TR2/3/3A TR3 hard top screw

[NutmegCT]

Would anyone know the size (thread, length, etc.) for the five screws which hold the hard top on the cockpit capping?

I've got the three front screws and brackets, as well as the rear brackets, but the screws for the five rear brackets are a different thread from the three in the front.

Thanks.
Tom

 

[TR4nut]

Tom-

I have a new mounting kit, as well as some original rear brackets. Near as I can tell, with the new kit the front and rear threads are the same - 1/4-28, at least for what is supplied with the new kits now. But I can't find a tap that fits the original rear brackets, but it is very close to 1/4-28. Perhaps a BA thread? Or maybe just age and corrosion are the issue. Shaft length of the mounting bolts is close to 1". If I were to reuse the original brackets, and I might, I would try to run a 1/4-28 to clean or recut to something standard.

Randy

Randy

 

[NutmegCT]

Thanks Randy. I took one of the front bolts (Moss calls them screws) and tried it in the rear holes. Wouldn't even fit in the hole, much less screw down. Thanks also on the length.

Tom

 

[TR3driver]

I checked one of the bridge pieces from TS39781LO. Basically no rust, but a 1/4-28 binds about halfway through the nut, indicating that the thread pitch is not exactly 28 tpi. My guess is that it is 1/4 BSF, which is 26 tpi. Sorry I couldn't find my BSF tap set to verify that guess.

I would not advise trying to retap to 1/4-28, as the tap is going to cut away nearly all of the threads, leaving it severely weakened and likely to fail. There is a surprising amount of upwards force on the hardtop at higher speeds.

 

[sp53]

If you pull the vinyl or leather capping off, I believe you will find a nut welded to a U shaped bracket that unbolts or unscrews. The nut in the center comes off kinda easily for being welded and stripes out easy also, at least that was how mine was/is. (They were probably over tightened by the PO and that made them weak. ) The tops fit on a couple of different planes and the bolt holes are made large in the chrome finish pieces in the back to help with that. I cannot not explain why the bolts did not fit from Moss, because mine did, but the front and the back bolts are different size. They could be British thread also, but either way the bolts/screws are special, so you are going to need to match the nuts to them.

 

[TR3driver]

If you pull the vinyl or leather capping off, I believe you will find a nut welded to a U shaped bracket that unbolts or unscrews.

That is the "bridge piece" that I was referring to.

IIRC the proper bolts for the front also have reduced shanks, to help with the alignment issue. But I've forgotten where I put the coffee can with them, so I can't go check