993 caliper conversion done at last...

[david.avery]

Hey guys

Just finished my conversion from Carrera brakes to 993 calipers. Oi, what a chore. I had numerous problems with machining, and even had a crossover tube not seat right, and blow fluid everywhere once I had pressure bled the system (only blew fluid after I bled the system and stepped on the pedal!)

I'll snap some before/after pics and answer some questions if you would like. IMO, this is a royal pain in the butt. stripping the calipers, getting them machined (properly) then PC'ed and back on the car is not as easy as it sounds. I went the DIY route and chose the services of another Pelican to get the machining done. In the future, buying a set of these calipers already machined and coated is definitely the way to go, as my car has been out of commission for months. Any savings with the DIY method has somewhat evaporated due to shipping costs, and dealing with the mishaps of involving three parties.

Also, as another note, anyone working on these cars owes it to themselves to get a cheapo motive bleeder. I got one locally for $47.00 with the 1100 adapter, wow, talk about easy bleeding. I had bled first with a mity-vac, and due to the master cyl replacement, I had tons of air, and lots of pumping to do.

Anyhow, these things sure do look pretty! I'll be stencilling on the logos once I am sure the calipers don't have to come off for any last minute fixes. I'll post pics when I get home...

[KTL]

Congrats David!

I'll agree the conversion is kind of a pain. The rears are the culprit for sure. The fronts are a simple bolt-on except for the fluid lines. If one were to have custom flex lines made? Front is a no-brainer.

If/when I do a brake conversion again, i'll do the rear calipers differently. Clearing the throats of a 993 rear is a bit tedious and I was trying to do my best to cheat and make them fit my 8" Fuchs. I ended up having to clear the inside of the caliper more than i'd like to.

Next time around i'll do one or both of the following:

-Locate a set of 965 rears to avoid widening the pad box and having to shave pads <------ I think this is a royal PITA.

-Take apart the calipers to make it easier to drill, tap, plug, re-drill the mounting holes.

-Have some custom flex lines made up. I found the bending of brake lines a bit bothersome too. I think if I were not to use flex lines, at least i'd bend and flare my own lines instead of buying 8 or 12 inch off the shelf pieces from the parts store.

And honestly, if I were to do it again? I think i'd look into using 996/Boxster calipers for the upgrade. Better calipers, better rear fitment with axial-radial adapters, and these 993's squeal like pigs if you're not careful. I shaved the edges of my street pads to reduce the squealing.

I can say after one track day that these brakes are a drastic difference from the stock setup. Very easy to lock up the brakes on street tires (although our day was a bit cold, rainy and the track was new to me) and even with Victoracers I found the brakes to be a bit touchy. They'll take some getting used to. So basically these brakes provide plenty of stopping power!

Fitting them under Fuchs is a tight fit. I had to get a 951 16x7 for the front and use 1/2 in. spacers with longer studs (H&R makes very nice spacers) on the rear to clear my 16x8 Fuchs. The simple solution is 951 16x8 front, 930 16x9 rear and clearance is no problem- that's big $$$. I managed to locate some BBS RS 1980's bling that suffices well for track wheels. If I were to do it again, i'd go with some nice 17's.

All in all a rewarding upgrade. Just takes some patience And of course a big thanks to the others who've been there, done that (Bill Verburg, JeremyD, Slider79SC, dinftown, ..........) couldn't have done it nearly as well as it turned out without their help.

[david.avery]

Thanks

Yeah KTL... true, true. The use of 993 calipers was solely to try to clear my 9" fuchs which I sold mid project due to needing 951 8's on the front. I think axial on the rear would be awesome, or some pre-made caliper setup, versus the surgery to the 993's. Talk about fun, trying to get them to bolt on (and reaching the bottom bolt, oww, my hands still hurt!)

[KTL]

Re: rear calipers. Yes indeed. That bottom bolt is a mutha. I have a floppy head ratchet and a shortened/shaved socket that I use to install that pesky bolt.

Which bring us to the reason why I like the monoblock rear calipers, or our calipers machined to accept adapters.

Check out TRE's solution



That adapter is really nice. I've played with one a little bit. Yes, the Boxster rears use a bit smaller pistons (30/28) vs. the 993/965 (34/30). But the resulting additional front bias is not the worst thing. TRE's arrangement lets you use a stock Carrera rotor without pad overhang or brake caliper clearance. I plan to give this setup a try to see how it compares with the 993.

[einreb]

Originally posted by KTL
Which bring us to the reason why I like the monoblock rear calipers, or our calipers machined to accept adapters.

Check out TRE's solution

That solution is the absolute schnizzle. Very nice.

I love the results of the my 993 brake setup and I was able to do mine on the cheap, but will agree that the rears are a bit of a pain. Of course I could do it again in half the time knowing what I know now.

[KTL]

No doubt.

It's always good to have a guy like Bernie on hand to keep things simple & show a simpleton like me how to do things easier/quicker.

Originally posted by einreb
That solution is the absolute schnizzle. Very nice.

I love the results of the my 993 brake setup and I was able to do mine on the cheap, but will agree that the rears are a bit of a pain. Of course I could do it again in half the time knowing what I know now.

