Funonthefarm
Active Member
Hi all, so in the process of re chassis’ing the 90... so it will be a bit and bolt rebuild... but stainless or zinc coated bolts?
Offhandlandy
Member
Hi, from what little I know about dissimilar metal corrosion, stainless fixings are a dangerous choice for the humble steel/ally defenders. SS A2 or A4 usually has the higher potential over the substrate material and in the case of the defender, it definitely does which will cause the substrate to "rot" quicker than if you had a zinc plated fixing instead.
I've been doing a lot of work on my 1988 LR90 and have used a variety of fixings from zinc plated rivnuts, high tensile bolts (8.8, I'm not fancy enough to go for 12.9) and I must admit there are many stainless bolts knocking around too.
I'm not an expert but I hope this helps a little. Ultimately something will rot and it's a question of how do I fix the problem in 5/10/15 years when it does (cut the head off a bolt VS cut a section out of the chassis)
Best regards
Connor
Flossie
Well-Known Member
I used stainless everywhere except the large expensive bolts like the ones through the hockey sticks and 'A' frame and the M6 ones all around the roof. Replace all the screws/self tappers holding all the lamps and grill stuff on too with stainless, makes it a joy to dismantle years later. Floor plates come out a breeze with stainless!
Bolts holding the bumper on is another important one IMHO.
Door hinge bolts is another.
Bolts holding the bumper on is another important one IMHO.
Door hinge bolts is another.
Funonthefarm
Active Member
So, this is the big thing I see lots of people offering SS, but from my understanding this is a worse combination on the anodic scale and will eat the alloy... technically I believe that the ally would eat the zinc first... so just trying to understand why SS is better and as they are way more expensive is it worth it?
jamesmartin
Well-Known Member
zinc fastenings it what i use and prefer except the specialist axle and suspension fastners unless thats how they are as standard
raywin
Well-Known Member
That's the main issue, standard SS bolts are not as strong as carbon steel 8.8 bolts.
Re the corrosion there is little difference between SS bolts and uncovered Carbon steel bolts if you look at galvanic charts they are not far apart.
Funonthefarm
Active Member
So fundamentally... no benefit other than removing them at a later date, or actually if weaker and more prone to reaction and eating the expensive aluminium parts, it actually worse, please let me know if I have understood this correctly.. With fingers crossed, as a nut and bolt rebuild should be a considerable time before I need to take it to pieces again!
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Funonthefarm
Active Member
On the inode scale it appears that SS is a good 0.2 difference which is pretty much 20% more reactive and is higher up so will react with the ally, and eat it faster... where the zinc is lower so the ally will eat the zinc first in a sacrificial manor till it hits the steel below...
eprothe
Member
I rebuilt my 110 and replaced pretty much every nut and bolt for stainless. I got most of what I used from YRM, who sell stainless kits, which is handy. Anything where the bolt tension was critical used A4-80, which has a tensile strength of 800MPa, the same as 8.8 rated zinc-coated bolts. Some bolts (like double-hex caliper bolts and the UNF suspension bolts) I couldn't get in stainless, so I just used zinc coated. I've driven mine on and off road in the Highlands now for a year since rebuilding it and I haven't found any obvious galvanic corrosion taking place on either the chassis or around the fixings. I had two stainless bolts bind on me while I was fitting them, but that was out of well over 200 nuts and bolts fitted during the rebuild. Given the choice, I'd go for a stainless option if there was one.
Funonthefarm
Active Member
But what’s the actual advantage of the SS bolts? As I said above, they are technically worse in both strength and galvanic potential, cost more all for the fact that I’m hopeful more than 20years time when another chassis is need that they are “a bit” easier to remove? There doesn’t seem to be a significant justification? If they prevent or help the corrosion issue I wouldn’t even be questioning it... but it seems like the emperors new clothes to me.... I also took advance from one of the leading chassis manufactures and they advise against the use of SS. So is there any clear justification for them?
Easier to gall (spelling ?) and jam the threads on stainless fasteners
Grease is essential
A2 stainless is okay, but will rust a litttle, A4 much better, often classed as marine grade.
Did I mention grease?
Funonthefarm
Active Member
Everyone likes shiny!!!Nope, not as far as I know - it's entirely up to you and how much value you put on the shininess of your fixings
The benefits and down-sides are exactly as you say (again, afaik)...
frog hopper
Well-Known Member
Probably doing the wrong thing, but whenever I remove a bolt the new one is given a good dose of copper grease 1st.
mick 1986
Well-Known Member
Are you sure they aren’t as strong? Can you define “standard” stainless bolts please?
On my rebuild, I have replaced every nut, bolt, or washer I removed with stainless steel, A4-80 (same strength as an 8.8 grade mild steel bolt, if you search for the specs you will find them), with the only exception being the seatbelts. The reason for that is, I was told these are “high tensile”, greater than 8.8 “standard tensile” bolts, and I couldn't find a suitable stainless equivalent.
When assembling stainless fasteners, always some form of anti-seize paste. It’s not nice when an A frame to chassis bolt binds up.
As for those saying these bolts will “rot away” the vehicle, how many of you have fitted any sort of gasket between the aluminium and steel when rebuilding bits of your Land Rover?
mick 1986
Well-Known Member
Can you show me where they are “technically weaker” please? I’m sure you have read the wrong thing somewhere. A4-80 is the same strength as 8.8 mild steel.
I am interested to know who the “leading chassis manufactures” is please?
I detest that stuff, it literally gets everywhere you dont want it to!
I always grease or oil everything I remove/refit, makes life so much easier next time, sadly no other bugger does.
You can get a sliver/alloy anti seize paste which is not as messy as copaslip.
