Shaunk10
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 posted on 31/7/14 at 07:43 PM |
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How to convert drums to disks!?
Hi chaps,
I currently have a mk indy which is based on a 1983 sierra.
Currently the setup is single piston disks at the front and drums on the rear.
Now I have bled the system with new fluid and it has new clippers, and now even a new master cylinder on the brake pedal (at a cost of about £80!)
however it still feels like it stops like a freight liner, I mean I can lock up if I stamp it down, but ild like to have this sort of braking with
much less effort!
My question is - how easy is it to change the front callipers to something with a little bit more bite, and what do I need to do to change my rear
drums to a disk set up.
It seams like it will be a fairly big task at a glance? Are there any ford parts that I can use to do this conversion.
My ideal world would be for someone to say - yes the ford "...." callipers will bolt straight onto the front, in place of the old
callipers, and the rear disks from the ford "..." Will bolt straight onto the rear of the car, with this modification plate that you can
buy here "..." However I know it's not going to be like this! 
Can I use front callipers from a doner car for both the front and back, like find 2 ford "...." And take both sets of front callipers from
both cars and fit one set to the front of the car and one set to the rear (as I know how much more bite front callipers usually have, plus I think it
would look better?)
Sorry to sound like a complete flop, but I don't even know where to start! I'm 20years old with fairly good mechanical knowledge (my job
is mechanical too) so I'm hoping it won't be too difficult!
I'm looking to do this as cheap as possible!?! And I really do mean as cheap as possible! Haha
Thanks again for your help!
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Scuzzle
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| posted on 31/7/14 at 08:08 PM |
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If it's Sierra running gear surely the Sierra 2WD Cosworth brakes will fit, vented discs and callipers up front and solid discs and callipers at
the rear.
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coozer
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| posted on 31/7/14 at 08:09 PM |
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The thing is without a servo you need to get used to pressing the brake pedal quite hard.
On mine I replaced the fronts with a Wilwood 4 pot kit from Rally design.
Used xr4 10 inch drums on the back. All good.
I would do the fronts first as I found the improvement over the standards calipers was very good.
Thing with discs is they can tend to over brake on a light car and you then need a bias valve or bias bar pedal box to compensate. I'm sure
someone will rubbish that in a minute tho.
Good luck!
Steve
[Edited on 31/7/14 by coozer]
1972 V8 Jago
1980 Z750
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Angel Acevedo
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| posted on 31/7/14 at 08:10 PM |
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To improve pedal feel pedal ratio and Master cylinder size are the easiest cheapest options.
Beware of what you wish.. for it may come true....
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ian locostzx9rc2
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| posted on 31/7/14 at 08:35 PM |
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Before you change stuff and spend lots of money get some decent front brake pads and make sure the rear brake shoes are adjusted correctly .the
brakes on your car are more than upto the job as your is approx 50 or 60 percent of the original donor car.
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SteveWalker
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| posted on 31/7/14 at 08:39 PM |
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It'll be the lack of a servo that makes it feel under-braked. I kept the servo and feel my braking is very good. I use the disks and calipers
from a 2l Sierra on the front and the 8" drums from a 1.6l Sierra on the back. I remember from SVA that it gave a good balance, with less chance
of locking the rears first than the 9" drums or the rear disks from a 2l.
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mookaloid
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| posted on 31/7/14 at 08:44 PM |
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if you haven't got them then fit mintex 1144 pads to the front - you will be amazed how much better the brakes are.
They will still need a good shove but they have good initial bite and you will have a lot more confidence in them
"That thing you're thinking - it wont be that."
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alfas
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| posted on 31/7/14 at 08:56 PM |
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"To improve pedal feel pedal ratio and Master cylinder size are the easiest cheapest options."
"Before you change stuff and spend lots of money get some decent front brake pads and make sure the rear brake shoes are adjusted correctly .the
brakes on your car are more than upto the job as your is approx 50 or 60 percent of the original donor car."
fully agree..its not necessary changing anything....try to investigate where the problem in your car is located...you might have only a wrong sized
master cylinder...or a wrong lever ratio at the pedal-box.
those 2 things need to be checked first.
can you post a pic of your master and do you know where it comes from?
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snapper
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| posted on 31/7/14 at 09:01 PM |
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To change drums to disc you need a hub bracket that provides a caliper mount
Then I am led to believe that Sierra rear discs just fit on with the matching calipers and pads
You may need to revise the handbrake cable
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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steve m
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| posted on 31/7/14 at 10:11 PM |
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One of my mods to make the brakes better , was to move the pivot pin on the peddal up about 12mm, thus increasing the leaverage, then four pot
calipers,
much nicer now !
Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at
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britishtrident
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| posted on 31/7/14 at 10:41 PM |
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Brakes 101
Fact (1) because it is longer the Sierra brake pedal has nearly 3 times the leverage ratio of the the brake pedal in your car.
Fact (2) the brake servo boost on the Sierra provides 60% of the force applied to the master cylinder.
