28 replies to this topic

[humph]

 need some advice from those of you more experienced in these things than I.

Background: It's MOT time and whilst giving the car a once over I noticed play in both radius arms I got a couple of astronomical quotes for the job and researched it thoroughly. I decided to have a go myself, as I'm trying to do everything myself at the moment (you've got to learn somehow). I'm going to Minispares tomorrow so wanted to get the two radius arms off so I could exchange them when I picked up the reconditioned ones.

So Far: I've spent the last two weeks giving all the bolts a daily soaking in plus gas, and before starting today I decided to use some Normfest super crack (I'd heard this couldn't fail to free seized bolts). So I set about removing the rear drums and backplates, no problem. Undid the inner and outer mounting bolts, got these too. Eventually got around to the dreaded bracket mounting bolts, so with everything crossed I set about having a go at them. I did as others had advised, and gave them a quick tightening nip in an attempt to break the rust bond. Then gently I tried undoing them one by one......and one by one they all sheared!!!! Well I say all, all but one. The remaining one broke the welds on the captive nut so is now spinning freely, but doing nowt.

So I am now left with:
Plus points - 2 radius arms off the car for exchange tomorrow.

Negative points - 7 sheared bolts stuck in the subframe. 1 freely spinning bolt that will need to be cut off to free the mounting bracket.

So where now? As far as I can tell I have three options:

1) With the subframe on the car - Drill out the seized bolts and weld in new captive nuts.
2) With the subframe off the car - Drill out the seized bolts and weld in new captive nuts.
3) Remove the subframe and replace with a new none genuine one. The genuine ones are way out of my budget at the moment.

Before you answer please take note that the lock up has no power so drilling and welding insitu will need the car moving to somewhere that has (more cost!). I'm very afraid based on the fact that none of this looks as though it's been apart in years that removing the subframe will just end up with me shearing off the subframe bolts, or screwing the captive nuts, leading to bigger headaches. Which do you guys think is the best option?

Has anyone got a foolproof way of getting the rear subby off without mullering the bolts in the heal board? Obviously I'm now very sceptical of the weeks of penetrating oil method .

Best laid plans and all that. I do wonder sometimes if these little cars are worth the heartache, but can't imagine being without one.

I would be grateful for any advice that will help. Cheers guys.

 

[M J W J]

Two more options for you assuming you can get hold of a decent battery drill and have the appropriate tools/ mind investing in them.

 

Option 1: Drill a hole into each of the broken bolts and use a set of easy outs/ stud extractors. Be careful with them though because if you break one you won't be able to drill it.

 

Option 2: Drill out what is left of the old bolts and tap them out to the next size up. You may be able to find a metric thread that is slightly bigger and just use metric bolts instead.

 

As for the sheared nut depending which one it is you could just get an open ended spanner in to hold it in place or there are special nuts out there (can't think what they are called at the minuet) that are inserted into a round hole and as the bolt is screwed into them they expand and grip the back side of hole they are stuck into. They are designed for use with vehicles. I saw some on a program where they were installing body protection panels onto a jeep.

[ibrooks]

If you're careful you should be able to drill the bolts out of the nuts without damaging the captive threads. You need to drill dead centre. Start with a smaller drill and work your way up to near the size of the bolt. Done properly you can remove the core of the bolt and leave just it's thread in the nut which will then unscrew and come out looking just like a spring.

 

If you make a horlics of it then you tap them the next size up. They are 5/16" which is a hair under 8mm (not enough to use 8mm as the next one up) 9mm is a really odd size so 3/8" would be the next one which is around 9.5mm.

 

Battery drill is your friend along with lots of care and patience (and good sharp drills).

 

Iain

[Kat7Racing]

or there are special nuts out there (can't think what they are called at the minuet) that are inserted into a round hole and as the bolt is screwed into them they expand and grip the back side of hole they are stuck into. They are designed for use with vehicles. I saw some on a program where they were installing body protection panels onto a jeep.

 

 

 

Hank Bushes or the sheet metal trade call them rivet bushes........is what I usually refer to them as but google it.  I did exactly this with mine and it works well but you do need the tool to insert them or they will spin later if you want them out,  I believe machine mart do them. As for the sheared ones the trick with drilling them is exactly as described,  small drill to larger but HIGH quality SHARP drills and make sure that the snapped off stud is ground or filed flat before you start or the drill will wander.

Edited by Kat7Racing, 09 August 2013 - 07:20 AM.

[Tamworthbay]

Just bear in mind that most rivnuts sold for 'amateur' use are aluminium and not suitable for used in a stressed application. There are steel types available but I have only seen them with a dedicated air tool to fit them. Ally Rivnuts are brilliant for door mirrors, mounting relays etc etc but shouldn't be used for suspension components.

