Why is this rubbing the back of my wheel?

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philthehill
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Re: Why is this rubbing the back of my wheel?

Postby philthehill » Thu Jun 25, 2020 4:33 pm

It is no good just fitting a new trunnion to a worn out swivel thread. The new trunnion will wear out in no time.
If the trunnion threads are worn it is highly likely that the swivel threads are worn too.
You do need to examine the swivel threads before making any purchases.
Unless the swivel threads are good it is a complete waste of time to only fit a new trunnion.
If the threads are worn I would recommend that you fit a complete swivel and trunnion(s) assembly and be done with it with new swivel and trunnion seals to keep out the crud.


Flywheel
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Re: Why is this rubbing the back of my wheel?

Postby Flywheel » Thu Jun 25, 2020 6:06 pm

simmitc wrote:
Thu Jun 25, 2020 1:43 pm
Most long term Minor owners know what trunnions are, yet it's very rare to find a reference to them in a dictionary (remember them?), spellchecker, or manual, so some puzzlement is understandable. In Haynes, page 147 the diagram shows 6 = upper link and 8 = lower link. Those are the trunnions. Item 4 = King pin and stub axle, also known as suspension upright or swivel pin. Hope that helps. The only thing not shown on that diagram is the brake back plate that is attached by bolts passing through the four holes in the upright.
Hi, many thanks for your explanation. Cheers.👍
What contemptible scoundrel has stolen the cork to my lunch? :roll:
W. Clement Stone

Flywheel
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Re: Why is this rubbing the back of my wheel?

Postby Flywheel » Thu Jun 25, 2020 6:09 pm

philthehill wrote:
Thu Jun 25, 2020 2:39 pm
The word trunnion relates originally to the cylindrical projection either side of a cannon or mortar which supports the cannon or mortar in the gun carriage. It allows the cannon or mortar to rotate about the trunnion carrier in the gun carriage to provide elevation or depression.

In relation to the Morris Minor - the trunnion (pin) to be specific is the pin that fits through the bottom swivel link and about which the bottom swivel link rotates when the suspension is elevated or depressed similar to a cannon or mortar.

The same can be said of the top trunnion pin about which the top swivel link rotates. The arrangement of holding the top trunnion pin is different to the bottom trunnion pin in that it is only fixed on one side but provided full support for the top swivel link as it passes right through the top swivel link and has clamping washers either side of the top swivel link to keep the top swivel link in place.


The two trunnion pins described above provide vertical rotation whilst the swivel pin which has the stub axle and steering arm attached to it provides horizontal rotation.

Tappets are another wrongly described item. With the 'A' Series engine they should be called cam followers as they follow the profile of the cam and do not act directly on the valve stem but via the rocker gear. The Minor side valve engine does have tappets as they act directly on the valve with no mechanical advantage.
Hi Phil many thanks.👍
What contemptible scoundrel has stolen the cork to my lunch? :roll:
W. Clement Stone

Andymoor94
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Re: Why is this rubbing the back of my wheel?

Postby Andymoor94 » Thu Jun 25, 2020 6:30 pm

philthehill wrote:
Thu Jun 25, 2020 4:33 pm
It is no good just fitting a new trunnion to a worn out swivel thread. The new trunnion will wear out in no time.
If the trunnion threads are worn it is highly likely that the swivel threads are worn too.
You do need to examine the swivel threads before making any purchases.
Unless the swivel threads are good it is a complete waste of time to only fit a new trunnion.
If the threads are worn I would recommend that you fit a complete swivel and trunnion(s) assembly and be done with it with new swivel and trunnion seals to keep out the crud.
This weekend will reveal what's damaged, but I've been lucky enough to source a complete front pin, trunnion, hub etc as a complete assembly. Not new, but it will be handy for seeing what they should look like and, if all is well, even be a replacement
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Andymoor94
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Re: Why is this rubbing the back of my wheel?

Postby Andymoor94 » Sat Jun 27, 2020 3:56 pm

Good news, my second hand swivel pin and trunnion arrived... Only to find he's provide nearly the entire thing! £30, and it all looks clean, straight, good condition. A bush missing on the top trunnion, but given that I have replacements coming anyway, it's spot on!

