Too close to tell

[GPster]

I can't tell on some cars/trucks whether nuts and bolts are USS or Metric. On taking this '87 S15 apart I pulled the "U" bolts holding the rear axel to the springs and pulled the springs and shackles and everything looked the same thread and came apart with the same size wrench. Now my collection of metric wrenches  is limited to smaller sizes and the larger sizes usually come apart with a crescant wrench but this time an American sized wrench (13/16", 7/8" or 15/16" I forget) seemed to fit well enough to work. All the nuts seemed to be the self-locking type so I was not surprised that everything seemed tight til the last thread. Because the "U" bolts will be clamping a thinner spring pack and the previously un-used threads were kind of dirty and the schackle bolts could stand to have their threads cleaned up I went over town and bought a die for what I imagined the thread was. As best I could measure and verify with my Dorman catalog of bolt sizes things looked like M14 2.00 thread. I bought a die that was that size and I went out this evening to start cleaning things up. I would have thought the die would screw on fairly clean threads rather easily, it didn't. I picked a bolt that I could run the die further down the threads and it was tighter than hand tightening. It looks like it's not cutting threads of a different dimension or thread count but it does look like it's removing metal. The nuts go on the threads but they certainly don't have the resistence that you'd think a self-locking nut would. Now I start second guessing myself. Would this thread be something else? M14 is awfully close to 9/16" and that is a registered bolt size but I don't know how close 12 threads/inch is 2.00. Dorman does show 9/16" "U" bolts but nothing small enough to hold the narrow S15 axel housings. Should I go ahead and go on my original plan or what? GPster

[enjenjo]

2,00 threads are roughly 12.5 threads per inch. And 14mm is slightly larger than 9/16" I am guessing on an S10 that old, the chassis will be mostly metric.

I would invest in a digital caliper, and a thread guage, with the mix we have now, It's needed.

[wayne petty]

almost everything that on that truck is metric except a few bolts that go into the block or heads.. and a few of those are also...

the u bolts like you describe really could either...

the biggest problem is with metric sizes...

sizes that are used in cars are not what is found in hardware stores...

6x1.0
8x1.0 +8x1.25
9x1.25   found on hondas.
10x1.0, 10x1.25, 10x1.5, 10x1.75
11x1.25, 11x1.5 (head bolts)
12x1.25, 12x1.50, 12x1.75
14x1.25(spark plug thread) 14x1.5, 14x1.75, 14x2.0  

i have most of these in my massive tool box.. a few had to come from mac and snap on.


if you want to get into wrench sizes.

5mm, 5.5mm 6mm 7mm, 8mm, 10mm, 11mm, 13mm, 15mm, 18mm, 19mm,  are all used on gm and other domestic cars...

12mm 14mm 17mm are added to the sizes used on japaneese and european cars.. 16mm is showing up on chrysler products..

now that you are totally confused..  watch sears for sales..  there is one coming up this coming weekend. i think..  i just got my craftsman club flyer .. the crossforce wrenches are on sale... but i like the 9.99 sets ...

[GPster]

Some more clues on this mystery. I wnet to the garage and checked the tool I had been using. I had been using a 13/16 box wrench and with the 12 pt head it might be questionable to size the bolt by it's size. The other thing I had been using was a 13/16 6 pt impact socket. The socket had fit snuggly and hadn't distorted the nuts even with the use of a 4' cheater bar on the handle of ratcheting "braker bar". Plus a look at my Dorman catalog shows 9/16 bolts with a 13/16 hex head. One more clue, a M14 bolt has a 22mm head which is marginally bigger than 7/8" so that wrench wouldn't have fit very well if I'd had it out. When we had a bolt out sizing it for size we had only checked mm thread count and it wasn't exactly the 2.00 but it wasn't even close to 1.25 or 1.50 but we had never thought to check the thread/inch gauge. Plus my "Ace in the Hole" I also visit an S10 site and I asked there. They said it was 9/16". I exchanged the die today and it seems to work. If the locking nuts seem not right I'll use lock washers too. GPster

[GPster]

I gotta a headache:shock:

Well that certainly wasn't my intention. Sorry! GPster