When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Wow, blue Loctite on a Philips head screw? How easy will that be to remove when the time comes to replace the friction ring without stripping the screw head? I was actually surprised to discover that the rotors are secured with just two screws, so Loctite makes sense to me in that sense, but even though these screws are easily replaceable, I'd rather not have to deal with drilling out stripped screws to replace a friction ring.
You are mistaking blue versus red loctite and their adhesion. In a lot of circumstances these screws are considered 1 time use anyway like so many others in the Porsche parts catalog. At $0.30 ea or thereabouts I'm not going to worry having to replace them.
I might take your stance if I had to replace the OEM Lenshead ones as the difference in price would be a 6-pack and a medium pizza for set of 8.
Not trying to be an asshat here but I addressed this issue with Jeff at Essex (AP) as well as Clark at Apex after fitting the original set as a test case. Originally I was told to reuse the Lenshead screws that came with the OEM steel rotors (999-015-025-09) only to find out that the correct ones were the ones for a 987.2 steel rotor (900-269-047-01) or the GT4 OEM PCCBs chamfered ones (900-269-047-03)
I was reassured and sent 1 screw per rotor by AP and after talking to Clark I was assured that he would cover the issue and supply 2 screws per rotor. The screws sent to me by AP were a bit longer than necessary. I bought the correct length screws through my dealer. The OEM screws had blue loctite applied whereas the AP supplied ones were bare.
Reading some of the other info jp supplied and finding all the screws in my second box for the rears I just received I am not sure what to think. I either bought one of the first sets of fronts and were not supplied the screws, or my shop missed them and re-used the oem ones. It was quite a while ago, so no way to know for sure. And unless you use wheels with a flat surface you won't realize it.
And unless you use wheels with a flat surface you won't realize it.
Not really. If you used the lenshead ones you might have enough slop in getting the rotors centered properly. The conventional wisdom is that the lugbolts will do it for you but keep in mind that both parts have tolerances that need to be kept.
I was uncomfortable reusing the lenshead ones with lugbolts to center the rotors. Luckily I had spare chamferred ones to try. I didn't finish my install til I had enough of the right ones; not comfortable otherwise in a track scenario.
Not trying to be an asshat here but I addressed this issue with Jeff at Essex (AP) as well as Clark at Apex after fitting the original set as a test case. Originally I was told to reuse the Lenshead screws that came with the OEM steel rotors (999-015-025-09) only to find out that the correct ones were the ones for a 987.2 steel rotor (900-269-047-01) or the GT4 OEM PCCBs chamfered ones (900-269-047-03)
I was reassured and sent 1 screw per rotor by AP and after talking to Clark I was assured that he would cover the issue and supply 2 screws per rotor. The screws sent to me by AP were a bit longer than necessary. I bought the correct length screws through my dealer. The OEM screws had blue loctite applied whereas the AP supplied ones were bare.
What is the issue with just using the stock screws in the counterbored holes (just like the stock rotors)? That's what I did when I installed my AP rotors, mainly because Essex didn't include enough of the conical head screws for me to do all 4 corners... When I pinged Essex about it, they told me that the conical holes / screws were for compatibility with the 991 Turbo OEM screws, and that I should use the stock GT4 screws in the counterbored holes and ignore the few conical head screws that I was sent. Odd that there was a note with them about using them in the GT4... not sure what the story is.
Looking at all the screws, the only advantage of the conical heads seems to be helping center the rotor over the lug nut holes on the first try. If you use the stock screws in the counterbored holes, there is enough slop in the counterbore for you to misalign the rotor such that the lug bolts will not thread in properly (easy to fix, just pay attention to the alignment of the holes in the rotor hat to the lug threads before tightening down the screws).
So I don't see any real advantage to using the conical ones provided by AP... plus, you can crank down the stock Torx screws quite a bit tighter than the small hex head of the AP screws.
What is the issue with just using the stock screws in the counterbored holes (just like the stock rotors)? That's what I did when I installed my AP rotors, mainly because Essex didn't include enough of the conical head screws for me to do all 4 corners... When I pinged Essex about it, they told me that the conical holes / screws were for compatibility with the 991 Turbo OEM screws, and that I should use the stock GT4 screws in the counterbored holes and ignore the few conical head screws that I was sent. Odd that there was a note with them about using them in the GT4... not sure what the story is.
Looking at all the screws, the only advantage of the conical heads seems to be helping center the rotor over the lug nut holes on the first try. If you use the stock screws in the counterbored holes, there is enough slop in the counterbore for you to misalign the rotor such that the lug bolts will not thread in properly (easy to fix, just pay attention to the alignment of the holes in the rotor hat to the lug threads before tightening down the screws).
So I don't see any real advantage to using the conical ones provided by AP... plus, you can crank down the stock Torx screws quite a bit tighter than the small hex head of the AP screws.
Initially I was told the same thing by AP as you: reuse existing hardware (at that time they didn't supply additional screws). The OD of the lenshead screws is larger that the OD of the chamferred one and therefore will sit on top of the hat instead of in it. I can't be certain as its been a while but I seem to recall that AP had indicated that on their next batch of hats they would look into a modification that would allow usage of both screws.
In the attached image you can see that hanging the rotor doesn't always guarantee its centered. My preference is to center it with the appropriate setscrew prior to installing the wheel and then messing with alignment via the lugbolts.
As mentioned before, these screws locate and hold the rotor in place before attaching the wheel. The clamping force of the wheel bolts take the braking load. I've had difficulty removing these rotor screws after they've been on the car awhile. I would not Loc-Tite them with Blue or Red.
