Thread: Steering Relay Unit Bolt Needed

Aren't they just a 1/4" UNF bolt? Could be BSF, but either way these are available, UNF from any fastener supplier, BSF from specialist suppliers.

John

Originally Posted by JDNSW

Aren't they just a 1/4" UNF bolt? Could be BSF, but either way these are available, UNF from any fastener supplier, BSF from specialist suppliers.

John

Thanks John- I'm still on a steep learning curve- haven't noticed it getting any shallower yet.
Didn't know what they were- figured they might have been specific to the Landrover (ie a specialty part).
Will try the specialty fastener place. The only spanner I could find that was a good fit was a 1/8" Whitworth, so perhaps its BSF.
Regards

Coop

Aargh! Having cleaned the crud off the top, find it stamped "BSF" <blush>. Promise I'll look more closely in future!

Originally Posted by C00P

........ The only spanner I could find that was a good fit was a 1/8" Whitworth, so perhaps its BSF.
.........

Actually, in my experience, the standard spanner size for 1/4" UNF and BSF is actually interchangeable - i.e. you can use 1/8"BSW or 7/16" AF. A bit of digging shows that they are actually slightly different;

1/8" BSW bolt head size 0.445-0.438", 1/4"UNF bolt head size is 0.438-0.428". For completeness, an 11mm spanner at a nominal 0.433" will also usually fit.

From these dimensions it is obvious that how good a fit you get will depend on where within the allowable tolerance of the bolt the size falls, and also how close to the allowable minimum the spanner opening is.

Note that the BSW threads and spanner sizes were the first standard established anywhere for these in the middle of the nineteenth century. BSF is essentially the same as BSW, but with the TPI and hexagon size for the next smaller BSW. During the 20th century, principally as steel replaced iron for fasteners, BSW bolts and nuts usually went to the smaller size as well, so it is today uncommon to find BSW bolts and nuts that need a spanner the size of the BSW standard.

America went their own way in the late 19th century, and developed NF and NC threads, which use a different thread profile and TPI to BSW and BSF, although TPI is the same in most sizes between NC and BSW (except 1/2"). After WW2, those countries using imperial measurements, mainly UK and USA, developed a unified thread standard, giving UNF and UNC. These are based on NF and NC but with a modified thread profile.

The first Landrovers used BSF and BSW threads (and occasionally others) with small body and electrical fittings using BA (BA is a late 19th century British metric thread used even today for some precision work - only in small to very small sizes).

With the introduction of the Series 2 in 1958 (possibly even earlier) the conversion to UNF instead of BSF started (I am not sure that UNC ever got used - there is little BSW anyway). This progressed gradually to the end of Series production. Parts that remained unchanged kept BSF, and it would seem the steering relay is one. Another one is the hubs, where the holes for the drive flange bolts are BSF.

Towards the end of Series 3 production, the conversion to metric threads started, particularly with the five bearing engine (virtually unknown in Australia). So you have a real mix of threads on these - and with the interchangeability of assemblies between Series Landrovers, the same could apply to any Series Landrover.

John

I just checked one of the bolts as I have a steering relay dismantled whilst waiting for parts to rebuild it!
The bolt shank is 1/4" BSF (26 tpi) and 5/8" long but has the smaller size 1/8 WW head on it instead of the usual 3/16 WW, possibly for clearance. You could try a standard size 1/4" BSF bolt and check that it does not obstruct the movement of the steering arms and you are still able to get a spanner or socket onto it. It may pay to ensure the bolt you use is only 5/8" long so that it does not foul any of the moving parts inside the relay box.

Cheers, Mick.

Originally Posted by mick88

I just checked one of the bolts as I have a steering relay dismantled whilst waiting for parts to rebuild it!
The bolt shank is 1/4" BSF (26 tpi) and 5/8" long but has the smaller size 1/8 WW head on it instead of the usual 3/16 WW, possibly for clearance. You could try a standard size 1/4" BSF bolt and check that it does not obstruct the movement of the steering arms and you are still able to get a spanner or socket onto it. It may pay to ensure the bolt you use is only 5/8" long so that it does not foul any of the moving parts inside the relay box.

Cheers, Mick.

THanks Mick,
My source may not have a 5/8" bolt (doesn't list it in his catalogue) so I'll probably get a 3/4" one and cut it short. Thanks for the info- I'll take this with me when I visit the man to collect a replacement.
Regards

Coop

Sorry Coop, been busy with work and haven't been on/didn't see your message. Even if you have got something and want one that looks just the same, you are more than welcome to pop around and grab one of my wreck. Sent a PM with phone number etc.

Originally Posted by Craigb

Sorry Coop, been busy with work and haven't been on/didn't see your message. Even if you have got something and want one that looks just the same, you are more than welcome to pop around and grab one of my wreck. Sent a PM with phone number etc.

Thanks Craig, will be in touch as soon as "Sandy" is back on the road.
Cheers,

Coop