Bargain Basement Big Brakes

[wortdog]

I solved my problem with an adjustable proportioning valve and just change the setting depending on what tires I've got on the car and what the weather is like, or I can be lazy and leave it fairly forward like stock. I've never had a temperature problem in the rear with the stock rotor/caliper setup from what I can tell.

 

[Jon Lane]

Using Eric's great design and artwork, I resketched in AutoCAD and finally had some brackets milled from 3/8" steel. It was a ton cheaper than buying them from someone else.

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I should have the brakes installed next week.

Eric, if you'd okay it, I'd be happy to get more made.

 

[wret]

Nice!

 

[wortdog]

Those look great compared to mine, which were made with a drill press and a bandsaw, heh.

I do know that I had to run a slightly larger drill bit through the mounting holes on the caliper, which could be an error in the drawing or a 'manufacturing' error on my part. You may need to tweak the final part to get it to fit perfectly without having to touch the caliper. Also, you might consider rotating the caliper up a bit to be perfectly vertical. On my car the brake line bracket that mounts to the shock had to be modified a bit to use stock length lines.

 

[Jon Lane]

I can ream these (mild steel) and I suppose that if I make more, up the holes to a flat half-inch in diameter.

I plan to use these for 12.5" AEM (now Powerslot) discs. Anyone know if I'll have to space anything with washers on a 2G to center '92 TT calipers (cheap from Rock) over the rotors? I'm prepared to shim my 17" wheels to clear the wider caliper bodies too.

At any rate, there's a local house that water cuts 4' x 12' steel. I can get a raft of these nested and cut for cheap.

Any more tips would be appreciated.

 

[wret]

I can ream these (mild steel) and I suppose that if I make more, up the holes to a flat half-inch in diameter.

I plan to use these for 12.5" AEM (now Powerslot) discs. Anyone know if I'll have to space anything with washers on a 2G to center '92 TT calipers (cheap from Rock) over the rotors? I'm prepared to shim my 17" wheels to clear the wider caliper bodies too.

At any rate, there's a local house that water cuts 4' x 12' steel. I can get a raft of these nested and cut for cheap.

Any more tips would be appreciated.

Hold up.

Eric's bracket is sized for a 13.1 inch rotor. Your pads will hang off the the rotor quite a bit, unless you already took this into consideration.

 

[Jon Lane]

I'm aware of that too, wret. We're prepared to slot them like you did yours. Eventually I'd like to home in on a new set of designs that can cover a range of diameters. Given the reasonable cost, something like this should be developed.

 

[wortdog]

Slotting them should be ok, but I'm not the world's biggest fan of slotted caliper adapters. I'd use steel locknuts to be absolutely sure the bolts don't back out.

 

[wret]

The only reason mine are slotted is because I planned to use a rotor that was bigger but it didn't work out. I used a serated flange nut against the slotted bracket as a precaution against movement but it has not been an issue.

You will also have to remove material from the mounting ears on both the caliper and the knuckle to get them that close together.

 

[Jon Lane]

Update: My new AEM (Powerslot) Big Brake rotors (12.5" / 317mm) and my particular 17" RH wheels are a definite no-go. Lots of interference. I estimate I'd have to space the wheels out 5mm or more to clear.

Wret, how did you measure offset? These appear to measure about 29-30mm from hat face to rotor face. How do they compare? wortdog, what can you tell me about the Mustang rotors and offset?

 

[wret]

If you can find any information on rotor dimensions, it will usually be height. Knowing the height and the rotor thickness, you can closely estimate offset. If the AEM rotors you bought were intended for a 3000gt/Stealth, they would be the same height. There is a spreadsheet I posted on page 2 of this thread with diemensions of the different rotors I investigated. The Cobra rotors have an offset disadvantage over VR4/TT rotors.

If you don't want to space out your wheels, and you are reluctant to have at your hubs with a grinder to use Audi discs, consider talking to Todd at TCE. He can work with different hats on a two-piece rotor to get you the offset you need.

 

[Jon Lane]

These rotors and hats are AEM/Powerslot for 2G Eclipse/Talon. Height measures 54mm and offset looks to be 24mm. [Corrected 9-Jun]

Without hat thicknesses in your table, I don't know how to compare them precisely, but they'd appear to be roughly usable as they are less than the A8 Lucas offset, which is too much. Maybe it's my wheels that are complicating things, but I doubt stock 17" wheels would fit either.

Can you post hat thicknesses and/or tell me how much more inboard I can space the rotors before hitting something? These rotors are 24mm thick.

The best option would be to surface the calipers a mite. Anyone know how much extra meat is on the outer surface of these things?

 

[Jon Lane]

A shot of the TT 4-pot caliper. Wonder if I cut a couple mm off the faces of these if I'd screw em up. Doesn't feel real good...

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A shot of the brackets laid at the mounting location:

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[Jon Lane]

As it now turns out, there's no chance of ever getting enough clearance by taking a couple mm off the caliper faces. The only salvation for this project (with these wheels) is setting the rotors as far back as possible.

This shot shows the spokes hitting the calipers on 12.5" (317mm) rotors. Note how the situation gets worse if the caliper moves further outboard. Stock 10" rotors may clear, but nothing close to 12" or over looks feasable, at least with these wheels.

This interference even includes the wheel hub standing still at least 2mm off the face of the rotor hat AND no pad clearance -- the calipers are sitting right on the faces of the rotors in this shot. Hard as it is to believe, I think I'd need the better part of 8mm of room to clear everything with this rather unfortunate choice of parts, led by the wheels.

