10 replies to this topic

[Archa]

As the title says really I've snapped the bolt for the trunion thingy and have no idea what to do... am I going to have to get a new subframe? :/

[attachment=129831:subframe.png]

[lrostoke]

If you have access to a welder then it can be repaired, fixed one about 3 yr ago still going strong

[lrostoke]

Sonic did you look at the picture :) Its the other end thats snapped, rear mount not front :)

[Archa]

Yeah it's the rear mount nuts that I've broken, would it still be the same fix? as from what i can see the bolts are welded in there..

[sonikk4]

Oh bugger, yes you are right i will delete what i have posted. Cheers

[Archa]

Is there a fix for these ones like or am I buggered then?

[lrostoke]

Like I say welder needed.

Mine just snapped the threaded section off, leaving a piece sticking out about inch or so long. I drilled into this section same size as the old thread size.

Also drilled a hole through the side of this section

Then found a bolt with correct thread, cut the hexagon head off and slide it into the hole drilled.

Then welded through the side hole to secure it

[Archa]

Right sounds good, I can do this. :)

[tiger99]

Be aware of one thing, if you are using a normal UNF bolt as part of the repair it will be high tensile and must be welded with low hydrogen electrodes, which need to be dried in the oven immediately before use, if you use an arc welder. Make sure that the bolt is the standard 8.8 grade, if it was 10.9 or higher I would expect the welding to be unsuccessful.

If using MIG, you can get special wire, but I would just ensure that the wire and the area to be welded is very clean and dry, and the gas mix used must contain no hydrogen whatsoever. No hydrogen means no trace of oil or water, amongst other things. I use pure argon, because I often have it available for welding ali.

The problem, if hydrogen is present, is that high tensile steel is prone to hydrogen embrittlement, which results in it cracking after a while. Having said that, I have welded quite a few bolts over the years. It just needs a little bit more care than usual, but there is no reason why your repair should not be successful.

If all else fails, find a scrap subframe (usually with rotten side members), cut the mount out of it, and graft it into yours. Tricky, but Rover did not use grade 8.8 steel for these, and the grade they used is weldable without special care.

[minidaves]

just the threaded bit or the whole thing

[tiger99]

minidaves,

If you are referring to the welding problem, the whole bolt is made of the same material, so the same care needs to be taken to avoid hydrogen embrittlement, even if your weld is only on the head of the bolt.