Lower trunnion

[les]

Years ago and for that very reason, I didn’t tap over the locking tabs; to enable occasional bolt checking. I nearly got a fail on the mot.

[philthehill]

Les
It is surprising how deep the bolt heads recess into the damper body over the years.
On my Minor I changed the bolts to cap headed bolts with a thick flat washer and a spring washer so thy can be checked on a regular basis.
Phil

[midget]

That sounds like an excellent idea Phil. Have you a link or source for the correct bolts please?

[philthehill]

https://www.ebay.co.uk/itm/BSF-5-16-Cap ... FlUMUlFHCQ

The bolts are 5/16" x 3 1/2" BSF Allen headed.

The fitment of the bolts is easier if you have a 3/8" drive x 7/32" long shank Allen key type socket.

Phil

[les]

Yes, my mistake was leaving the lock washers in place. Plain and spring washers, good solution Phil.

[LaughingBoy]

Yes a good modification but I don't quite see how the bolt head can form a recess in the shock absorber body when the tab lock plate is in position ...? My dampers are also not taking much strain as they are purely acting as a pivot point and not actually doing any damping.

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Anyway as I mentioned the noise definitely seems to be coming from under the wheel arch. The eye-bolt would be the normal suspect but I have cleaned it up and greased the poly bushes. I'm not sure how much clearance/gap there is meant to be between the front end of the torsion bar and the rear of the spigot cup? There does seem to be quite a wide gap as you can see from the following pics. I am wondering if somehow the pin is not turning in the bushes? I will check that the nut holding the spigot onto the pin is fully tight (only checked it was finger-tight when I refitted).

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Maybe I'm missing something obvious ...

Graham

[les]

Its a valid thought you raise about the lock tabs acting as a washer, maybe a bit thinner but no doubt capable of resisting too much recession. However the two washer idea does assist in checking the bolts.

[philthehill]

The body of the damper being of aluminium is subject to deformation/squashing and that allows the bolts to loosen. The lock tabs are not sufficiently rigid enough stop the aluminium body deforming/squashing.

As regards the interface between torsion bar and thick suspension arm splines. The gap shown above between the front end of the torsion bar and the eye bolt cup is too much.
The torsion bar has to be just clear of the rear of the eye bolt pin to achieve the necessary contact between the male and female splines.
The correct interface of the splines can be achieved by packing with washers at the rear of the torsion bar. The amount required and what can be safely installed is totally dependent upon the spare length of the threaded spigot on the rear of the torsion bar.
This problem usually occurs (but can still occur with the original cross member in place) when a new cross member has been installed
The aim should be to achieve a balance between the front and rear splines and their respective suspension levers.
Moving the torsion bar forward may require the rear torsion bar reaction lever to be packed away from the cross member.
The correct spline interface is achievable if care is taken on positioning the torsion bar.
Your problem could be caused by there not being not enough interface between the torsion bar splines and the splines of the thick suspension arm.
The Morris Marina overcame the interface problem between eye pin and thick suspension arm by utilising a eye pin (item No: 2 in the illustration below) without the cup and which had splines on the outer edge of the rear raised portion which fitted into the front of the thick suspension arm as per the eye pin cup. The thick suspension arm was splined right through with no recess for an eye pin cup.

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Here is a link:-
viewtopic.php?f=6&t=53114&sid=45ce4709f ... 4761fd4f61
which gives some additional information.

See also:

viewtopic.php?f=4&t=71989&hilit=torsion ... 46#p653646
Phil

[LaughingBoy]

Thank you for the detailed information Phil.

The solution used on the Marina looks ideal - is there any way a Marina arm and splined pin can be used on a Minor? I guess the answer is no as I would expect the Marina arm to be different in more ways than one to the Minor's. Great shame as it looks to be a much better piece of engineering.

When I last re-assembled the arms on my car it seemed that the splines engaged enough but I'd need to do some more detailed measurements.

Anyway now that I have everything apart it makes sense to try and pack out behind the lever arm to get the balance right. Where exactly do the padding washers go? I assume the lever arm bolt (where the adjustment plate is) also needs padding out by supplementing part 80 (EDIT in front of the adjustment plate) on the diagram with extra washers whilst ensuring that the bar is aligned as correctly as possible with the front eye.