Fact (3) because of weight transfer on front engined rwd car the rear brakes can only contribute at most 30% of the braking.
Fact (4) drum brakes have an inherent self-servoing effect at the low end of the applied force range.
Fact (5) 9" Sierra drums were more than adequate for a vehicle of the Sierra's weight.
Fact (6) standard after market brake pads are very variable in friction performance.
If you put the above together you will see that with a car less than half the weight of Sierra you will to apply to 3 to 4 times the force to the
brake pedal to achieve the same deceleration as the Sierra.
So how to fix the problem? The easiest options are :
(1) fit front brake pads with more suitable friction characteristics. Mintex M1144.
(2) Change the master cylinder to one with a more suitable (smaller) bore.
(3) Both of the above
These aren't the only options you could fit a servo, fiddle with the pedal leverage ratio or fit massive front discs and callipers with bigger
effective hydraulic area but option (3) is relatively simple and cheap.
[Edited on 31/7/14 by britishtrident]
[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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Angel Acevedo
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| posted on 1/8/14 at 04:07 AM |
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quote:
Originally posted by Shaunk10
Hi chaps,
I currently have a mk indy which is based on a 1983 sierra.
Currently the setup is single piston disks at the front and drums on the rear.
Now I have bled the system with new fluid and it has new clippers, and now even a new master cylinder on the brake pedal (at a cost of about £80!)
however it still feels like it stops like a freight liner, I mean I can lock up if I stamp it down, but ild like to have this sort of braking with
much less effort!
My question is - how easy is it to change the front callipers to something with a little bit more bite, and what do I need to do to change my rear
drums to a disk set up.
It seams like it will be a fairly big task at a glance? Are there any ford parts that I can use to do this conversion.
My ideal world would be for someone to say - yes the ford "...." callipers will bolt straight onto the front, in place of the old
callipers, and the rear disks from the ford "..." Will bolt straight onto the rear of the car, with this modification plate that you can
buy here "..." However I know it's not going to be like this!
Can I use front callipers from a doner car for both the front and back, like find 2 ford "...." And take both sets of front callipers from
both cars and fit one set to the front of the car and one set to the rear (as I know how much more bite front callipers usually have, plus I think it
would look better?)
Sorry to sound like a complete flop, but I don't even know where to start! I'm 20years old with fairly good mechanical knowledge (my job
is mechanical too) so I'm hoping it won't be too difficult!
I'm looking to do this as cheap as possible!?! And I really do mean as cheap as possible! Haha
Thanks again for your help!
Step by step....
quote:
Originally posted by Shaunk10
I currently have a mk indy which is based on a 1983 sierra.
Fact...
quote:
Originally posted by Shaunk10
Hi chaps,
Currently the setup is single piston disks at the front and drums on the rear.
Fact...
quote:
Originally posted by Shaunk10
Now I have bled the system with new fluid and it has new clippers, and now even a new master cylinder on the brake pedal (at a cost of about £80!)
however it still feels like it stops like a freight liner, I mean I can lock up if I stamp it down, but ild like to have this sort of braking with
much less effort!
Fact....
although... He CAN lock up, but feels like Freightliner... It means that there is no apparent problem with Stopping Power,
He wants to reduce his effort while braking.....
In order to reduce effort he can either
- Increase Pedal Leverage.
- Reduce Master Cylinder Area (Diameter).
- Increase Slave Cylinder Area (Diameter or Number of Pots per Caliper)
- Fit Vacuum Booster.
- Fit Hydraulic Booster.
In order of Ease-Price, I have arranged them in ascending order.
- It would be relatively easy and cheap to modify Pedal Fulcrum to modify Pedal Ratio.
- It may be relatively easy to find a Master cylinder with the Same Mounting Hole Arrangenment, this would accomplish higher System Pressures with the
same Pedal Pressure, therefore less perceived Braking Effort.
Note that these two options may increase Pedal Travel.
Other options are not that easy/Cheap...
- To increase Slave Cylinder Area, he must... either:
- Increase the number of Pots...
increase the Size of Pots...
For any of the above he must Buy New Calipers and these calipers may need new new Mounts.
To change Rear Brakes from Drums to Disks...
May be easier, but not cheaper than the first two options.
quote:
Originally posted by Shaunk10
My question is - how easy is it to change the front callipers to something with a little bit more bite..
!
Question:
To answer question:
It may be easy, buy may not be cheap....
quote:
Originally posted by Shaunk10
, and what do I need to do to change my rear drums to a disk set up.
It seams like it will be a fairly big task at a glance? Are there any ford parts that I can use to do this conversion..
Question:
To answer...
No idea, but somebody would come in with appropriate answer...
quote:
Originally posted by Shaunk10
My ideal world would be for someone to say - yes the ford "...." callipers will bolt straight onto the front, in place of the old
callipers, and the rear disks from the ford "..." Will bolt straight onto the rear of the car, with this modification plate that you can
buy here "..." However I know it's not going to be like this!
