Good Old Trunnions Again

[MrIan]

Bit of advice needed.
Front suspension stripped for clonk searching !!!! Bottom trunnion pin very loose in bushings due to worn pin, so I feel clonk has been found, so new top and bottom trunnions ordered from BM for both sides (oh and seals from Declan !!).
King pin threads cleaned and look ok, assembled completely dry and without seal to make sure all's well yet there is a slight bit of movement/wobble with the trunnion wound on to where it should be. Now the engineer side of me feels without any movement at all then grease isn't going to be able to be forced through. Yet the Morris Minor owner in me thinks the kingpin is worn !!
So do we think there would be a slight wobble when assembling completely dry ?

[MrIan]

The detected wobble isn't with the kingpin back on the car, just the trunnion screwed onto the kingpin on the bench.

[philthehill]

When bench assembled there should be no discernible play between the new trunnion and the old swivel pin (king pin).
If there is play it indicates that the swivel pin needs renewal.
Fitting new trunnions to old threads is false policy as the male and female threads are mismatched and rapid wear will take place.
Always better to replace the trunnion and swivel pin as matched pairs.
When the suspension is assembled on the car - unless the trunnion/swivel pin is exceptionally worn you will not be able to discern wear in the trunnion/swivel pin threads unless you take the load off the suspension.
Phil

[MrIan]

Cheers Phil. As I've just bought the full set of new trunnions from BM I'll get 2 new swivel pins from them too. I assume they use the same parts in their complete pin and trunnions setup.

[philthehill]

The trunnions and swivel pins bought separately or as a full set (that is trunnions/swivel pin) are all interchangeable and your already purchased R/H & L/H trunnions will fit the respective R/H & L/H swivel accordingly.
Phil

[MrIan]

Cheers Phil

[MrIan]

New swivel pins ordered ! Also found that there was absolutely no resistance in the passenger side damper. The car mind you has got telescopic dampers also but I've bunged some thin oil in there to see if it leaks.
Does anyone know what oil should be put in the dampers when the car also has telescopic (spax gas adjustable). Valve removed or something to check? . Not sure as I bought Boris Minor with them already fitted. Drivers side had a slight resistance, passenger side as said had nothing at all.

[philthehill]

If you have the SPAX dampers fitted the original Minor damper valves should have been removed.
The SPAX dampers are not additional or secondary dampers but are replacements for the Minor dampers.
You do need to make sure that the original Minor damper valves are removed.
With the original Minor damper valves removed you will get no resistance when you move the Minor damper arm.
As regards oil you can put ordinary engine oil in the Minor dampers as it is only required to lubricate the lever arm and redundant pistons inside the Minor damper.
I have SPAX gas adjustable dampers fitted to my Minor and the original Minor damper valves have been removed.
Phil

[bmcecosse]

Are they 'bolt on' dampers - or a properly engineered set with welded on brackets?

[philthehill]

There are bolt on dampers and bolt on dampers.
The later Marina/Ital had tele dampers fitted and they were bolted on.
The top was secured in a similar way to the Mini and the bottom was bolted to the lower suspension arms which on a Marina/Ital are the same as a Minor.
The problem with the bolt on SPAX kit as supplied to me was that the bottom bracket that fits into the rear of the thick suspension arm is not a snug fit.
I also had to weld up and drill new holes in the top mounting bracket to suit a revised mounting position.
When fitting the kit to my Minor I had to give the lower mounting bracket a very shallow 'S' bend and remove some of the flashing from the suspension arm. I also fitted an additional bolt through the arm. All bolts were fitted - that is a snug fit.
Before alarm bells are rung about drilling the suspension arm(s) the Marina/Ital when fitted with the front antiroll bar had an additional hole drilled in the arms for mounting the antiroll bar connecting link.
A lot of fettling had to be undertaken before I was satisfied with the fitment.
I could fit a thick arm with the damper mounting welded on but that would interfere with the current antiroll bar mounting.
As the front suspension is always in a state of metamorphism the damper mountings & anti roll bar connections may change.
Phil

[bmcecosse]

There are of course bolt-on designs on production cars - which are engineered into the design and are fine - and there are some poorly 'engineered' bolt-on after market kits going around that use a bracket supported by the Minor damper bolts..... This of course moves the top of the trunnion forward by the thickness of the plate (not a great idea for the KPA) - and the valves are to be removed because the combined loading if both dampers are in use would overload the bolts ! Some kits simply rely on a 'clamp' round the bottom arms - hardly the best idea either. I'm sure there are very well engineered kits entirely suitable for competition use - with good long stroke dampers, and not just short 'Mini' dampers which are of course designed for a much lighter car with short movement suspension and self damping rubber springs.... I see nothing wrong with the lever arm dampers for road car use - they are after all just folded up teledampers - with the advantage that the damping can be adjusted partly with the valves - and mostly with the viscosity of the oil used in the damper. I saw a Minor recently that had been fitted with tele dampers - and the rear end bounced about like a beach ball!

[MrIan]

Yes the Spax tele damper fitting on Boris Minor is a bolt on job but the lower mounting is a thick plate that fits into the rear of the lower minor suspension arm. It's then bolted through the 2 lower minor arms and the outer end has a clamp arrangement which I wouldn't say has any stress on it at all as it's there to just hold the plate tight into the slot in the rear arm. It'll be an old set up as it doesn't look like the new type spax kits. Neither does the rear set up.
So hopefully the mysterious 'Clonk' on assembly will be gone !! with loose/worn lower trunnion pins and the empty / dry damper on one side I should think would have been creating it.
Thanks again for all advice .

[MrIan]

Just my luck, Boris is in bits on stands and there's a 5 - 6 week wait on L/H swivel / kingpins !!

Can't be helped, also the sun is out ! so you can all assume that when it starts raining i'll have Boris on the road again !

[bmcecosse]

Try elsewhere for a l/h kingpin? They all come from one source. Meantime - get on with the r/h. Do you have to swap over the steering arm ? Could be 'fun'...... I would re-assemble the l/h side if you can't get one right away - and as long as it's not obviously/stupidly loose use the car meantime.

[MrIan]

Yes i'll have to assemble the old L/H kingpin for now, not really a big problem as although the threads are showing a little wear they are nowhere near the point of ''letting go'' so will do till new part arrives.
Steering arm yes ! I hope to be able to push it out carefully using a hydraulic gear puller if not I have the use of a press at a railway museum / workshop where my father in law helps out.

[bmcecosse]

Maybe easier to just carefully cut through the old kingpin to release the arm.