[Kat7Racing]

Just bear in mind that most rivnuts sold for 'amateur' use are aluminium and not suitable for used in a stressed application. There are steel types available for I have only seen them with a dedicated air tool to fit them. Ally Rivnuts are brilliant for door mirrors, mounting relays etc etc but shouldn't be used for suspension components.

An excellent point well made here.  I only needed one when I did mine and got it fitted at our sheet metal work suppliers when I had the subby out.  The ally ones would indeed NOT be suitable

[Barman]

My ...

 

Given the problems you have found so far, I'd want the subby out to have a good look at it...

[humph]

Cheers for the responses guys.  I had thought briefly about rivnuts, but agree that I'm not sure they're suitable in this application.  I am resigned to the fact that the bolts will need to be drilled out, an possibly new nuts welded in.  I'll have to find a mobile welder I think & hire a genny for the drill/grinder.

 

Ideally I would want the subby off so I can give it a good looking at as it's covered in underseal and I think it needs something better. Obviously this could (and probably will) lead to my problems getting worse.

[Ethel]

They were probably going to fail anyway, but heat would have helped, penetrating oils won't work if they can't penetrate. The cheapest/simplest solution would be to weld the brackets on. If you're not in a rush I'd be tempted to try removing the subby. At least, if  those bolts shear too, you'll be tooled up anyway for tackling the brackets and the job's already half done in stripping off the radius arms.

[tiger99]

Neither ali nor steel rivnuts, hank bushes or any similar devices are strong enough for use on any stressed part of a car. The only safe option is to weld in a nut, properly.

 

I don't like to be pessimistic, but if you do decide to take the subframe out, please prepare yourself for all the horrors of rotten heelboard ends, captive nuts breaking loose, etc. Been there.....

 

The big problem comes when the captive nuts break free of the vital inner stiffening bracket, because then you are in to, at the very least, cutting out the rear few inches of the outer sill to enable repairs to be made,and then fitting a sill patch afterwards. Not as difficult as it might seem, but really tedious and annoying.

 

Give yourself far more time than you think you will need, and use the very best penetrating oil that you can get, several times, over a week or so, to give yourself the best possible chance of an easy outcome.

 

Good luck!

[DILLIGAF]

What I've always done, is using a suitable punch hammer the broken stud into the subframe. The welds on the captive nut will break off, leaving you with a hole. Get a new nut and file the corners of said nut, now drill out the hole in your subframe so the filed down nut is a tight fit. Screw the nut onto a bolt loosely, then holding it in position wearing a welding glove, weld it in place. Grind down excessive weld, re-paint any damaged areas and refit the subby........

[M J W J]

What I've always done, is using a suitable punch hammer the broken stud into the subframe. The welds on the captive nut will break off, leaving you with a hole. Get a new nut and file the corners of said nut, now drill out the hole in your subframe so the filed down nut is a tight fit. Screw the nut onto a bolt loosely, then holding it in position wearing a welding glove, weld it in place. Grind down excessive weld, re-paint any damaged areas and refit the subby........

 

He has no power at his lockup so can't weld a new nut in. That is why I suggested the other types of nut.

 

How about gluing the nut in with something like a 2 part epoxy?

 

Before people say that's a terrible bodge and shouldn't be used on suspension bolts, the glue won't be taking any load. It will just be used to prevent the nut from turning when the bolt is done up. The clamping force to hold the braket in place will still be done by the nut and bolt as was always intended. Glueing parts in place on cars is not uncommon either. Adhesives can often result in a stronger stiffer joint than welding.

[Tamworthbay]

What I've always done, is using a suitable punch hammer the broken stud into the subframe. The welds on the captive nut will break off, leaving you with a hole. Get a new nut and file the corners of said nut, now drill out the hole in your subframe so the filed down nut is a tight fit. Screw the nut onto a bolt loosely, then holding it in position wearing a welding glove, weld it in place. Grind down excessive weld, re-paint any damaged areas and refit the subby........

 
He has no power at his lockup so can't weld a new nut in. That is why I suggested the other types of nut.
 
How about gluing the nut in with something like a 2 part epoxy?
 
Before people say that's a terrible bodge and shouldn't be used on suspension bolts, the glue won't be taking any load. It will just be used to prevent the nut from turning when the bolt is done up. The clamping force to hold the braket in place will still be done by the nut and bolt as was always intended. Glueing parts in place on cars is not uncommon either. Adhesives can often result in a stronger stiffer joint than welding.

Can you get to the back of the subframe where the nut sits with it fitted to the car?

[DILLIGAF]

Can you get to the back of the subframe where the nut sits with it fitted to the car?

 

 

Not without cutting a hole in it........

[Tamworthbay]

Can you get to the back of the subframe where the nut sits with it fitted to the car?

 
Not without cutting a hole in it........

That was what I thought, no chance of just glueing some nuts on unfortunately.