Jasper
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| posted on 25/3/09 at 03:53 PM |
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Balance bar locking again!!!!
Balance bar is driving me nuts, broke 3 drill bits trying to drill through it.
Anyway - does it need to be locked solid, as in not able to wind either way at all, or is a little bit of movement allowed? At the moment, I can turn
the bar about 3 turns.... if it's no good I'll pack one end with nylon washers.
If you're not living life on the edge you're taking up too much room.
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adithorp
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| posted on 25/3/09 at 03:58 PM |
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It has to be locked so that it can't be adjusted. Three turns is deffinatly adjustment! You do need some play though, otherwise the balance bar
won't operate.
adrian
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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Mix
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| posted on 25/3/09 at 04:24 PM |
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Hi
I think I'm correct in saying that under SVA as long as the sytem passed the test at both extremes of adjustment it was OK to have limited
adjustment.
However an extract from draft IVA
23. It must not be possible to manually adjust braking rates between axles: (:
Regards Mick
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Gav
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| posted on 25/3/09 at 04:36 PM |
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At my test the tester told me that you CAN have a range of adjustment it so long as that the adjustment does not cause a fail condition.
If you can adjust it, it will be tested at the each extreme of adjustment.
Play it safe, fiddle with it to make sure the fronts lock up first then pin it so that their is no adjustment, which in effect makes it a locked bias
and will be tested as is.
[Edited on 25/3/09 by Gav]
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MikeR
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| posted on 25/3/09 at 05:47 PM |
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Daft question - what is the definition of 100% welded? If I seam weld the bar and continue the seam onto the bias bar would that be enough?
I'll be IVA'ing and i'm wondering about how exactly i'll weld up the bias bar once everything is fitted.
(the intention to go, fail, adjust so its a pass and then weld and retest).
I suppose another question is - would a car that passes MOT on brakes pass IVA so i could set the car up on the MOT rollers, then weld.
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Andy W
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| posted on 25/3/09 at 06:12 PM |
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you can't test the bias on most mot rollers as they have no way of recording the pressure applied to the front or rear
Andy
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Jasper
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| posted on 26/3/09 at 03:24 PM |
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Cheers chaps....
If you're not living life on the edge you're taking up too much room.
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NS Dev
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| posted on 26/3/09 at 08:12 PM |
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sorry for this but get ready for a rant.............
WHO THE HELLL SAID WELD THE BLOODY BIAS BAR  
DECENT ONES ARE MADE FROM HIGH STRENGTH ALLOY STEELS (such as EN24 etc) AND WILL HAVE THEIR STRENGTH SERIOUSLY COMPROMISED BY WELDING THE THREADED
BAR!!!!!!!!!
This is utter rubbish and if it came from VOSA then they need their heads examining.
if it is somebody's interpretation of the rules then I hope they don't build cars!!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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coozer
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| posted on 26/3/09 at 08:24 PM |
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How about a dash adjuster then drill through that to lock it??
1972 V8 Jago
1980 Z750
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wicket
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| posted on 26/3/09 at 09:56 PM |
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From the draft IVA manual
Note 5: Bias bars and other mechanical adjusting devices fitted to twin master cylinders must have no means of adjustment. However they will be deemed
acceptable if the all nuts etc are fully welded to their relative threads and all the threads originally intended to provide adjustment are welded
along their length i.e. permanently rendering them un-adjustable.
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NS Dev
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| posted on 26/3/09 at 10:21 PM |
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I am quite happy with the blanket statement about no adjustment.....it removes all the potential debate at the test centre, anything designed to
adjust, whether locked or not, fails.
pretty simple when building the car, make up a (non threaded) bar with spacers of fairly thin width (washers even) to control pivot position, test the
car to determine if the guessed initial position is right, reset if not, once right, replace washers etc with machined distance pieces pinned at
either end of the bar, outside of the stressed portion.
Nothing can be said about the bar being "dismantlable" because it must be to enable construction, and therefore can be again in the future
for the distance pieces to be remade to different dimensions should the need arise. the bar is not "adjustable" because no adjustment can
be made without adding new parts.
Suggesting welding the threads along the bar is a ridiculous suggestion, and sorry if my comment seemed aimed at the tester on this thread, I assure
that it was not, I didn't notice that the post way by a tester until aster I made the comment.
nonetheless, for VOSA to include that statement leaves me rather shocked!!!!
My advice....most barke bias bars are rather weak to start with, I would not drill and pin in the stressed part of the bar, let alone weld it
anywhere.
I have broken one on a competition car due to fatigue failure originating from the thread form, if that puts things in perspective..............
[Edited on 26/3/09 by NS Dev]
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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