So my next job after I get this fitted will be to tackle to driver side wheel bearing. I do have a bearing kit coming, before I realised the gent sent the entire left side assembly. Do I need specific tools for the job, such as a bearing puller? If so, to make my life easier and get me back on the road quicker, can I fit the hub from this old-new assembly to my driver side instead?
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kennatt
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Re: Why is this rubbing the back of my wheel?

Postby kennatt » Sun Jun 28, 2020 7:08 am

before you fit the suspension you really need to take the top and bottom trunnions :D :P :P off the arm and look closely at the threads,the tips of the threads should be flat,if they show any sign of being sharply pointed the whole lot is scrap and should not be fitted. Take it to bits and photo the threads and let us see them,its not always possible to check by just feeling for movement.

Andymoor94
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Re: Why is this rubbing the back of my wheel?

Postby Andymoor94 » Tue Jun 30, 2020 3:56 pm

kennatt wrote:
Sun Jun 28, 2020 7:08 am
before you fit the suspension you really need to take the top and bottom trunnions :D :P :P off the arm and look closely at the threads,the tips of the threads should be flat,if they show any sign of being sharply pointed the whole lot is scrap and should not be fitted. Take it to bits and photo the threads and let us see them,its not always possible to check by just feeling for movement.
Hi bud,

Will do, thanks for the warning. What causes the sharpening of the end then?
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philthehill
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Re: Why is this rubbing the back of my wheel?

Postby philthehill » Tue Jun 30, 2020 4:43 pm

Wear.

If the swivel seals are not good and they allow water and crud into the threads it just grinds away at the threads and they end up sharp.
The thread is of a Whitworth but is only 75% in height of the full thread. That is why the thread has a flat top when new. If the threads are sharp the swivel threads are worn and unsafe. If the threads are worn the swivel and trunnions should be replaced as a full set.


Andymoor94
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Re: Why is this rubbing the back of my wheel?

Postby Andymoor94 » Thu Jul 02, 2020 3:35 pm

philthehill wrote:
Tue Jun 30, 2020 4:43 pm
Wear.

If the swivel seals are not good and they allow water and crud into the threads it just grinds away at the threads and they end up sharp.
The thread is of a Whitworth but is only 75% in height of the full thread. That is why the thread has a flat top when new. If the threads are sharp the swivel threads are worn and unsafe. If the threads are worn the swivel and trunnions should be replaced as a full set.
Thanks for the explanation. The fantastic news is within the hour, ESM have received stock of the full swivel pin and trunnion kits, so even though I have my £30 used replacement, I've took my hands out my pockets and bought new. It's just piece of mind that my wheel won't fall off, really
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simmitc
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Re: Why is this rubbing the back of my wheel?

Postby simmitc » Thu Jul 02, 2020 5:50 pm

Apply loads of grease to the threads on the swivel before fitting the trunnions. Also put grease in the trunnions, then when assembled, use a grease gun to add grease via the nipple. Once on the road, the grease should be injected every 1,500 miles.
I recommend fitting the seals supplied by Declan Burns. See viewtopic.php?f=4&t=61637&p=569162&hili ... al#p569162
Declan can supply the cup seals and the rings around the thrust washers. Standard seals fail very quickly, Declan's last forever and fit better. You only want to do this job once, so now is the time to get the good deals :D

Andymoor94
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Re: Why is this rubbing the back of my wheel?

Postby Andymoor94 » Sat Jul 04, 2020 1:14 pm

kennatt wrote:
Sun Jun 28, 2020 7:08 am
before you fit the suspension you really need to take the top and bottom trunnions :D :P :P off the arm and look closely at the threads,the tips of the threads should be flat,if they show any sign of being sharply pointed the whole lot is scrap and should not be fitted. Take it to bits and photo the threads and let us see them,its not always possible to check by just feeling for movement.
Now then,

So although I've bought a brand new pin and trunnion kit from ESM, I still took apart the used assembly I bought from a gent online, just for off-car learning.

I can see the lower thread on the pin seems alright, but the upper thread is nigh shafted! Threads in the trunnions themselves look ok.

Like I said, I won't be using these, but it's handy to see for myself how it all comes apart and once the new ones come, I can compare so I know what they should look like.

I've also photographed the hub and bearings. How do these look? There's no play in the bearings and they spin well.
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paul 300358
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Re: Why is this rubbing the back of my wheel?

