Brake Cylinder Sizes Hawk 289

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kdavies3
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Brake Cylinder Sizes Hawk 289

Post by kdavies3 » Thu Jan 30, 2020 7:52 pm

Hi Guys,
I've already searched the forum and come up a little confused.
I have Gerry's balance bar pedal box.
I need to know what size brake cylinders to use.
I have Princess 4 pots at the front and Jaguar XJ40 outboard rears.
No servo planned.
I'm leaning towards a pair of 5/8" cylinders from what I've read?
Hopefully a little less pedal effort but maybe a slightly longer stroke.
Any help and advice greatly received.
Kev Davies
DAX Mk4, 383 Chevy Stroker, Tremec. SOLD
Contemporary CCX 3-4028, 445ci Big Block FORD FE,TKO 600. SOLD
Dax De Dion LS2 and T56. SOLD
1965 Ford Mustang 289 Convertible FOR SALE
In build Hawk 289 Sebring. :D

peterc
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Re: Brake Cylinder Sizes Hawk 289

Post by peterc » Fri Jan 31, 2020 10:36 am

Hi Kev,
I don’t know the relative sizes of your princess callipers or outboard rear callipers but I can advise what my set up is as a guide.
Front callipers are Willwood 4 pots and rears are standard inboard Jag.
My master cylinders are 0.625” with the balance bar set equal front to rear.
As the master brake cylinders and front callipers were supplied by BGC Motorsport in Wisbech as a package I have gone back to them for any spares/ replacements.
I would contact them for advice and purchase.
Peter C

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kdavies3
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Re: Brake Cylinder Sizes Hawk 289

Post by kdavies3 » Fri Jan 31, 2020 6:39 pm

Thanks Peter, I might just do that.
Yours are 0.625" which is 5/8"
I read that many folks seem to have the balance bar biased all the way to the front brakes.
Maybe your Wilwoods are very good?
Kev Davies
DAX Mk4, 383 Chevy Stroker, Tremec. SOLD
Contemporary CCX 3-4028, 445ci Big Block FORD FE,TKO 600. SOLD
Dax De Dion LS2 and T56. SOLD
1965 Ford Mustang 289 Convertible FOR SALE
In build Hawk 289 Sebring. :D

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Re: Brake Cylinder Sizes Hawk 289

Post by FIAJack » Fri Jan 31, 2020 7:22 pm

Hi Kev,
I have Hi Spec Brakes front and Jag inboard rear. Passed IVA comfortably with 5/8" - 0.625" cylinders and with balance bar fully biased to the front.
Same setting works equally well with MGB drum brakes on rear. Hope that is of some help.

Cheers
Jack

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nikbj68
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Re: Brake Cylinder Sizes Hawk 289

Post by nikbj68 » Sat Feb 01, 2020 9:59 am

Don’t forget that for IVA, the balance bar must not be adjustable!
Hawk 289 FiA...AT LAST!!!

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clive
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Re: Brake Cylinder Sizes Hawk 289

Post by clive » Sat Feb 01, 2020 11:29 am

I have Princess 4 pots front and Jag inboard rears with a heavy Ford 302 engine. The cylinders are Gerry's standard supplied. Prior to SVA I had the balance bar set to 50:50 and the rears would lock way before the fronts. Following advise from Gerry, I set the brake balance bar to max front and the car handles wonderfully.

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kdavies3
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Re: Brake Cylinder Sizes Hawk 289

Post by kdavies3 » Sat Feb 01, 2020 11:40 am

Thanks Guys, I think I'll order up a couple of 5/8" (0.625) cylinders and a 3/4" (0.75) for the clutch.
Kev Davies
DAX Mk4, 383 Chevy Stroker, Tremec. SOLD
Contemporary CCX 3-4028, 445ci Big Block FORD FE,TKO 600. SOLD
Dax De Dion LS2 and T56. SOLD
1965 Ford Mustang 289 Convertible FOR SALE
In build Hawk 289 Sebring. :D

peterc
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Re: Brake Cylinder Sizes Hawk 289

Post by peterc » Sat Feb 01, 2020 2:47 pm

My front discs are the max size that fits inside the alloy wheels. E.g 298 mm. The callipers clear the wheel weights by around 1.5 - 2.0 mm.
For the SVA I had to perform an emergency stop in both directions so the inspector could check for lock up of the rears. He was happy and I have never been aware of a problem but then maybe I just don’t make a habit of braking that hard.
Back in the SVA days you didn’t have to permanently lock your adjustable balance bar.
Peter C

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