Hi all,
Back again, after a very productive day in the shed. This morning I headed off to the wreckers to get a calliper that would fit the 28mm thick discs, and headed straight to the Holden Commodores as the later VT, VX, VY & VZ models have discs the same thickness. There's no shortage of Commodores at the wreckers and quickly found what I was looking for, costing only $35ea, and headed back to my shed. The calliper is not small, and has twin pistons in an alloy body which floats in a steel mounting bracket.
After some general looking and measuring I reckoned that this is going to be close. At this stage I hadn't managed to get the discs and hubs machined, so rather than wait I headed of to where I work as we have a lathe there and decided to do it myself. Now with the centre hole of the disc opened up to 75mm and the hub machined to suit it was back to the shed again to check out the results. Roughly assembling them I quickly discovered that the flange of the hub was too big and prevented the callipers from sitting down far enough, so it was back to work and machining the flange down. Fortunately I live only 3km from work, so all this didn't take too long.
Once back again I drilled a pair of temporary mounting holes in the disc and bolted them up and this time the calliper cleared, just. I grabbed a calliper mount that I had knocked up from some plywood some time back and to my amazement it was perfect, locating the calliper perfectly in line with the disc and giving a couple of mm clearance on the hub flange. With a few spare nuts & bolts I put it together, as can be seen in the pictures below.
The next test was to see if they would actually fit inside the wheels, which they did with good clearance as can be seen in the pictures below. Somewhat relieved I now wondered if the 330mm Navara discs would have fitted, but was feeling gratefully for the result that had.
On a high I took the assembly out to the Van to see if the calliper would clear the suspension etc. After initially fitting them up the original way with the calliper to the rear I quickly discovered a major problem with the steering arm fouling badly and no way was it going to fit. So I quickly removed them and rotated them 180 degrees so the calliper is at the front.
This isn't a problem for these callipers as this is the way we used to locate them on our Datsun 1600 rally cars years ago. They were the smaller single piston version, but they too fouled the steering arms so we used to swap the struts around left to right & right to left so the callipers were at the front. The added benefit was that located in front they cooled better, a definite bonus in competition. So once spun around things were looking much better, the only problem being on full lock the alloy part of the calliper was just hitting the metal base plate of suspension bump rubber. Looking at it I reckon I can grind it back to give me just enough clearance. The pictures below show the setup on full left & right lock and a trained eye can just see where the calliper hits the bump rubber.
Very happy with the result and relieved that it's worked out. Next weekends job will be to make up a pair of real calliper mounts, which will be from 10mm steel plate to make sure there's no flexing. The Mount isn't very complicated as you can see in a picture above, it's just going to be an exercise in very accurate measurement and drilling. The advantage is that they are identical and I'll just tack weld them together back to back so I only have to drill all the holes once. I have discovered during this exercise that using the bigger size discs give you much better clearance with the inner diameter of the disc, so the fixing bolts to the stub axle and calliper don't create any problems.
That's it for now, I'll leave you with on last picture of the setup.
Yes I know the wheel studs need to be fitted and the disc bolted properly to the hub, but I'll get around that during the week hopefully. Plus I still need to get the stub axles shortened, which explains the strange bearing and nut arrangement holding the hub on, but today’s priority was to see if this was all going to work, which it has.
Cheers Stephen