Bolts on rear springs

[Orkney2]

Started dismantling and renovating a pair of rear springs yesterday.
Going to replace the bracket bolts and the centre bolt - wondering are these high tensile?
If i can find the right sizes will probably replace with stainless steel ones to look nice after the paint job

[bmcecosse]

Don't use stainless - it's not high tensile! The standard bolts will be fine - or if really knackered, use Allen Cap bolts.

[Orkney2]

Hmm live and learn ! always thought stainless was HT ! Least they seem that way when they break !
BTW BMC they are in really decent condition now taken apart - think I'll try them as are given the improvement over whats on there - if they feel too soft once fitted then try beefing them up a bit, but dont doubt they will be a 100% improvement once on especialy as they will have bushes too which there are hardly any of currently

[rayofleamington]

Don't use stainless - it's not high tensile!

????

Bolts are graded and the average mild steel bolt has a lower tensile strength than a standard stainless bolt.
High graded steel fasteners are, of course, higher grade material than standard fasteners, and the same applies to Stainless grades.

[Orkney2]

Allright - calm down i'l rephrase the Q
should i use mild or stainless to replace the ones i had to remove with teh grinder spanner

[bigginger]

Some more bolt grade explanation here -
http://www.minormania.com/smf/index.php?topic=1169.0

a

[bmcecosse]

High tensile stainless bolts are very unusual - unless going to Aircraft grade? Allen Cap screws/bolts are high (and higher) tensile as standard.
In any case - mixing stainless and ferrous is not a great idea - an electrical 'couple' is set up when wet and the ferrous steel rots away!

[leyther8008]

I second that! in the construction industry we specify 'isolation washers wherever theres a steel/stainless steel interface. (And other mixed metal points as well) In fact it has got me thinking about a sacrificial anode plate like they have on ships to try to protect my chassis a bit, anybody know what they use?

[simmitc]

A steel hull in fresh water would have a magnesium anode.
A steel hull in saltwater would have either an aluminium or a zinc anode.
A steel hull in brackish water would have an aluminium anode.
I'm not convinced that an anode would work on a chassis unless it was immersed in water; but if you did try it then arguably you would have to swap according to summer driving with fresh water spray and winter with salt on the roads.

[leyther8008]

See you learn usefull stuff all the time on this forum! I thought I,d hit on a winner there and was thinking if ways of marketing it when!!!
Seriously thanks for that but why do van gutters sacrifice themselves to save the rest of the box?

[bigginger]

Isn't that down to the way they're fixed to the box being a water trap on the inside?
a

[alainmoran]

Humm .. surely having the car set to a -ve earth will have the same effect as an anode?

In fact, isnt that one of the main reasons that they switched?

[bmcecosse]

The -ve earth change was to stop the electrical contacts corroding - but does nothing for the rust!! You can add zinc anodes - but only likely to have very local effect. Hence modern cars are zinc galvanised = and really suffer very little corrosion unless horribly abused.
I ran a thread a few weeks ago on a -ve charge system from USA - the car was made a capacitor with isolated charged plates placed within the shell - and claims are made for anti-rust properties, but most seemed to be highly sceptical! Perhaps rightly so - I simply put it up for discussion.