02GF74
|
 posted on 15/4/09 at 01:24 PM |
|
|
4 pot brakes?
Front brakes:
M16 caliper, 2 pot, 54 mm dia
Sierra master 22 mm dia
but Mk2 escort had 20.9 mm master. Now I just realised that the calipers are on mk3 cortina uprights so the mk2 escort data is irrelevant, but
I'll continue anyways...
I want my brake to be more grippy - i.e. I have to press quite hard to slow down and stop.
Maybe this is due to being used to servo brakes I don;' know as last non servo car I had was an MGB over 10 years ago but can't remember
it being this bad.
So ..... one way would be to decrease the master bore - a no-no since this would need a lot of modifications unless there is a sierra master with
smaller bore, or else calipers with larger piston area.
I am looking at the dynalite?, about £ 100 per side.
RD do a set that are direct replacements but the piston area is much less that what I have. I am guessing that the pads are larger than for single
piston - anyone know that to be the case?
And if anyone has used them, was there an improvement?
I am a bit sceptical that these will be an improvement due to having smaller piston area or is there some other effect that I am not aware of?
|
|
|
|
|
JAG
|
| posted on 15/4/09 at 01:39 PM |
|
|
For a more responsive bite to your braking system there are a few things you can do;
1) new pads - different materials behave very differently. Try a few and see which you like.
2) Fit calipers with bigger pistons (will give a longer pedal travel).
3) Fit a master cylinder with a smaller bore (will give a longer pedal travel).
4) Add a servo. Most will mock this suggestion but I have a servo on my car and they make for very good brakes.
Otherwise do some squat/lifts with dumbells and build bigger, stronger thighs   
Edited to correct the stoopid mistake 
[Edited on 15/4/09 by JAG]
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
|
|
|
alistairolsen
|
| posted on 15/4/09 at 01:44 PM |
|
|
quote:
Originally posted by JAG
For a more responsive bite to your braking system there are a few things you can do;
1) new pads - different materials behave very differently. Try a few and see which you like.
2) Fit calipers with bigger pistons (will give a shorter pedal travel).
3) Fit a master cylinder with a smaller bore (will give a longer pedal travel).
4) Add a servo. Most will mock this suggestion but I have a servo on my car and they make for very good brakes.
Otherwise do some squat/lifts with dumbells and build bigger, stronger thighs
bigger pistons will give a longer travel.
you brakes rely on this:
(foot force*pedal ratio)/area of master cylinder bore = line pressure.
so at this end you can press harder, or increase your pedal ratio, or decrease the are of the master cylinder to gain line pressure.
At the other end:
effective disk diameter*piston area*line pressure*CF = brake torque
so you can fit bigger disks, calipers with bigger pistons, or stickier pads for any given line pressure.
almost all of these increase pedal travel (you cant have something for nothing, you just exert less force for a greater distance) which is why oe
manufacturers fit a servo which gives a mechanicl advantage from outwith the system
|
|
|
02GF74
|
| posted on 15/4/09 at 01:44 PM |
|
|
pads - yes, forgot to mention those; I did post about that before, need to look up what was recommented but £ 30 a pair, I am almost 1/6 of way for
lighter 4 pot calipers.
2 and 3 both will give longer pedal travel.
my legs are plenty strong enough, problem arises is that I have size 12 and brake pedal is too low to instead of pressing with my ball of my foot, I
end up using my instep. (I think this is the real problem but I cannot shorten the pedal nor raise the master).
|
|
|
Mr Whippy
|
| posted on 15/4/09 at 01:48 PM |
|
|
Got room to length the brake pedal? Dead easy fix and also gives you more feel. This is how I solved the beach buggy’s dodgy unassisted all-round
drums no brakes problem
pah you just posted above...sounds like you going to have to spend some money or lose weight
[Edited on 15/4/09 by Mr Whippy]
|
|
|
02GF74
|
| posted on 15/4/09 at 01:50 PM |
|
|
^^^ ok, larger discs, that is another option. are these avaialble for cortina uprights? and what calipers do use? I don't have machining
facility to make brackets. 
.... but back to M16 4 pot replacment - these are available in 2 piston diameters, both of which combined diameter is less than that of the M16 2 pot
brakes - so how do they perform stopping power wise compared to originals?
|
|
|
britishtrident
|
| posted on 15/4/09 at 02:33 PM |
|
|
The problem with a lot of four pot calipers is they will give you lost pedal travel even if they are the same toatal effective area or smaller than
Sierra or Escort/Cortina/Capri calipers.
The reason for this apart from mounting issues (calipers need to be bolted on dead square to the disc in all axies) are I suspect due to the caliper
body flexing under the hydrualic force exerted the and the design of the seals. In this respect it it may be more than possible that some brands
are better than the market leaders.
If you want better brakes that don't require a massive push even for a gentle stop it really is down to more pedal leverage &/or smaller
master cylinder bore --- or fit a servo.
(
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
britishtrident
|
| posted on 15/4/09 at 04:59 PM |
|
|
quote:
Originally posted by 02GF74
pads - yes, forgot to mention those; I did post about that before, need to look up what was recommented but £ 30 a pair, I am almost 1/6 of way for
lighter 4 pot calipers.
2 and 3 both will give longer pedal travel.
my legs are plenty strong enough, problem arises is that I have size 12 and brake pedal is too low to instead of pressing with my ball of my foot, I
end up using my instep. (I think this is the real problem but I cannot shorten the pedal nor raise the master).
Just to be clear you have top pivoted pedals ?
In that case easiest solution is to install an off the shelf floor mounted pedal box.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
