lower trunnion; upgrade - extra grease nipples

[danielvoorwerk]

Hi all,

finally i've come to the stage of rebuilding my front-suspension (after a looong wait for new kingpins/trunnions ;-) )

I remember a frequent poster on the forum has added a topic about adding two extra grease nipples to the lower trunnions...but despite a thorough search on the forum, i cant find it anymore....can anyone indicate me where to find that post please !?

Thanks in advance,

daniel

[philthehill]

Daniel.
Whilst there was two grease nipples fitted as part of the experiment to see which location an additional grease would be of benefit I determined that the most beneficial place would be to fit the additional grease nipple near the bottom of the trunnion opposite the vertical grease groove.
Unfortunately since the web site change over I am unable to post photos even though those photos were posted successfully previously.
With an original bottom trunnion - between the two trunnion pin bushes there should be a grease deflector ring which ensures that grease is prioritised to the swivel. Unfortunately the grease deflector appears not to be fitted to many aftermarket trunnions.
If you have any difficulty please come back to me by PM if necessary.
Phil

[danielvoorwerk]

Hi Phill,

thanks for the super-quick reply ! unfortunatedley with the new site there are some losses of interesting topics...

So as my reproduction trunnions dont have such as deflector ring, i will add an extra grease nipple at the bottom, oposite of the vertical grease groove ! thanks !

daniel

[BLOWNMM]

Hi Daniel
I may be able to help as I have modified my trunnions to Phil's specs. See pic.
Bob

[simmitc]

Morris Minor Centre Birmingham (David Manners) have been selling trunnions with extra nipples for many years. Highly recommended, all three nipples always accept additional grease before it starts spurting out anywhere else.

[RobThomas]

We don't often see the original Bronze trunnions, Bob. Where di they come from? NOS or are you making new ones???

[philthehill]

Rob
I suspect that the trunnion has been cadmium plated and is not manufactured in bronze.
The additional grease nipple must be fitted opposite the grease slot otherwise the grease just goes straight up and out past the trunnion seal and is therefore of no benefit.
Phil

[BLOWNMM]

The trunnion shown is the original bronze one from my 1952. The extra grease nipple is fitted opposite the grease slot. It was my intention to use it on the new swivel pins when they were removed to fit Declans seals. However even though they were a good fit to the MM swivel pin they were quite loose on the new one suggesting some serious differences in tooling when comparing old with repro ones. They have done approx 50,000 miles. Ended up having to fit extra nipples to the new cast steel ones. When grease was pumped in it blew out the botton welch plugs which had not been peened over or expanded. Ended up silver brazing the plugs in using Johnson Matthey Easyflo No. 2 with appropriate flux which did not leak.
Bob

[philthehill]

Bob
Many thanks for clarifying what material the bottom trunnion (photo above) is made from.
It is a long time since having seen a bronze one.
Those bottom welch plugs are not always as secure as they should be. With the NOS (not all BMC) spare bottom trunnions I have there is a distinct variance in the quality of the peening.
As regards the top trunnions - the screwed plug is some cases is not much better than the bottom trunnion welch plug and it is important to ensure that the screwed plug is properly secured.
The screwed plug is easy to remove if the threads of the top trunnion need to be examined or cleaned.
Phil

[danielvoorwerk]

Oh, much more replies than i hoped for, with very usefull info !

Ill be adding one extra nipple on each lower trunnion, as said opposite of the grease slot. After that, i will finally installing declans seals too and ill be ready for 2017 !

thanks all !

[BLOWNMM]

Following Rob's question re am I making new ones I tried to determine the thread out of curiosity. The MM swivel pin thread measured 0.721 inches dia. and was 11 TPI. I could not find a reference to this thread. It may be that if the thread was not machined to present a flattened outside it may be 1/2" dia. However 11 TPI makes it a non standard size. Does anybody know what thread the pins and trunnions are?
Bob

[philthehill]

Bob
The thread may be 11/16" x 11 TPI Whitworth.
I have tried a Moore and Wright 11/16" Whitworth thread gauge on a good swivel bottom trunnion thread and the thread gauge fits perfectly.
I have also tried the thread gauge inside a bottom trunnion and again it fits perfectly.
The swivel thread has a flattened tip (which is a prerequisite for grease circulation) but the trunnion thread root appears to be as per the Whitworth pattern.
Unfortunately I do not have a 11/16" x 11 TPI Whitworth tap to confirm and L/H and R/H thread taps will be required.
It may be worth considering 11/16" x 11 TPI BSCY/UNS which has a basic Whitworth form but slightly different root and tip.
Phil

[BLOWNMM]

Phil
The dia. of 11/16" Whit. is 0.6875". I have measured the MM thread at 0.721" so I cannot see how 11/16" W. would be anything like a proper fit into a trunnion that accepts a thread 0.721" dia.?
Bob

[philthehill]

Bob
The thread is of Whitworth form.
It cannot be 3/4" Whitworth as that has 10 TPI.
The only other reference to a 3/4" thread with 11TPI I can find is Unified National Special (UNS) which has 11 TPI.
The use of UNS threads on the Minor whilst not prolific does pop up in various applications.
You have measured the OD of the swivel thread as 0.721" - does that measurement take account of the flattened tips of the thread which if not flattened would or could be 0.75".
You may find the attached link useful.
http://www.gewinde-normen.de/en/index.html

The taps must be available as they are used in the production of aftermarket trunnions.
Conversely the aftermarket manufacture may be using a BSCY thread which is similar to the UNS thread except for the root and tip profile.
No doubt all will become clear in time.

Phil

[BLOWNMM]

Phil
I did take into account the flattened tips of the thread (see my post of Fri Jan. 13 at 12:02) and guessed the thread was probably 3/4" nominal dia. Perusing the link you attached to your last post the only 3/4"UNS threads refered to have 14, 18, 24 OR 27 TPI. I have also looked carefully through the twenty-fifth edition of 'Machinery's Handbook 25' and there is also no reference to any 3/4" UNS thread with 11 TPI. A total mystery!
Bob

[philthehill]

Bob
Yes a mystery.
My other reference was to the use of a BSCY thread.
I recently ordered a UNS tap to chase the rocker adjuster threads and was supplied with a BSCY tap. When I queried it with the supplier the reply was that the thread form is the same - which it is except for the tip and root.
The BSCY tap fitted the rocker adjuster threads perfectly without cutting additional metal.

My supplier lists a UNS 3/4" x 11TPI.

http://www.tracytools.com/taps-and-dies ... 4-x-11-tpi.

Note the description of the link above.

Note also:
http://www.tracytools.com/taps-and-dies ... ct_id=1126