Donners90
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 posted on 15/4/06 at 01:13 PM |
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Locking of brake bias bar
In my wisdom, I drilled, pinned and cut the bias bar before I knew for sure that it was set correctly. Well it wasn't and consequently failed the
sva as the rears locked up before the front!
Anyway, I un-pinned the bar and wound it across until the front brakes lock up before the rear. However there is no longer any space on the bar to fit
a locking nut!
In the eyes of the SVA man, does it HAVE to have a lock nut (pinned) or can I pin the bar throught the nuckle? (shown in pic below)
Alternatively should I separate the bias bar and replace it?
Any advice is much appreciated
Thanks
James
 
Rescued attachment 100_0393.jpg
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Humbug
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| posted on 15/4/06 at 01:19 PM |
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Hi James
I has the same question, i.e. before the SVA how would I know what the brake bias was?
In the end I drilled through both knuckles (so that's what they are called!) and put split pins in, with no locking nuts at the ends. To
allow for some future adjustment, I drilled a number of holes: when the bar was all to one end, then every 5 or 10 turns of the thread, so I had the
option of changing the bias. At SVA the guy looked to see that the bar was locked, and this method was fine (caveat: at Gillingham, on that day, with
that examiner...).
Cheers
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MikeR
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| posted on 15/4/06 at 01:36 PM |
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whats your setup....
m/c, brakes front and rear.
Curious if i'll have a similar problem.
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rusty nuts
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| posted on 15/4/06 at 03:11 PM |
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When I did mine I put the knuckles in a lathe, drilled and tapped them to take a socket head screw used with a lock nut. The bias bar had a small flat
milled on it . At SVA car failed on brake bias but tester had a cuppa while I tinkered. Just slacken locknut and socket head screw , turn bias bar and
relock. Tester was happy with solution
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nitram38
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| posted on 15/4/06 at 05:36 PM |
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For the SVA, the brakes must not be able to be adjusted beyond their worst case senario. This means they can still be adjustable but not beyond the
limits already out lined. I have adjusted mine until just before the rears bite and then introduced pinned locknuts.
I also have locknuts that still allow adjustments within these limits.
For instance, a race car may put half to one turn towards the rear bias in certain conditions.
The bias cannot be adjustable from the driving position either.
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Dusty
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| posted on 15/4/06 at 06:03 PM |
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Just read my manual.
Specificaly states that lock nuts, split pins or adjustable stops are not in isolation considered acceptable. However a roll pin that penetrates the
full width of the bar is.
It doesn't specificaly mention adjustment from the drivers position but states that if an adjustable device is present the decelerometer test is
to be done with the bar adjusted for maximum rear bias. I have heard of this test also being done with maximum forward bias and then both sets of
figures being checked against the tables which leaves very little margin for a pass.
Looking at your pedals you should have large penny washers between the clevis and pedal tube to stop interference. There is very good tech info on
assembly, adjustment and setup of pedal boxes in the Rally Design catalogue and possibly on their website?
[Edited on 15/4/06 by Dusty]
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wheezy
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| posted on 15/4/06 at 07:32 PM |
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You could also try turning your bias bar round the other way so you have the shorter threaded portion on the left and the longer thread on the
right.
This should give you more room for adjustment towards the front.
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Mave
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| posted on 15/4/06 at 07:49 PM |
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I'm considering the option below. Apparantly, this STM Phoenix has passed SVA with it. Just cover the brake balance bar, after you've set
it up correctly, with a cover.
However, I can't make out if this is exactly according to the rules, or that this guy was just lucky at SVA. What do you think?
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nitram38
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| posted on 15/4/06 at 08:06 PM |
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Looks too risky to me!
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britishtrident
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| posted on 15/4/06 at 08:26 PM |
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Tackle the problem at the root not the symptoms get the cylinder sizes right so the balance bar bearing is close to the centre of the pedal cross
tube.
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britishtrident
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| posted on 15/4/06 at 08:34 PM |
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And don't put any penny washers in they aren't required and will only cause problems just set the clearance between the crosstube and the
trunnions so as it is just enough to allow the balance bar to work but still give a fall back to single circuit brakes in the event of one circuit
suffering complete hydraulic failure.
For info see the AP Racing site.
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Dusty
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| posted on 15/4/06 at 09:37 PM |
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I'm baffled as to what problems penny washers could cause. There is definitely a possibility of the back of the clevis catching on the tube in
the pedal and stopping rotation without them on mine.
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nitram38
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| posted on 15/4/06 at 09:41 PM |
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quote:
Originally posted by Dusty
I'm baffled as to what problems penny washers could cause. There is definitely a possibility of the back of the clevis catching on the tube in
the pedal and stopping rotation without them on mine.
Mine catch without them
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Mix
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| posted on 17/4/06 at 08:04 AM |
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I've fitted penny washers in accordance with info from the AP Racing site
http://www.apracing.com/car/drawings/cp5500_4cd.pdf
Mick
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MikeR
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| posted on 17/4/06 at 02:57 PM |
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In theory I think the shield would pass. The SVA inspector isn't allowed to remove fixed parts of the car as i recall, therefore he can't
see the bias bar therefore he has to assume its ok. He may ask you. If you lie ..... ?????!!!!!
Of course the inspector is just human, if he sees lots of stuff covered up, he's going to get suspicious and start trying to fail you. I'd
rather have him in a good mood trying to pass me than the opposite.
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Donners90
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| posted on 20/4/06 at 02:27 PM |
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quote:
Originally posted by wheezy
You could also try turning your bias bar round the other way so you have the shorter threaded portion on the left and the longer thread on the right..
Good point, I hadn't actually thought of that. The simplist things are often overlooked!!!!
Anyway, thanks all for the advice and ideas ....not such a big problem as I originally thought!
Cheers
James
[Edited on 20-4-2006 by Donners90]
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chaos999
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| posted on 20/4/06 at 02:51 PM |
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Hi,
Triton Challenger SVA'd by boxing the balance bar assembly up so pedals visible. Rivet box to floor and it beomes fixed and therefor not
removabl by mr SVA. They have no issue with it as it is no longer adjustable.
Mitcham in Croydon SVA centre.
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Peteff
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| posted on 20/4/06 at 03:54 PM |
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The SVA inspector isn't allowed to remove fixed parts of the car as i recall,
He can ask you to remove them and fail you if you don't though.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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MikeR
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| posted on 20/4/06 at 05:06 PM |
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yeah but he can't ask you to remove riveted in bits .......... can he?
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