Rusty bolt heads on rear cross member

[mike56]

I am considering replacing the bolts on the rear cross member and wondered if the nuts are captive. Can I just unscrew the old ones and screw the new ones back in. If nuts are not captive they look tricky to reach!. Vehicle is 2008 Defender 110 Hard Top.

Thanks

Mike

 

[james6546]

I am considering replacing the bolts on the rear cross member and wondered if the nuts are captive. Can I just unscrew the old ones and screw the new ones back in. If nuts are not captive they look tricky to reach!. Vehicle is 2008 Defender 110 Hard Top.

Thanks

Mike

The middle ones are captive, but the ones at the edges are not

 

[mike56]

Thanks.

Sounds like the ones that are tricky to get at are captive then. Good news.

Mike

 

[james6546]

Thanks.

Sounds like the ones that are tricky to get at are captive then. Good news.

Mike

Yeah, I think that is why they did it. Although the ones that have real nuts are the ones that would get mud on them and corrode.

I put round allen head stainless steel bolts on mine and it looks good

 

[lynall]

They grind off easy enough and you wont cause any damage so long as you dont grind past the washer under the head of the bolt, I just used A2 stainless M8 on mine with std nuts all fitted easy enough

 

[ebbadger]

Your far better off going for BZP rather than stainless, zinc and ally are as good as next to each other on the galvanic scale so far less of a galvanic cell reaction, stainless is several steps closer to a noble metal so will have a much higher corrosion potential

although stainless wont rust solid it will cause the alloy to sacrifice itself far faster

I went for BZP 12.9 throughout my rebuild so should be good for years, stainless is strong enough for body bolting but I wanted high tensile throughout...


IMG_1838 by The_Wild_Boar, on Flickr

IMG_1836 by The_Wild_Boar, on Flickr

Untitled by The_Wild_Boar, on Flickr

IMG_2966[1] by The_Wild_Boar, on Flickr



cheers steve

 

[ebbadger]

heres a bit more info as i did a hell of a lot of research before my rebuild....

The table below is an example of these 'metal to metal' relationships, including graphite as conductive non-metal.

ANODIC (Least Noble)
Magnesium
Zinc
Aluminium
Carbon steel or cast iron
Copper alloys (brass, bronze )
Lead
STAINLESS STEEL
Nickel alloys (Incoloy 825,Hastelloy B)
Titanium
Graphite
CATHODIC (Most Noble)
The further apart the metals are, in terms of relative potentials, the greater the driving force in a cell. So, for example, stainless steel in contact with copper is less likely to be a risk than when it is in contact with aluminium or galvanised (zinc coated) steel.

so basically stainless may not rust up and seize and you will be able to undo it in years to come the problem is that galvanic corrosion (the white crud as your ally turns to salt) seen on door bottoms etc is even worse than using ordinary carbon steel.

The ally will sacrifice itself even more... whereas BZP is less noble than alloy so the BZP bolt will sacrifice itself rather than the ally panel and as they are so close the sacrifice will be very minimal... bit of copperslip and it'll never be an issue

what would you prefer at the end of the day?? a bzp bolt that may need replacing in 30 years or an ally panel that will be eaten away far faster??

hence the reason steel ships are equipped with sacrificial zinc anodes (which are only any good if always submerged .. wont work on a landy lol)

Cheers Steve

 

[lynall]

Alloy anodes for salt water
Zinc for brackish water
Magnesium for fresh water
Weird thing is my stern drive is alloy with stainless bolts and stainless jubilee clips no corrosion at all, just the anodes doing their job, and them little sea critters trying to block up the water intakes.