twybrow
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| posted on 18/5/09 at 07:25 PM |
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Brake Balance - help wanted
I booked my SVA retest today, for a week on Friday. Fantastic, except I tested the brake balance today at the local MOT station, and it was
rubbish!
My setup is:
M16 front calipers, with new grooved discs (old pads)
Escort 9" drums, all new bits
Bias bas, with 2 x 0.75 MCs
At SVA, all of my brakes work wonderfully, but the fronts locked after the rears. I thought it was my stupidity for setting up the balance bar
incorrectly, so I switched the lines. When I tested again today, it was worse.
My plan is to switch the lines back around, and then tackle the lack of balance. My bias bar doesn't seem to make enough of a difference on its
own, so I am thinking of fitting something else. As far as I see it my options are:
- Wilwood/AP adjustable (suitably locked)
- Fiat Uno (seen a few posts on this - is it easy?)
- Bargain ebay bias valve (£30)
- Modifed mini valve (seem expensive for what they are)
- Mondeo non-ABS reduction valve
Can anyone tell me what they would advise? I would be happy with something non-adjustable, as I have the bias bar for tweaking. On the other hand, I
think I need to reduce the rear pressure by a reasonable amount, so it might be good to have the full range. Any advce from those in the know?
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blakep82
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| posted on 18/5/09 at 07:31 PM |
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is it twin master cylinders? different size master cylinder i'd say, but i can remember how it works. is it a smaller one you need?
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twybrow
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| posted on 18/5/09 at 07:35 PM |
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Twin master cylinders. I was trying to avoid changing master cylinders, as I think with 10 days to go, it would be a tall order! I have no idea, as I
didn't fit the MCs to my car, but I cant see it being a quick fix!
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blakep82
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| posted on 18/5/09 at 07:41 PM |
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as long as you can get a new mc within 10 days, which should be easy enough, it should only really be a case of undoing the 2 nuts or bolts that hold
it on, and unscrewing it from the clevis on the balance bar. then do it again in reverse to fit the new one.
ok so i've not actually filled up my system yet and used it, but it shouldn't really take any longer than about 30mins.
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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twybrow
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| posted on 18/5/09 at 07:44 PM |
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How do you unscrew it from the clevis? Is it literally a case of turning the pivot to MC pushrod, or am I missing something?
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big_wasa
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| posted on 18/5/09 at 07:46 PM |
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Acording to what I have read you should have a smaller front cylinder. ie .625"
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Andy W
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| posted on 18/5/09 at 07:50 PM |
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Just wondered how you tested the bias at the MOT station, has he got the gear to tell what pressure you are putting on the pedal?
Andy
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tomgregory2000
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| posted on 18/5/09 at 07:50 PM |
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The shafts on the mc turn so all you have to do is get your hand down behind your pedal and spin the shaft with your fingers.
As easy as that 
And yes you should have .625" front and .7" rear
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twybrow
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| posted on 18/5/09 at 07:56 PM |
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The MOT station didnt have the pedal thingy, he was just looking at how much force (kgF) it took before the brakes locked. When testing the rears, the
gauge went much higher before locking than the front.
I am now wondering if a change in MC is the way to go. Do the wilwood MCs have their size on them? I did notice a few numbers on there last time I
looked at mine, but can't be sure. I want to be certain of what I have before I buy anything else!
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blakep82
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| posted on 18/5/09 at 07:59 PM |
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wilwood are stamped in inches, 0.75, 0.7 and 0.625 should be stamped (or raised?) on the sides of the body.
if you can't get your fingers round to the pushrod (i can't on my car) then turning the whole thing round will work just as well
[Edited on 18/5/09 by blakep82]
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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cd.thomson
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| posted on 18/5/09 at 08:59 PM |
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i have a 0.625 surplus to requirements if you find you need to fit one 
Craig
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twybrow
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| posted on 18/5/09 at 09:09 PM |
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CD. Thomson - u2u sent.
Well I have just taken out one of my MCs. What a PITA those bolts are - oh how I wished I hadn't pinned the bias bar already!
I get the feeling getting the old one out was the easy bit....! Hopefully, I have sorted a 0.625" to put in place, which I am hoping will make
all the difference! Now I just have to hope my brake light switch will still work (in the rear line, which will now be lower pressure).
Thanks for the replies chaps - you lot never cease to amaze me with your speed and depth of knowledge.
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