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PostPosted: May 22, 2020, 10:11 pm 
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Joined: March 3, 2006, 10:48 pm
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Location: Shawnee, Ks
Brake bias adjuster needed?

OK let me explain what I have and what the problem is. My Locost used a British 1979 Escort MK2 estate as a donor. I just upgraded my front brake calipers to Wilwood 4 pots. I have the standard drum brakes in the rear and the standard single master cylinder with separate lines going to the RT front and LF front brakes and a single line going to both rear brakes. These brakes are a LOT better than the original ones I had and I love them. But I am having trouble when applying hard braking. The RF front caliper will lock up especially when cornering while braking. The car does not seem to pull to either side on hard braking. Rear drums will lock up under panic stops. Do I need a bias adjuster? How do you plumb it in to the lines. Any recommendations of what brand? Thanks and stay safe by social distancing in your se7en, Russ

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PostPosted: May 22, 2020, 10:24 pm 
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Joined: February 8, 2014, 10:47 pm
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Location: Cornholio OR "Where the magic happens"
If you want to threshold brake you will likely want 2 master cylinders and a balance bar.

And some pressure gauges to tell you what is happening.

I don't recommend using a single master and a proportioning valve, inadequate and unpredictable performance.

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PostPosted: May 22, 2020, 11:35 pm 
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Joined: September 30, 2005, 1:28 am
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Location: Sunny-Okanagan, Canada, eh?!
If you're finding the rears are locking under hard panic stops, I would recommend a proportioning valve.

Light braking can have more rear brake pressure without issue, but that same brake balance will be too much for the rear when all that weight shifts forward. In that case, you would want a proportioning valve to limit brake pressure to the rear under heavy (panic) stops.

If you don't have a well balanced system with a single master, I recommend dual masters and a balance bar (I did that on my car - best upgrade of all time). You CAN have a well balanced system with a single master, IF you can size the brake caliper pistons appropriately. I run dual masters, a balance bar, AND a proportioning valve. Haters gonna hate. It works awesome.

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PostPosted: May 23, 2020, 5:41 am 
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It seems that you may have one or more issues to attend, but make sure you're treating the cause(s) and not the symptom(s).

Just one caliper in the front circuit having a tendancy to lock up, that the other caliper in the front circuit doesn't have, does not sound like a bias issue to me.

I also don't know anything about Mk2 Escort drums, but my only experience with (modern) drums was that a quick stab of the brakes would cause the leading shoe to self-energize and result in premature (and unexpected) lockup. So I'd argue that's not necessarily a bias issue either.

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PostPosted: May 23, 2020, 7:30 am 
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Location: 4AGE in S.E. Michigan
Driven5 comments = Just one caliper in the front circuit having a tendancy to lock up, that the other caliper in the front circuit doesn't have, does not sound like a bias issue to me.

I would bet that with a passenger, you would not have that braking lock-up tendency on the RH front. Try putting in a couple turns in the RH front spring. It's always a compromise between brake balance with one or two people in such a light car. You may find that you will also have to add turns to the LH rear shock, ending up with a diagonal wt balance.
Davew


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PostPosted: May 23, 2020, 9:58 am 
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Joined: July 17, 2008, 9:11 am
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Location: West Chicago,IL
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The RF front caliper will lock up especially when cornering while braking.
Russ, you don't say which way you are cornering, This might help in determining if the front wheels are not matched in performance. I would first start on the balance of the front brakes in both LH and RH corners before trying to balance front/rear.

BTW, I would think that by getting the brake balanced without a passenger, when a passenger is added, the balance will be "off". By how much? I don't know. You will have to decide where you want things balanced and go on to the rear brakes from there.

The above is just a novice's musings. I am not a brake expert. BTW you might want to enter your car's data into the brake calculator found somewhere on the sight and see what it says.

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