Thread pitch help

[greasepixels]

My Truck: 1995 Explorer Limited - RWD

Hey guys. I'm swapping in a used 8.8 from Pull-A-Part to replace my fubar unit, and have a specific question:

What is the size / thread pitch of the fastener which secures the central sheet metal bracket on the top of our rear diffs?

This is the bracket that retains the top bend of the rear hard brake lines, as well as the parking brake cable going to the right rear, and provides a spot to attach the wires for the Rear ABS wheel speed sensor.

I doubt I'll be able to clean up the existing threaded hole, but would like to know what I'm starting from before I enlarge it slightly and tap it for something new. I am sure I am not the only one to experience the frustration of the crazy mix of metric and standard fasteners which ended up being used to manufacture our trucks!

 

[BrooklynBay]

You could try a tap to see if it goes in easily. If not, then it's not the correct size. A lot of times a repair manual will tell you the size of the bolt with the amount of torque to apply to the bolt.

 

[greasepixels]

That bolt is *really* short. Unfortunately there was tons of rust in there, and when I was stripping down the diff to prep and paint it, half the threads from the cast iron housing came out with the bolt. So, I've got maybe 1/4" left in the threaded hole.

That is a great point about the bolt sizes being mentioned in some repair manuals, though!

I need to find a Haynes manual. The Ford service literature I was using prior to switching PCs a few years back was actually contained in a cd image which installed some Windows XP era Ford service software. I remember having a rough time getting it to work well in Windows 10.

I will scour around and try and find a PDF of a Ford factory service manual. It looks like I can't order a physical one from helminc.com anymore

 

[C420sailor]

You’re gonna need a special tap known as a bottoming tap in order to thread a short hole like that.

 

[BrooklynBay]

You said that some threads came out of the cast iron. You could fix it with a helicoil repair kit.

 

[greasepixels]

You’re gonna need a special tap known as a bottoming tap in order to thread a short hole like that.

Thanks sailor! I would have likely run just any tap down in there, with my luck breaking the end off. I appreciate the warning!

 

[greasepixels]

You said that some threads came out of the cast iron. You could fix it with a helicoil repair kit.

I'd still have to know what the original size was for it to even be worth restoring the threads with any kind of inserts. Original fastener is buggered, too, so I'm just thinking enlarge to either 3/8 or M10 at this point.

 

[410Fortune]

It’s not metric
That corporate 8.8 axle uses all standard sizes threads and pitches
My guess is 3/8”
You could just wedge some
Sort of stud in there and get it to grip.. then use a nut to retain the brake line holder

Just confirmed it is 5/16 18 pitch

I happen to have a 8.8 axle in the shop and a thread checker

 

[greasepixels]

It’s not metric
That corporate 8.8 axle uses all standard sizes threads and pitches
My guess is 3/8”
You could just wedge some
Sort of stud in there and get it to grip.. then use a nut to retain the brake line holder

Just confirmed it is 5/16 18 pitch

I happen to have a 8.8 axle in the shop and a thread checker

Hell yeah 410!

Thank you very much for confirming the size. I was having trouble getting a 5/16-18 bolt to start, but now that I know that's what it was originally tapped for, I'll try and chase the threads.

If that fails I like the stud idea - didn't even think about that.