corrosion of ally body blocks where they touch steel?

Post by **marin** » Mon Jun 14, 2004 6:21 pm

ive been thinking of an aluminium body lift this time around, but have heard something about corrosion/rust where the aluminium block touches the body/chassis. Does this happen? Is there a certain grade of aluminium to use to reduce the risk of this? What about the bolts through the middle, will they do the same thing as the body block/chassis joints? (although i think the 1's i will be getting are Zinc plated) Do people use rubber in between the blocks and the chassis/body? Any other things to think about with ally?

Post by **Grantw** » Mon Jun 14, 2004 7:24 pm

I always thought that contact between dis-similar metals created electrolosis. I know this isnt the same, but on a fitup of my boat (ally) I had to use a substance called duralac that prevented electrolosis between the metals.

Post by **maty** » Mon Jun 14, 2004 7:28 pm

the steel will be fine but the aluminium will corrode away. zinc coating help however if sea water gets between the two they will only last a few month especially on the ones near the engine bay that gear warm air and salty water.

go steel blocks or if you want to keep noise and vibration down use either HDPE or nylon blocks - the down side is if these are close to a turbo they could soften - melting point about 180 degrees

mat

Post by **landy_man** » Mon Jun 14, 2004 7:28 pm

that is correct...electrolosis occurs between 2 different metals in contact with each other... The first place an aluminium bodied Rover corrodes is where the ally is in contact with steel. It is not the same as rust (ferous oxide) which is caused by oxidation of steel, but more of a powdery rot...

Post by **marin** » Mon Jun 14, 2004 8:27 pm

Grantw wrote:but on a fitup of my boat (ally) I had to use a substance called duralac that prevented electrolosis between the metals

This sounds like a good preventetive measure, approx what is that stuff worth, and would it be suitable for putting on body blocks? Does it stay wet/tacky or does it dry? and is it black?

Post by **landy_man** » Mon Jun 14, 2004 8:44 pm

why go through all that hassle when you can just use steel ones

Post by **bazzle** » Mon Jun 14, 2004 8:47 pm

Ive fitted Ally blocks to many vehicles over the years.
Ive also fitted steel.

A coat of paint when 1st fitted to both surfaces has always been enough. Ive never had any corrode away.
Ive had more problems with steel ones getting surface rust (visual)

The chassis and body is painted anyway.
Ive done many trips thru bog holes, rain, beaches..
I am strongly in favour of Ally..

If I was a beach fisherman 'maybe" i would think different but then I probably would set a vehicle up differently and wouldnt need a body lift.

Bazzle :cool:

Post by **marin** » Mon Jun 14, 2004 9:18 pm

bazzle wrote:A coat of paint when 1st fitted to both surfaces has always been enough. Ive never had any corrode away.

any special type of paint? or just the spray can $4 a can type

Post by **ISUZUROVER** » Mon Jun 14, 2004 9:31 pm

The best thing to use would be DURALAC - it is spedially made for preventing corrosion between dissimilar metals. It works on boats in salt water so no problem on a 4x4. It is a paste and comes in a tube - you just smear some on each side before bolting everything up.

Post by **Cheezy4x4** » Mon Jun 14, 2004 9:41 pm

Have cut quite a few bolts out of alloy blocks over the years, also sometimes have probs with front blocks being noisy. :?:

Post by **marin** » Mon Jun 14, 2004 9:45 pm

Cheezy4x4 wrote:Have cut quite a few bolts out of alloy blocks over the years, also sometimes have probs with front blocks being noisy.

Good to know, cauz i kinda wanted the option of pulling them out as easily as i put them in, if need be

Post by **ISUZUROVER** » Mon Jun 14, 2004 10:31 pm

Removing the bolts won't be a problem if you put Duralac on them too when installing. All good boat places sell it.

Post by **HSV Rangie** » Tue Jun 15, 2004 12:21 am

DURLAC

REGARDS
Michael.

Post by **Goodsy** » Tue Jun 15, 2004 3:42 am

Whats wrong with nylon blocks. Used them on my last hilux and didn't have a problem.
Would solve you corrosion problem

Post by **-Scott-** » Tue Jun 15, 2004 8:37 am

Cheezy4x4 wrote:Have cut quite a few bolts out of alloy blocks over the years, also sometimes have probs with front blocks being noisy.

Cheezy, can you be more specific? I've got aluminium blocks, and took them offroad for the first time on the weekend - I get horrible groaning noises from the front over rough stuff. Is this the sort of noise you mean? Should I pull the front blocks out and Duralac them?

Thanks,

Scott

Post by **Roctoy** » Tue Jun 15, 2004 10:08 am

c'mon people!

Over what time frame does this type of corrosion occur?

Most of us will have sold, rolled or had the truck stolen before this kind of corrosion has made any significant damage to the block or the truck. Unless you spend every 5 minutes driving through the waves at the beach, Just like the adds!!!

