tr7triumph.com

Hi All
might sound daft but what is a service brake

I would of guessed hand brake but I guess thats parking brake

As you might of guessed I've just failed an MOT
MOST things I've sorted BUT have 4 brake failings

1/ service brake efficiency below requirements[3.7.A.8]

2/ parking brake efficiency below requirements[3.7.A.9/10]

3/ nearside rear parking brake recording little or no effort [3.7.A.7a]

4/ offside rear parking brake recording little or no effort [3.7.A.7a]

any translation would be appreciated
ATB Dave

Its hard not to be big headed driving it

Hi Dave,
The brake test is normaly (not always depends on vech and equipment available) on a roller tester. The wheels are driven by motors via drums, a reading is taken of the force the brake applies against this turning force and a note made. Front brakes are measured invidually and as a pair for balance, the rear are individualy (can be an advice if effort widely different) and the parking brake is done indvidually and as a total effort. At the end of the test the figure are fed into the computor and efficeny are worked. But is only simple maths-
Total vech effort x 100 and then divided by vech wieght equals efficency, parking brake is the same ie,best side to side readings added then x 100 divided by wieght.
Will however pass if at least 3 wheels lock up on test on service brake (normal brakes)
If both parking brake wheels lock when that is tested will also pass
The sevice braking eff (foot brake) has to be at least 50% eff
The parking brake on our cars has to be at least 16% (same as holding on a 1 in 6.25 hill!
The balance cannot be greater than 25% on the steered wheels (our tester display's balance as you test the wheels together)
Your fail has been broken down to show where your problems lie, poss wheel cylinders leaking / seized,linkages seized ect. It looks like a lok inside those rear drums is needed [:(]
Hope that is al resonably clear [?]
Cheers John

LIVE LIFE A QUARTER OF A MILE AT A TIME!
1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6 WILL BE ON THE ROAD VERY SOON!
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Thanks John
I looked inside the drums after reading your reply nothing seems siezed works fine ,manually pulling the cable end things the shoes moved ok
no leaks can be seen i changed a cylinder last year as it was siezed but all fine now.
ATB Dave

Its hard not to be big headed driving it