Twin Pot Calipers

[elbon50]

Would I be correct in thinking that ST185 front calipers are the same as ST165 and will fit my Mk1b ?

Peter

[Jaspa]

Would I be correct in thinking that ST185 front calipers are the same as ST165 and will fit my Mk1b ?

Peter

ST185 is a large single piston. Still a good upgrade though.

Pics of the different calipers if you're interested Here

[SuperRedMR2]

Paul would be the best person to ask, I didn't think the 185s were a direct bolt on.

[Jaspa]

Paul would be the best person to ask, I didn't think the 185s were a direct bolt on.

They are but you can't use the 1b disks IIRC.

Edit - You've reminded me, I have a set of calipers, carriers, disks and pads in the shed. Won't need them now that I've got the WMS calipers on

[Charged]

Yes they area direct fit, I have them on my Mk1.5

http://s63.photobucket.com/albums/h135/ ... nt=Mk1.jpg

You just need the discs re-drilled.

[stenky]

To puzzle you even more, some jdm narrowbody st185 used the smaller twinpots. As for the big singles, post '92 gti celicas used them as well. Both however are direct bolt on. Singlepots need jus the 277mm disc redrilled to 4x100 and will just fit under 15" alloys.

[Finn]

I'm lost with all these different alternatives.

[Charged]

I'm lost with all these different alternatives.

What you REALLY want in the GT4 ST205 calipers

[Finn]

[elbon50]

I'm lost with all these different alternatives.

What you REALLY want in the GT4 ST205 calipers

Lol

Are they twinpots

[Jaspa]

Are they twinpots

4 pot

[LimeyMk1]

My L-reg ST182 had twin pot calipers on.

Confusion REIGNS!!!!!

[PW@Woodsport]

Paul would be the best person to ask, I didn't think the 185s were a direct bolt on.

Well he could ask the man that invented the mod, but will he listen?

Just to clear this up, you can bolt ANY of the Celica calipers to a Mk1 hub, be it Mk1a or Mk1b, all Celica caliper bolt spacings are the same as Mk1.

Where the confusion starts is folks try to bolt the caliper part to the Mk1 slider bracket, which doesn't work.

You need to buy the complete Celica caliper, bracket as well, and it will bolt sraight on to your Mk1 hub.

Now if you got the caliper from a 256mm disc'd Celica then they will plug and play onto a stock Mk1b disc, if you're doing this to a Mk1a then buy Mk1b discs. Some St185 Celicas had a 277mm disc, in which case you buy the Celica 277mm disc as well and drill 3 holes in its face (one of the 5 stud Celica holes is already in the right place. Don't worry about the holes not being exactly right, luckily the Celica discs share the same centre spigot as a Mk1 too (almost as if they had planned it) so it will remain hubcentric regardless of being a few mm out on the stud holes.

Which Celicas had 256mm and which had 277mm i've never taken the time to study, i just know when i first discovered the upgrade that they all worked.

The monster st205 4 pots again bolt up, but need the Mk1 hub holes tapping out to take a bolt and a 2mm washer placing between caliper and hub to retain the correct spacing. You will need to do a fair bit of machine work to the St205 discs to get them working, Spigiots needed and a reduction in diameter too, but they will endo your Mk1 i kid you not, to date the best brakes i've ever had on a Mk1, they do have a tendancy to squeal though, a common complaint from Gt4 owners.

Hope that helps.

[Adam W]

Worth noting that ST205 calipers will not fit under 15's though, and only fit under selected 16" wheels, which is a bit of a drawback to them.

[PW@Woodsport]

Indeed, and offset matters greatly with the St205's, i had to shave the embossed "Celica" off the outside of my calipers to get 2mm of clearance between it and the wheel spokes

[Finn]

I reckon I'm splitting hairs here but nevertheless:

with the ST165 twin pot upgrade would I need anything changed with the master cylinder ie. does it have enough flow for twin pots?

Will the brake balance be affected by this so that a proportioning valve would be needed?

[PW@Woodsport]

Your best bet is to fit a Mk2 Mr2 rev2- master, it's 15/16ths bore compared to the Mk1 7/8ths bore, so it moves more fluid to the twinpots at a slightly reduced pressure (we've found this helps negate front lockup), you can also gut the bias valve which at present gives you a 55/45 split front to rear, gutting the valve gives you a 50/50 split, again improving things.

A little techy info, if you have a Mk1a, the Mk2 MC won't bolt to the servo, different bolt pattern, so you will need to fit a Mk1b servo to your Mk1a and then fit a Mk2 MC to that. Be aware that rev1 Mk2's had a 7/8ths bore MC same as Mk1, so be careful when ordering.

[Finn]

Thanks, Paul.

Now, where could I get my hands on the ST165 calipers and brackets?

[PW@Woodsport]

There's always plenty of old Gt4's breaking on Ebay etc

[mulaz]

If your were to upgrade the front brakes with st 165 / 185
could your original vented fronts be fitted to the rear or would you also have to buy and fit all four from a st165 / 185?