zetec-Sam

iTrader: (2)

Surey not? My Landy isn't able to be done 1 at a time!

cossie legend

Depends what landrover your talking about. freelanders and range rovers have to be done 1 wheel at a time, the defender doesnt matter its done as normal apart from the hand brake which has to be done with both wheels at the same time where as cars is one wheel at a time for the handbrake.

zetec-Sam

iTrader: (2)

Which means the MOT tester will have to remove the prop to the front diff every time he gets a Defender in? Brilliant.

richard youll

im an mot tester and i'd love for someone to tell me exactly why i shouldnt roller test a 4x4 cossie, i roller test every one i do, and various other 4x4 vehicles, i know full well why i can just would love to hear a horror story as to why i shouldn't?

daz1968

I have an impreza 4wd and they always use the tapley meter, although my 3 door cossie has always been done on the rollers without issue, but it does have the standard diff. My brothers discovery automatic is also always done with a tapley meter. I was lead to believe on a 4wd car the centre diff can be damaged but never heard of it happening. I didnt know there was issues with 2wd cars with LSD though.

RS2000CUSTOM

Like any "woolly" VOSA directive it states something along the lines of "if you know a certain type of transmission is SAFE then proceed with RBT"

Most 4 x 4's with no LSD's can be fine for roller testing BUT be carefull when applying Park Brake as in the case of a Range Rover/Defender etc it is a transmission brake and it will lock the prop and not the individual pair of wheels (as in a Cozzy) which will most likely throw the car out of the rollers or snap something within the transmission

steve4i

also knowing as a decelerometer test all 4x4 and LSD cars should be done with a tapley meter unless you know its safe too do a roller brake test

richard youll

bang on, if you know its safe to do so which it is, also in regard to prop handbrakes on older landrovers on my refresher, a newish tester all ways brings this up for correct method of testing, i was actually suprised with the answer, the chap doing my refresher actually said it is perfectly acceptable to roller brake test prop brakes, using this method, calculate minimum required brake effenciency required for a pass, start roller 1 apply handbrake untill minimum required % achieved stop roller and then do same again on roller 2!

i was shocked at that

RS2000CUSTOM

I agree a prop brake on a RBT is fine as long as the vehicle is not a permanent 4wd and you can operate 1 roller at a time

But would love to see him do this with a Range Rover on an ATL RBT (spins both rollers for each reading) - video camera ready and £250 coming my way from Harry Hill

richard youll

Unfortunately there aren't many clued up testers and there are far more car owners that believed they know more than they actually do which is probably far more dangerous!!!

RS2000CUSTOM

My all time fave was when I got a call to ask if I could price up a repair of an inoperative handbrake on a car.

As a rule I never normally quote brake repairs over the phone (straightforward pads etc I will) as it is safety related so asked the owner to bring car round to my unit for a free estimate.

As soon as car (a fairly new clean Citroen Xantia) arrived I guessed where this was going to go and got the owner to sit in his car with park brake on and then got him to try to pull away - he was unable to without stalling the car !

What the MOT tester had done was pull Park Brake lever up and noticed no brake effort reading was being registered on rear wheels so he failed it for little or no effort on N/S/R & O/S/R Park Brake - whats wrong with that you may well ask - well the Park brakes are on the front wheels - lol

I then carried out a full RBT test to put the owners mind at rest and readings were all perfect for the vehicle yet the MOT station had just failed them - needless to say owner was not a happy bunny

He went back to MOT station and demanded his car pass its MOT and not surprisingly they offered him a refund on his MOT test fee (they knew if he had appealed it would have cost them a lot more)

To this day he still brings his family's cars to me for service/mot and repairs.

richard youll

That's ace, I still make silly mistakes because of auto pilot being on while doing tests, such as watching rear lights and calling side lights, dip head lights ..... Doh I'm at the back brake lights....

Mister G

Interesting thread, I'm ignorant to all this stuff, but does this mean a fwd with a LSD shouldn't be roller tested? Or, should be fine if it's brief? Or, stop being an idiot, of course it's fine!

RS2000CUSTOM

FWD with LSD = fine to RBT
FWD with "welded or heavily locked" LSD = Decelerometer
RWD with LSD = fine to RBT
RWD with "welded or heavily locked" LSD = Decelerometer
All 4WD = Unless the tester is certain that no damage will be caused then Decelerometer every time

Just to add to the confusion you may see a 4WD vehicle on the RBT but be aware a lot of 4WD's can be selected to only be 2WD until 4WD is required - others are permanent 4WD