Chris

Post by **bazzle** » Tue Jun 15, 2004 10:40 am

Dont worry about the Ally blocks. Just fit them and go. Use grease on the bolts if you are concerned inside the blocks.

I have only ever used cheap black spray paint.

Noisy front blocks Ive found to be not the lift block but the hole where the body mount sits on chassis being worn oval. When wet it clunks more due to extra levaearage from block height.

bazzle

Post by **shorty.mqute** » Tue Jun 15, 2004 6:09 pm

has anyone heard of alloy blocks pulling through the floor of the cab under body/chassis twist?

Post by **ausyota** » Tue Jun 15, 2004 7:49 pm

Im thinking of using ally chequer plate on my tray.
Should I put anything between the steel frame and the ally plate? just paint?
Whats the best way to attach it the tray frame, countersunk bolts, rivets?
Paul.

Post by **HSV Rangie** » Tue Jun 15, 2004 8:13 pm

Corosion acurs when you have 2 disimiloar metals in contact and they are WET, salt water propigates electolisis more so than water, using alloy blocks steel bolts moisture is a recipe for future problems.

takes a while but it hapens.

Michael.

sorry about the spelling.

Post by **Cheezy4x4** » Tue Jun 15, 2004 8:41 pm

Last week I pulled out bolts from a alloy lift that was 2 years old and had to cut 3 bolts out :shock:

(what would I know I only do 5 body lifts a week).

Post by **bazzle** » Tue Jun 15, 2004 9:25 pm

He who does the most Wins

Bazzle

Post by **bogged** » Tue Jun 15, 2004 10:29 pm

I took my alloy blocks out few weeks ago when I did the bodymount rubbers.

There was no issues with the bodywork, or alloy itself... Go with it, no hassles dude, piss easy

Website · Post by **murcod** » Tue Jun 15, 2004 10:35 pm

What about using marine grade stainless bolts with the aluminium blocks? Stainless and aluminium don't react- that why they use stainless fittings on ally boats.

Post by **ISUZUROVER** » Tue Jun 15, 2004 10:45 pm

murcod wrote:What about using marine grade stainless bolts with the aluminium blocks? Stainless and aluminium don't react- that why they use stainless fittings on ally boats.

Who told you that - they still react - that's why they use DURALAC on boats. It's not difficult, JUST BUY SOME DURALAC and put them on the bolts and between the alloy and steel. A lot cheaper than buying stainless bolts!!!

Post by **bogged** » Tue Jun 15, 2004 10:47 pm

NJ SWB wrote:Cheezy, can you be more specific? I've got aluminium blocks, and took them offroad for the first time on the weekend - I get horrible groaning noises from the front over rough stuff. Is this the sort of noise you mean? Should I pull the front blocks out and Duralac them?

They can wear the body mount rubbers out faster, but not an issue I dont think bodymount rubbers when worn, cause all sorts of noises... Clunks when going round corners, up gutters etc...

Post by **bj on roids** » Wed Jun 16, 2004 10:33 am

marin wrote:
Grantw wrote:but on a fitup of my boat (ally) I had to use a substance called duralac that prevented electrolosis between the metals

This sounds like a good preventetive measure, approx what is that stuff worth, and would it be suitable for putting on body blocks? Does it stay wet/tacky or does it dry? and is it black?

DURALAC, its like a green pasty substance, dries fairl hard, can be painted over, get it from any marine chandlery, stops corrosion between metals, eletricians and yachties use it a lot. :armsup:

Website · Post by **murcod** » Wed Jun 16, 2004 10:42 am

ISUZUROVER wrote:
murcod wrote:What about using marine grade stainless bolts with the aluminium blocks? Stainless and aluminium don't react- that why they use stainless fittings on ally boats.

Who told you that - they still react - that's why they use DURALAC on boats. It's not difficult, JUST BUY SOME DURALAC and put them on the bolts and between the alloy and steel. A lot cheaper than buying stainless bolts!!!

Probably the place we bought the ally boat off years ago!?

Here's some info on ally corrosion:

http://www.afsa.co.za/download/tech/intro8.pdf

You could always attach sacrificial zinc anodes onto each ally lift block! :rofl:

Or just get nylon blocks and save all the hassle. :roll:

Website · Post by **murcod** » Wed Jun 16, 2004 10:54 am

BTW Duralac is also known as Zinc Chromate paint from the info I just found:

http://www.eng-tips.com/gpviewthread.cf ... 15/lev3/55

Post by **bj on roids** » Wed Jun 16, 2004 11:02 am

murcod wrote:What about using marine grade stainless bolts with the aluminium blocks? Stainless and aluminium don't react- that why they use stainless fittings on ally boats.

mate, thats the biggest load of crap ever, there is a really bad electrolysis and corrosion action between alloy and stainless!! DAMN!

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