daveb666
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| posted on 28/9/15 at 07:35 AM |
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Sticky Brake Pedal
My car has an OBP floor mounted pedal box and bias bar with wilwood masters (front and rear separate of course).
When driving on Saturday the car felt like it was being dragged by something. At a trackday before I have had the brake pedal stick down when
returning to the pits so I gave it a stamp a couple of times in case that was the issue. This caused the car, to bring itself to a complete stop as
the pedal got further and further down LOL
I jumped out and reached under the dash and gave the brake pedal a shake and it popped back to its resting position, and off I went again.
This happened 2 or 3 times over the course of a 50 mile journey, quite un-nerving especially on the motorway.
I know people have had issues with master cylinders failing but I'm fairly sue the issue is with the bias bar binding/being too tight.
This is what mine looks like. (The dots indicate where I've added split-pins, post IVA).
 
Description
Anything look a miss there?
Feedback welcomed, I don't want this problem to happen when I'm on the track!
2007bc Photography - Commercial and Wedding Photographer based in West Yorkshire
http://www.2007bc.co.uk / http://www.huddersfieldcommercialphotographer.co.uk
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CosKev3
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| posted on 28/9/15 at 08:01 AM |
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Not got a bias set up myself but after a bit of reading on here is the lock nut set up too tight and not allowing the clevis things to move slightly
as the angle changes?
Also looks like the threaded part coming out of pedal on right hand cylinder is bent?could just be pic though.
Another thing I've seen people have issues with is not having any play in the rod from pedal to mc's,then when fluid gets hot the brakes
drag.
Were your issues only when hot or anytime?
[Edited on 28/9/15 by CosKev3]
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daveb666
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| posted on 28/9/15 at 08:17 AM |
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I think the 'bent' bit is just the camera angle, I hope. ha.
Over the last 2.5 years it's maybe done it twice, generally after a proper blat. On Saturday it was within the first few miles of the journey,
and then subsequently after pressing the brakes a few times so I'm fairly sure it is the bias bar but am just a bit confused as to why
it's started all of a sudden.
Should I have washers between the nuts and the clevis?
2007bc Photography - Commercial and Wedding Photographer based in West Yorkshire
http://www.2007bc.co.uk / http://www.huddersfieldcommercialphotographer.co.uk
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CosKev3
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| posted on 28/9/15 at 08:20 AM |
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Yeah pretty sure there should be washers between nuts and clevis,and clevis and pedal.
Should also be some slack so they can move as the angle changes due to the rods being set at different lengths.
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joneh
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| posted on 28/9/15 at 08:50 AM |
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There should be a gap, not washers. Looks like they're binding in the image.
Look at the OBP instructions on their site.
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daveb666
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| posted on 28/9/15 at 08:59 AM |
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This looks like there is a spacer on the inside of each locking nut in this image?
[Edited on 28/9/15 by daveb666]
2007bc Photography - Commercial and Wedding Photographer based in West Yorkshire
http://www.2007bc.co.uk / http://www.huddersfieldcommercialphotographer.co.uk
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gremlin1234
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| posted on 28/9/15 at 09:06 AM |
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it looks from your picture like the right hand bit of the bar may hit the box frame, that would give all sorts of issues, (including possibly bending
the bar...)
and otherwise, it just looks too 'tight'
this link from wilwood may help
http://www.wilwood.com/TechTip/TechPedalTip.aspx
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rusty nuts
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| posted on 28/9/15 at 09:16 AM |
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Three doesn't seem to be any clearance at all on the right hand Clovis as others have pointed out . Try taking off one of the lock nuts nearest
the Clovis? My car has the Luego version of the bias box , when I built the car I drilled and tapped each of the threaded boss's and fitted a
grub screw as a locking device , easy to slacken off if ever I need to adjust the bias. I have found a squirt of silicon grease on all the moving
parts helps to keep things free
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daveb666
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| posted on 28/9/15 at 09:24 AM |
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I'm fairly sure it doesn't hit the frame, but I will check tonight.
This photo shows some 'spacers' on the inside of the nuts on a different installation.
Does everyone else have these spacers? If I remove the inner of the 2 nuts to give a bit more slack then surely, with the increased room the bar will
be free to rotate?
[Edited on 28/9/15 by daveb666]
2007bc Photography - Commercial and Wedding Photographer based in West Yorkshire
http://www.2007bc.co.uk / http://www.huddersfieldcommercialphotographer.co.uk
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britishtrident
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| posted on 28/9/15 at 10:43 AM |
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quote:
Originally posted by daveb666
I'm fairly sure it doesn't hit the frame, but I will check tonight.
This photo shows some 'spacers' on the inside of the nuts on a different installation.
Does everyone else have these spacers? If I remove the inner of the 2 nuts to give a bit more slack then surely, with the increased room the bar will
be free to rotate?
[Edited on 28/9/15 by daveb666]
As on yours the bias bar is set way off centre, bias bars really don't work well with the fulcrum bearing set so far away from the centre
position,
It is best to try and size the master cylinder bores to get the balance fulcrum position within a few turns of the halfway point.
[Edited on 28/9/15 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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CosKev3
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| posted on 28/9/15 at 11:26 AM |
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quote:
Originally posted by daveb666
I'm fairly sure it doesn't hit the frame, but I will check tonight.
This photo shows some 'spacers' on the inside of the nuts on a different installation.
Does everyone else have these spacers? If I remove the inner of the 2 nuts to give a bit more slack then surely, with the increased room the bar will
be free to rotate?
[Edited on 28/9/15 by daveb666]
Yeah you need spacers like that.
They will allow the clevis to pivot side to side,but not allow it to turn on the threads.
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adithorp
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| posted on 28/9/15 at 12:33 PM |
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Couple of things from that picture...
As BT says you'd improve the set-up by putting a smaller dia' master on the righth hand side thus allowing the fulcrum to be more
centered.
Having the spacers is fine but their diameter looks close to being a tight fit in the clevis and might be binding (also check the plain section of the
bias-bar for the same thing). Is there good clearance?
However I'd always say illiminate the obvious before looking for other things... There's a lot of crap around so I'd clean all that
out and re-lubricate it all; bias bar and the main pedal pivot.
[Edited on 28/9/15 by adithorp]
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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daveb666
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| posted on 2/11/15 at 09:48 AM |
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Further to this post.
I've slackened off the nuts next to the pedal, still have the same issue.
Does that mean a faulty MC?
2007bc Photography - Commercial and Wedding Photographer based in West Yorkshire
http://www.2007bc.co.uk / http://www.huddersfieldcommercialphotographer.co.uk
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daveb666
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| posted on 14/2/16 at 02:49 PM |
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Further to my post above - I've replaced the full pedal box with a posher OBP one, the front callipers with wildwood dynasties and bigger discs
and one of the master cylinders for an OBP one.
It STILL does it - does that mean that the problem MUST be the remaining Wildwood master cylinder or is there something else I've missed?
Please help 
2007bc Photography - Commercial and Wedding Photographer based in West Yorkshire
http://www.2007bc.co.uk / http://www.huddersfieldcommercialphotographer.co.uk
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Chazzy
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| posted on 28/2/16 at 10:10 PM |
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Maybe you have fixed this by now, but I had a similar situation where one of the MC rods would not fully return which led to the next application
could be a little eye opening. The problem was the rubber bellows grabbing the rod. Dab of grease and wiggling sorted it.
Good luck, I've got nowhere near your p/w ratio so things happen a little less rapidly.
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