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Balance bar and IVA
Thinking about it - 6/9/10 at 08:48 PM

Are balance bars ok for IVA?

I understand they have to be so they can no longer be adjusted once set.

If this is the case is a welded nut, a pin through the bolt of a cover over the whole thing acceptable?

interestedparty - 6/9/10 at 08:57 PM

needs a roll pin through the nut each side to be sure of passing, or maybe lockwire, and the bar has to be correctly adjusted first, and the only way you can be SURE of that after an IVA. Catch 22 IOW

marcjagman - 6/9/10 at 09:02 PM

Surely to set the correct brake force you could take it to your local MOT station? Pay for an MOT and I'm sure they would let you use their brake machine for the length of a test so you could adjust the bias.

Thinking about it - 6/9/10 at 09:03 PM

quote:
Originally posted by marcjagman
Surely to set the correct brake force you could take it to your local MOT station? Pay for an MOT and I'm sure they would let you use their brake machine for the length of a test so you could adjust the bias.


Just what I was thinking. At the MOT station next door to the workshop.

blakep82 - 6/9/10 at 09:10 PM

i didn't think mot brake testing machine tested quite the right thing?

iank - 6/9/10 at 09:42 PM

The rules were eased recently, IVA originally insisted it was welded up. But you can just use lock-wire to do the job (smaller hole so stronger than a roll pin), but if you do you need a label warning people not to touch it... The wording is in the latest IVA manual.

Discussion here:
http://www.locostbuilders.co.uk/viewthread.php?tid=137353

Ben_Copeland - 7/9/10 at 06:14 AM

Mot brake machine will only give rough settings. As iva have special foot pedal that measures the pressure the tester is applying. Doing it different pressures and the brake must reach a certain force.

Not something the average mot brake machine is capable of

big_wasa - 7/9/10 at 06:34 AM

Nottingham Iva guy said as long as it could not be adjusted without tools he was happy. He also went onto say that two nyloc's would be fine.

His feeling was, it was unsafe for an amature to be welding and drilling such a critical item.

It does look like that not all Iva inspectors are using this interpritation though.

gavin174 - 7/9/10 at 07:04 AM

"Unsafe for an amateur to weld or drill such a critical item...."

But they can build a complete car

interestedparty - 7/9/10 at 07:38 AM

quote:
Originally posted by marcjagman
Surely to set the correct brake force you could take it to your local MOT station? Pay for an MOT and I'm sure they would let you use their brake machine for the length of a test so you could adjust the bias.


You would think so, but not, unfortunately.

The problem is that they test at different pedal pressures, and it is perfectly possible (even likely) that a set up which is ok at full pressure is not ok at a lower pressure (think light dab on brakes on slippery road).

As to what constitutes 'locking', that varies from one test station to another, but the official word, from their big cheese, is nylocs are NOT ok, needs to be some positive, and observable system such as wire or pins.