1973 Rebuild

[Matthew Abate]

The measurements of the hole diameters on my struts from my micrometer are as follows:

Left Front: 10.71

Left Rear: 10.68

Right Front: 10.52

Right Rear: 10.43

 

So not a full MM off, but enough to explain why the 11mm tap went it like it was the right size and why these aftermarket bolts are having a hard time.

 

I’m pretty sure running an m12x1.25 tap through them will solve this.

 

[Patcon]

1 hour ago, Matthew Abate said:

The measurements of the hole diameters on my struts from my micrometer are as follows:

Left Front: 10.71

Left Rear: 10.68

Right Front: 10.52

Right Rear: 10.43

 

So not a full MM off, but enough to explain why the 11mm tap went it like it was the right size and why these aftermarket bolts are having a hard time.

 

I’m pretty sure running an m12x1.25 tap through them will solve this.

 

Just be sure there is enough metal there to take the re-threading. These are fine thread bolts, which implies they have a lot of load on them

[Matthew Abate]

Yeah, that’s what I’m worried about. I have a time-sert kit waiting to be ordered in case I need to repair them.

 

Here’s the deal with the measurements in millimeters:

ZCD’s Stainless Steel bolts: 60.06 long (28.96 grip, 31.1 threads)

Strut-base hole depth: 16.04 to 17.55 (top is angled)

Front knuckle hole depth: 13.93

Rear knuckle hole depth: 11.6

Spacer hole depth range: 25.83 to 25.04

M12 lock nut thickness: 2.5

New Front Bolt: Min - 16.04t / 41.47gl (57.51mm), Max - 17.55t / 42.26gl (59.81mm)

New Rear Bolt: Min - 16.04t / 39.14gl (55.18mm), Max - 17.55t / 39.93gl (57.48mm)

 

I found a place that has 55mm long grade-8 bolts for the rear knuckle holes, although I could just get thicker lock washers. I’m not going to find anything where the grip length and thread lengths are different and I don’t want to cut them, so there are going to be some threads inside of the spacer. If I gets 60mm bolts and let them go all the way through (which looks okay from a quick google image search) I can keep it simple AND put more grip inside the spacers.

[Matthew Abate]

 

Problem solved.

Ran the tap. Cleaned it out. Ran the bolt. Cleaned it out. Ran the tap. Cleaned it out. It’s bright and shiny and very little damage to the threads. The bolt goes in smoothly but not easily. Feels correct now.

 

I have some new bolts coming to replace this cheep junk.

[Matthew Abate]

Alright! All those holes have been tapped. I started with the largest diameter (easiest) and worked through to the smallest (most difficult) in case the last one needed a drill, which it didn’t. The one in the photo above was the first one, which gave me mostly just rusty sludge and a little coil of por-15 that had dripped into the first few threads. The last one yielded the same rusty sludge plus a bunch of shiny silver metal.

Now they are all clean, shiny, and the same size. I can’t find a difference I can’t blame on my micrometer being less than top shelf and my test bolt feels pretty much the same in all of them.

I did the brake caliper and dust shield bolts, too, since I was in that mode already.

[Matthew Abate]

Done.

 

Ran into a few surprises (spacers aren’t relieved for an o-ring so I made a gasket out of Blue RTV, had to press the spacers on with a pile of washers and old hardware) but it was a straight forward mini-job.

All torqued down and ready for bearings and discs.

[Matthew Abate]

Front legs done.

Flowed this: http://atlanticz.ca/zclub/techtips/frontwheelbearings/index.html

[Patcon]

Are the grease caps supposed to have an "o" ring? I don't think I have ever seen that. Might help though...

[Matthew Abate]

Are the grease caps supposed to have an "o" ring? I don't think I have ever seen that. Might help though...

That’s how the new ones came. One of the old ones I pulled had one and the other didn’t.

[Matthew Abate]

4 hours and counting. The insides of these were black with brake dust and Missouri swamp grunge. I think I’ve figured out the winning combination of degreasers and acids (all aluminum safe), various brushes and elbow grease. Hopefully I’ll have these ready for filing, sanding, and polishing by next weekend.

[Matthew Abate]

Some progress:

[Patcon]

4 hours ago, Matthew Abate said:

Some progress:

How did you accomplish that?