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Graham

[philthehill]

As regards the Marina lower front suspension being suitable for the Minor - one my next tasks is to see what is interchangeable and what can be used for the Minor.
I see no problem with the Marina thick arm being used (the splines are the same size as the Minor) in conjunction with the Marina splined pin. My only concern is that the actual pin which goes through the Minor eye bolt will be too big but I may be able to reduce the pin diameter to suit. So watch this space.

To move the torsion bar forward packing washers need to be inserted between item No: 74 and No: 75. A reduced diameter stepped washer with plain washers is a better way of packing the torsion bar after discarding the horseshoe washer item No: 74.

Whilst not strictly Minor but can be used to fit a Marina torsion bar to a Minor the adapters in the pictures below have to be adjusted with washers. These adapters replicate the rear end of the Minor torsion bar. The Marina torsion bar does not have a threaded spigot at its rear end.

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The torsion bar reaction arm can be moved forward and the number of washers (item No: 80) can be increased to suit.
The aim is to try and get the maximum spline interface at the front and rear of the torsion bar. Until you strip and rebuild you will not know what packing washers you will require.
Phil

[LaughingBoy]

My only concern is that the actual pin which goes through the Minor eye bolt will be too big but I may be able to reduce the pin diameter to suit.

Surely the Minor pin would no longer be needed? I have just read fully through the thread re metalastic eye-bolt bushes and according to the information you and others posted it seems that the Marina eye-bolt bush has the same ID as the Minor bushes i.e. 12.77mm and thus the Marina and Minor eye-bolt pins are the same diameter i.e. 1/2" or 12.7mm. So if (big IF) the Marina thick arm is identical to the Minor's (apart from being splined all the way through) then should it not be possible to replace both the Minor thick arm and pin with a Marina thick arm and splined pin doing away with the Minor pin altogether?

I think my torsion bar might still need to be packed away from the cross-member to move it further forward into the Marina thick arm but the splined pin would be a great improvement.

[philthehill]

As the last post of the thread mentioned was in August 2016 I have rechecked the dimensions of the Minor eye bolt pin and a NOS Marina eye bolt Metalastic bush (Pt No: 21H5158). The Marina eye bolt pin and the Minor eye bolt pin are identical except for the Marina eye bolt pin having the splined boss.
So you are right in that the Minor eye bolt pin and cup can be discarded and the Marina eye bolt pin, thick arm and thin arm can be used instead.
The problem with this idea is that of obtaining the Marina suspension parts in any numbers - no doubt you read in the thread you refer to that I did try to get Marina suspension parts for comparison but was unsuccessful. Surprisingly there is a full set (both sides) of Marina front lower suspension arms on 'e' bay at the moment and with all the necessary parts at a 'Buy It Now' price.

https://www.ebay.co.uk/itm/Morris-Marin ... SwzYVeyAzF

Phil

[LaughingBoy]

Interesting. The ones you found have been modified with an extra hole for the telescopic damper mounting. I am not sure this would be a problem for me as I would need to have my existing pin removed from my arm and welded onto the Marina arm in roughly that position for my telescopic damper. I don't know how to weld and am not sure whether it would be an easy / expensive job or indeed how easy it is to find someone who could do it. Here is a pic of my existing rear arm with the pin tele mounting -

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[philthehill]

The additional holes in one of the thick/thin arms are for mounting the Marina anti-roll bar.

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The Ital (Marina) factory fitted front tele dampers are fitted in a completely different way. I have the factory fitted lower mounts which attach to the thick/thin arm but I am having difficulty getting the long tailed tie bar bracket which goes through the thick/thin arm and damper mount so the brackets are still on the shelf. The factory lower bracket is similar to the bracket offered way back by Leadbetter of Lancashire as part of their Minor tele damping conversion kit.
The other thick/thin arms have holes but they do not look like they have been fitted with tele damper mounts so I do not know what the holes are for.
The Spax tele damper kit bottom mount is similar to the Minor Spax fitting kit and uses the anti roll bar bolt hole if there. See picture below:-

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As regards welding the Spax pin to the Marina thick arm - jlh Morris Minors do a weld on exchange conversion so You may be able to get him to weld on the pins for you or use a shortened Minor Spax bottom bracket.

https://www.jlhmorrisminors.co.uk/

[LaughingBoy]

Thanks for the info.