Postby paul 300358 » Sat Jul 04, 2020 3:51 pm

The bearings look like the original RHP, if so, and there's no play, I would add some lithium bearing grease and leave well alone. You wont improve on "no play"

Andymoor94
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Re: Why is this rubbing the back of my wheel?

Postby Andymoor94 » Sat Jul 04, 2020 5:39 pm

paul 300358 wrote:
Sat Jul 04, 2020 3:51 pm
The bearings look like the original RHP, if so, and there's no play, I would add some lithium bearing grease and leave well alone. You wont improve on "no play"
That's good to know. I have new bearings for my driver side hub, but I'm considering just swapping the hub if this is decent
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kennatt
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Re: Why is this rubbing the back of my wheel?

Postby kennatt » Sun Jul 05, 2020 7:27 am

yes wise move ,its always better to fit new or re conned items for steering, suspension and brakes Used to be common way back for the top to separate and drop the car, when maintanence was neglected,happened to me once, fortunately usually happened when turning slowly .I was five miles from home and in 1965 certainly didn't have the money or inclination to pay for recovery so found some fencing wire jacked the car up and forced the top back together ,wired it up and drove it,very slowly back home :D :D :D :D Joined the police shortly after that, kept this infringement of the road traffic act quiet :D :D :D :D

pgp001
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Re: Why is this rubbing the back of my wheel?

Postby pgp001 » Sun Jul 05, 2020 11:31 am

Kennatt

I am not disputing your experience of joint failure, but I always thought the bottom trunnion was the one that was under most pressure and likely to part company.
The weight of the car is hanging on the bottom ones via the bottom arms and torsion bars.

You must have been unlucky for a top one to come apart, but as you say probably easier to jury rig it back together at the roadside.

Phil

Andymoor94
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Re: Why is this rubbing the back of my wheel?

Postby Andymoor94 » Sun Jul 05, 2020 2:16 pm

pgp001 wrote:
Sun Jul 05, 2020 11:31 am
Kennatt

I am not disputing your experience of joint failure, but I always thought the bottom trunnion was the one that was under most pressure and likely to part company.
The weight of the car is hanging on the bottom ones via the bottom arms and torsion bars.

You must have been unlucky for a top one to come apart, but as you say probably easier to jury rig it back together at the roadside.

Phil
I'd say that the pictures of my swivel pin threads actually support the notion of the upper trunnion being the weaker one, in this case
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philthehill
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Re: Why is this rubbing the back of my wheel?

Postby philthehill » Sun Jul 05, 2020 3:29 pm

The amount of wear to either the top or bottom swivel threads greatly depends upon the quality of the seal and the frequency of greasing. The seal has to be tight to both the swivel and the trunnion to be effective.
The original BMC seals were reasonably effective but latterly the reproduction seals in some cases can prove worthless.
The seals provided by Declan Burns are very good. Contact Declan by PM for more details.

Below is one of my swivels fitted with NOS BMC swivel seals.
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Last edited by philthehill on Sun Jul 05, 2020 3:34 pm, edited 2 times in total.


Andymoor94
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Re: Why is this rubbing the back of my wheel?

Postby Andymoor94 » Sun Jul 05, 2020 3:32 pm

philthehill wrote:
Sun Jul 05, 2020 3:29 pm
The amount of wear to either the top or bottom swivel threads greatly depends upon the quality of the seal and the frequency of greasing. The seal has to be tight to both the swivel and the trunnion to be effective.
The original BMC seals were reasonably good but latterly the seals in some cases can prove worthless.
The seals provided by Declan Burns are very effective. Contact Declan by PM for more details.

Below is my swivel fitted with NOS BMC swivel seals.

100_2617.JPG
Hi Phil,

Yes, I'm already on that :D
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pgp001
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Re: Why is this rubbing the back of my wheel?

Postby pgp001 » Sun Jul 05, 2020 3:47 pm

Unfortunately Declan does not have any stock of seals at the moment or for the foreseeable future, I have already been in touch this week.

Phil

philthehill
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Re: Why is this rubbing the back of my wheel?

Postby philthehill » Sun Jul 05, 2020 4:10 pm

A pity about Declan's seals but no problem.
I have just compared a NOS BMC swivel seal with those supplied and branded MMC by the Morris Minor Center and they are near identical.

https://www.morrisminor.org.uk/parts/34 ... the-thread

Phil



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