gearbox cross member...theres always one bolt

[sb]

so i've removed three of the four bolts and yes the finally ONE spins.
After reading a related thread i moved in side the car and removed the gear box cover, a little bit of rust dust in the box sections but pretty good.
The bolt still spins so i've hamered a screwdriver onto the nut casing in order for a bite but no it still spins.

I'm considering cutting off the bolt head from below however, that leaves me a fixing down. Or drilling from above through the bolt although again i won't be able to use the fixing any advice please?

cheers sb.

[57traveller]

Experienced similar a couple of years ago. Of course it had to be the passenger side and after removing g/box cover cut off offending bolt head, removed captive nut/remainder of bolt and fitted nut and bolt on reassembly. I suppose a nut could be tack welded in the chassis rail but this needs access to a welding machine and the necessary skill.

[rayofleamington]

I have had success using mole grips onto the nut casing if you can get to it (but that doesn't work if t's the one under the m/c). If it does work it is still likely to spin next time.
I tend to just cut the bolt head off, yank out the nut and remaining stud and weld a new nut into the leg. Then the only difficult bit is not to mix up the 1 metric bolt with the 3 remaining original threaded ones.

[sb]

I tend to just cut the bolt head off, yank out the nut and remaining stud and weld a new nut into the leg. Then the only difficult bit is not to mix up the 1 metric bolt with the 3 remaining original threaded ones.

Fair point, how about welding a bolt droped in the chanel from above therefore allowing nuts to removed from below each time.

[57traveller]

Don't see why not, just make sure there isn't excessive thread below the nut when it's in place otherwise that will rust and the same will happen. Use a BSF bolt and nut then there's no thread confusion.

[rayofleamington]

Fair point, how about welding a bolt droped in the chanel from above

I wouldn't want a bolt sticking out of the bottom of the car (especially living in a town with plently of speedbumps) as it only takes one knock to render the thread damaged or the bolt bent and it would be unserviceable.
Mig eelding the nut unto the leg is very easy - generally it is best to do it with the bolt inside the nut, but no bolt thread sticking through so that you won't get any spatter onto the male or female thread.
For the gearbox crossmember captive nuts this is pretty simple as gravity holds it all in place but on other places you can use packing nuts or washers so that the nut can be tightened up prior to welding to make sure it sits central and is not at an angle. It's best to avoid the temptation just to do the bolt up fully leaving a lot of male thread poking through the side you will weld as 9 times out of ten it will be ok but on the other time you will get some weld onto the male thread and all will be lost as it won't come out and you are worse off than being back at square one as the nut is now firmly in place.

This technique can also be used for captive nuts where you can't access the rear (like the front most bolt for the rear wing). Once you have wrestled the old nut away (probably by hammering the remains of the bolt with it's head cut off) you need a whole just larger then the new nut, then you can weld the nut in place from the bolt side (with bolt in place to locate the nut) then just flatten off the weld with the grinder to get a flush face.

[custommartin]

Hi,
I think it was Rob (Thomasson), the club technical guy, who suggested welding bolts into a thick metal plate cut to the same width as the inside of the leg.
Grind off the old captive nuts and drop the plate into the leg!!

The plate spreads the load over a larger area and prevents the bolts from pulling through the chassis, as is common on the Mog.

I intend doing this on the Pick-up, after I have ground the drivers side cross-member mounting bolts off!!!!!

Cheers

Martin

[les]

When I did mine I used 5/16" plate the width of the chassis leg and tapped the appropriate holes in it.

[sb]

When I did mine I used 5/16" plate the width of the chassis leg and tapped the appropriate holes in it.

what type of metal is used, I.E steel, or bimetalic bearing in mind strengh and welding properties. Where would i get such a plate, minor garage or metal fabrication co. ?

What does BSF stand for? I assume an early british thread standard.

Cheeers, sb

[sb]

Hi,


The plate spreads the load over a larger area and prevents the bolts from pulling through the chassis, as is common on the Mog.

I intend doing this on the Pick-up, after I have ground the drivers side cross-member mounting bolts off!!!!!

Cheers

Martin

should this new plate be droped in or welded?

As for the drivers side, doe'nt that have the additional bonus of the brake cylinder to deal with.

[57traveller]

What does BSF stand for? I assume an early british thread standard.

Cheeers, sb

British Standard Fine, still available and used all over the Minor.

[Kevin]

then just flatten off the weld with the gringer to get a flush face.

Really Ray

[rayofleamington]

Kind of like that kevin - this way you can replace captive nuts without needing access from the rear. You might also be able to do it using gas but it can be done in minutes using Mig.

[Alec]

Hello Ray,
gas would be fine and quick also, and you don't have to remember to disconnect the alternator if you have one.

Alec

[rayofleamington]

Alec,
Cheers Alec - wasn't sure how well it would cope with heating up the nut and bolt enough without melting away the surrounding metal or the threads as I've only used gas at college, not on cars. Mig by its nature copes well with nearby threads and differential thicknesses as it only gives local heating.

As for alternators - Dynamos seem to work OK after Mig welding and I'm lucky that the traveller hasn't been changed to alternator when they added all the extra fog lights etc.. as it would take hours to change back to Dynamo.

[Alec]

Hello Ray,
Yes, it is the solid state components that don't like sparks from welding machines, modern cars must be a nightmare from that point of view. I understand that even using the old fashioned jump leads can cause ECU modules harm.
I would probably braze a nut on in that situation, it could then be easily removed if damaged in the future.

Alec

[custommartin]

should this new plate be droped in or welded?

As for the drivers side, doe'nt that have the additional bonus of the brake cylinder to deal with.

I guess welding the plate in would make the whole thing stronger, but there is a chance that the weld would create a weak spot over time (metal is highly stressed around a mig weld)

Last time I just dropped the plate in, and this worked fine.

Unfortunately, you do have the pleasure of removing the master cylinder.
I have to do this anyway at some point.

[rayofleamington]

I would probably braze a nut on in that situation

Doh! Yes - now you've said it, it's an obvious choice. Anyway I'll stick to my lumpy spitty mig weld for now ;-)

I understand that even using the old fashioned jump leads can cause ECU modules harm.

Well if you've seen the design specs for modern electronics (overvoltage protection, spike resistance etc..) you'd start to believe that kind of thing was only an old wives tale....
Until you consider people fitting jump leads the wrong way round. Many electronics have fail safe features to prevent misfunction with reverse power. (the fail safe can actually mean fail permanently )
moder cars are becoming computers on wheels and we know how GGGRREEAAT computers are - Presently I'm back at work on a disaster recovery mission as my laptop just died and Monday morning I'm at a customer site giving presentations.. not just my presentation - I'd also got veryone elses presentation on my machine
It could have been worse - it could have gone into 'invalid kernal' completely creamcrackered mode on Monday instead of Friday night.

[les]

what type of metal is used, I.E steel, or bimetalic bearing in mind strengh and welding properties

If you choose this method, there is no need to weld the plate if it is made a snugg fit within the chassis leg. Use ordinary mild steel and cut to size. Radius the edges slightly to suit the inside of the box section. Also put a smear of grease between plate and inside chassis.

[Kevin]

Just been talking to a friend who`s car had this problem in the past on the drivers side and he needed a new clutch only to find out that the previous owner or repairer had welded the crossmember in place to save doing a proper repair so its turned into a much longer job, so thats something else to look out for when buying a Moggie.