ST 185 Brake conversion

[acexxx]

Hi everyone I was wondering if there are and guides to putting Celica ST 185 Brakes on a Mk1? My rear calipers are on the way out and I fancied better stopping power. Could you use standard Celica calipers (or indeed any other!) and are they any better?

[SuperRedMR2]

I just bought the grooved disc and greenstuff package on ebay for £159.99 and I doubt ud need bigger brakes after that, unless your upgrading or swapping the engine.

the stopping power is immense. feels like im left foot braking!

there is a brake upgrade on ebay at the moment for £200 from a ST185 and there is a write up somewhere on here.

[Jaspa]

Not for the rears, But the 185's are a reasonable upgrade for the fronts. Pop over to Twobrutal.com and see what they say

I've just bought the 185 fronts ready for a 3sgte conversion

[crazybrightman]

im sure the st185 upgrade is fronts only, not sure what the upgrade is for the rear maybe mk2 turbo?
anyhow as superredmr2 said they standard brakes are great if you havn't already got a the bigger brakes of the mk1b then fit them. overhall the lot, slides, seals, brake lines and put some decent brake fluid in. fit high quality standard replacement discs and some uprated pads and you wont need anything else for the road or track. you can lock the wheels with only a moderate amount of brake pressure so why you would want anymore stopping power i have no idea, it would be a waste imho.

[bburn13]

Check this out
http://www.mr2mk1club.com/Bigbrakes.html
Should answer all your questions

Dave

[MR2sRuleTheRoad]

I think all of the Celica calipers will fit straight onto mk1 hubs, but the ST205 4pot alloy calipers will only clear most 16" rims or bigger. The ST185 Celica has a twin pot and a single pot caliper depending on the year, the disc sizes are also different between single and twin pot calipers.
The discs need three holes drilling in them for the 4x100 pcd of the mk1 if you match one hole up but the center bore is the same i belive on all but the ST205 which needs spigot rings. Ive heard of people using mk2 turbo rear calipers and modified brackets, with VW Corrado G60 rear discs and the brake master cylinder from a mk2 aswell. I dont now if this is true or not though and I dont know why you'd want any better brakes on the back anyway!

[PW@Woodsport]

yep we invented this upgrade and that post is pretty much spot on,only thing id add is that you can use the celica single or twin pot caliper with a standard mk1b front disc,no need to drill or use the celica disc.The exception to the rule is when the celica has the bigger 277mm discs which is on some models....then you will need to use the celica disc and drill 3 holes in its face,but it won't need spigot rings or anything else.

So the "258mm" celica calipers are a plug n play upgrade,"277" models need 3 holes drilling,couldn't be easier.

The st205 4 pot conversion requires the most work but to date is the most awesome stopping power ive ever felt on a mk1 if a little unnecessary!

[cartledge_uk]

yep we invented this upgrade and that post is pretty much spot on,only thing id add is that you can use the celica single or twin pot caliper with a standard mk1b front disc,no need to drill or use the celica disc.The exception to the rule is when the celica has the bigger 277mm discs which is on some models....then you will need to use the celica disc and drill 3 holes in its face,but it won't need spigot rings or anything else.

So the "258mm" celica calipers are a plug n play upgrade,"277" models need 3 holes drilling,couldn't be easier.

The st205 4 pot conversion requires the most work but to date is the most awesome stopping power ive ever felt on a mk1 if a little unnecessary!

Maybe the early celica ones are the same as the levin ones then, as the big single and twin front caliper upgrades from the AE111, AE101 and late AE92 on AW11's has been done in the states for years. They are just bolt on replacements on the std mr2 disc

[Xhermes]

I'm looking on doing this aswell together with a MK2 turbo master cilinder upgrade.

I feel that when on track and repetitive hard braking in a short time span you will get a bit fading with just new discs and sport pads + goodridge lines.

With that bit of extra disc things should work out just fine.

[Tom G]

I dont know why you'd want any better brakes on the back anyway!

well if you like to only use 2 wheels to stop then no need to bother with the rears but I've found with the front brake conversions, using brakes from front-engined cars, it's way too easy to lock up the front wheels.

To overcome this you need to add more rear bias, by upgrading the rears or messing with the hydraulics.

You can bolt on mk2 rear calipers along with the mk1 front discs and 5mm spacers, or if the carriers are modified then bigger corrado G60 discs can be used with spigot rings

Here's the route I went down:
1. I put st165 twin-pot calipers on the front, but too much front bias and pedal too soft.
2. So I gutted the toyota bias valve and added the mk2 master cylinder to firm up the pedal. Still too much front front bias but better pedal feel.
3. I upgraded the rear brakes, still way too much front bias.
4. I realised the only advantage of 165 calipers was a bigger pad, so I put the mk1 front calipers back on. I should have a 55f/45r bias split by now, but at the track the fronts were smoking and the rear were just warm.... I'm confused!
5. After overhauling the rear calipers (no improvement) I guess the only way to fix this is add an adjustable bias valve to reduce front bias. This will allow me to run bigger discs (st185 or 205) without making the problem worse.

