MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - NMC - breaking corrosion between alu and steal

Happy Eater all :)

It is not midget, but still car... And hopefully it will be interesting not only for me :)

On my modern, the upper ball joint, made of some kind of steel, is screwed into an aluminium carrier. I am fighiting with it since few days, trying heat, Plus Gas ... without any success. It won't unscrew. I even broke my breaker bar!

Any idea of what I can use instead of Plus Gas, that would be more efficient in "aluminium+steel" corrosion?

I am looking for full carrier in breakers in the meantime :D

Thanks!
Enjoy those sunny days :)






CH Hamon

Hi Cedric---Happy Easter
Not sure of the setup but it appears there might still be a wire retaining clip in there, If you've been trying to pull it you might have to tap it back up a bit to get the clip out, then it should pull out ok
willy

What make/model car is that on
William Revit

Just blew your pic right up and yeah there's no clip by the look of it----You could try slowly pouring a bucket of boiling hot water over the top of it to get some heat into it and then try undoing it --get some pressure on it,pull as hard as you can and give it a sharp pull while the pressure is on--the sharp pull might just crack it loose
William Revit

Cedric,
you should bin/recycle that breaker bar as it is broke.

Instead of PlusGas you could try GT85 as it is also a longer lasting lubricant with PTFE as well as a penetrating/releasing agent so would probably aid disassembly however it is achieved.

As I have put before formerly a British company but like so many others including PlusGas taken over by a company from abroad, in GT85's case one of the the invasive American corporations that is WD-40 Company. - https://gt85.co.uk/
Nigel Atkins

Hi Cedric,
what is the thing around the top of the black cylinder, it's shaped a bit like a piston oil control ring? Is that a security clip of some sort? It appears to be wedged against a small protrusion of the alloy carrier. Will it lever out at the right hand end to allow the peg on the black cylinder to move to the left as it is unscrewed?

What car is this? An Alfa
GuyW

Thanks for the feedbacks!

I do have some GT85, advised by someone here :D I didn't think of trying it... I will give it a go!

It is the part "B" and the part 12 screwed in it on this diagram (the image is taken from an ad selling the lower bush, which is still fine on my car :p) It is a C5 (Citroen, not Corvette :)) from 2008, same front suspension/pivot than Peugeot 407 and Peugeot 508. I start to know those car well :p

I read that a 50:50 mix of ATF and acetone gives good results too, as do liquid wrench.

I found a part for £70 and might give it a go. I will soon have spend this money on solutions than might not work... I even went to some tyres shops around my place with the arm removed, but all their impact drivers are too big and can't fit (they were really kind trying!)

Aluminium casing and steel thread for cars living close to the coast and/or going t Alps without any protection was not smart (french) engineering... :/


(EDIT: the black part is the specific socket, which I hold using the thread of the ball joint to prevent it from slipping)



CH Hamon

This is how the new upper ball joint look like :)
I should have explained better, sorry :p


CH Hamon

That breaker bar is only fit for ballast - it should not have buckled - but you must have put a fair bit of welly on it !

As Willy - try some heat.

I have a 3/4" drive socket set for the bad boys and that has a serious breaker bar ! - it was a gift but has come in useful.

Could try tightening then undoing.

A simple impact driver 1/2" drive - hit it with hammer is worth a try and not that expensive.

This type of thing :-
eBay item number:
384783963318


Bonfire !

R.
richard b

As Guy said earlier it looks like there is a tab of some sort stopping it turning. I didnt notice it until I blew the picture up.

Trev
T Mason

Steel bolt into threaded aluminium hole - I think the problem is a galvanic reaction. It happens on bikes where an aluminium seat post is stuck in the steel frame. I doubt a releasing agent will work because rust isn't the problem. I'd try more heat assuming there's no rubber or plastic close by. You don't want the bolt to shear off!

As Richard says, try tightening slightly before undoing (after applying heat) - it's counter-intuitive but often works. Be patient - heat then try undoing, repeat several times. Heat usually works in the end.
Bill Bretherton

At least aluminium expands more than steel so that'll work in Cedric's favour.
David Billington

Just realised it's not a bolt but the threaded end of the ball joint screwed into the ally arm. Known to be difficult according to a forum I found. It might also be locked with a tab as others have said.
Bill Bretherton

Here you are Cedric!

