GT6 Failed MOT - Small Question

Wizardskills · 13 Sep 2010 at 16:12

So the GT6 went in to have its MOT done today and it has failed. Here are the things it failed on:

1.Parking brake lever has no reserve travel [3.1.6b]
2.(release button faulty) Parking break leaver is defective [3.1.3]
3.Parking brake efficiency below requirements [3.7.A.10] **Dangerous**

To be honest this isn't to unexpected however it is quite annoying as I am unable to drive the car now. I did 'fix' the handbrake when I got the car as it was basically non existent. However, according to the MOT failure certificate it is only 9% efficient. There is no more room for adjustment on the cable now so I think the cable has stretched over time and as such I am going to have to replace it.

I was told at the garage that it had to be 25% efficient however I thought for a car with a dual braking system this only has to be 16% (Source : link). Now I'm no mechanic so I thought someone here may know if my car does indeed have a “dual braking system”? Here is an exploded diagram of the handbrake system on a Mk 1 GT6. The diagram clearly shows the cable going to both rear brake drums so to me that would indicate that is is indeed a dual brake system?

I'm not to bothered about point 2 as I think that was just the mechanic not knowing how to operate the handbrake on this car (despite me explaining it to him when I dropped it off that it was a fly-off handbrake). :rolleyes:

Matt82 · 13 Sep 2010 at 16:16

whats a gt6?

Wizardskills · 13 Sep 2010 at 16:18

Matt82 said:
whats a gt6?

The car in my sig.

http://en.wikipedia.org/wiki/Triumph_GT6

Frozennova · 13 Sep 2010 at 16:22

I thought fly off handbrakes we're illegal all together?

Hawk Tuah · 13 Sep 2010 at 16:24

As it only achieved 9% its pretty irrelevant isnt it?

TaKeN · 13 Sep 2010 at 16:35

It has one main cable coming from the Handbrake lever as such.. so IMO it isn't a dual braking system

Wizardskills · 13 Sep 2010 at 16:45

frozennova said:
I thought fly off handbrakes we're illegal all together?

I wouldn't know, however this is the system that it was fitting with when it came from the factory so i guess it is legal.

TaKeN said:
It has one main cable coming from the Handbrake lever as such.. so IMO it isn't a dual braking system

Yeah that is where my confusion is. I know some old cars only have the handbrake applied to one rear wheel whereas mine goes to both. As such im not sure what the 'dual' corrisponds to (the braking applied to the number of wheels or the number of cables) :confused:

Dogbreath · 13 Sep 2010 at 16:56

A "dual" system in this context is nothing to do with the handbrake - it's whether the car has a split hydraulic system on the service brake i.e. separate circuits front and rear or diagonally. Your GT6 could be fitted with either a single or split system depending on year. Since failure of a single circuit system means no service brakes will be operable, the MOT requires the the handbrake to have a higher efficiency to cover this eventuality.

Which old cars only have one wheel braked? Certainly some old vintage/veteran stuff but nothing remotely recent.

Biohazard · 13 Sep 2010 at 16:59

Its 16%, mine was in the other month there got 16% on those nose and an advisory for it.

Mines runs two cables from an equaliser plate, and I suspect most cars will. Its not about the cables attaching directly to the lever mechanism.

Looks to me like your running a single cable pulley to me.

Biohazard · 13 Sep 2010 at 17:03

Dogbreath said:
A "dual" system in this context is nothing to do with the handbrake - it's whether the car has a split hydraulic system on the service brake i.e. separate circuits front and rear or diagonally. Your GT6 could be fitted with either a single or split system depending on year. Since failure of a single circuit system means no service brakes will be operable, the MOT requires the the handbrake to have a higher efficiency to cover this eventuality.

the horizontally split system is rubbish, the twice I've had a line go you'd be as well opening the door and jumping out.

PardonTheWait · 13 Sep 2010 at 17:05

Matt82 said:
whats a gt6?

Alarmingly, it's the first thing that comes up when you google 'GT6'

Dogbreath · 13 Sep 2010 at 17:12

Biohazard said:
the horizontally split system is rubbish, the twice I've had a line go you'd be as well opening the door and jumping out.

You've had a brake line fail twice? :eek:

It's never happened to me in 22 years of riding/driving.

If the front circuit goes then obviously you are going to have very limited braking, but any is better than none.

Wizardskills · 13 Sep 2010 at 17:22

Dogbreath said:
A "dual" system in this context is nothing to do with the handbrake - it's whether the car has a split hydraulic system on the service brake i.e. separate circuits front and rear or diagonally. Your GT6 could be fitted with either a single or split system depending on year. Since failure of a single circuit system means no service brakes will be operable, the MOT requires the the handbrake to have a higher efficiency to cover this eventuality.

Ah ok, that makes sense then. From looking at the brake pipe diagram it looks like it is all on a single system

Looks like it will be 25% then.