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Rear brakes - That old chestnut!
Richard Quinn - 22/9/07 at 08:16 PM

Expecting delivery of my IRS chassis fairly soon so deciding which bits to go for.
It's Cortina front end and I'm pretty much decided on the Wilwood Cortina upright kit but at the back end I will be using a sierra disk brake back end. The options, as I see it, are std Sierra disks and calipers, the hydra mech kit from RD or the Wilwood handbrake kit from RD.
Opinions, as ever, welcomed and any advice as to any mods/fab work needed for any of the options for my set up.
Thanks in advance.


v8kid - 22/9/07 at 08:28 PM

Phew Richard this time on a saturday night what chance is there of a half way sensible reply!!! Oh well here is my tuppenceworth - it dosent matter a hoot. With a front engined car and a relatively high Cof G all the braking effort is on the front wheels - that is where all your cash should be spent. As for the back wheels? The lightest cheapest option that will satisfy the local regulators cos it wiull not materiallyaffect the braking performance ogf a front engined car with sensible road clearance.

Beware the snake oil salesman!!!

Hey just reviewed my reply and it even reads like a half cut scotsman!!

Cheers


zilspeed - 22/9/07 at 08:30 PM

What he said.

Fastest non single seater I know has fiesta non vented front disks on the back and single pot calipers.


Richard Quinn - 22/9/07 at 08:33 PM

I suppose I was being optimistic! Just to emphasize the fact that I am after lightweight rather than braking power on the rear (obviously!). If only you didn't need a handbrake eh?

Edited to add - Ok, so what disks and calipers (single pot with handbrake) will fit on the Sierra back end with minimum fuss?

[Edited on 22/9/07 by Richard Quinn]


blakep82 - 22/9/07 at 08:38 PM

Sierra ones should fit easily enough

sorry, I'll stop now...


Richard Quinn - 22/9/07 at 08:43 PM

Arghhhh! You know what I mean. As was said above - It's Saturday night and our local Asda has an offer on Duvel. Please don't make me think!


v8kid - 22/9/07 at 08:48 PM

Well I've got fiesta non vented front disks on the back and single pot calipers and for sure I aint the fastest Zil knows ( well in my dreams mebbe) Unfortunately I've got the bloody engine at the back!!!!!

Rich you don't need fancy stuff on the back Fiesta stuff will be OK, stick to unvented discs so they get a chance to warm up and go for cheap and cheerfull Willwood. If you want grief in this life go for sierra stuff and I'll sell you it for half what I paid for it


iank - 22/9/07 at 09:16 PM

Maybe not a mainstream suggestion, but if you get some mini rear drum backplates I think you could redrill them to fit sierra hubs (this is a common-ish trick on mini based middys though admittedly using mini front hubs)

It's then not hard to get aluminium drums to fit, they used to be called minifins (they have steel rings the shoes work against).

Can't really get lighter brakes (with handbrake) than that, and they give a good handbrake. Downsides are they are drums and need regular manual adjustment.


RazMan - 22/9/07 at 10:39 PM

Having recently swapped my Sierra caliper for Wilwood Powerlites (with handbrake) I can honestly say that the Wilwoods are no better - in fact the handbrake performance is crap, so don't park on any hills

As already said, standard solid discs will give better bite too.


britishtrident - 23/9/07 at 09:28 AM

Standard Sierra rears or if you want to cut the unsprung weight a bit look at RD Golf alloy rear calipers.

Wilwood's handbrake mechanism design is to say the least "hinky" --- ie more iffy than iffy. If such a simple cheap way of doing it actually worked the major braking system manufacturers would have adopted it 50 years ago

Just because parts are shiny and more expensive don't assume they are better for your purpose.

Also be aware that although alloy calipers have been around almost as long as disc brakes they never caught on with volume manufacturers (apart from Fiat) because in nothern europe we use a lot of salt on our roads


tomblyth - 23/9/07 at 10:27 AM

modern astra calipers are alloy, light in weight and work really well you will have to modify the mounts but its not hard!


adithorp - 23/9/07 at 05:52 PM

I've got the Wilwood hand brake caliper and there are problems with leverage but it can be overcome.

see this thread... http://www.locostbuilders.co.uk/viewthread.php?tid=73110

adrian


NS Dev - 23/9/07 at 08:56 PM

Hi Rich,

I have the very same setup.

I am using std cortina solid discs up front, with raceleda (same as outlaw etc) 4 pot calipers and mintex 1144 compound pads. I have std sierra rear calipers (xr4x4 etc ones) and std rear discs on std cheapie road pads.

I have 5/8" master cyl for the front and 3/4" for the rear, and it flew through sva without even needing ANY adjustment, so fear not!!

Dont forget youll need at least 14" wheels to clear the rear brakes though unless you find some of the magical 13" wheels that somehow clear the calipers!


RazMan - 23/9/07 at 09:21 PM

Adrian, Interesting tip about the lever to multiply the pressure to the handbrake cable. I have a feeling it might not work in my case as a 6:1 ratio would make the handbrake need all of its movement to fully apply it - I think Mr SVA will need just a few clicks.


Minicooper - 23/9/07 at 09:26 PM

I have 13" on my standard sierra disk braked rear, I do have a 5mm hub centric spacer on though, not for the brakes themselves but the handbrake lever was too close for my liking, some people just bend them

Cheers
David

[Edited on 23/9/07 by Minicooper] Rescued attachment DSCF0013.JPG
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Minicooper - 23/9/07 at 09:27 PM

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britishtrident - 24/9/07 at 01:12 PM

quote:
Originally posted by adithorp
I've got the Wilwood hand brake caliper and there are problems with leverage but it can be overcome.

see this thread... http://www.locostbuilders.co.uk/viewthread.php?tid=73110

adrian


Fine until the pads wear even slightly.
Pigs ears - silk purse.


adithorp - 24/9/07 at 03:04 PM

"Fine until the pads wear even slightly."

...and thats why my adjuster is easy to get at. With it living in the workshop it'll be a regular tweek...besides thats why I leave cars in gear.


"Pigs ears - silk purse."

...personaly I prefer leather wallets but if you like purses...but I know what you mean and I wouldn't normaly put form over function...but they look so good (and weigh so little)!

Razman, before I played with it I struggled to get 1 click, It now comes up a nice 3-4 clicks.

adrian


RazMan - 24/9/07 at 06:02 PM

quote:
Originally posted by adithorp
Razman, before I played with it I struggled to get 1 click, It now comes up a nice 3-4 clicks.



That curious, I can't stop them binding with 4-5 clicks. Originally I thought they were ok until I jacked up the rear wheels and discovered that I needed to back off the adjustment a fair way to free up the wheels.


adithorp - 25/9/07 at 11:12 AM

It could be the modifiction that Fishers do to the handbrake lever thats the difference. That in itself reduces the leverage. I'm not getting any binding.

adrian