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> Rear rotor hold-down screws, ....are they necessary? (five lug conversion question)
jaybird840
post Dec 12 2007, 02:45 PM
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I just bolted up my new Eric Shea control arms with the Elephant poly bronze bushings for my five lug rear conversion and I'm really psyched. They installed almost effortlessly, and I'm completing the install. However, when I went to install the new 914/6 rear rotors (thanks Mark H!) the holes for the two little screws that hold the rotor to the hub no longer line up. What are my options? 1) drill and tap for the new location 2) can you let the rotor "float" and just keep it held down with the torque of the lug nutz? Thanks guys!!!

--Jaybird
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Spoke
post Dec 12 2007, 03:01 PM
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I don't believe you need the little screws. They basically keep the rotor locked to the hub. When you put lugnuts on the wheels, these basically keep the rotor locked anyway. My Audi A6 doesn't lock the rotor on the hub either.

Spoke
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SLITS
post Dec 12 2007, 03:02 PM
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On a /4 the screws keep the rotor from falling off when you pull the lug bolts (so do the calipers for that matter)

On a 5 lug or /6, the studs hold it and the wheel nutz will keep it in place when torqued.

I didn't redrill mine ... they don't do nuthin' 'cept rust and make it hard to get the rotor off.

PS ... If you had gotten them from a quality machinst he could have indexed them .... Hi Eric .....
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Jeffs9146
post Dec 12 2007, 03:41 PM
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I drilled mine but I was told I didn't need to!
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Eric_Shea
post Dec 12 2007, 04:13 PM
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914 and 911 (hence 914-6) hold down screws are in different locations.

You should have the rotors snugged down to set the handbrake properly. You can redrill and tap if you'd like but, the best method I've found is to simply have a few open ended nuts available. Use those to tighten the rotor into place, set the handbrake, yank the bolts, install the wheel and be done with it.
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rfuerst911sc
post Dec 12 2007, 04:33 PM
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Funny you posted this because I'm in the same situation. If we decide to redrill/retap do we have to do both holes or just one?
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jaybird840
post Dec 12 2007, 04:40 PM
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QUOTE(rfuerst911sc @ Dec 12 2007, 04:33 PM) *

Funny you posted this because I'm in the same situation. If we decide to redrill/retap do we have to do both holes or just one?


Let me know if you have trouble spreading the pads far enough for the six rotors. One pad went far enough... the other hasn't (yet=bfh). Haven't tried the other caliper yet..... LMK
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Jeffs9146
post Dec 12 2007, 05:23 PM
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Let me know if you have trouble spreading the pads far enough for the six rotors. One pad went far enough... the other hasn't (yet=bfh). Haven't tried the other caliper yet..... LMK


You need to loosen the pad adjuster on the outside of the caliper!

Also make sure your hub is pressed all of the way into the bearing.
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Eric_Shea
post Dec 12 2007, 05:24 PM
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QUOTE
Funny you posted this because I'm in the same situation. If we decide to redrill/retap do we have to do both holes or just one?


If you decide to tap, tap both. It's best to have the rotor uniformly tight on the hub surface. That's why I suggested 2 nuts above. You don't want an unusual runout while adjusting the e-brake.

QUOTE
Let me know if you have trouble spreading the pads far enough for the six rotors. One pad went far enough... the other hasn't (yet=bfh). Haven't tried the other caliper yet..... LMK


That's a caliper issue that is probably unique to you not necessarily Rich. I would not take a BFH to your caliper. (IMG:style_emoticons/default/wink.gif)

Which piston is not retracting all the way? I guess, regardless, you should/could apply pressure to the piston top while turning the adjuster in the proper direction (which is clockwise for the outer and counter clockwise for the inner)

QUOTE
Also make sure your hub is pressed all of the way into the bearing.


It is... (IMG:style_emoticons/default/wink.gif)
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Eric_Shea
post Dec 12 2007, 06:19 PM
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QUOTE
PS ... If you had gotten them from a quality machinst he could have indexed them .... Hi Eric .....


