake and noticed it works but itsnt that great, but its failed the MOT, car is a 2008 CLS 500, what is the usual cause and remedy for sticky handbrakes on these ?

 

[DSM10000]

Rarely use the handbrake and noticed it works but itsnt that great, but its failed the MOT, car is a 2008 CLS 500, what is the usual cause and remedy for sticky handbrakes on these ?

Presumably you mean the foot operated parking brake?

Not sure if your car has the same system but a lot of MB cars have a brake drum inbuilt to the rear disc. This is cable operated so the cables may need adjustment and / or the brake shoes and mechanism need cleaning or adjusting.

I would get into the habit of using it, the metal pawl that locks the transmission in Park is not that strong and is not designed to take the full mass of the vehicle on slopes etc

 

[J4CKO]

Presumably you mean the foot operated parking brake?

Not sure if your car has the same system but a lot of MB cars have a brake drum inbuilt to the rear disc. This is cable operated so the cables may need adjustment and / or the brake shoes and mechanism need cleaning or adjusting.

I would get into the habit of using it, the metal pawl that locks the transmission in Park is not that strong and is not designed to take the full mass of the vehicle on slopes etc

I do use it on slopes but on the drive and whatever, which is flat, never bother, they also found a bulge in a tyre, £141 !

 

[Deleted member 6183]

Presumably you mean the foot operated parking brake?

Not sure if your car has the same system but a lot of MB cars have a brake drum inbuilt to the rear disc. This is cable operated so the cables may need adjustment and / or the brake shoes and mechanism need cleaning or adjusting.

I would get into the habit of using it, the metal pawl that locks the transmission in Park is not that strong and is not designed to take the full mass of the vehicle on slopes etc

I've read this a lot on the forum but am yet to hear of any runaway cars left in Park.

 

[Yugguy]

I've got in the habit of putting mine on every time.

Give it all a good overhaul and it'll be back to normal.

 

[DSM10000]

I've read this a lot on the forum but am yet to hear of any runaway cars left in Park.

At what point did I mention runaway cars left in Park?


My comment was that the locking pawl is not designed to secure the vehicle from moving when parked.

Whilst it may do so it is not it's intended design function. The slight rolling forward of a vehicle in Park is caused by the locking pawl dropping in to a position where it can lock the transmission with wear this may become less effective,

At least by using Park and the parking brake one has a back up.

I believe the handbook is quite specific on the use of the parking brake.

 

[DSM10000]

I do use it on slopes but on the drive and whatever, which is flat, never bother, they also found a bulge in a tyre, £141 !

My parking brake was borderline at a previous MOT, I tensioned the cables (under the rear seat on a C class) and also drove the car up to about 30mph on a private road and operated the parking brake a few times. It then passed with what the tester described as an "excellent"result.

I am sure a little fettling will bring your car back to a pass.

As for the tyre, £141 against a potential blow out saved at speed............priceless.

 

[b1g1an]

DSM's advice is a good starting point, but obviously don't go mad, as there is almost certainly rust build up on the surfaces if you don't use it much and you may have glazed pads too.

If you look at your brake discs after it's rained whilst parked up and then imagine that untouched for several months you get the idea.

Have to say I thought the foot operated brake like the Americans tend to have (but never use!) was a bit of a daft design but the 'hand'brake on mine is stronger than any other I've ever had by some margin.

 

[Deleted member 6183]

At what point did I mention runaway cars left in Park?


My comment was that the locking pawl is not designed to secure the vehicle from moving when parked.

Whilst it may do so it is not it's intended design function. The slight rolling forward of a vehicle in Park is caused by the locking pawl dropping in to a position where it can lock the transmission with wear this may become less effective,

At least by using Park and the parking brake one has a back up.

I believe the handbook is quite specific on the use of the parking brake.

I was wondering what the consequences might be, as it turns out there are none.

Even google threw up no horror stories of leaving auto cars in P with no handbrake.

No need to get defensive, really, I did say that I've heard the warnings on the forum previously.

 

[DSM10000]

I was wondering what the consequences might be, as it turns out there are none.

Even google threw up no horror stories of leaving auto cars in P with no handbrake.

No need to get defensive, really, I did say that I've heard the warnings on the forum previously.

Not remotely defensive, merely factual.

I know from experience that the parking pawl can be fragile,especially when abused.

On a previous car (Saab 9-5 Griffin) madam somehow managed to move into Park just before coming to a halt, she was only moving at a very slow pace but the bang as Park engaged shook the whole car. It bent the pawl as well.

The gearbox failed (unrelated we think) a few months later

 

[190]

MB's tiny parking brake shoes inside the rear disc hub are not very effective by normal automotive standards. They work well enough when operated by the leverage provided by a foot pedal but a model with a conventional hand brake lever can be hard work.

Getting the parking brake to work well is not just about cable adjustment. The shoes have a mechanical star wheel adjuster inside the hub which can be accessed through one of the wheel bolt holes. With the parking brake off, you flip the star wheel around which pushes the shoes outwards causing the wheel to bind and then back off enough clicks for the wheel to rotate freely again.

 

[Auto-mobile]

9 times out of 10 the mechanism is partially seized and needs a good spray of wd40 and a few swift operations.

 

[J4CKO]

Cheers chaps, that is tomorrow's job then, along with my sons non starting Astra, hopefully the weather is ok.

The tyre is annoying as it is a PZero Rosso with six thousand on it, it's like new, why couldn't it have been one of the rears that are looking a bit tired

 

[OneForTheRoad]

do what 190 says , a few turns of the star wheel and jobs a good n . hardest part is finding it lol . from memory 11 and 2 o clock cant remember which side though . 1 way is up the other down . hth .

 

[tonysmb]

I was wondering what the consequences might be, as it turns out there are none.

Even google threw up no horror stories of leaving auto cars in P with no handbrake.

No need to get defensive, really, I did say that I've heard the warnings on the forum previously.

I wouldn't say there were none. I know of one instance of the parking pawl 'pin', or call it what you want, breaking off on what was then a virtually new Ford Granada. They aren't very strong and I certainly wouldn't rely solely on it.

Apart from the potential damage, if it breaks off the cost of fixing the subsequent mess won't be cheap.

Not everybody puts everything on t'internet, especially if they think they might have caused the problem in the first place.

 

[stwat]

I hads one break on a RR classic.

 

[Deleted member 6183]

So twice in the 1970s then?

 

[b1g1an]

Common sense was more common in the seventies too. Can only assume they took it off the school curriculum as my kids don't have a lot either.

 

[tonysmb]

So twice in the 1970s then?

And your point is?

Did anybody actually say when it occurred; Granadas, and RR classics for that matter, were current until the mid-1990s and, on a point of accuracy, auto Range Rovers weren't introduced until approx 1984.

Strange attitude really, when some people are simply advising that it isn't unheard of for them to break.

 

[tonysmb]

Thinking about it, perhaps I'm being a bit harsh on DrFeelgood. After all, I'm only aware of one person who came unstuck, in a big way, whilst playing Russian Roulette (well, that was the conclusion) and that was a long time ago as well, late 1980s.

No doubt it's fine nowadays, things have probably improved. However, I would still choose not to play it if offered the chance - maybe I'm just old-fashioned