HELP! brake upgrade stalled...again

[raceman]

brake upgrade topics can get old for those of you out there that have been there,done that and continue to dispense advice that may or may not be followed.Anyhow l`ve got an 84 Carrera and l finangled 86 951 calipers onto the car and l`m not happy with the hardware on the rear calipers.The stock rotors were a tad thin for the squeeze of the 951 units so l bit the bullet and fabbed some fattie rotors on custom hats but the main problem is getting to the lower mounting bolt on the caliper.l really can`t get in there and l need a socket head bolt but can`t find.Does anyone know the exact size designation for the caliper mounting bolts?My guage shows 1.5 pitch,M12 but l can`t find a socket head in that size and the clearance issues require a socoket head....any help/info appreciated...

[Zeke]

Here in Long Beach CA, we have a place called the Brown Nut and Bolt Company in Paramaount, next door. They have a very agreeable $5 min for walk ins and have never failed me. Surely you can find a specialty house in NM like Brown. Worst case, look them up and call them. All you need additionally is to tell them the length and strength class and I bet they have it.

[astark]

Raceman-

If you can't find a local source: I've used Maryland Metric for specialty fasteners. They are great, low minimum order and reliable.

http://mdmetric.com/prgde3b.htm

Hope it helps,
Alan

[89911]

Without going into detail about the bolt size, I have found two approaches to getting to that bolt. The simpliest is to use a metric allen bolt the same size and pitch and then cut off the allen key to allow for room to get to the bolt. The second way to do it is to grind down a socket so that it is as "short" as possible but still able to grab the edges of the bolt (non allen). The clearance is tight, but I was able to do this with my 930 rears.
Picture shows the tight space. I used the ground down socket for my brothers big reds also.

[JeremyD]

Go ahead and grind down the socket you will use it for years to come - I also found that after trying four different rachets - that my "craftsman" was the only one with a skinny enough head to fit back there (and I have 993 rears that are pretty meaty)

[cstreit]

I bought an el-cheap socket and turned it thin then cut it short. The used a non ratcheting extension on it. Works great...

[raceman]

thanks guys,all good ideas.The bolt is an M12,1.5 pitch and so far the socket heads l found are all 1.75 pitch.l`ll get it done here using one of these ideas here,thanks again

[don911]

I had the opposite problem when installing my 930s. I have socket head bolts and was looking for allen head. I had the same issue finding the correct thread pitch. Anyway, I gave up and used the hex head bolt.
My solution to the access was a 19mm offset box end wrench. I ended up cutting off the opposite end of the wrench in order to clear the oil lines on the right side.
I also tried the cut down socket but the offset box end wrench worked much better for me.

[raceman]

l need allen head bolts here for clearance,not hex head.l don`t know where l came up with "socket head"...l think l`ve come up with a solution though after measuring carefully.l`m going to weld an allen head onto the top of the bolt.l`ll keep you posted and show pics when done.

[fred cook]

If you can find an allen head 12mm bolt with a section of unthreaded shank, just buy a 12 x 1.5 mm threading die and make your own! I recently ran into the same situation needing a 12 x 1.5 bolt for a transmission mount. The local hardware store which has a pretty good assortment of metric hardware only had the 12 x 1.25 and 12 x 1.75 bolts. I bought the longest 12 mm bolt they had and was able to thread the shank to 1.5mm pitch. You will probably need a bench vice to hold the bolt while rethreading. While cutting the new threads, back off the threading die a little bit every couple of turns to clear the metal from the cutting teeth. Also, be sure to use plenty of cutting oil to make the job go easier.

Good Luck!

Fred Cook
'80 911SC coupe