Hi Guys,
Sorry for the confusion on the set screw issue! We can chalk this one up to some odd/inexplicable choices by Porsche, and us (Essex) working through some revisions with our disc hats as we develop new Porsche applications. Here's the situation...
Disc Set Screw Function
The only function of the set screws is to hold the disc in place when the caliper is removed (when changing pads for example). The set screws aren't intended to bear any load. There is a small lip on the inside of the disc hat that registers the hat on the hub (see pic below). When the wheel is bolted onto the car, that lip is pressed around the outside of the hub. The disc is centered properly and cannot move, wobble around the wheel studs, etc.
It is perfectly acceptable/safe to run the car without having the set screws installed. Once the wheel is bolted on, the disc isn't going anywhere. The only downside would be that when you remove your wheel and/or caliper, the disc could potentially tilt or shift. Keep in mind that it will still be hanging on the wheel studs.
If you do decide to run the set screws, you only need one or two at most per disc to hold it in place.
Essex/AP Racing GT Disc Development Timeline
Our initial design included two countersunk (V-shaped) holes placed in our hats to accommodate those OEM countersunk screws
We test fit our 991 GT3 and 991 Turbo discs on the GT4, and found that the offsets on the GT4 are the same as they are on the 991 Turbo.
We went back to the drawing board for our next production run, and released a Revision B hat that includes two counter-bored holes to accommodate the OEM GT4 disc set screws. The screws that we were providing were supposed to be removed from our GT4 disc kits, since they are no longer needed. That was mistakenly overlooked however.
Which Screws Do I Need?
If your Essex disc hats are from our first production run (it will not have any laser engraving on the outer hat face), you’ll need to run aftermarket 6mm countersunk screws in the provided countersunk holes (V-shaped). The pic below shows the two types of holes. At this point everyone with the original design should have the screws they need and have the discs mounted on their car. Again, you only really need one or two per disc at most.
If your Essex disc hats are the newer design, it will have Rev B laser engraved on its outer face (see pic below). You can use your OEM disc set screws in the provided counter-bored holes. The counter-bored holes are the ones with the indented flat bottom (not the V-shaped ones). All discs shipping from this point forward, front and rear, are Revision B, and you can use your OEM set screws in the counter-bored holes.
Front vs. Rear
Everything above applies for both the front and the rear. All of the revised hats that can use the OEM set screws will have REV B laser engraved on them, and all discs shipping from this point forward are REV B.
We are currently updating our documentation/installation manual included with the discs. It will have a pic and explanation of which holes to use depending on the car model. Thanks for your patience, and again, sorry for any confusion!
__________________
'09 Carrera 2S, '08 Boxster LE (orange), '91 Acura NSX, Tesla Model 3 Performance, Fiesta ST
Jeff Ritter
Mgr. High Performance Division, Essex Parts Services Essex Designed AP Racing Radi-CAL Competition Brake Kits & 2-piece J Hook Discs Ferodo Racing Brake Pads Spiegler Stainless Steel Brake Lines
704-824-6030 jeff.ritter@essexparts.com
Great clarification! I have rev A for the front, Rev B in the rear and I suspect either my shop lost the front screws or I never got them with the fronts. No wonder I was confused...not that that is too hard to happen either.
Regardless, its great info to know as folks start replacing their rotors
Jeff, while I'm looking at my shiny new rotors in boxes, can you let me know where the minimum thickness rating is stamped? I can't seem to find it. Or else can you just let me know what the minimum thickness is for these rotors front and rear for my notes?
Wow, blue Loctite on a Philips head screw? How easy will that be to remove when the time comes to replace the friction ring without stripping the screw head? I was actually surprised to discover that the rotors are secured with just two screws, so Loctite makes sense to me in that sense, but even though these screws are easily replaceable, I'd rather not have to deal with drilling out stripped screws to replace a friction ring.
Actually, by function of design, the rotor doesn't technically need the rotor hat screws if the wheel is secured to the hub. The rotor set screws only keep the rotor hat flat against the hub when the wheel is removed. However, when thinking about it from an engineering point of view the stud, wheel and nut (assuming you switched to racing studs) will hold everything in its place [think sandwich]. The rotor set screw is that extra insurance if you will. It is not necessary to use blue loctite when installing these screws. That's really a personal preference.
I am getting ready to pull the trigger on a suspension and I was hoping for input. Driving will be 75% track, 25% street.
I am leaning toward JRZ pro or the MCS. I think that these will be better performing than installing the after market DSC controller and leaving the stock suspension in the car. I am set on spring rates and alignment...I am wondering about dampers.
Can't wait to get started.
All opinions welcome. Thank you.
Last edited by texasviany; 06-15-2016 at 01:15 AM.
Reason: spelling
Actually, by function of design, the rotor doesn't technically need the rotor hat screws if the wheel is secured to the hub. The rotor set screws only keep the rotor hat flat against the hub when the wheel is removed. However, when thinking about it from an engineering point of view the stud, wheel and nut (assuming you switched to racing studs) will hold everything in its place [think sandwich]. The rotor set screw is that extra insurance if you will. It is not necessary to use blue loctite when installing these screws. That's really a personal preference.
I also view the rotor screws as helping keep the rotor tight against the hub during wheel removals to keep dirt or debris from getting back there and keeping the rotor and wheel from torquing down flat against the hub face...
Regarding dampers, I ran MCS 2-Way remote canisters on my 987.1. Very well made with very positive click adjustments. MCS insisted on using remotes due to the high temperature in the rear. You can call and get direct information.
06-13-2016, 09:43 PM
