Aborted MOT

latil · Post by **latil** » Sat Mar 25, 06 2:56 pm

I thought there was no lube unless the convertor or input shaft were turning?

Rebel · Post by **Rebel** » Sat Mar 25, 06 6:37 pm

you can tow an auto, but only for 30 miles at no more than 30mph, which is probably why most are recovered on a dolly. Apparently you can even bump start them (never tried, don't intend to either) but it takes bravery as they reckon theres something like a 50 / 50 chance that it'll blow the box

Anonymous · Post by **Anonymous** » Sat Mar 25, 06 6:43 pm

i cant think of any auto that will bump start (but i heard a rumour about bmws once?) like steve says the clutches/bands ect wont operate without the engine turning the oil pump so there surely is no way to get it to engage

Cannonball · Post by **Cannonball** » Sat Mar 25, 06 8:14 pm

will some old auto boxes had a rear pump it was driven by the output shaft so you could bump start em, strike xx so your car weighs 37401bs what engine is in it??????

Rebel · Post by **Rebel** » Sat Mar 25, 06 8:16 pm

there is every possibility of it being an urban legend, I've never seen it done and don't know anyone who has tried it, I just remember being told it was possible. Doesn't sound right though

Derek · Post by **Derek** » Sat Mar 25, 06 8:50 pm

I tow started a ford Corsair 2000E auto, It was about 30 years ago, the battery was flat and it was the only way to get it home from Portsmouth.

Anonymous · Post by **Anonymous** » Sat Mar 25, 06 9:02 pm

I used to have a 1982 BMW 528 auto you could bump start. You had to go 20-30mph for it to work though and the gear change was naff for about 20 minutes after.

latil · Post by **latil** » Sat Mar 25, 06 10:32 pm

I've heard stories of it being done with BW35 boxes in old Granadas etc with towing speeds above 50mph before anything happened

Cannonball · Post by **Cannonball** » Sun Mar 26, 06 2:14 am

some bw boxes also had a rear pump............ thats your answer guys REAR PUMP drive shaft driven by the rear wheels

Dave-R · Post by **Dave-R** » Sun Mar 26, 06 11:13 am

But my question was;

Could a roller type brake tester used during the MOT damage the trans on our Mopars?

Anonymous · Post by **Anonymous** » Sun Mar 26, 06 3:41 pm

Presumably you are meaning if the rollers are turning with the engine off ?

If the engine is running, and the car is in netutral, then the rollers would turn the rear wheels without any problem. Similar, I would think, to having the car coast down a hill and expect to be able to brake to a halt at the bottom without any drama to gearbox or diff.

I guess also that the engine must be running during the brake test to provide vacumn for the system so there is a 'true' representation of the system as it supposed/designed to work.

Theoretically, I would hope that MoT stations run the tests with the engine running anyway ? They need the cats to light off at temperature, plus they pick up engine rpm from a plug lead for the emissions tests.

Kev · Post by **Kev** » Sun Mar 26, 06 3:46 pm

Brake test is done side to side and can kill the LSD? My old station didn't test LSD cars on the rollers after blowing up a 4x4 axle and having to have the vehicle craned out of the rollers. They did mine with the brake balance meter thang on the road. Strange seeing yer car being driven off and coming back

Anonymous · Post by **Anonymous** » Sun Mar 26, 06 4:26 pm

The brake test is done on the rollers at a speed less than the equivalent of 5mph. The rollers turn so slowly (<20rpm) that you can almost watch the tyre markings go around and round. The two rollers are run simultaneously to centre the car and get a preliminary setting on the scale, and then each runner is run separately for each wheel, and an avaerage is taken for all four wheels on the foot brake (which must be more than 50% efficient) and the two rear wheels for the handbrake (must be more than 18% efficient).

The engine is running to give vacumn and the transmission is in neutral and the whole brake test should take about a minute to carry out.

LSD's shouldn't cause a problem, as they are designed to slip or differentiate between wheels. Even something like a Detroit Locker will slip enough to allow side to side testing.

Four wheel drives are a problem though if they are permanent four wheel drives and the tester should ask you, or know the vehicle, and instead use the G-meter for a road test. Even then, the speed should be between 5 and 20mpn max. There is trouble if the test is taken in the wet though.

The weight of the car needs to be known for the brake test, but going to a weigh bridge is excessive. Most testers would accept a book or manual showing the weight. The weight of the vehicle has always needed to have been known for the MoT test. So, it will be worthwhile if eveyone takes proof of vehicle weight for their tests. Figures from books should be sifficient. I assume that most testers in the past have 'guessed' a weight for the car.

The VoSA database is independant of anything else, even the V5.

Adam shouldn't have had a problem as (as Dave M. pointed out) you enter the details (rego number and VIN) and if the system does not recognise them it asks again, and again, and them allows you to put in your own details, so no Dodge Coronet should end up being a jeep, especially as it asks you what vehicle type it is; coupe, four door, etc...

The roller won't blow up LSD's, otherwise there would be plenty of broken Jaguars, Mercedes, Lexus, etc, etc lying about the place.

Got this from our friendly MoT man.

Storm in a teacup .....

P.S. Adam, my friendly MoT man was a bit concerned that your car is now Chrysler/Jeep and not a Dodge, especially if you should have, heaven forbid, a 'problem'.

Alex · Post by **Alex** » Sun Mar 26, 06 4:30 pm

I agree, about the only rear that may cause a problem would be a spool !

Adam · Post by **Adam** » Sun Mar 26, 06 9:30 pm

Thanks for the advice Sandy (& others). I didn't mention that the MOT tester also insisted on putting the year of first use as 1980 (the year it was imported to the UK), and he never asked for the weight. So I'm a bit hacked off that I have an MOT certificate for a 1980 Chrysler-Jeep that doesn't weigh anything

.
I'll see if I can straighten it out with the nearest VOSA office tomorrow, but I have a feeling I'm going to have a long day...