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Rear suspension top bolt

Posted: Sat Jan 24, 2015 1:36 pm
by Bertie the Bullet
Afternoon all, Bertie's rear suspension top mount bolt is bent, further more the nut is seized on solid, the only solution is to cut it off, what I'm not sure about is the replacement bolt, can I use a normal one of the same size or do I need a special one, made of hardened steel or something similar.? Thanks

Rear suspension top bolt

Posted: Sat Jan 24, 2015 2:17 pm
by papasmurf
Check our hosts catalogue. (Do not just fit any old bolt in a suspension related part, it could end in catsarsetrophy.)
Personally on non Enfield related applications, like when I uprated from 3/8th to 10mm bolts on sidecar fittings I went to an agricultural engineers they only do very high strength bolts. (I have had a fitting break but never a bolt.)


Rear suspension top bolt

Posted: Sat Jan 24, 2015 10:32 pm
by neddy
Not a normal bolt, but find a "grade 8.8 type", in fact slowly change all the bolts to this grade

Rear suspension top bolt

Posted: Sun Jan 25, 2015 6:18 pm
by Bertie the Bullet
Thanks gents

Rear suspension top bolt

Posted: Sun Jan 25, 2015 10:36 pm
by PeteF
I can't see how you managed to bend these. I wouldn't have thought there was enough moment to bend them.

Rear suspension top bolt

Posted: Mon Jan 26, 2015 6:30 am
by Count Johnny
I would go further that Neddy and suggest that - if you are worried about breaking bolts - you go for AN or UnBrako brand bolts.



There are lots of knock off 8.8 bolts around whereas, with AN and UnBrako, you'll be getting the real deal.



Trident Racing Supplies are a good source in the UK.

Rear suspension top bolt

Posted: Mon Jan 26, 2015 9:42 am
by MadMike
Like PeteF I frankly do not understand how you have managed to bend a suspension top mounting bolt. If it is fitted through 2 sections of frame bracket and through the bush in the top eye of the suspension unit then it cannot be bent in normal use. There cannot be a turning moment to cause the bend as each side of the bolt is supported in such a way as to prevent turning moments. So before worrying about the composition of the steel making the bolt you need to establish what has happened to the bolt and what has caused it. To illustrate this, I have a number of bikes varying between 65 and 3 years of age. On the older ones I simply fit stainless steel bolts, with copper grease on the threads. They simply do not bend. The suggestion that you should use hardened or tempered high tensile bolts I find both astounding and amusing. Now you have referred to a bent bolt, BUT is it really a bolt which has become loosened and then developed a worn centre section on the shank of the bolt? This would cause 2 steps to be created and this might seem to be a seized bolt as it would be very difficult to drive it out of the brackets and the top eye of the suspension unit. If the bolt is truly bent, then as it is presumably about 3/8inch diameter then I can only assume that battle tank has run over the back of the bike. This would be obvious to spot as there would probably be some paint damage caused by the tracks. LOL. No seriously it is essential to find out the real cause of the problem otherwise it will simply happen again. HTH.

Rear suspension top bolt

Posted: Mon Jan 26, 2015 9:44 am
by MadMike
Oooooooopsy. Sorry. For "turning moments" I should have said "bending moments". Stupid man fingers. An edit facility would be very useful in these situations.

Rear suspension top bolt

Posted: Mon Jan 26, 2015 3:54 pm
by PeteF
I've since thought of a way how this could happen (possibly) I would be looking very hard at the frame forming the top mounting of the sus unit.

Rear suspension top bolt

Posted: Mon Jan 26, 2015 9:25 pm
by Bertie the Bullet
Regarding the bolt being bent, it may have happened as I was trying to undo it since the nut is stuck fast, I managed to partially open up the open ended spanner before rounding off the head of the bolt.