Trunnion replacement first timer

[bmcecosse]

The dampers work much better with SAE 30 oil - Tesco garden section.......

[MarkyB]

I washed out my new trunnions before greasing and fitting them, I have a feeling there was some swarf in them.

[PaulTubby]

The dampers work much better with SAE 30 oil - Tesco garden section.......

Surely the correct damper oil you can buy would work the best? Thats what they was made with ?

[bmcecosse]

Suit yourself - certainly changing the horrible/smelly/watery old oil will give an improvement back to something approaching 'as new' performance - but it's been standard practice for many years to improve the performance by using more viscous oil in the dampers - it works!

[Matt531]

Well, a big box with kingpins, trunnions and eye bolt bushes arrived from BullMastiff spares this morning. These aren't assembled so will provide plenty of opportunity to make sure they are packed with grease. I've decided to renew the front wheel bearings while I'm injuring myself with the spanners. I have Marina front hubs so ESM are furnishing me with some Marina hub to Minor axle bearings. I do feel my debit card and I are keeping the classic car industry going this week.

So, the left hand kingpin (I keep wanting to call it an upright but I guess this isn't technically correct?) has left hand threaded trunnions. What's all that about then? Is it to alleviate some negative aspect of the thread pitch during steering movement or to stop something dropping off?

SAE 30 oil - Tesco garden section...

Being in the hinterlands between the Wharfe and Aire I'm blessed with being nearer a branch of Moss than I am a branch of Tescos. I've splashed out on some Penrite shock oil. No.1 weight. It says 'for piston type shock absorbers' on the front then 'Application…Armstrong type lever arm shockers' on the rear. Nothing like clear labeling then. It also states the weight as SAE 15. The very helpful fellow (I say fellow, he looked 12 years old to me) behind the counter at Moss seemed to think this would do the trick. I need to return on Thursday to collect some pieces they didn't have in stock, I'm tempted to go all sporty and change this for the No.2 weight. Mmmh, I'll have a ponder on that one.

Cheers for the input everyone. I've not actually wielded a spanner on the job yet...

[MarkyB]

SAE 15 will probably be an improvement on what ever is in there.
SAE 20/50 engine oil will be better, and much cheaper, it will never get hot enough to be more than SAE 20.

If it still rolls too much, try something thicker.

[bmcecosse]

Def go for the 'No 2 ' weight - whatever it is. I believe the standard damper oil is SAE 20 (some sources say SAE10) - so SAE 15 would be a down-grade in damping performance. As above - standard 20/50 engine oil is fine too (and much cheaper). I thought everyone was within 20 miles of a Tesco - well maybe not in N of Scotland - but in the habitable parts of the country, surely. Motorcycle places sell fixed grade oils too - but often in 5 gall cans only and not inexpensive. I was lucky enough recently to pick up a 1/2 litre can of SAE 50 oil - for £1. Yet to try it! I used EP90 in my old Rally Minor dampers and never had any probs - but I hesitate to suggest that seriously on here...... they did work really well.....

[PaulTubby]

I may try engine oil myself then as being thicker etc..

[Matt531]

First problem is the lower-wishbone is coming into contact with the chassis so raising it is proving difficult. Argh.

Same issue as this post below...

http://www.mmoc.org.uk/viewtopic.php?f= ... 4&p=396179

[Matt531]

I went ahead and disassembled the lower suspension front and removed the kingpin as per the book but without the top link coming within 1/4" of the bump stop. All seemed fine.

I'm now struggling to remove the top trunnion/damper arm bolt from the damper arm. Despite plenty of hammer action all I seem to have dome is slightly mushroom the end with the castellated nut. Is this just a very tight interference fit on the damper arm?

Edit: My braincell came in useful and I used a ball joint splitter after slicing the slight mushroom off.

Now the eyebolt bushes.

[Matt531]

How easily should the rear wishbone move along the torsion bar spline?

Mine isn't moving with wd40 and gentle persuasion. I don't want to go overboard with the hammer blows but I just can't get the wishbone to shift to get at the eyebolt.

Still, having 'fun'. Or should that be frustration? Time for a brew I think...

