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4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

st185 gt4 single piston caliper onto aw11 conversion?	Mon, 28 February 2005 09:15

I have some st185 gt4 calipers which im going to bolt to my aw11. But im wondering if anyone has done this conversion and if so what dics they used. Ive done a bit of measuring and test fitting to some spare hubs and and supercharged mr2 disks that i have lying around and have come up with this so far... -the gt4 calipers will fit onto the mr2 hubs. -They require a slightly larger disc of 278mm diameter by 25mm thickness. -The calipers on the mr2 hubs should clear this size disc perfectly. Also i have come up with a few questions. -Will the increased diameter still allow me to use the 14" standard rims? (i think i might be able to just) -If i was to use the gt4 disc and drilled holes for the mr2 stud patter would the slightly smaller (1mm smaller) height of the disc be a problem? - I was thinking of running the gt4 caliper on the standard disc for a while. Although this would make the pad bite the top of the disc I have heard this can make for slightly better intial bite? (i dont really care if it affects the life of the disc or pad) I know joshtix is attempting this conversion so any info would be appreciated. [Report message to a moderator]

fatmr2
Forums Junkie

Location:
sydney
Registered:
November 2003

Re: st185 gt4 single piston caliper onto aw11 conversion?	Mon, 28 February 2005 09:45

Ask toof. I think he has done it. [Report message to a moderator]

4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?	Mon, 28 February 2005 13:24

cheers fat i will Ive been talking to a mate suggested that i run the st185 callipers on the aw11 calliper bracket and if theat fits it should allow full contact of the pad with the disc. Fingers crossed. He also suggested running the sw20 turbo mr2 brake booster and a proportioning valve from a abs equipped levin. Anywyas ill let u know of the results. [Updated on: Mon, 28 February 2005 13:27] [Report message to a moderator]

3sfe
Regular

Location:
Brisbane
Registered:
March 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?	Tue, 01 March 2005 04:58

you will need 15"+ rims for those calipers [Report message to a moderator]

fatmr2
Forums Junkie

Location:
sydney
Registered:
November 2003

Re: st185 gt4 single piston caliper onto aw11 conversion?

Tue, 01 March 2005 05:17

4agte wrote on Tue, 01 March 2005 00:24

cheers fat i will

Ive been talking to a mate suggested that i run the st185 callipers on the aw11 calliper bracket and if theat fits it should allow full contact of the pad with the disc.

Apparently it bolts straight on Smile

[Report message to a moderator]

Joshstix
Forums Junkie

Toymods Vice President

Location:
Sydney
Registered:
May 2002

Re: st185 gt4 single piston caliper onto aw11 conversion?	Tue, 01 March 2005 05:29

The twin spot calipers fit with the AW11 disks. I'll be redrilling the ST185 late model disks to run with the single piston calipers for mine. The disk specs are so close to the AW11 it's uncanny it even has the correct centre bore to keep the disk hub centric. [Report message to a moderator]

Classique71
Forums Junkie

Location:
Colac, Victoria
Registered:
May 2002

Re: st185 gt4 single piston caliper onto aw11 conversion?	Tue, 01 March 2005 06:19

alot of aw11/st165/185 parts seem interchangable - i guess because of the hybrid partnership of the toyota group b rallycar .. its basically the bastard child of st165 and aw11 ST205 calipers also will fit aw11 in the same way you fit them up to st185 i believe but you need a minimum 16 inch rim + plenty of outward clearance [Report message to a moderator]

4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?	Tue, 01 March 2005 06:25

i thinks if i use the st185 caliper on the aw11 bracket then i shouldnt need 15's but with st185 disks i definatley will. Thanks for all the help guys. I will eventually use the st185 disk when my disks need replacing. Also when i bought these calipers from a guy in qld i was told these calipers were twin pistons. From what i gather the group A gt4 had both single and twin pistons? Anyways i looked at the piston and its quite sizable over the aw11 caliper and it also has the advantage of being able to get ur hands on a wider range of brake pads than the aw11 and for $150 bucks coplete with pads i thought it was a bargin anyways. [Updated on: Tue, 01 March 2005 06:26] [Report message to a moderator]

Miss MR2
Regular

Location:
Newcastle
Registered:
April 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?	Tue, 01 March 2005 07:20

toof: the twin piston St185RC calipers will bolt directly up to the aw11 bracket and disc. no grief at all. perfect fit the single piston units from the st185 (non group A) will fit onto the bracket to my knowledge but must have a larger disc. you do definantly not want to use the smaller disc on with the larger calipers the swept area on the disc must cover the entire pad.. if you have a region at the outer edge of the pad not being swept by disc it is dangerous and no doubt illegal. i do believe that if you take the st185 single piston and disc (from 185) and redill 3 new holes in it to pcd4x100 it will fit on no grief. you may need a spacer ring in the centre i cant remember off hand. if you caxn get twin piston calipers they will fit straight on and still allow you to run 14" stock teardrop rims. the single piston i dont think will fit under 14" rims. edit the st185 had single piston and the group A st185rc had twin on a slighty smaller disc. [Updated on: Tue, 01 March 2005 07:22] [Report message to a moderator]

Miss MR2
Regular

Location:
Newcastle
Registered:
April 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?	Tue, 01 March 2005 07:21

oh and for newcastle people feral will be here friday so bbq and beer at my place... alternativly we can goto the pub [Report message to a moderator]

