Trunnion replacement first timer

[Matt531]

Hello people of mmoc.

My bunions need attention. No, sorry, trunnions.

I have a lovely '57 four door which I use as my main vehicle but it's time for some trunnion attention. I've never tackled this job before (eeek) so I'm after some help and pointers. Mr Haynes of Yeovil has given me a good direction and the info on this site is very useful. However, my 54 year old turquoise terror has a Marina disc conversion (something has to reign in those 37 rampant horses my 948 is producing after all). So, my questions are…

What difference does the Marina disc conversion make, if any, to the uprights and what effect will this have on my trunnion replacement?

I could also do with replacing the shock absorbers whilst I've got the spanners out and I am also planning on replacing eye bolt bushes. Is there any other jobs worth doing whilst I have the front suspension apart? No "replace and gold plate everything and fit some of the rarest Riley drums money can't buy" suggestions, this is my 'daily' so I don't want it off the road for too long (not to mention my lack of Premiership footballer style pay-packet).

Also, do any of you well informed Minor owners know what size Whitworth sockets are needed for a front suspension overhaul? I need to purchase some Whitworth sockets and would rather spend my 'hard earned' on high quality sockets in the sizes I actually need.

Hopefully three questions isn't too much, and I have tried to be fairly concise. This is my first big job on a Minor so…

If anybody needs anymore info feel free to let me know…

Matt.

[mike.perry]

You need 1/4, 5/16, 3/8, 7/16 Whitworth spanners and sockets for many jobs on a Minor, not just the suspension

[dunketh]

In theory its very easy when you've got the bits infront of you.
Marina uprights should make no difference.

In my exprience I found the following:

The top trunnion would not come off the bar that joins it to the suspension lever arm.
It took all manner of heavy beating to shift it. I beat the thing to the point of (expected) destruction before it gave up the fight and came loose. (The bar is tapered, so its like a stubborn bicycle crank).
Given the above its an ideal time to replace the shocks as you already suggested, though you could just drain and refil them - makes a world of difference.

The threads on my kingpin/upright were worn. This meant that the bottom trunnion would not screw on properly.
If this is the case, you need a new kingpin. Not cheap but then they do a fairly important job so can be forgiven for this!

Also, obvious tip but, make sure you dont do the trunniosn right up right, theere needs to be enough thread left above/below them to enable them to turn the wheels.

[robertquarmby]

Bull Motif do a complete replacement kit which I think is the best option. You may find a short time after replacing one trunnion then there is a need to replace the other, so, get it all done at once.
Regards Bob

[bmcecosse]

I wouldn't waste time/money replacing only the trunnions - do it properly and fit complete new kingpins. Easy to do - don't even try to take the top pin out of the damper arm - just slide the trunnion off the pin. Only snag may be if your kingpins have been fitted with special stub axles to take the discs - but this is not usually how it's done. And since you have only a 948 engine - no need to upgrade the discs to 9" drums - Riley or Wolselsey. If you treat the discs lightly they should cope ok. Unless the dampers are leaking - just drain them and refill with SAE 30 (or even better SAE 40) oil.

[Matt531]

Many thanks for the swift replies everybody. Excellent stuff. I think the 'replace the kingpin' idea is a good one. As Dunketh said "they do a fairly important job". I can imagine replacing just the trunnions only to then have to take everything apart again could make my hair go thinner than it already is.

Mike, great info with the sockets, there's nothing like buying shiny new tools but I can't see the sense in purchasing items I'm not going to use.

I'm sure replacing the oil in the shock absorbers is a good step-one for those. I'll see how everything feels after I've done that. Everything feels under-damped currently but my Minor is my first car without telescopic shocks.

So, full kingpin kits from Bull Motif ordered (and some eyebolt bushes), additional sockets and shock oil to be purchased, then a wrestle with the old components (I've had plenty of wrestles with stubborn bike cranks over the years, I'll let you all know whether this was good training for the damper arm taper), after al of that the job should be a good 'un. Obviously I've missed out various bits about bloody knuckles, swear words and tea but, you catch my drift…

I'll keep you all posted how I get on.

[mike.perry]

Most important. The suspension is under load. Make sure that the lower arm is properly supported and carefully lowered before you start taking bits off.

[autolycus]

You need 1/4, 5/16, 3/8, 7/16 Whitworth spanners and sockets for many jobs on a Minor, not just the suspension

I'd add 3/16 Whitworth to the list - remember that a 1/4 Whitworth spanner or socket fits 5/16 BSF,and so on. Still Minorless, and it's too long since the last one to remember where they are, but I'm sure there must be 1/4BSF somewhere.

Kevin

[bmcecosse]

Don't touch the damper arm taper! Just slide the top trunnion off - keep the job simple. You may however have a struggle getting the steering arms out of the old king pins - so save your strength for that job. SAE 30 oil from Tesco ga rden section for the dampers.

[dunketh]

Don't touch the damper arm taper! Just slide the top trunnion off - keep the job simple.

I dont remember why I did mine the other way but I know there was a reason at the time. (Granted 'stupidity' could constitute a reason)

[MarkyB]

Make sure you remove the pin from the bottom trunnion before you fit or remove it or it will ruin the thread!

[bmcecosse]

Do complete new Kingpins not come already assembled - complete with the bottom pin ?

[mike.perry]

They need to be taken apart to pack the trunnions with grease and you will not get the bottom trunnion on without removing the fulcrum pin.

[MarkyB]

A bit of force will get it on and wreck the thread.
Someone had done it, and posted on here a month or two ago.

[bmcecosse]

I just imagined they would be supplied - 'ready to fit'. Obviously a few squirts with the grease gun....... Is this not the case ?

[fussyoldfart]

I just imagined they would be supplied - 'ready to fit'. Obviously a few squirts with the grease gun....... Is this not the case ?

I have bought and fitted that kit from BM and it comes as separate parts, not assemblies. It is only a few minutes work to assemble them and that way you know they have been properly greased. Someone said "Fill the hole with grease and then thread the trunnions on to the swivel pins." That certainly ensures they're fully greased but those pins displace more grease than they leave, fortunately I did them one at a time and on the last three a good dollop was lots.

[bmcecosse]

Oh well - DIY kit then !

[mike.perry]

I prefer to pack the trunnions with grease before assembling

[dunketh]

Ditto. Doesnt matter if it squirts a load out, its not really expensive stuff.
You cant overpack like you can wheelbearings.

Prob best to hit them with the grease gun too, after for good measure.

[PaulTubby]

I agree just change the full king pin assembly, some recon units come with the steering arms fitted, depends what you going for. Birmingham morris minor centre do trunions now with twin greese nipples, so a great improvement for future maintence and will last alot longer if well greesed regular etc..... they do these trunions complete with kingpins also.
Also moss europe do the proper armstrong lever arm damper oil and do mail order also. Paul