See here for another discussion on this:
http://toymods.net/forums/showthread.php?p=636234

[Tom G]

PS, anyone know if the ST205 setup fits under 16" roadster alloys?
(sorry for hijack)

[MR2sRuleTheRoad]

Sorry mr Woods I feel like ive ripped off your idea! In fact now I think about it I think all the info I put in that last post was remembered from an article you wrote somewhere! So please dont think im trying to pass off your idea as my own I was just reciting from memory! Just to double check on what you said, I have bought a pair of twin pot front calipers from an ST185 Celica (Not sure of year) can I use the mk1b original disc's? As I thought I would have to use the Celica disc's?
Tom G I just meant upgrading your rear brakes too much might make it snatch a bit on heavy braking as the standard rear brakes seem to do a good eneough job, but you seem to know more about it than me

[mr2mk1chick]

I feel that when on track and repetitive hard braking in a short time span you will get a bit fading with just new discs and sport pads + goodridge lines.

I still don't know why people bother with this upgrade. If you ensure you do a good caliper refurb so they work properly, use braided lines, grooved discs front, std discs back, good fluid, and decent pads (i use EBC yellowstuff on track) you will have no brake problems. You then upgrade your tyres to help with grip too as you will find the brakes bit too well.

i have driven loads of circuits now in the UK and abroad with no probs, and i'm not being a slow driver either TBH.

A track prepped mk1 or SC should be fine without an upgrade. can't comment on a 1.5 apart from Sy taylor who uses the same as i have said above and is fine with it.

[Jaspa]

Jo, Are you still running the 1a brakes? or have you replaced them with 1Bs?

Stuart

[PW@Woodsport]

I still don't know why people bother with this upgrade.

Jo you pretty much answered your own question,reason being it IS an upgrade over stock brakes.

Tim we discovered the celica upgrade back in 99,ive no idea if the US guys were using corolla calipers before then or not,or if the corolla caliper is the same as a celica? ,but certainly here in the UK we were fitting celica calipers to mk1's before anyone else.

[Jim-SR]

I feel that when on track and repetitive hard braking in a short time span you will get a bit fading with just new discs and sport pads + goodridge lines.

I still don't know why people bother with this upgrade. If you ensure you do a good caliper refurb so they work properly, use braided lines, grooved discs front, std discs back, good fluid, and decent pads (i use EBC yellowstuff on track) you will have no brake problems. You then upgrade your tyres to help with grip too as you will find the brakes bit too well.

i have driven loads of circuits now in the UK and abroad with no probs, and i'm not being a slow driver either TBH.

A track prepped mk1 or SC should be fine without an upgrade. can't comment on a 1.5 apart from Sy taylor who uses the same as i have said above and is fine with it.

there is enough stopping power in the stock braking system, especially if the car has been lightened. with a mk1.5 conversion the extra weight could arguably change that balance

the issue isnt so much, IMO, with the stopping power as it is with durability. ive overheated pads AND fluid on a stock braking system with brand new everything, and everything properly serviced. the pads can be upgraded to something that can handle more heat, but with bigger discs and a bigger caliper youve got more disc area to dissipate heat, more fluid in the caliper to dissipate heat, and most importantly more braking torque so that you dont need to work the brakes so hard in the first place, thus generating less heat

people bother with this upgrade because, as Paul has pointed out, it IS an upgrade. it improves the braking system, and there isnt really a major downside to it (£150. oh and maybe an extra kg of unsprung weight, which on an MR2 isnt an issue in any circumstances, nobody is racing mk1 MR2's in touring cars or GT's these days, at club level there is more time in the driver than there is in 1kg of unsprung weight). there are however many upsides.

if youre someone who finds the stock braking system sufficient and who doesnt suffer any problems with it, then thats fantastic. i wish i was one of those people as it would save a bit of cash and effort, but im sure im not the only one who isnt

[Jim-SR]

I still don't know why people bother with this upgrade.

Jo you pretty much answered your own question,reason being it IS an upgrade over stock brakes.

Tim we discovered the celica upgrade back in 99,ive no idea if the US guys were using corolla calipers before then or not,or if the corolla caliper is the same as a celica? ,but certainly here in the UK we were fitting celica calipers to mk1's before anyone else.

i dont think the Corolla caliper is the same. its a twin pot i know that much, and the discs are somewhere around the 280mm mark. its more of a hybrid between the small and large ST185 options. weve got an AE101 at work with these brakes fitted, and i noticed in the past the brake setup, i didnt know for sure that the calipers were a direct fitment to the MR2 though (although knowing Toyota im not sure i ever doubted they would be lol)

[PW@Woodsport]

yep,totally agree with jim,the celica upgrades are done to combat the overheating and fade issues we come across when the stock brakes are used excessively.... if you have never had this problem on your mk1 then quite simply you aren't over working the stock brakes and they are coping with heat produced on your everyday driving.

I guess a lot of it boils down to how hard you drive your car really.

[Flat Pack]

Moving the brake bias forwards doesn't sound like the best plan though... Any situation where you could lock the fronts with standard brakes and you'll be worse off with the 'upgraded' setup

[PW@Woodsport]

I can 100% assure you that isn't the case.