Now I need to find out just how far back I can distance the rotors with new hats before I hit the knuckle with the back of the rotor itself. Either that or ditch these 7" wheels and get some eight's with more spoke offset...

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[wret]

I've seen pictures of the calipers shaved though I have no idea how much is safe.

It's been a while since I looked at the clearances but during the early part of this thread I was convinced that the Audi S8 Brembo rotors with a height of 52mm would fit. The A8 rotors, with a height of 59mm hit the ABS sensor, though not by much. The S8 rotors do not have much of an offset advantage (wheel clearance) over the A6 rotors that I am using due to the greater thickness at the disc.

 

[Jon Lane]

I've seen pictures of the calipers shaved though I have no idea how much is safe.

It's been a while since I looked at the clearances but during the early part of this thread I was convinced that the Audi S8 Brembo rotors with a height of 52mm would fit. The A8 rotors, with a height of 59mm hit the ABS sensor, though not by much. The S8 rotors do not have much of an offset advantage (wheel clearance) over the A6 rotors that I am using due to the greater thickness at the disc.

If there were no ABS sensor, do you know how much further you could offest the rotors? I don't have ABS so I assume the rotor would eventually contact the knuckle as it moved back?

 

[Todd TCE]

consider talking to Todd at TCE. He can work with different hats on a two-piece rotor to get you the offset you need.

We are chatting about it. But that pic is incorrect.

OFFSET is the distance from the dotted line to the outer friction surface of the rotor. NOT the rotor centerline.

 

[Jon Lane]

For anyone reading, the AEM hats appear to be 6mm thick, giving an offset of 24mm.

 

[wret]

We are chatting about it. But that pic is incorrect.

OFFSET is the distance from the dotted line to the outer friction surface of the rotor. NOT the rotor centerline.

Picture fixed, thanks, but that kind of sucks. It makes it harder to describe the caliper position, unless you have a term for that too?

 

[Jon Lane]

Update: The 3000 4-pot caliper project at my house is dead. The problem is excess caliper width (these guys have outboard-side pistons whereas the stockers are floaters that only have inboard pistons where they don't go banging into wheel spokes.)

The possible solutions and problems are these:

1. Offsetting the rotors inboard. Involves quickly running into rotor-to-knuckle interference and grinding away on my knuckles isn't my idea of either a fun time or the best possible engineering. Don't get me wrong; it works and may be a solution many are willing to try, just not me. Add the fact that there are no available perfect fits in the non-standard rotor department (lug stud holes, centerbores, offsets, etc.) and I have to wonder if there's something a bit more elegant out there.

2. Modifying the Mits 3000 4-pot calipers. In theory you could pick up a half-inch added spoke clearance redoing the calipers. I actually strongly considered this until I came to realize that milling material off the mating faces of the two halves of the calipers to reduce their mouth from 1.25" to 1" (my AEM/Powerslot rotors are 24mm thick) would make pad fitment a huge pain. Milling perhaps .200" off the front face of the caliper alone isn't enough to clear the spokes and may also compromise the caliper -- I don't know how thick that metal is or where its fail point would be. Plus caliper replacement suddenly gets really expensive, negating the project.

3. Wheel spacers and/or new wheels with lots of spoke offset. Don't like spacers and I'm not doing the wheel clearance experiment as it would leave hundreds of possible wheel choices forever off the list as well as presenting a huge financial risk in trial and error.

Nope, there has to be a better way...and I think I may have found it in the form of a Wilwood caliper that'll fit both the 12.5 diameter, stock-offset rotor, as well as most 17" wheels with stock offsets and spoke profiles.

We'll see. If I'm lucky and this works, I also get a far larger pad and don't have to compromise by rubbing the stock pads around only the outer 75% of the rotor friction surfaces. The rotor and pad I'm looking at will precisely rub the entire friction surface from hub to edge without overhang. If it works and the caliper-to-hub clearance and caliper-to-wheel spoke clearance is what it looks like it'll be, this is probably the largest combo you can fit in a 17" wheel.

If it is I'll post it up.

 

[wret]

Sorry to hear you have given up, Jon. If you read the beginning of this thread, and I'm sure you did, wheel clearance was the biggest issue.

1. No wheel spacers.
2. Simple enough to be repeatable by others.
3. Affordable
4. and of course, functional.

It looks like you failed challenge #1 and I failed #2.

 

[Jon Lane]

You're correct, wret -- not a problem. But I had to give it a go and see what would happen.

The good news is that there could now be another alternative that doesn't involve worrying about spoke clearance. And only about $150 more if it works...plus I have a good source for the brackets now so it all works out.

 

[Omega]

Jon, where did you get the brackets made? I am having trouble getting a set done for less that $250

 

[3literpwr]

If you guys want I could water jet tons of those brake adapters for ya....
I write ALOT of water jet programs and there is a ton of water jet parts on my rally
car... Navigator foot rest, Handbrake, Sturt reinforment plates, Control arm reinforment
plates, Gauge councel, master cylinder mount plate... and on and on.... O2 jet is cheap and fast and can hold a TOL of +- .0005

I will only make them IF you guys make more that a couple as I have to drive around and
get material and all that jazz... Oh and if the gentleman that made the file would like a cut I would be more than happy to give it to him... I know I dont like when people take MY design and trty and make money on them...

Regard
Larry Parker

 

[Jon Lane]

Omega, PM me. I have an extra pair now...