The procedure during an MoT test for brakes shows the efficiency and also any imbalance between left and right braking. The same checks are applied to both front sand rear brakes.
When my AWD is tested the old method is used, drive it, hit the brakes and see what the Tapley meter registers.
To me this seems rather crude and could mask imbalance etc.
Are there any MoT places that can test 4X4s on rollers without damaging LSDs and clever drive systems?
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Good question. Apparently there are some rollers that can rotate the pair of wheels being tested in opposite directions so as not to put any net rotation into the centre diff/clutch.
I'm pretty sure that on others they just run them slowly for a very short time (assuming they are aware of what they are testing).
I had never thought about this until driving my Outlander away from Motstop in Wycombe after its test in March. I wasn't watching what they did - I have decided to assume they know what they are doing as they only do MoTs, and the couple of fairly mature blokes you see there have been doing it a long time. £44 per MoT at the moment I think (discount via internet).
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Testing a system that is in permanent 4WD would surely require 2 sets of rollers, at the spacing dictated by the wheelbase?
My Landrover is not in permanent 4WD, so they test the axles separately in the normal way.
Testing the handbrake is trickier when it acts on the transmission, not the wheels, and requires a tester specially trained who knows what he is doing.
The correct procedure is to run the rollers, and then apply the lever very cautiously, stopping the instant the minimum braking standard is reached. Applying any more braking risks doing severe damage to the vehicle, and possibly the rollers.
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>>£44 per MoT at the moment I think (discount via internet).
Correction £39 now, but only in Watford. I've been jizzed.
www.motstopwatford.com/
(no connection other than as a user of the Wycombe branch)
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>> >> I've been jizzed.
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Crumbs. Where'd you get that turn of phrase from? Means something entirely more unsavoury round my way.
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Maybe it does here too. No wonder I get so many funny looks. I probably have no need of the other definition. I'll delete it from my personal dictionary.
Maybe I make them up without knowing. I got a quizzical eyebrow the other day for 'jasper' (wasp).
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A tapley meter to register efficiency-if you can't tell if it's pulling left or right,you shouldn't be driving!
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>> if you can't tell if it's pulling left or right,you shouldn't be driving!
Indeed.
I've noticed in the past when testing the brakes of unfamiliar, large, drum-braked vehicles including Land Rovers and the like that a light application will quite often make the car try to swerve about - you don't let it of course - whereas a firmer or even hard application will straighten everything up and restore balance and tracking.
That's if the brakes are a bit worn but essentially in sound condition. If they aren't basically sound, caution is the watchword. But as soon as you get a suitable wide place try some emergency braking, so that when the emergency arises you at least have some idea what the jalopy's going to do... Seems commonsense to me.
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I know I've described the experience before, but almost nothing would induce me to stamp on the brakes in a 'classic' drum braked Land Rover. Fortunately it wasn't necessary for the tester to do that in my Series III, which defaults to rear wheel drive.
Last edited by: Manatee on Wed 30 Jul 14 at 15:56
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>> Maybe I make them up without knowing. I got a quizzical eyebrow the other day
>> for 'jasper' (wasp).
>>
Haven't heard that term for years ... we used to use it as kids.
Edit, from Wikipedia:
Other uses
A colloquial name for the common wasp in southern England and the English Midlands
Last edited by: Westpig on Wed 30 Jul 14 at 20:10
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>> >> >> I've been jizzed.
>> >>
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>> Crumbs. Where'd you get that turn of phrase from? Means something entirely more unsavoury round
>> my way.
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Think it means the same here to. Certainly not something I'd advertise on the net......well, unless it was a "specialist" site
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>>
>> Think it means the same here to. Certainly not something I'd advertise on the net......well,
>> unless it was a "specialist" site
>>
It's a term used to describe all the attributes of a species - the characteristics that are used in identification.
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"Are there any MoT places that can test 4X4s on rollers without damaging LSDs"
Could I buy some LSD at a MoT gaff?
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As a child, I remember my father's SIIa Landrover failing the MOT on something to do with the front diff/driveshafts.
The mechanic loaned him a couple of spanners and he removed the front propshaft. It then passed.
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MoT. Testing brakes on a 4X4 or AWD. - Manatee