You just need a monster stillson wrench!

https://m.youtube.com/watch?v=EJUDsbdHbQM

(at 1 min 30secs)

Get a bigger breaker bar and a length of scaffold pipe onto it!
GuyW

on a Pug 406, (same car in disguise) it looks like the lower one is screwed in and then locked in place by hammering (peening) an edge of the top ring over into a notch on the alloy carrier. Maybe the top one is the same? Have you carefully checked all round?

Given the attachment method of the joint being simply screwed in and with the rotational movement of the steering hub in use, it seems surprising there isn't a locking mechanism or security lock tab of some sort involved.
GuyW

Having looked on the computer screen rather than phone there seems to be a lug or possible peening which drops down into the ‘oil ring ‘ type groove of the ball joint.
I guess this is stopping rotation and needs to be removed ?
Not sure how the replacement is staked / peened to stop it undoing ?

R.
richard b

That's the bit I was looking at Richard.

Cedric, I would remove the black special tool and check that notch. It looks like the top collar of the ball joint has been staked in there. And possibly at the other 3 notches that the special tool engages with. Knock the staking back with a punch - or drill out perhaps? and then refit the tool and try again.
GuyW

Agreed, it looks like a tab from the ally arm is peened into the ball joint slot to lock it - you'll have to free that first. I'd still use heat to expand the aluminium. If mechanics struggle with it (as one forum I read says) then it's going to be very tight!
Bill Bretherton

That's right, its what it looks like. But logically you would design it so that the tab that you peened over was a part of the renewable ball joint element, staked into a notch in the housing, not the other way round. But then, it is a french car!

But this may not be the case. There may be no locking tabs. I've not found it mentioned anywhere else. But then, did I mention, it is a french car!
GuyW

I am glad you all give it a go :) I was worried my question would not be interesting... Always feel less lonely to ask opinions here when stuck at home :)

For the tab, I am sorry, it is me not being really good at taking pictures. There is not tab... What some people do is, to bend the steel collar into the aluminium to prevent it from unscrewing (exactly as Guy just explained).

From my research, Bill gave the engineering word of my problem: "galvanic corrosion", as I also ended-up on bikes forum doing my research.

Already tried heat and stillson (new word to me!), but I was heating the steel (I now know that aluminium expand more than steel!) and the arm was still on the car. I can give it more go from the vice (like on Guy's video), and heating the aluminium.

If still nothing, then I will give £70 to a breaker :p
CH Hamon

Interesting, I thought it was staked or a wire clip or something in there to begin with then changed my mind but looking again I do think there's something in that slot---------I'm thinking that while trying to undo the balljoint,--- the steel end piece of the balljoint(blue arrow) has probably been punched into the housing and when trying to unscrew the joint this end piece has collected aluminium from where the orange arrow is and it's bunched up where the yellow arrow is preventing it from turning any further--
As the others have mentioned, I reckon you need to try tightening it up a bit first, then remove that built up material in the groove and the same on the other grooves before it will undo

willy



William Revit

Aluminium conducts heat away very well, and that is a big chunk of it, so I suspect a propane torch won't put heat in fast enough to be useful. Will it fit in your oven? :)

Otherwise 3/4" breaker bar needed.
AdrianR

Cedric,
thought of you tonight.

I had to borrow a breaker bar from my neighbour tonight and was offered a choice of long or longer. As they were stored behind the stacked tool chests I don't know how long was long, but as he had to climb up and lean over the tool chest I guess 4 or 5 foot (1.2m or 1.5m) and when he started lifting one it was either 3/4" or 1" drive, I said a 1/2" drive would be enough so took the 30" (75cm) long MAG as it has a plastic handle which is more comfortable than metal.

I wished I'd asked earlier rather than straining and risking busting a gut. So much easier with a wide selection of tools.
Nigel Atkins

Funny thing with power bars-
You can have two bars exactly the same length, one 1/2" and the other3/4"----Try and move something with the 1/2" and have no luck but the stiffer 3/4" drive bar will undo it without an issue
If I were to be going out to buy a new one I'd get a 3/4" and a 1/2" reducer/adapter to take smaller sockets if needed
An example is truck wheelnuts, no way with a 1/2" bar you just spring about all over the place but 3/4" moves them easy

willy
William Revit

Yes I was imagining the fun Cedric would have with the all the adapters, possibly 1" to 3/4" then 3/4" to 1/2" and possibly 1/2" to 3/8".
Nigel Atkins

For those who "feedbacks".

