MOT & brakes

[rcraven]

My S4/Sprint has just passed its MOT at a local garage I knew of but haven't used before and they've attached a print-out I don't remember having before and which I couldn't study in time to ask them about it.

It says measured weight 820kg, which is I suppose about right (or a bit high?): there was little petrol in it, but a typical collection of tools, and a Safety Devices (T Thomson) roll-bar & side members.

The footbrake figures were 329 kgf (hardly an SI unit) front & 304 kgf rear (all locking), with 27% difference and 77% efficiency, and the handbrake 258 kgf and 31% efficiency. Apparently (as I did) it's not unusual to get different left and right figures, partly because the tester will be sitting on the right.
I've given up trying to see how the 27% difference is calculated; the nearest I get from permutations of the various figures on the form is 28%, and apparently it shouldn't exceed 25% and yet the car passed.

Apart from the fact it passed (which requires 50% and 16% efficiency respectively apparently), are these figures good for an Elan? It has a servo but I don't suppose that matters once the wheels lock because I assume you could lock the wheels without a servo.

PS if there any Elan owners in my locality (Swansea - but as far as I know there aren't anymore) I recommend the garage for MOTs: Jenkins Brothers of Bishopston.

[jono]

..that surely includes the weight of the MOT guy?

[elansprint]

Robert I was trying to work out the weights against the stated figures on my TVR's came to the conclusion as they measure each axle weight when dropped into the brake tester their is some weight transfer it is not measuring all 4 wheels together. I believe on brake force the rear has to be 50% of the fronts not 25%
Ian

[alan.barker]

The handbrake is 20% minimum in France.
In France they also measure the "Angles Ripage" which i don't understand what it is.
Alan

[nmauduit]

Robert I was trying to work out the weights against the stated figures on my TVR's came to the conclusion as they measure each axle weight when dropped into the brake tester their is some weight transfer it is not measuring all 4 wheels together. I believe on brake force the rear has to be 50% of the fronts not 25%
Ian

on the type of bench on which it is usually done here there should not be any noticeable weight transfer, since the axle under test is assessed quasi statically on 2 rolls, for pulling until slippage occurs and measuring at about the same location (it still makes sense to assess brake operation statically so without weight transfer, since light to moderate braking is the most common situation, and provides a reasonable assumption on what would happen on the road under hard braking).

[nmauduit]

The handbrake is 20% minimum in France.
In France they also measure the "Angles Ripage" which i don't understand what it is.
Alan

"ripage" means being pulled sideways, in MOT context is represents the side motion of the car, measured in meter per kilometer forward when the steering wheel is left free (usually showing a geometry issue)

[alan.barker]

Thanks, i understand it means to drift or pull to one side. If it is more than 10 mtr /100 mtr it is just marked excessive.
I think i need to have a close look to see if there is any wear and also check the Tow in.
It also seems if the tester has not driven the car straight onto the test rollers but done a last minute manouvre it changes the result. Like when you adjust the Tow in you need to roll the car backwards and forwards to let the adjustment settle.
I must get my laser Tow in tool down from the shelf and check this out
Alan

[Chancer]

Angle de ripage is toe in / toe out, as they drive the front wheels over the grease plates they will move relative to each other by a tiny angular amount unless the track is exactly parallel, if the measure is outside of the CT (contr?le technique) limits then it really is a long way out by Elan standards.

I really like the dynamic damper testing that they do, I havnt had an MOT in the UK since 2002 so do they do that there now, is it part of the test?

What else has changed in that time?

[Chancer]

Years ago you used to be able to buy a tracking guage that worked like the ripage plates, might have been called a Trakrite, it seemed pretty flimsy yet expensive to me and anyway I am Lucky to have some vintage Dunlop tracking guages (note to self get them back from friend who does not look after Tools ) does anyone have one of those guages and do they actually work? I realise the principal works hence their use in the CT test but their plates are a bit more than 2 pi?ces of cardboard or plastic.

[Craven]

https://www.amazon.co.uk/Gunson-G4008-T ... 74ZWMZ4DRG

[AHM]

What else has changed in that time?

The UK MOT has been brought into line with the EU - There is now no test for dampers.

[alan.barker]

In France contr?le technique the Dampers are tested.
Alan

[rcraven]

It depends what you mean by a "test for dampers".
Section 2.7 requires shock absorbers to be examined for e.g. leaks and security, and the suspension as a whole has to be examined but generally it's a manual examination rather than some automated test, and I suppose it's true that the test doesn't expressly require the actual damping effect to be checked.

[alan.barker]

When i go to "Contr?le Technique" and the wheels are on the rollers the rollers vibrate a lot to test dampers.
For sure the dampers/shocks are inspected also for any leaks.
I have lived in France for 25 years and it has always been like that each time.
I don't know the section number or reference bla bla
Alan

[englishmaninwales]

When i go to "Contr?le Technique" ........... on the rollers the rollers vibrate a lot to test dampers

Sounds like typical bureaucratic tick box snake oil to me. A 2CV would probably fall off the rollers regardless of how serviceable the dampers are