Attaching brake calipers to hubs?

[wagonist]

I am in the final stages of fitting the ST205 Celica GT4 calipers to my car.

I have sorted out the offset issues to do with this conversion and am now looking at how to attach the calipers to the steering knuckles (or hubs or whatever else people call them).

This is only an issue for the front.

The original calipers are fitted to the outside of the steering knuckle.
Therefore, the knuckles are drilled through whilst the caliper is threaded.

For the ST205, the calipers are drilled through, with the knuckles being tapped instead.

The issue is that both systems use identical bolts (12 x1.25).

writeup and pics of this brake upgrade:

Link to Brake upgrade writeup

Pics of this setup:



My options are (and I'd like opinions from those who may have done them):

1. drill & tap the knuckles larger to suit a larger bolt (14 x 1.25). This also requires redrilling of the calipers. I have done this in the past on a previous conversion. It works well, but does not allow for "retro-fitting" of the original equipment, something that I did do later & required replacement knuckles to do it.

2. re-drill the knuckles to suit a helicoil. This was done by the TRD Australia rally team as this conversion was done on their Group NP turbo 4wd Corollas.

3. use bolts & nuts.
3a. Suitable nuts fit on the outside of the knuckles without touching the brake rotors. Questions regarding how to secure the nuts to tighten them (some accessibility to the nuts is available) need to be checked. Also the issue of having them secured (copious amounts of loktite would be used).
3b. welded nuts:As the hub is cast, could the nuts be welded on (though how this effects the strength, etc is another question).

Opinions/comments/suggestions?

[Cuzzo]

Depending on how the load would transfer onto them.

Could you weld nuts on the hub to allow bolting through? If you wanted to remove them you could grind them off.

But i dont know how the st setup is...as in would you get the bolts through the caliper?

[wagonist]

I've edited my post, but the welding was part of option 3.
And as you've said, grinding off the nuts later wouldn't be an issue.

The bolts come through from the inside (ie from the chassis rail side), so access for them is not an issue.
Holding a spanner (socket or ring wouldn't work) on any nuts would be difficult, and therefore hard to ensure that they are tight.

I think nylock nuts would melt also.

I will try to get some photos of the clearances tonight to make it clearer.

[wagonist]

I've got an Adobe file of the write up I did of the last time I did this conversion with pics, etc.

I don't know how to get it hosted though (it's too large to make an attachment @ 549kB)

[WDE_BDY]

You can load PDF's to Imageshack and then post the link.

Callum

[wagonist]

You can load PDF's to Imageshack and then post the link.

Callum

Fail.
Just tried it at this website:
http://imageshack.us/
Is this the same one you were thinking of?
The file is a pdf format.

[WDE_BDY]

Yep, Ive loaded PDF's before. Will just go look. Do you have an account there or loading as a guest?

Callum

[wagonist]

Guest. Maybe that's the issue.
Any dramas with emailing you the file to upload & sending me back the link to attach?

[WDE_BDY]

Loaded up for you.

http://img151.imageshack.us/img151/2...esfor5x100.pdf

Callum

[wagonist]

Awesome, thanks for that.
I've added the link into the first post too to help.

[Cuts]

any idea if your dina hubs(knuckles...whatever) are the same as 185 hubs?

if they are the same are you willing to sell a set of brackets? do yours require the 205 rotors to be turned down?

[thechuckster]

I'd go for option #2 - the TRD Corolla's have never DNF's because one of the brake calipers fell off.

[wagonist]

any idea if your dina hubs(knuckles...whatever) are the same as 185 hubs?

if they are the same are you willing to sell a set of brackets? do yours require the 205 rotors to be turned down?

Almost the same, except the caliper mounting lugs are about 5mm further inboard.
Therefore, I've had the issue of the outside of the rotor rubbing against the caliper, meaning the caliper requires machining to move it outwards.
The ST185 needs a spacer behind the rotor to move it outwards to centre it.

Brackets?

And yes, I've had the rotors machined down to 300mm.

[wagonist]

I'd go for option #2 - the TRD Corolla's have never DNF's because one of the brake calipers fell off.

true, but the TRD Corollas also have their knuckles, etc changed a bit more often due to the wheel bearings overheating & copping a pounding.

[Cuts]

ahh i thought you were making brackets to move the calipers out further. but your screwing the caliper directly to the hub. I see.

starky wants me to do some brackets for his car, i thought if you had some brackets i could buy it would be easier haha.

[jonathan yee]

what about pressing some wheel studs into the hub then a bolt to hold the caliper?

[wagonist]

ahh i thought you were making brackets to move the calipers out further. but your screwing the caliper directly to the hub. I see.

starky wants me to do some brackets for his car, i thought if you had some brackets i could buy it would be easier haha.

If you're going to use non Toyota rotors (ie something with a different hat height), then maybe that would work, but otherwise it's impossible (or at the least extermely difficult).

Someone in central America has done an EVO brembo combined with an STi on his Caldina (link to his thread in the first page of the Caldina dedicated thread), but you'd need at least 18s to clear (plus a 25mm spacer)

[wagonist]

what about pressing some wheel studs into the hub then a bolt to hold the caliper?

I'm guessing you mean studs & nuts?

Stud faces inwards for the caliper to go.
Wheel studs face outwards for the rotor to go on.
Caliper fits either side of the rotor.
Fail.

Had already attempted that because the studs from the lower ball joints are perfect.

[AL510]

I'd go with the heli coil. the outside of the coil is just a larger thread so it should be just as strong if not stronger.you would want to remove the part from the car and have it drilled in a drill press or a mill though to make sure it is square though.

Al.

[jonathan yee]

I'm guessing you mean studs & nuts?

Stud faces inwards for the caliper to go.
Wheel studs face outwards for the rotor to go on.
Caliper fits either side of the rotor.
Fail.

Had already attempted that because the studs from the lower ball joints are perfect.

d'oh...yeh makes sense.

i had my caliper's helicoiled in my mini ages ago becuase some douch put a coarse thread bolt in and it shear'd of when i was doin 110kph on the way to kalbarri.

fortunately it was the one towards the front of the car so when i applied the brakes whilst going forward the caliper pulled itself onto the rotor, but when applied going in reverse the caliper pulled away and jammed itself onto the inside of my rim creating lockup and a nice groove