😉


anamnesis

"Aluminium conducts heat away very well, and that is a big chunk of it, so I suspect a propane torch won't put heat in fast enough to be useful. Will it fit in your oven? :)"
==> That's what I found out yesterday... Other half is being pretty patient at the moment, and I still have to do the other side + timing belt. On top of that, when moving the Midget out of the drive, and doing a "detour" to find a parking space (I didn't see the one available in front of my flat :)), I realised she would be happy with a new left wheel bearing. I will try to avoid the kitchen area if it is not for cleaning dishes :)

"You can have two bars exactly the same length, one 1/2" and the other3/4"----Try and move something with the 1/2" and have no luck but the stiffer 3/4" drive bar will undo it without an issue"
==> I trust you without a doubt, but wonder what is the reason behind this ?

"I was imagining the fun Cedric would have with the all the adapters, possibly 1" to 3/4" then 3/4" to 1/2" and possibly 1/2" to 3/8"."
==> I am tempted! :D

...but, I decided to give up... That's not how I want to represent the French here, but I decided to stop before visiting A&E (and running out of gas for my creme brulee!).
Thanks for your ideas and tips, made me try harder. Not successful this time, but everyday is a lesson! (especially here :P)






CH Hamon

Cedric

This special tool might be what you need:
https://www.lasertools.co.uk/Product/7332/Upper-Ball-Joint-Socket-60mm-for-PSA

Cheers
Mike
M Wood

Mike that is what he has in the first picture. Surely now you have it off the car you can get an impact driver on it. If you havent got one it may be worth getting one as you have the other side to do. I have a Draper electric one which I think was about £70 a couple of years ago and havent found anything it wont shift so far.

Trev
T Mason

Cedric
Have you tried wacking it with a cold chisel/ old screwdriver and big hammer in those slots (wearing suitable gloves)?
Bill Bretherton

Cedric something for your diy tool collection that might help here

I’ve a smaller one of these but it’s fantastic for driving screws into/out of wet wood

It’s not the torque as such but the vibration combined with driving in and out that frees up stuck screws

Probably a good general investment but the vibration might break the seal here




timmyk

Bill, that also occurred to me but without the gloves!

Trev
T Mason

:)


CH Hamon

The winning armada 8)


CH Hamon

Glad you won in the end Cedric. The other tool none of us suggested is a C spanner and hammer.

Trev
T Mason

Thanks :)

I think cutting out the ball joint itself helped, as the heat was directed straight to the thread. That's my theory... :P

Assuming the car will leave 10 more years like this, and I want to help the future myself (or just experiment): should I put some product to prevent/limit corrosion between the aluminium carrier and the the metal thread? What do you recommend? :)
CH Hamon

PTFE "plumbers" tape works pretty well. Partly by keeping water out and grease in, and party by introducing a layer of PTFE between the parts. Not really recommended for fasteners which rely on friction to provide a high breakaway torque but the assembly you are dealing with doesn't as it mechanically retained by staking.


Greybeard

Lotus specify Permabond A131 for threaded steel fasteners into aluminium. It's sold as a pipe sealant, and is supposed to be non-setting to allow disassembly.
AdrianR

That's interesting Adrian. I had to look it up, I'd never seen it. But I used to use a pipe sealant paste called SWAK, at least when someone else was paying for it. It wasn't cheap!
Greybeard

"If I were to be going out to buy a new one I'd get a 3/4" and a 1/2" reducer/adapter to take smaller sockets if needed"


Exactly what I do. I find the 1/2 inch bar will flex too much. The 3/4 bar is my Heavy Weight Undefeated Champion :)

3/4 drive bars arent that expensive and come in useful, well worth buying. Buy a good quality 3/4 to 1/2 inch reducer to use with the bar rather than risk breaking a cheap one.
Chris Madge

This thread was discussed between 18/04/2022 and 27/04/2022

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.