Agreed, it would be fairly easy at machining time however, if he did, they would cost more than the average 914 owner would want to pay. (IMG:style_emoticons/default/lol3.gif)

(did I mention I hate my old machine shop... I'm sourcing elsewhere after my last go-round with them.)
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Jeffs9146
post Dec 12 2007, 06:30 PM
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Was the hub powder coated on the face between the studs?
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Eric_Shea
post Dec 12 2007, 06:31 PM
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No. Why would that matter though...? (IMG:style_emoticons/default/confused24.gif)
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Jeffs9146
post Dec 12 2007, 06:44 PM
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It would move the rotor outward by .006 - .008 which could make the alignment of the caliper and rotor difficult.
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Cap'n Krusty
post Dec 12 2007, 07:15 PM
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To emphasize what was mentioned earlier, ALWAYS apply pressure to the piston while turning the adjuster screw. ALWAYS. The Cap'n
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jaybird840
post Dec 12 2007, 08:31 PM
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QUOTE(Cap'n Krusty @ Dec 12 2007, 07:15 PM) *

To emphasize what was mentioned earlier, ALWAYS apply pressure to the piston while turning the adjuster screw. ALWAYS. The Cap'n


That makes good sense... (now it does, anyway). Yeah, I was turning the screw clockwise (as the instructions indicate, and the piston started moving in--just not enough. The other piston retracted fine with no pressure. I've tried GENTLY pressing the un-retracted piston with a screwdriver, and it won't retract enough to move the pad flush with the inside of the caliper. So Krusty, should I run down to my FLAPS and purchase one of those brake-caliper-mashy-openy tools? Any good DIY solutions? Thanks
--bird
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Jeffs9146
post Dec 12 2007, 08:55 PM
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should I run down to my FLAPS and purchase one of those brake-caliper-mashy-openy tools?


A C-clamp with an old brake pad will work, just take it slow (small adjustments at a time) you could have a rusted piston cylinder end and cause damage. You need to turn the screw as you adjust the clamp.
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Eric_Shea
post Dec 12 2007, 09:01 PM
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It would move the rotor outward by .006 - .008 which could make the alignment of the caliper and rotor difficult.


Nada. The width of a business card isn't going to make any difference here. He has caliper issues.

From your description of the process/instructions, it seems this is an outer piston.

I don't think there's any need for fancy tools. You may want to pull that caliper and stick your thumb on it. Rock it back and forth meaning; spin the adjuster counter clockwise just enough until you feel it start to move out. Stop. Now turn it clockwise again to pull it in. Your internal adjuster mechanism is hanging up just enough to cause it to spin inside the piston. There might be some grundge in there... working it back and forth might free up the threads a bit.

I'll try to grab a picture of the internal mechanism so you know what's probably happening. The only thing I can think to do at this time is to rock it back and forth as described. if you have a plastic mallet you may want to tap it a bit and try rocking again. Ask El Capitan states... apply pressure to it while you do this.
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Eric_Shea
post Dec 12 2007, 09:10 PM
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Here's one that was on the bench. The assembly is probably spinning inside that snap ring. You need to work the threads back and forth on that adjuster so it will screw in all the way and pull in the piston.

C-Clamp will be difficult on the caliper face. The adjuster on the outer piston is smack dab in the middle. Anything offset from that and the clamp will want to slide off the face. If it doesn't work it's way in with hand pressure it may not work at all... worth a try though.

Good luck with it.

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Jeffs9146
post Dec 12 2007, 09:28 PM
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QUOTE
C-Clamp will be difficult on the caliper face.


Thats what the old brake pad is for! (IMG:style_emoticons/default/idea.gif)

I know you do this for money but I have done it this way a few times with no problems.
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Eric_Shea
post Dec 12 2007, 09:59 PM
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Thats what the old brake pad is for!


Other side... difficult to keep the c-clamp on the other side as the face of the caliper there is uneven. The old brake pad or even the piston itself is obviously flat and hence not the problem area.

This is the outer piston as well. The adjuster is smack dab in the middle of where the c-clamp would hold best. If it were the inner piston, which is gear driven it wouldn't be an issue as the adjuster hole is below center.

I've never had to use a clamp to adjust a 914 caliper and I would venture to say, if you've had to do this a few times, it's best to step back and fix the actual problem...

I just said it would be difficult... worth a try and it might even work but, that's not what his problem is. (IMG:style_emoticons/default/wink.gif)
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