The guy I use currently, moaned when I asked him to take it out on the road cos he used the rollers last time (I didn`t know then ) I might go back to the guy I used to use (now I have a legal car...emissions, HID`s etc.) as he has a 4 wheel roller setup

 

hi mate i see your in watford. The place i take mine is ricky mot just behind whippendell road. The owner has a scoob and no test drives forsure

 

Not with an awd car no. Two of the wheels are still going to be stationary on the ground

 

ive never heard of this, bet there`s quite a few out there aswell. ive never had any problems with the roller test and ive had quite a few 4wd cars but it is something i will bear in mind

 

my 1st time MOTing my scooby a while ago , the tester took mine round the building . He never said he was doing it , and i've never seen it before , so when i seen my car dissapearing out the door I pooed a wee bit !

 

I had mine done last Saturday and queried this with the tester, he assured me that his rollers (2 wheel) was set up for 4wd - he showed me the setting on the big digital screen too which confirmed this. These were very recently purchased rollers.

I watched him throughout (as with the rest of the MOT) and the wheels were turned for a couple of revolutions at very slow speed front and back so I was happy with that.

 

In actual fact Imprezas can be safely tested on a 2wd brake tester as long as a DCCD equipped car isn't set to "Lock".
The centre diff is viscous and allows for a certain amount of slip. If it didn't, you wouldn't be able to lock up the front wheels on a non ABS Scooby, and you most certainly can!

 

If the rollers wound up the diff, wouldn't the car be spat off the rollers?
Dip

 

Correct..

 

So what about non dccd cars?

 

People are forgetting the rear LSD.

This can also suffer damage. Some single axle brake rollers in alledged 'AWD mod'e turn the one wheel in reverse and the other forwards.

Fine for the a "4x4" with open front/rear diffs.....but not brilliant for the rear LSD!!


None of my LSD equipped cars (BMWs, Jag, Scoob, Monaro etc) have never been let near a brake roller for MOT brake testing, and I ensure to keep it that way - All were road tested.

 

All I know, is my car was fine until put on a sun brake tester, then it stuck in fith gear and that was 10 mins after leaving the MOT station, car was fine before hand. So I'm with Ali on this one.

 

My local MOT station that I have used for years used to use the meter on my old Hawk but this time for my 08 Hatch they put it on the rollers, this email got me thinking so I called up the garage and they said that some AWD cars can go on the rollers and some cannot, it comes up on a VTS form when they set the MOT up on the computer and they go by what that states.

Guess now it's all electronic (even the MOT cert is different now and is just a print out) that the system gives them more info to check things like this.

 

My subaru dealer did my mot testing for 3 years using rollers. Not noticed any damage and its a 2003 sti without dccd but does have lsd's front and back.
I now use a local guy and he wanted to use the tapley meter thing.
Looks like there is no real answer then?
But as I said above, if the center diff was fighting the rollers it would spit the car off, remember its a viscous center diff.
Dip

 

No problem at all.

 

Brake testing won't hurt them, what do you imagine happens on cornering?

 

I'd say that was a complete coincidence, and it was just going to happen sometime.

 

Being fair, I'd say most MOT station staff wouldn't know one way or another, all they want is an easy life!

 

safest bet not just to test on the road though

potentially it can be tested 1 wheel at a time footbrake , then 2 together

then 1 wheel at a time handbrake, then both together, and if readings borderline, may go through the same again.

testing the front brakes alone can take a fair few revolutions, many tester start rollers to centre car, then sit chatting with wheels constant turning - i know i did lol

all in all not better just reducing risk and going on the road?

 

on my tester course many moons ago it was most definitely pointed out not to test 4 wheel drive cars on the rollers around at the time, maybe changed days?

so is there now zero risk of damage, or just minimal?

 

You don't exactly corner with one wheel stationary or forcefully being turned backwards though? (which some rollers do)

Whilst ulimately it is the tester's decision and responsibility, IMO why take that risk? And there is a risk, otherwise VOSA wouldn't bother pointing it out.

If a MOT tester crashes a car its obvious who is liable from that immediate point and its on their insurance, but if you find out 2000miles later that the viscous diff has become contaminated with gearbox oil, its hard cheese old boy as the car has driven far too far to prove 'without doubt' that the test caused the problem.

It like prefilling oil filters during a service and the engine going pop a week later. Its ok not to prefill it, but do you chance it, or not?

 

VOSA don't know their ar se from their elbow to be honest. All they'd bother about is being sued. You'd get more sympathy from Vogons.
As far as diffs are concerned they are constantly running at a different speed one side than the other. Hence the name! It's the amount of difference that's the issue, and a piddly little brake tester will not break a diff at what is no more than walking speed.
All I'm saying is that I'm not at all worried about MOT stations testing Subarus.
Hey, we've got to worry about something, and I'd be a damn sight more worried about some erk running about in my car ta very much.

 

Maybe you are right Alan, and I was just unlucky, but it's strange how the car was ok before, I mean it's not like fith gear is under a lot of strain on a standard 99 Uk turbo, car had only done 68.000mls and was in perfect mechanical condition. Changing into fith felt notchy straight away after leaving the station that's why I suspected it was down to them. When I confronted the tester (young lad) the senior tester there said oh you didn't put it on the rollers did you. So even he thought it shouldn't be done.

I've asked a few testers about this, some agree some don't.

 

pete, seeing as the tester all but admitted 'liability', what happened? Did you get recompense? What?


But I'm with AJ on this one... The very low speeds involved surely(?) aren't gonna be troubling the 4WD system.


This is a bit like the 'disconnecting the crank sensor before an oil change' debate (which I agree to, I might add).

 

You have to remember that you do not have to be a mechanic or even qualified to be an MOT tester. Unless the rules have changed it used to be that you had to have been in the motor trade for two year and pass the VOSA mot course. In fact they prefer non mechanics becuse a mechanic is more likely to use discretion and pass on minor things.
It's very likely the tester and even his boss did not know wtf their talking about.

 

No kidding, I have every sympathy with your situation. "Sod's law" applies of course, as it does in many cases where "it didn't do that before"
In this particular case, the reason I'm doubting the culpability of the MOT tester is the fact that the brakes would be tested in neutral, very likely engine off and fifth gear wouldn't be engaged.

 

Well I can't really argue with you Alan considering your reputation, so like you say it must of been coincidence, and I say that in ernest not sarcasm.
It's just very confusing when I took my new car to my current tester (he drives a bug STI ) he said no you never put a Subaru on a 2wd brake roller ? It would be a lot more reassuring if everyone knew for sure.

Joz to give them credit they did offer to take a look, but as they were not Subaru specialists I didn't fancy them taking the box apart, I ended up selling the car at a loss to me.

 

Even more confusion, this seems to of been talked about on here before.
https://www.scoobynet.com/general-te...t-rollers.html

 

Sorry, I just scan read that, and dropped it as soon as I registered the Bollocks.
A brake test will not hurt Impreza transmission.

 

And it's not just that thread, there are plenty more, hence my confusion, but if you can 100% say it won't do any harm, then it's good to finally know for sure
Thanks
Peter.