[aupickup]

you need to hit it quite square close to the spline

[Matt531]

OK, That sounds good. I've been using a long screwdriver to get in past the tie bar etc and giving it a fairly heavy tap with a 16oz hammer - distributed around the wishbone, not just a single place.

[bmcecosse]

In past the tie-bar ???? The front part of the arm should be removed - the tiebar is well out of the way - the load must be removed from the T bar - and then you can just 'tap' the arm along. Don't go so far that it falls off the splines..........

[MarkyB]

As the torsion bar is in effect a spring it will absorb, and shrug off a lot of the energy of your blows.
As aupickup says hit it near where you want it to move, you could hit the outer end until you are blue in the face and nothing will budge.
You can also try holding a dead weight (club hammer or other big heavy thing) against the outer end while you beat on the inner end.

NEVER beat on something that is threaded, you will ruin it in no time.

Loosen the nut right back to the beginning of the thread so the whole presents a flat surface to hit.

If it's a Nylock nut take it right off and put it back on with the flat surface outermost.

Often one or two good hard blows will do less damage than hours of slight whacking.

If things aren't going as hoped always stand back and have a think before upping the brute force, I had to do this last weekend when removing a diff, gave it enough oomph to make it move a bit at least, but it didn't, had a feel around in 40 years of filth and found that I'd missed one of the nuts
If I'd gone nuclear on it, I'd just have busted several things and felt like a complete idiot.

[Matt531]

Thanks folks, I'll give the offending spline and rear arm a good overnight drink of WD40.

In past the tie-bar ????

Yes, that's kind of how I've been attempting it, tapping the rear arm square - as per aupickup's post, with a long screwdriver with the blade end on the rear arm as close to the torsion bar as possible. Then tapping with a hammer. All the other bits, kingpin, front arm etc, are off the car. I'm guessing 54 years of crud doesn't make for a slidy spline.

you can just 'tap' the arm along.

That sounds my idea of torsion bar heaven currently.

Don't go so far that it falls off the splines...

Ooh, it would be lovely to be in danger of the arm moving too much.

stand back and have a think before upping the brute force

I think that's the first thing to do tomorrow. As far as I can tell everything that needs to be undone or taken off has been, but, a thorough check has to be first on the 'to do' list.

I'll keep you all posted.

[MarkyB]

The occasional tap in the other direction often works well, it catches recalcitrant parts off guard and they lose their grip!

I'd hit it directly with the hammer, maybe put some tape round any exposed splines, the screwdriver will be bending when you hit it and absorbing some energy.

[bmcecosse]

A 'screwdriver' is for (surprisingly) driving screws....... it is not suitable for moving a suspension arm. Brass drift is what you want! And -it's been said many times - WD40 is an excellent product, for Water Dispersal - it is however NOT a penetrating oil......

[Matt531]

There is now some play between the rear suspension arm and the spline when I wobble it with my hand, it just isn't moving rearwards on the spline. When I move the rear arm it also moves the spigot bush along with it, ie. there is no relative movement between the arm and bush suggesting that that is where the 'barrier' stopping rearward movement is. It's all so tight space wise with the eyebolt there isn't it?

The occasional tap in the other direction often works well, it catches recalcitrant parts off guard and they lose their grip!

Excellent. I've taped up the splines, as best i could given their oily nature, and given it a tap forwards also. I like the idea of catching it off guard. I'll have a brew, then run out as quickly as I can and make it jump.

A 'screwdriver' is for (surprisingly) driving screws....... it is not suitable for moving a suspension arm. Brass drift is what you want!

A rear suspension arm that moves on its torsion bar splines is actually what I want (...'surprisingly'...). However I did have an old screwdriver to hand so I used that.

it is however NOT a penetrating oil...

You are right. However I don't have any Plusgas etc on my shelf and WD40 has worked perfectly for me in the past. It also says 'penetrates' on the back of the tin.

[MarkyB]

Take your much abused screwdriver or a tyre iron type lever and use it to lever between the eye bolt and the arm.
With a hammer in your other hand tap the arm, no need to beat it now, in fact it would be counter productive, the arm has to come off square to the bar.

Now you have some lubricant on the splines you can tap the arm forwards too as it will help spread the lube and clean more muck off the splines.