MoT Brake Efficiency results

zeaphod · Oct 19, 2015

The old girl went through the MoT second time around, after changing a rear wheel cylinder. The tester mentioned my brake efficiency was low (52%) - but above the threshold. The landy drives OK, but I don't feel I could lock the front wheels easily. Anyone have any recent results to hand? My Volvo had a reading of 80%, but then it has brakes that can throw you out of your seat - I don't expect a 30 year old Land Rover to compare to it.

lynall · Oct 19, 2015

You cant always go by the figures, not sure on cars buy hgv is 45 and 16 percent pass for foot and handbrake, sometimes they dont make the grade and there is nothing wrong with them a little roadtest and warm up sorts them out.
Have you tried to lock the wheels?
If it stops in roughly a straight line when stamping on the brake the callipers are most likely okay.
People will rave on how good their defender brakes are, but these are also the same people who will tell you the defender is the best car ever made!

zeaphod · Oct 19, 2015

Thanks for you reply. Pass figure for cars is 50%. It does stop in a straight line, but I doubt it would lock up the fronts, and the system has been fully bled. I'll try new discs and pads to see if there's much improvement before looking at the calipers.

trax · Oct 19, 2015

think i was up in the 80's with a 110 rear drums

you got drums? they can be a bit fiddly to setup correctly. a 4 way brake tester would tell you what's going on at each wheel

ONE LIFE LIVE IT. D90 · Oct 19, 2015

My brake efficency wasn't the best at 65% either.

That's with a whole new braking system on my 300tdi defender 90. Literally everything ! I was disappointed when the tester told me

lynall · Oct 20, 2015

The rollers we have at work are like most and finicky at the best of times, wet tyres, wet tyres and wet rollers, not quite square on the rollers, wrong dau of the week, all effect the figures.

I bet they would lock if you gave the pedal some abuse, if not then maybe you need to look further.
You may find the pads have glazed slightly especially if you are a careful driver, you can deglaze them by giving them some abuse a few times in a row so they get nice and hot, doesnt always work, but easy to do.
EBC greenstuff are pretty good.

zeaphod · Oct 20, 2015

Thanks guys. Lynall - I am a careful driver, so may have glazed the pads. Curiously, I have upped the idle speed a little to reduce vibration since the test, and the brakes feel a bit more potent. I wonder if there is increased vacuum from the pump? I think I'll fit new discs and pads in the next month. it will give me a chance to look at the calliper pistons, in case they are partially seized.

tottot · Oct 20, 2015

Hi zeaphod, I note you have a new system.When brakes are new they are not at their best,you need to drive between 200 and 500 miles to bed them in before you get the best from them.

lynall · Oct 21, 2015

zeaphod said:
Thanks guys. Lynall - I am a careful driver, so may have glazed the pads. Curiously, I have upped the idle speed a little to reduce vibration since the test, and the brakes feel a bit more potent. I wonder if there is increased vacuum from the pump? I think I'll fit new discs and pads in the next month. it will give me a chance to look at the calliper pistons, in case they are partially seized.

The britpart callipers are pretty good, should you need any Island 4x4.
Might be worth checking you vac pump/servo non return valve assuming it has one fitted?

MoT Brake Efficiency results

zeaphod

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lynall

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zeaphod

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trax

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ONE LIFE LIVE IT. D90

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lynall

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