Rear 914-4 calipers with a spacer?

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supaninja
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Re: Rear 914-4 calipers with a spacer?

Post by supaninja » Tue Feb 19, 2013 10:51 pm

Nevermind, you need a rear caliper with a built in e-brake, wilwood makes a small 4 pot with built in e-brake.
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Re: Rear 914-4 calipers with a spacer?

Post by aircooledtechguy » Wed Feb 20, 2013 12:03 pm

The pistons are larger in diameter in the factory 914-6/Ferrari calipers giving the added braking over the 914-4 calipers. I WISH it were that easy. . .

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Re: Rear 914-4 calipers with a spacer?

Post by crankwalk » Wed Feb 20, 2013 8:50 pm

supaninja wrote:Nevermind, you need a rear caliper with a built in e-brake, wilwood makes a small 4 pot with built in e-brake.

I don't NEED a built in ebrake but I do need 3 inch bolt spacing and 20mm rotor gap in a skinny caliper that would hit the wheel.

Ebrake not a real priority
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Type 4 Unleashed
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Re: Rear 914-4 calipers with a spacer?

Post by Type 4 Unleashed » Thu Feb 21, 2013 12:12 pm

crankwalk wrote:
supaninja wrote:Nevermind, you need a rear caliper with a built in e-brake, wilwood makes a small 4 pot with built in e-brake.

I don't NEED a built in ebrake but I do need 3 inch bolt spacing and 20mm rotor gap in a skinny caliper that would hit the wheel.

Ebrake not a real priority
I believe Ebrakes are required by law and there is even an issue with insurance.
You'll need to check the law for your state.

http://boards.answers.findlaw.com/index ... violation/

In Ca, I know of a city for revenue, that writes tickets if you don't have your wheels turned toward the curb, the street has a very slight grade.. :roll:
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jkftl
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Re: Rear 914-4 calipers with a spacer? (off-topic)

Post by jkftl » Mon Jun 24, 2013 5:25 pm

I need to reach 'crankwalk' to compare notes on his 308GT4 swap project. As he notes the calipers are SIMILAR to 914-6, but ports are in different places, requiring machining, even if you make spacers. I got lucky and scored a set of used GT4 calipers and had them redone. I need to get in touch with Jay Gilling on my project. Thanks

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Re: Rear 914-4 calipers with a spacer? (off-topic)

Post by Type 4 Unleashed » Wed Jun 26, 2013 2:37 am

jkftl wrote:I need to reach 'crankwalk' to compare notes on his 308GT4 swap project. As he notes the calipers are SIMILAR to 914-6, but ports are in different places, requiring machining, even if you make spacers. I got lucky and scored a set of used GT4 calipers and had them redone. I need to get in touch with Jay Gilling on my project. Thanks
Just call Eric Shea @ http://www.pmbperformance.com/catalog/i ... 786365.htm he has converted a number of Ferrari calipers, and has no problem answering questions.
Richard

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have the money to do it right, but can always
find the money to do it twice ?”

H2OSB
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Re: Rear 914-4 calipers with a spacer?

Post by H2OSB » Sun May 20, 2018 11:10 am

This is an ancient thread, but I've recently come upon info that may help the next person doing research on this subject.

Takes a bit of sourcing, but Porsche 914 early calipers have 3 inch bolt spacing and have 42mm pistons. Early 911 REAR M calipers use the typical Porsche rear caliper bolt spacing of 94mm, however, the casting for the body of the 911 rear M calipers and the early 914 front is the same. Therefore if a person were to source a set of rear M calipers and dismantle them for parts (CAREFULLY...those damn Ribe bolts are difficult and expensive to replace. They're M7. Ask me how I know this.), along with a set of EARLY 914 front calipers, you could put together a set of calipers with 42mm pistons that will fit over 20mm thick rotors and have 3 inch bolt spacing. All of the hardware from the rear M calipers works with the newly widened 914 calipers, including brake pads.

Something to note: Both calipers use M7 bolts. M7 was never a standardized size and thus a very difficult to find (at least here in the States). In researching this, I found M caliper guys who were simply wanting bolts to replace aging and worn Ribe bolts (out of production for approximately 40 years) and finally found a company in Germany called Tola-Tools. They do, indeed, have socket head bolts of the correct lengths and hardness (12.9) for this conversion (well, ok, you're supposed to use one 60mm and one 65mm bolt per caliper but Tola only offered 60 and 70, however, I found the 70 worked nicely.). The bolts, themselves, were not outrageously expensive, however shipping from Germany to California was nearly double to cost of the bolts. Cry once and do it right, I say.

My machinist friend thought it was silly to spend that much on bolts when M8 and 5/16th can be had for far less, as they are standardized. However, I simply wasn't brave enough to take that plunge. I figured Porsche would have used M8 if they felt there was enough material in the calipers to allow it. I'm quite happy with the result.

Another note: The 914 calipers used for this must be the early species. The share the same flow passages as the rear M calipers. The late 914 calipers, though they look similar externally, have different flow passages and thus the spacers won't line up correctly.

The correct square shouldered rubber grommets that go betwixt the caliper halves can be sourced from PMB Performace for a very reasonable price. It's important to remember, however, you need twice as many than for a typical 914 caliper rebuild.

Hope this helps someone
H2OSB

EDIT: Small correction. The 911 rear M calipers have 3 inch bolt spacing. It wasn't until the 964 that Porsche went to 94mm spacing

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