<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Just verified on my 61 TR3A project: The bolts that connect the plate to the frame are 3/8 x 24 (fine thread). The ones that came with my car (probably factory - they have the “correct” markings on the head) are 5/8” in length, though 3/4” length bolts would work just fine, and are probably easier to find locally.<div>Cheers, Dennis</div><div><br></div><div><blockquote type="cite"><div>On Aug 29, 2025, at 3:10 PM, Allen Hess <allen.k.hess@gmail.com> wrote:</div><br class="Apple-interchange-newline"><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Hi Teri, First of all I have a 62 TR4, but I remember seeing a TR hardware catalog and I have found one on Triumph Experience. The nuts and bolts have part numbers and you will need a factory parts catalog to find those. <br id="lineBreakAtBeginningOfMessage"><div><br></div><div><blockquote type="cite"><p><font size="4" face="Adobe Garamond">I would like to replace the bolts that connects the mount to the plate on the frame</font></p></blockquote>Aren't these studs integral to the trans rubber mount? If so I think it is a 7/16 fine thread nut</div><div><blockquote type="cite"><p><font size="4" face="Adobe Garamond">and possibly the bolts that connect the frame plate to the frame.</font></p></blockquote>these are ones that I can’t find but I would guess they are 3/8 fine thread and if not then 5/16. 3/4” length </div><div><br></div><div>The big bolts trans to trans mount are #HB1112 1/2 x 1 1/2 fine, right side. #HB1115 is 1/2 x 1 7/8 left side when trans is fitted with the strap from bolt to gear shift.</div><div><br></div><div>Hopefully someone has a TR3 all apart and can give you a more definitive answer.</div><div></div></div><span id="cid:A39D4AC5-8595-4FF3-9FCB-63235813EB8A"><Triumph hardware sizes.pdf></span><meta http-equiv="content-type" content="text/html; charset=utf-8"><div style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div><br><blockquote type="cite"><div><br></div><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);"><b>From: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;">"TeriAnn J. Wakeman" <tjwakeman@gmail.com><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);"><b>Subject: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;"><b>[TR] TR3 bolt size?</b><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);"><b>Date: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;">August 29, 2025 at 9:10:54 AM EDT<br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);"><b>To: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;">Triumph List <triumphs@autox.team.net><br></span></div><br><br>
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<div><p><font size="4" face="Adobe Garamond">My TR3 is currently my only
functional vehicle and I need to replace the rear gearbox mount.
Since the nearest hardware store is about 10 miles away I would
like the swap to go quickly & smooth (yah right). I have a
new mount & nuts that attach to the back of the gearbox. I
would like to replace the bolts that connects the mount to the
plate on the frame and possibly the bolts that connect the frame
plate to the frame.</font></p><p><font size="4" face="Adobe Garamond">Could someone please let me
know what size bolts are need to fit the gearbox mount to the
steel frame bracket? And the size bolt that connects the steel
frame bracket to the frame? Since the TR is my only
transportation I would like to quickly get in get the
replacement done & get back on the road (as if any project
goes as planned).</font></p><p><font size="4" face="Adobe Garamond">By the way, the U-joint part
numbers I asked about earlier received a few replies all of
which were obsolete numbers. Thank you to the people who took
the time to reply and I suggest that you update your part
numbers lists.</font></p><p><font size="4" face="Adobe Garamond">My TR's 20+ year old
U-joints were badly worn but I discovered a broken rear gearbox
mount. Hopefully to be sorted out soon.</font></p><p><font size="4" face="Adobe Garamond">My area's rainy season is
due in the next month or so. It is getting to be time to remove
the factory style luggage rack, polish it and place it into dry
storage then get out the side curtains.</font></p><p><font size="4" face="Adobe Garamond">My baby doll</font></p><p><font size="4" face="Adobe Garamond"><br>
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