The seller says the extra holes were drilled to mount brackets for an upgrade to telescopic dampers.

My lower telescopic mounting pin is a CW MM Centre conversion which I had done many moons ago. I have since installed Protech dampers using the same mounts which turned out not to be so simple as I had hoped. I was told the pins were 16mm and had the Protechs made with the appropraite size metal-sleeved bushes. Bottom one wouldn't fit so I accurately measured the diameter and it was 16.08mm. So I ended up having to shave off .08mm from the inner sleeve of the bush with a hand reamer in order to get the damper on. Anyway it all ended up fine but having been to all that trouble I want to keep the existing mountings in the existing position.

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JLH have done a lot of work on my car including fitting the torsion bars and poly bushes etc etc. so there should be enough engagement on the rear arm splines.

Graham

[philthehill]

If the seller says that the arms have been drilled to fit a set of tele dampers I would expect all of the holes to be configured the same so as to suit the damper mounting brackets.

One thick/thin arm has been drilled but the other has not - only the factory spec holes are in place and as I said above the additional hole is for the anti-roll bar link.

Below is a pair of NOS Marina/Ital thick suspension arm with the additional hole for the anti roll bar link.

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Your torsion bar should be moved forward to correctly engage with your existing thick lower suspension arm. Once you have the front engagement correct you can then concentrate on correctly engaging the rear torsion bar reaction arm with the torsion bar.

[LaughingBoy]

Yes the ones for sale don't look like a matching pair - the thick arm on the right of the photo has a raised oval on the inside around the top hole whereas the other thick arm doesn't.

I have been taking some measurements with regard to moving the torsion bar forward. There is 3cm of male splined length on the front end of the bar and also 3 cm of female splined length in the arm. As things stand approximately 2 cm of the splines on the bar engage in the splines of the arm when it's all assembled. Do you think that is not enough? The smooth recess in the arm for the spigot cup is 1 cm deep but the cup does not go all the way into the recess even when everything is tightened up - I'm still wondering if it's slipping. When dismantled there is a gap of about 1cm between the end of the bar and the spigot cup. I hope to pack out the rear end by 5mm although I may need a new longer bolt for the end of the reaction lever as there is not much spare thread. Any idea of a suitable bolt off the shelf so to speak? The thread on the end of the torsion bar is long enough.

[philthehill]

The front end of the torsion bar should be just clear of the eye bolt pin so you have plenty of scope to move the torsion bar forward.
The length of reaction arm bolt will depend on how far the torsion bar reaction lever is moved forward. You will need some packing washers as well to go between the vernier plate and reaction lever bolt hole.
The only limiting factor when moving the torsion bar forward is the length of the spigot on the rear of the torsion bar but you appear to have enough length to satisfactorily accommodate whatever packing is required between the torsion bar and cross member.
Good luck.
Phil

[LaughingBoy]

Thank you. I have bought some longer reaction arm bolts (which are 3/8" UNF not BSF) and they do not have a shoulder as per the original - is the shoulder necessary? I bought the bolts from a reputable Minor parts supplier so they should be OK but wanted to check ...

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Also when I dismantled the reaction arm the bolt was inserted from the front of the arm i.e. with the nut on the back / rear of the cross-member whereas the manual shows the opposite -

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I doubt if it makes too much difference but I want to get it right when I re-assemble.

Graham

[philthehill]

It is always better if there is a shoulder on the bolt as a full threaded bolt does not have the fit of a shouldered bolt.
It does not really mater which way the bolt is fitted as it is there to clamp the parts together.
What does matter is that the bolt is of the correct tensile strength i.e. strong enough for the job. I always try and fit at least 8.8 tensile strength bolts/screws.