[JeremyD]

Glad you got it to work out David - I tried to answer your PM but your mailbox was full.

It's a pain in the ass - but you only have to do it once... and the rewards - well the rewards on the track are hard to describe...

[Jbabic]

don't take this as a smart@@@ comment..just trying to be funny..cuz im proud. Here is a pic of my 993 brake conversion.

[david.avery]

Originally posted by JeremyD
Glad you got it to work out David - I tried to answer your PM but your mailbox was full.

It's a pain in the ass - but you only have to do it once... and the rewards - well the rewards on the track are hard to describe...

Thanks Jeremy, I saw it and cleaned my box out, sorry, what a pain (wish we could donate for a larger PM inbox)

[Bill Verburg]

Is there an echo in here?

I went the DIY way the first time, bought a full kit from Race Tech the second, My mamma didn't raise no dummy, slow yes but not totally senile (yet)

The DIY is not ever going to be the easist way to do it.

[htron435]

Hey Bill or Kevin-

I have 965 brakes on the rear of my SC. What length of wheel stud is needed to allow for 1/2" spacers to work with normal ole 16x8" Fuchs? Can I use stock lug nuts with that setup?

[KTL]

Lane (Jay),

I have regular 911 16x8's and I use H&R 14mm spacers with them. These come with the studs you need. They're very nice spacers. I'll measure the stud length and let you know if someone else doesn't chime in.

Since I didn't know the H&R spacers came with studs, I bought 72mm studs for my car for a reason you'll see shortly. I havent' tried to use the alloy lug nuts with the 14mm spacers and extra long studs because the stud sticks out of an open steel lug a good bit. I should try an alloy lug with the 14mm spacers and let you know.

I used 72mm (901 331 671 01) studs with factory 930 rear slip-on spacers because of the mildly large offset wheels I was planning to use. These spacers are 28-29mm wide, so they are not technically 1 inch spacers. In a pinch I decided to use a BBS 16x8 wheel with a ET +28mm offset (actually a front wheel application for 930 cars) that works just about perfect for the combination of studs, spacers, wheel width and offset. I can use stock alloy lug nuts for this wheel and spacer combo since the stud just barely peeks out of the open steel lug. Using this spacer with regular 911 16x8 (ET +10.6mm) pushes the wheel out a bit too far and you have to max out the camber to ensure there's no fender-to-tire interference.

The long wheel studs are a pain for a couple of reasons:

1. I always have to use a spacer with the studs because the stud is not threaded enough to let a lug nut snug all the way down- I run out of threads at the very end. I'll have to check this for you on my multitude of four different wheels I can use on the rear

2. Installing the 72mm studs is a bit tougher because you have to bend the parking brake backing plate to get them in and it can gouge your threads a bit. Shorter studs slip right in by removing the star wheel adjuster on the parking brake assy.

3. Exposed threads on the end with the open lugs can also allow the threads to get damaged by tools and track debris (the latter not as likely) and make it a pain to get your nuts off!


If I had it to do again I would use 65mm studs (911 331 671 00) with 928 factory rear spacers that are 21mm. Others on Pelican have done this with great success. I've seen this done in person on a friend's car. They use the std. 911 16x7 in this case but I think there's plenty of room to use a regular 911 16x8's extra inch of outboard width.

[htron435]

My rear street tire/wheels are 16x9's, but I have a set of Kumho MX's on 16x8's that I'd like to use at the track (much cheaper and easier to find quality tires to fit the 8's). I'd like to go with whichever will allow me to use both combos without a fuss. Knowing this, would your choice be the H&R combo or the 65mm studs/928 spacers?

[KTL]

Jay,

Given your need to use both the 8's and 9's with one spacer, you'll want to go with the 14mm spacer. Cost will be about the same either with the H&R kit or the 928 spacers + longer OEM Porsche studs. But the upside to the H&R is you get nice anodized spacers and the perfect size studs that work with your existing alloy lugs.

Just make sure to increase your rear camber since you'll be using the spacers with 9's. Jeremy Dixon's done it.

Anyone have 928 21mm spacers on a 911?

With the 9's you can really just leave the spacer off if you use open lugs.

[htron435]

Thanks Kevin. I ordered the H&R Spacers today. I'll let you know how they turn out.

[KTL]

Jay,

I measured the studs and the ones that come with the H&R kit are 65mm studs. So you can experiment with the 928 21mm spacers to see if they'll suit your needs.

I know that when I put the 930 spacers on the rear of my car, the 8's seemed like they sat outboard a little too much. With a 7mm narrower 928 spacer and some added rear camber, the 911 8's may be just right?

I can experiment with the 8's and the spacer collection I have, whenever the heck I get my car back in action.

[htron435]

I was at MidOhio last weekend and put on a set of 1" wheel adapters with the 8's. They hung out too far but they didn't rub -- but the clearance was extremely tight. I went out for one lap just to see what they'd do under load. Sure enough, the left side did in fact rub under load. However, based on that experience and the measurements that we took, I'm about 95% certain that the 14mm spacers will be just right. It's a shame that they rubbed with the 1" adapters, because that car looked seriously mean with the rears hanging out just a tad too far! Very RSR-like.