Desire??
It would be nice, but maybe not necessary if you try the simplest, cheapest solutions first, if not what you expect, then you may try more complex and
more expensive solutions....
quote:
Originally posted by Shaunk10
Sorry to sound like a complete flop, but I don't even know where to start! I'm 20years old with fairly good mechanical knowledge (my job
is mechanical too) so I'm hoping it won't be too difficult!
Don´t be...
I think a lot of us started like you, before you know it you will be giving TOP advice as a lot of people do on this forum which makes it such a great
place.....
quote:
Originally posted by Shaunk10
I'm looking to do this as cheap as possible!?! And I really do mean as cheap as possible! Haha
Please read my first post on this threada and read some other threads on the subject...
The advise I´m giving is not something I came up on by myselg, but from reading from more experienced people on this forum... I just happened to be
one of the first ones to reply...
Based on what you read and asking some questions will help you make up your mind before jumping in and getting the best solution...
Hope this helps...
Angel Acevedo
Beware of what you wish.. for it may come true....
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whitestu
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| posted on 1/8/14 at 07:30 AM |
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I'm very happy with the brakes on mine and never find them wanting. On the track days I've done I just haven't noticed the brakes,
which tells me they are spot on.
I have a totally standard Sierra disk/drum set-up except for a 19mm Fiat 124 master cylinder [Sierra CVH m/c is 22mm] with the pivot on the pedal
changed slightly to give a bit more leverage and EBC yellow stuff pads. The total cost being about £55.
I can easily lock the wheels from cold and they just get better as they warm up [not that they warm up much as the vented 240mm disks aren't
ever working very hard stopping such a light car]
Obviously this assumes your sierra brakes aren't knackered to start with.
Unless you are making a lot of power there is no need to do any major brake upgrades, unless you want the bling factor!
Stu
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mcerd1
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| posted on 1/8/14 at 08:08 AM |
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quote:
Originally posted by britishtrident
Brakes 101
Fact (1) because it is longer the Sierra brake pedal has nearly 3 times the leverage ratio of the the brake pedal in your car.
Fact (2) the brake servo boost on the Sierra provides 60% of the force applied to the master cylinder.
Fact (3) because of weight transfer on front engined rwd car the rear brakes can only contribute at most 30% of the braking.
Fact (4) drum brakes have an inherent self-servoing effect at the low end of the applied force range.
Fact (5) 9" Sierra drums were more than adequate for a vehicle of the Sierra's weight.
Fact (6) standard after market brake pads are very variable in friction performance.
If you put the above together you will see that with a car less than half the weight of Sierra you will to apply to 3 to 4 times the force to the
brake pedal to achieve the same deceleration as the Sierra.
So how to fix the problem? The easiest options are :
(1) fit front brake pads with more suitable friction characteristics. Mintex M1144.
(2) Change the master cylinder to one with a more suitable (smaller) bore.
(3) Both of the above
These aren't the only options you could fit a servo, fiddle with the pedal leverage ratio or fit massive front discs and callipers with bigger
effective hydraulic area but option (3) is relatively simple and cheap.
^^ what he said
as to your original question, yes you can just swap the brakes for bigger ones / discs - but that's not the first thing you should try 
I assume you have the 240mm diameter vented front discs ?
if so then the ABS / XR4 discs and callipers are a strait swap - these have 260mm vented discs, larger pistons and a bigger pad area
or with a bit of fiddling its possible to use the even larger cossie 4x4 calipers with ~280mm discs, but these aren't a strait fit and are very
heavy!
as for the drums - as above they come in different sizes, but if you want to swap to discs (a lot of money for minimal gains) you'll need an
adapter kit as your bearing carriers don't have the lugs to mount the discs - you can't just swap to the disc braked hubs without changing
the whole rear axle as all of the disc brake hubs use bolt-on driveshafts and different bearing sizes
exactly which calipers and discs you'd need will depend on the adapters you get
[Edited on 1/8/2014 by mcerd1]
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big-vee-twin
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| posted on 1/8/14 at 03:01 PM |
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To convert from Drums to Discs is a relativity straightforward job, which does not involve changing the rear axle.
What you need as previously said- is the caliper mounting bracket which bolts to the drum brake bearing carrier as per below pic - remove drums and
back plate fit bracket.
[img]
 
Rear Caliper Bracket
[/img]
Once a bracket has been fitted you can fit standard Sierra Discs and Handbrake calipers pic below or use a Wilwood Kit.
[img]
 
Rear Brakes
[/img]
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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Shaunk10
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| posted on 2/8/14 at 12:56 PM |
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Thanks a bunch to everyone , only just been able to get back to a computer, I think I will try the pad upgrade first and see how that improves, iv
funnily enough just gone from 15s down to 13s in wheels size and the drivability is much more improved, as well as this I'm thinking of getting
some yokohoma tyres to suit the wheels. Ild imagine this would help a fair amount when braking?
Cheers again chaps
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