inspection door bolt

[Redav72]

Does anyone know what size bolts are needed for the inspection door on an A4LD? I've tried both M6-1.0 and M8-1.25. The M6 seems the closest on the actual bore but binds on the threads. I've not wanted to chase a bolt down and risk damaging the threads. My local Ace doesn't carry M6-1.25 so I haven't been able to try that.

 

[pjtoledo]

1/4 - 20 ????
6mm x 1.25 is not a standard pitch, it's way too coarse.

 

[Curious Hound]

Probably 1/4"-20.

There were a bunch of years where the fasteners on Ford trucks were mixed SAE and metric. So, if the transmission was American made, it might have a lot of SAE measurements. But other things on the truck would be metric.

I just chalk it up to the "USA's failed miserable attempt to convert to the metric system" which started way back in the 70's (Or earlier) and hasn't been accomplished yet.

 

[sgtsandman]

My local hardware store has one of those panels with threaded inserts and studs of various sizes and thread pitches mounted on them. See if yours does too. If it does, thread one of your good bolts into that (if you have any). Like mentioned above, Rangers have had a lot of mixed SAE and metric fasteners in them for quite a while. So, you could be barking up the wrong tree and need to look at SAE fasteners.

 

[Brain75]

1/4 - 20 ????
6mm x 1.25 is not a standard pitch, it's way too coarse.

Since pj didn't say what is standard I will throw out what I am "fairly sure" is.. M6 standard thread would be 1.0 (i.e. 6mmx1.0) for coarse thread and 0.75 (rare) for fine thread.

 

[Curious Hound]

Since pj didn't say what is standard I will throw out what I am "fairly sure" is.. M6 standard thread would be 1.0 (i.e. 6mmx1.0) for coarse thread and 0.75 (rare) for fine thread.

Standard pitch for M6 is, indeed 1.0mm

 

[Redav72]

I ended up using 1/4" coarse bolts, they were still a little stiff going in but threaded all the way without cross-threading the bore. I bought a handful of candidate bolts at Ace and used the ones that were the closest match. Inspection hole is now covered.