4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?	Tue, 01 March 2005 12:15

update... I have picked up my spare front calipers from a mates house and had a quick look at the brackets and tried to test fit the pads. The pads look as if they will fit but the place where they sit in the clip is ever so slightly small. I will take a proper look tomorrow but i thinks i can make the clip area slightly larger and fit the st185 clips to the bracket allowing the pads to slip in. I have spoken to a few ppl in the know and they all agree there shouldnt be an issue with running the calliper higher on the disk and that the only issue should be a shorter pad life and that the pad face will not make contact with the whole disc which would not give the maxiumum braking force but i dont think its worth it. [Report message to a moderator]

toof
Forums Junkie

Location:
Newcastle
Registered:
July 2003

Re: st185 gt4 single piston caliper onto aw11 conversion?	Tue, 01 March 2005 21:05

ummm pad face not coming in contact with whole disc = very very bad think as the pad wears a section of unworn pad will be produced outside the swept area of the rotor. these two sections (one per pad) will get closer and closer until they touch stopping your brakes from working.... at to add to that given the correct size of the st185 rotor there is be a fairly significant portion of pad not being swept by the rotor which will hamper braking force greatly. as well as... since say ~10mm of pad will not be swept the piston pressing at the back of the pad will no being recieving equal (over the face of the pad) recative force from the pad impacting with the rotor hence it is more likley that the pad will either slip or move in a fashion you would not like. id speak to your engineer keeping in mind all brake conversions must be tested and engineered, before continuing i think form a puerly legal sense you may need to have the correct size rotor/caliper combo.... try and grab the twin piston numbers as they are a perfect fit. and use the same pad to boot. [Report message to a moderator]

4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?

Wed, 02 March 2005 01:30

toof wrote on Wed, 02 March 2005 08:05

ummm pad face not coming in contact with whole disc = very very bad Razz

think as the pad wears a section of unworn pad will be produced outside the swept area of the rotor. these two sections (one per pad) will get closer and closer until they touch stopping your brakes from working....

at to add to that given the correct size of the st185 rotor there is be a fairly significant portion of pad not being swept by the rotor which will hamper braking force greatly.

as well as... since say ~10mm of pad will not be swept the piston pressing at the back of the pad will no being recieving equal (over the face of the pad) recative force from the pad impacting with the rotor hence it is more likley that the pad will either slip or move in a fashion you would not like.

id speak to your engineer keeping in mind all brake conversions must be tested and engineered, before continuing i think form a puerly legal sense you may need to have the correct size rotor/caliper combo....

try and grab the twin piston numbers as they are a perfect fit. and use the same pad to boot.

I dont think u read my msg properly toof.

I dont intend to do this for some of the reasons that you listed there as i dont belive it would make any difference in braking over the original braking setup. The pads that i was going to use to see if it worked are half worn (i wouldnt use brand new pads it would be a waste) for this reason i dont think that they would ever have a chance of touching each other however i dont think they would anyways they would have to wear 13mm each.

Also i intend to get my brake conversion legal but for the moment im experimenting.
I appreciate the feedback tho

[Updated on: Wed, 02 March 2005 01:32]

[Report message to a moderator]

toof
Forums Junkie

Location:
Newcastle
Registered:
July 2003

Re: st185 gt4 single piston caliper onto aw11 conversion?	Wed, 02 March 2005 10:41

yup i think i have just read it briefly. if you can hunt down the st185rc twin piston numbers (i think there are a set on here for sale atm) they just drop straight on and work a treat [Report message to a moderator]

4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?	Wed, 02 March 2005 10:48

yeah i know im trying to be cheap about it atm kinda got conned in a previous sale where i thought i was buying twin pistons and it ended up being the singles so im stuck with em also im going to japan in 2 months so im trying to save like crazy. Had a good look at the aw11 brackets tonight and it looks like the pads wont fit into the bracket. I could grind some metal off the brackets but ehhh i dont think it will be neat so ive ordered a disk brake pad book from bendix (wait and see if they will send it their website says they will) and im gonna go thru the measurements to see if there are any other pads that will suit. The only reason the st185 pads wont fit is the clips that hold the st185 pads to the caliper bracket is slightly larger than the aw11 pad so if im lucky i might find a pad that fits and is larger than the aw11 pad. Would kinda like to do something a little different. Im also keen to see how well a sw20 turbo master cylinder will work i definatley have to push alot harder with the n/a aw11 master cylinder. [Updated on: Wed, 02 March 2005 10:50] [Report message to a moderator]

toof
Forums Junkie

Location:
Newcastle
Registered:
July 2003

Re: st185 gt4 single piston caliper onto aw11 conversion?	Wed, 02 March 2005 10:58

with the st815rc calipers i havent found the pedal effort to be any real difference over the standard calipers. i know a bigger master cyl would be an improvment but ive never really had any grief with the stocko. the nice thing about the twins is the only thing you have to mod/cut is about 20mm off the dust shield to clear them in other then that they are a direct fit. [Report message to a moderator]

4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

Re: st185 gt4 single piston caliper onto aw11 conversion?	Wed, 02 March 2005 11:09

yeah thats all i thought id have to do.... then i opened the box and they werent twins. [Updated on: Wed, 02 March 2005 11:09] [Report message to a moderator]

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