Calling the MOT testers - handbrake Q

[r.welfare]

So, this Volvo V40 I'm fettling ('99 2.0 petrol CD). I have the VT30 in front of me and it states at the top "brakes failures: RBT Park Brake Efficiency: 10%". Also:

 

- Nearside rear parking brake recording little or no effort [3.7.A.7a]

- Parking brake efficiency below requirements [3.7.A.10]

 

I also have the Tecalemit brake test report. This states that the handbrake recorded 14kgf on the nearside, and 124kgf on the offside.

 

Now, obviously the n/s handbrake is not working (I'm going to change the cable first, as it's obviously stretched, but suspect this is a symptom of a wider issue with the caliper), but my question is - is the o/s up to snuff at 124kgf? I must admit, this is the first time I've seen one of these reports (my own MOT centre don't supply 'em, only the emissions report, but then I've never had one of my cars fail on brakes before!) and know bugger all about braking really.

 

The total weight of the car is quoted at 1310kg if that helps.

 

Any guidance gratefully received!*

 

* SCRAP IT, of course, being my preferred response to the owner of said vehicle. But she is female, so logic does not always enter the equation.

[scaryoldcortina]

Offside is fine... you need 16% minimum handbrake efficiency on a car with dual circuit brakes, this is calculated by adding together the brake forces for the wheels and dividing by the brake test weight of the car. You would have scored 20% if the nearside one had worked.

[r.welfare]

Fantastic, many thanks SOC. Glad I only need to sort the n/s one. Hopefully I won't have to go down the new caliper route, but all will be revealed this weekend...

[red5]

Well, the parking brake efficiency required is 16% for dual circuit brakes - so on that basis if the repaired one is 124kgf or thereabouts it'll be fine.

 

There is an allowance for fuel etc on brake weights, so it'll be slightly more than manufacturers figures.

 

* damn it. must learn to type faster

[oldford]

To pass the parking brake needs 16% (on a dual circuit system), the offside at 124Kg is providing 9.5% and the nearside 1.0%, so in theory if you can get the nearside to the same as the offside you'll get nearly 20% overall which is enough for a pass.

 

There weren't any other replies when I started on my answer.

[TimothyClaypole]

Or do as my tester did and break it so it fails altogether.

[Conrad D. Conelrad]

What is the required efficiency for single circuit brakes?

 

edit: shit, 25%??? What do they want, a magic handbrake?

[alf892]

Before fitting a new cable check this...........

 

The main problem with handbrakes in calipers is they tend to stick.....but the problem is usually just the lever/shaft which sticks really. The lever coming out of the caliper does not move far and will tend to not fully return over time. Next time the handbrake is applied it starts its travel from part applied. And then does not fully return. And so on so you end up with the lever in the applied position with no further travel available.......and the cable looks too long. If you are lucky you will be able to disconnect the cable and work to operating lever to and fro.......use silicon lube. Then refit and adjust cable .