Some reading for you guys !
https://www.f150online.com/articles/...e-pedal-ratio/
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Some reading for you guys !
https://www.f150online.com/articles/...e-pedal-ratio/
quote...https://emoji.tapatalk-cdn.com/emoji23.pnghttps://emoji.tapatalk-cdn.com/emoji23.pnghttps://emoji.tapatalk-cdn.com/emoji23.png meanwhile, in my confused, or is it just confusing, world, I've just got a rough measure of my brake pedal and I reckon it's about 13" or so on the big dimension. Brakes are manual and work great btw. Making me think that 9" / 1" might be on the overall slightly too small size to work properly given the masters requirements, or maybe its perhaps there or thereabouts OK and it's a bleeding issue as Neil's pursuing. Who's confused now!!
My confuser is refusing to work right now ( Ms upgrades no doubt) else I'd do some pressure sums.
Line pressure can be checked with a gauge, typically screwed into where a bleed nipple would be, but a disconnected line works too.
Chris
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13" on the big dimension, but is your cyl' pushrod somewhere along that dimension? ie the pivot is on end, pedal pad the other and pushrod attaches somewhere in the 'middle'.
neil.
Nope, the pushrod isn't 'somewhere in the middle', it's very much opposite the pedal end, but as I'm sure we know it makes no difference, but admittedly can introduce confusion for some into the measurements.Quote:
Originally Posted by mygasser
Picking up on John's link which I think is substantially ultimately derived from Wilwood info, it doesn't mention actual lengths in number but has A and B etc. In the text it talks about a say 10" length (doesn't say oh er missus) and 2" thus giving a 5:1 ratio and uses ratios to compute line pressures, but it doesn't give any suggestion as to proper lengths other than the say 10". Makes me wonder what the shortest workable length might be. Can't recall seeing that anywhere. Hhhmmm.
Chris
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The acceptable pedal pressure is 75lbs.... too some this will feel heavy and give an unacceptable feel too the brakes. Remember most of the time these are not race cars. Also with the double booster it should feel much lighter than Phil is getting. I reckon the ratio needs refucing snd possibly the 11/8 cylinder
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Looking at Wilwood as a hopefully reliable source, their swinging pedals, which are adjustable for length / pedal ratio have just shy of 11" as the shortest and somewhere over 12.5" for ratios between circa 6 and 7 :1 ( sorry, didn't make a proper note). The floor mounts are shorter with much lower pedal ratios but they're operated by skinny, super fit farquars who can press twice their body weight!
John, where did a comfy 75 lbs come from? I've never seen it expressed so low, but typically 100 as standard and 200 in a clencher! Curious!
Chris
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LBs input in the chartAttachment 64736
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Ha!
Attachment 64737
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Remember when this was THE go to?
https://www.uk-hotrods.co.uk/v2/tech/brakes/brakes.php
https://www.uk-hotrods.co.uk/v2/tech/brakes/brakes_part_2.php
Princess front 4 pots with cosworth rear calipers require a 22.2 mm m/c using a 4.5 to 5:1 pedal ratio with a servo fitted.
Smaller m/c will give greater line presure but at the cost of longer travel.
Bled movement at m/c is normally about 10mm multiply by pedal ratio = brake pedal travel at pedal pad . So 10mm x 4.5 =45mm.
The distance of the pedal pad from floor can give the illusion of too much travel ie Static pedal measurement to 90mm makes the pedla mmmm but 135mm to floor makes it look good . No actual physical effect on braking :)
if we're posting helpful charts, try this from wilwood....
neil.
https://www.wilwood.com/PDF/Flyers/fl162.pdf
Right. I'm back.
Thank you to all above for your input.
"Half an inch makes all the difference!" as the actress said to the Bishop :whistle:
After much reading and puzzeling I bit the bullet and made another new brake pedal.
I needed to put a curve in so the pad missed the steering column so used my new toy.
Its an induction heater, it worked really well.
Attachment 64846
Just fit the correct size coil and hold over where you want to get hot. It took three minutes to get red enough to bend with a gloved hand.
Attachment 64847
Attachment 64848
Forgot to take photos but powder coated satin black and installed
The new pedal has 2" below the pivot with a couple of 10mm holes for adjustment.
The top hole was 1/2" lower than the original.
I also shortend the push rod 1/2" and re mounted the brake light switch.
The pedal now sits where I would expect it to and the feel is just what I was looking for.
There is around 10mm of movement before you feel any resistance and a nice firm feel almost to the floor.
Just got to take her out for a run now to see if theres been an improvement.
Also took the near side front A arms off and replaced the old blue bushings with the new black ones.
Then went 'Old School' to do the steering alignment.
Some poles, string and some plastic chopping boards with grease in between them for swivels.
Attachment 64849
Attachment 64850
0.5 degress of toe in, sorted.
Good idea on the chopping boards :thumbsup2:
That is a good idea on the chopping boards lol!
Funny what our brains come up with
Repurposing household items. Resourceful, and brave.
Chris
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Was the induction heater expensive?
schrolling down past the additional coil sets the tool with 3 coils start at £140 mate. that's just from uk suppliers, direct from china they're cheaper but take longer to arrive.Quote:
Originally Posted by tom.marg
neil.
https://www.ebay.co.uk/sch/i.html?_n...c&LH_PrefLoc=1
I paid £204 from Amazon last year.Quote:
Originally Posted by tom.marg
Its been used a lot.
Very good for heating up stubborn nuts & bolts.
Quote:
Originally Posted by fabphil
Not bad, good bits of kit !