owelly
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| posted on 20/5/08 at 09:08 AM |
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Brake M/C bore size?
I've done a search and spent a fair bit of time reading through posts that don't tell me what I want so.............
When I got my (pre-built/dismantled) car, it had the M/C of a 1936 Hohoofer Mk6 (probably). It was full of sand and spiders so I replaced it with a
dual circuit item (previously a single) built form several other random components tyhat I found in my 'Brakes box'. The items I used were
from a M/C that should be bolted to a servo. As I have no need (or room) for a servo, I didn't use it!
The problem is that you need two feet on the brake pedal to have much effect on the speed of the car and even then, it just saunters to a halt. It
passed the brake test for the MoT but god knows how!
I have now found a M/C of a Mondeo that I can fit. It also used to have a servo but now doesn't!
The car has standard Escort calipers and drums but will soon have Mondeo fronts.
Is it worth me fitting the Mondeo M/C?
Should I splash out on a new M/C from Rally Design? And if so, what size? I'll revert back to a single circuit because thay are cheaper
M/C's!!
Cheers folks.
http://www.ppcmag.co.uk
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JAG
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| posted on 20/5/08 at 10:12 AM |
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Firstly I think the single circuit stuff is now illegal to use on the road unless OEM.
Secondly; If you can't/won't/don't want to fit a servo then you need a small bore m'cyl' something around 17-18mm bore
diameter. Such things were fitted to MkI & MkII Escorts and Triumph Spitfires. Westfield and Caterham use similar parts so maybe somthing from
them.
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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britishtrident
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| posted on 20/5/08 at 10:14 AM |
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Using a master cylinder from a car with servo but without a servo fitted will make the brake very heavy to use.
You need a smaller bore cylinder from a non-servo model.
ie servo equiped cars have 0.81" or bigger bore master cylinder, you need a master cylinder with a 0.7 or 0.75" bore.
Brake pedal effort is in inverse proportion to area of the master cylinder piston --- ie in inverse proportion to the square of the bore.
However in the UK donor cars with dual circuit brakes and no servo are rare.
Fiesta Mk1 1976-83 950 & 1100 car and van (non servo models).
Cortina Mk3 1300 1970-76 (non servo models)
Triumph Spitfire 1500 1975-1980
VW Polo 1100 1975-81 (non-servo models)
Brakes International should be able to supply although you may have to source a resevoir seperately.
The brakes internation site shows l the bore each of of the cylinders in mm.
Westfield also sell a 0.7 bore master cylinder as supplied as standard with their kits under part number 2314186
[Edited on 20/5/08 by britishtrident]
[Edited on 20/5/08 by britishtrident]
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owelly
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| posted on 20/5/08 at 06:51 PM |
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Cheers folks.
Like this?
http://www.rallydesign.co.uk/product_info.php?cPath=562_582_584&products_id=4052
http://www.ppcmag.co.uk
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britishtrident
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| posted on 20/5/08 at 10:09 PM |
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Thats a single circuit cylinder you really want to use a dual circuit cylinder and stick to mainline volume manufacturers parts -- Girling, Lockheed,
ATE (Teeves).
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britishtrident
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| posted on 20/5/08 at 10:12 PM |
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like this
 
Rescued attachment 173.jpg
[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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owelly
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| posted on 21/5/08 at 10:06 PM |
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Cheers. I'll see what the local factors have sitting on the shelf!
http://www.ppcmag.co.uk
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