Stripped thread

[les]

I'll come straight to the point, the shock absorber fixing plate (in the bulkhead) can it be pulled out through the inner wing if a slot is cut out, or is this plate captivated to make this a non starter. I'd prefer fitting a new plate than using a helicoil.

[bmcecosse]

I think it's captive! I would drill it out slightly larger - and tap a new thread - to take a larger diameter bolt. Then just drill the damper to take the new bolt - there's plenty of 'meat' on it.

[les]

Thanks for reply, yes it probably is captive, but if the captive brackets are on the top and bottom of the plate, the plate could be pulled out from the inner wing. This is the info I need really. Not happy with having an 'odd' bolt fitted, if it can't be replaced I would rather use a helicoil and keep standard. Maybe best to drill a test hole and have a look!

[bigginger]

FWIW, it definitely doesn't pull out. If you want, I have one in a state whereby I can have a go at photographing it.

[IaininTenbury]

As far as I can recall, it is captive. not loosely captive like the door hinge pillars, as movement for adjustment is certainly not required here! Thing the plate is spot welded to the bulkhead. I got round it once by cutting a hole in the inner wing and welding a new 5/16bsf nut to the back of the plate and welding the hole up. The other side of that vehicle, en ex GPO van had been well butchered to repair it in the past and I cut a section of bulkhead out of a scrapper and grafted it in. Both repairs worked and looked ok. I'd imagine the first one would be adequate for you, if its just one bolt. The bolts are long enough to screw into the new extra nut btw.

[chickenjohn]

"I got round it once by cutting a hole in the inner wing and welding a new 5/16bsf nut to the back of the plate and welding the hole up. "

I would do this- go with Iainin's suggestion. Whilst I usually agree with and like BMC's suggestions, my neighbour who is a retired engineer warned me against drilling out and tapping a larger thread for a larger bolt in a captive fixing. Its apparently not good engineering practise.

[les]

Thanks again for the interest taken, woiuld be nice to see a picture Andrew, but don't go to too much trouble, especially if the weather is the same as it is here! I hadn't considered the plate being 'fixed' in which case I will need a rethink; the nut idea sounds good, but if the plate is fixed I am inclined to try a helicoil first, nothing lost, if no good, nut it is!

[bmcecosse]

I think the plate is quite thin - hence easy to strip the thread. I dunno if a helicoil will have enough grip - they are really for casting repairs where plenty depth.

[bigginger]

OK, rubbish pic, but you can see the *TWO* mounting plates - that's looking down the 'beam', btw.


...and they're welded there

[les]

Andrew, rubbish picture or not---- it tells me just what I needed to know, thanks for your time. I hear what you're saying bm, I'll have to weigh that one up.

[bmcecosse]

They look a bit thicker in that pic than I thought - may well be ok - worth a shot!

[bigginger]

I didn't measure the thickness, I'm afraid - it was raining and I was squatting in a pool of mud

[RogerRust]

I didn't measure the thickness, I'm afraid - it was raining and I was squatting in a pool of mud

Where else in the classic car world would you get such devotion?

[simmitc]

Depending on which bolt you need to fix, you might be able to simply put a lock washer and nut on the end of it from behind the plate - there is an opening accessible from just above the steering rack. I don't know why it's there, but I've used it to inject rust proofing, and also the add a nut to overcome exactly the same problem. Fiddly but possible.

[alex_holden]

there is an opening accessible from just above the steering rack. I don't know why it's there

They're the air intakes for the early type of heater.

[rayofleamington]

The welded nut seems a decent way forward, however if the rest of the vehicle is 'show car' kind of level then it'd be a shame to cut and shut the iner wing to get in there. If it was one of my cars with a patchwork inner wing I'd have no hesitation to get the grinder out!

Helicoils will be stronger than the standard thread if done properly, but as already mentioned they are not recommended unless you have enough depth (ie you need to be able to get enough turns in there). From BG's pic it looks like a Helicoil may be possible but it would be fairly easy to measure the plate thickness with a bit of bent wire if needed.

[les]

The hole above the rack idea got me straight out to check, but being the top r/h thread that has stripped, N/S, I could not get to it, but good thought Simmitc. I sent for some helicoils today so if the plate is thick enough I'll use them, if not the nut welding trick. Actually welding a nut behind the plate will give me enough metal thickness to be sure a helicoil will work, nut and insert ott maybe, but who cares!

[bmcecosse]

But to weld the nut you would need to hack into the inner wing. Give the coils a chance - if the plate is 3/8" thick it may well be ok.

[RogerRust]

At the risk of being shot down. Three good bolts and a lightly torqued fourth one sounds fine to me.

[MoggyTech]

Shot in the dark here, but surely that box section must be accessable from the rear, rather than through the inner wing? Stick a long punch through the offending hole, and belt it with a hammer. Find ding inside car dash panel area. Drill 1" hole for access. Options are then open, like fit a long bolt with a nut on the inside. When done fit a grommet to the drilled hole.

I'd just drill and tap to next size, as the shocks have plenty meat around the mounting holes.

And thinking outside the box, if the car wasn't a show car, I'd fit three bolts, and splash the MIG to the damper and box section. After that velcro.