Brake Experts???

[Gojeep]

OK, what I have done is to transfer the template to some 12 mm HD plastic that I normally make my coil spacers from. This will make sure I have every thing right as far as fitment issues go before then using the plastic piece for the CNC machine to follow and cut it out of 10 mm plate.

Made sure that all the holes lined up perfectly and that it would clear everything. I also checked my fathers XJ which has ABS and the sensor will actually sit under the bracket so will not interfere at all.

This shows the part that will be the spacer, although it will be much thicker than this, but it is just to make sure the holes all line up.

Bolted in just fine and wondered if I could have made the centre hole even smaller.

This shows the front view.

Now I see why I cant make the centre hole any smaller as at full lock it gets very close to the uni. You can see how the stock bolt actually just touches. I cannot use these anyway as 4 mm too short in length.

But now I have a problem that could end this project!!! This is looking down on top of the bolt and remember that I cannot use these bolts otherwise I would just shave a little off the integrated washer to clear the uni as the head itself is fine. But I don't think I can get these in a longer bolt anyway as have never seen them aftermarket? So was going to use a socket head cap screw or some times called a Allen key bolt. I was looking at this chart, http://a-sp.org/Standards/chapters/assembly/F1-23.pdf and in section F6 they have low profile head ones. The hub takes 12 mm 10.9 grade bolts. I only have 10 mm from the centre of the hole to the inside edge of the bracket where the uni is at it's closest. That head is 18 mm in diameter which means the radius of 9 mm would just sit short of the edge of the bracket. If you look at the last photo and follow the edge of the bracket down and then out vertically 8 mm, which is the height of the head, I think it will just clear! That stock bolt head is 15 mm and there is fraction over 1.5 mm of clearance between that and the uni.
So this should just work but anyone know of any other solutions? I cannot even use a counter sunk socket head as they are around a 1" in diameter so would hit the uni and be off the side of the bracket. Also, I am better off running the same 10.9 grade bolts or stepping up to 12.9? Don't want them too brittle either. I will have a chat with the engineer but would like to know your thoughts as well.

 

[bj-666]

not sure where mcmaster-carr is located i beleive its based in the states but they are great for fasteners and such may want to check there catalog. as far as the bolts to use i would not think twice about using a 12.9 over a 10.9 i don't have the numbers in front of me but i bet the break strength is of a 10.9 is under the yeild strength of a 12.9 read up on the strength differences if you wish. there was a good article i beleive i posted here that was first posted on pirate4x4 that goes into much detail about fastener differences)

 

[Gojeep]

You are looking at 15% extra clamping force going from a 10.9 to 12.9.

 

[Gojeep]

Well I just got back from the engineer and grabbed some cap screws and talked to him about the options. He actually preferred to counter bore the bracket 4 mm rather than use the low profile cap head bolts as they are too easy to strip the head. I just tried a standard cap bolt in there and at full lock I can just see day light between the head and the uni. Don't forget that this is at full lock only and at straight a head for instance I have 11 mm of clearance. Even if you had a single washer behind the steering stop you would have more clearance already. The only other option is to try a button head but he didn't have any so might still look at that. So at least there seems to be nothing stopping it going ahead and it can now go ahead with getting a quote on the brackets to be laser cut. But normally a minimum run of a 100 so he would have to think he can sell 50 of the kits afterwards. Not sure if there is that much of a market out there? The bolt holes will actually be laser cut at a smaller size and then a drill or reamer run through at the actual bolt size to keep movement away.
Also he didn't think that 12.9's were needed in this application and normally only uses grade 8 even in his race car kits holding the brackets and calipers on so the stock 10.9 will be plenty. The 10.9's ar actully grade 8 anyway way and just another way of saying it! This little site has got some information about it and also shows that shear force does not decrease with the higher tensile bolts.
http://www.bigcee.com/reference.html

 

[Gojeep]

Just had a chance to give everyone a update.
I have drawn up a CAD file and the main brackets are getting laser cut out this week.

I also finally found a supplier that sold button head screws in 12.9 grade and 90 mm long in a M12. Companies like UnBreakco don't make them over 50 mm in length in that size. So I bought just a short one as they still have to special order them in by the box to see if it would clear the head at full lock.

As you can see I have plenty of clearance and will have 2 mm more when using the 10 mm steel plate rather than the 12 mm plastic template used here and no need to counter bore the holes.

This shows the view you will get through the wheel once completed.

Both the front and rear bolts need the button heads but might even fit them in all three positions.

The top view also shows the spacer. This will be made from bar stock and drilled out on a lathe and then tig welded to the main bracket. A brace will then be welded between these two and to the bracket to make it as completely ridged. I came up with this after having 40 mm plate cut out with a water jet was going to cost me $79 per spacer!! The laser machine here could also not cut 40 mm plate but only had a maximum of 20 mm. Thought about stacking them and welding them together but the machine could also not cut holes less than the plate thickness either so too much work. This way allows me to cut to the exact length I need and I also may need to cut to a different length for the 99+ models that have a different hub.

 

[Wayne Sihler]

Have you looked at Flat Head cap screws? They are counter sunk in the material,and can be flush.The counter sink would help in the location of the spacer.
Found them in M12x1.75 80,90,or100mm long in just a quick look.
Wayne

 

[Gojeep]

Have you looked at Flat Head cap screws? They are counter sunk in the material,and can be flush.The counter sink would help in the location of the spacer.
Found them in M12x1.75 80,90,or100mm long in just a quick look.
Wayne

I did but they have a wider head than these so would be off the edge of the bracket on the inside. Thanks for thinking about them though.

 

[Gojeep]

Look what I just picked up today from the laser cutters.

Also there at the back is the 1" bar stock that will be cut to length for the spacers and drilled out to 10 mm on the lathe. These will then be tig welded to those plates which have matching 10 mm holes. The hole will then be drilled through from the plate side on a drill press out to 12 mm to make sure it is a perfect match and spacing. The whole bracket is then sent off for zinc plating.