Triumph Herald Front Trunnions - Grease or EP90 oil?

Trunnions snapping is real. It's never happened to me, but I've seen plenty of photos and heard stories from people I know and trust to make me worry. It's a real thing but thankfully tends to happen at slow sounds and heavy steering lock. Although I do know of one going snap on an A road at speed.

Oil is the right thing to use and if you have any rust marks on the threads make sure to replace them. I went trunnionless in the end. With the added strain from the bigger engine I didn't like the thought of a front wheel lodging itself into the bonnet.

Do a Google image search for "triumph trunnion snap" and "triumph trunnion broken".

Not sure if it’ll work in your situation, but have a look at Land Rover front swivel grease, comes on sachets and was mainly designed to slow the exxon valdez style leaks that those who love landies know so well
Like I say, use at your own rick😳

Hi comfortablynumb, I've been trying to resist the lure of old Land Rovers for years so will certainly take a look at that.  

You would hope a product exists with the right balance of viscosity, lubricity and water resistance to protect trunnions.

Chris

Thanks dodgerover , from what I've read (again on the internet so pinch of salt needed)  some of the modern replacement trunnions aren't sealed properly at the bottom so the oil can leak out of the bottom.  I have a brand new replacement trunnion in front of me now and can see that might be the case.

I suppose there must have been a reason 90 grade was specced when heavier oils were available at the time. My 1950s rotovator needs 150 grade in its bevel box. That stuff still flows unlike grease.

The book says EP90 oil..... It also says they should be oiled often.

The first thing is that the loadings are quite high so the EP rating is important. The second thing is that that the “sealing” is rudimentary and water (dirty water) getting in is a problem. The main advantage with oil in my view is that when you squeeze more in through the nipple, you can see the old contaminated stuff push out around the seal and keep squeezing more in until it runs clean and be fairly confident you’ve got most of the contamination out. Not so much with grease.

I wouldn’t completely rule out using a modern grease type product but it must have EP additives and should be semi-fluid (at the thick oil end of things). I don’t see the problem using EP oil myself though. I’ve had the same set of vertical links on my Vitesse for most of the 85k I’ve put on it and replaced the trunnions just once. I do oil them a couple of times a year though. They are now on my GT6 as I put trunnionless on the Vitesse. Not an unqualified success as it’s messed up the geometry and leverage factors more than anticipated.

As already mentioned, corrosion in the thread roots causing stress risers is a leading cause of fracture. IMO, excessively tight nylon bushes where it attaches to the wishbone is another, induces a bending force to the top of the thread.

One final thought..... modern MoT men, especially those with the mechanical “shaker” ramps are really bad at spotting knackered trunnions. The correct way to do it is to raise the wheel then put a lever between tyre and floor and try to lift the wheel while watching the trunnion/VL joint. Anything more than a hint of relative vertical motion is a problem.

Nick

I started my apprenticeship on Triumph in 1970 and have been closely associated with the marque ever since.

If I had a quid for every broken trunnion i've encountered in that time, I could have retired a year earlier. The one common denominator in all these failures was grease found on dismantling. Even my first wife's first Herald 12/50 suffered this fate in an excruciatingly embarrasing location (to be fair, she'd not had it long and i'd not even got around to servicing the car before it failed!)

The one saving grace is that 99% of failures are on full lock and at 10mph or less. The wife's failure was in exactly these circumstances. It was just trying to circumnavigate a tiny roundabout in Ruislip station car park, a manoever the local buses also had to achieve and couldn't with an immobile Herald in their way! The gridlock was unbelievable!

Here's my tip for it, get a cheap grease gun from Halfrauds to use exclusively for trunnions. Fill it when you want to use it and empty the remainder back into the bottle when finished or it'll leak everywhere! A couple of pumps per side every 3-6 months will suffice once they are all cleaned out and serviced as required.

So my advice is, stick to the book! If you must experiment (and I can understand why professional curiosity would lead you to want to) go ahead! but I don't see the need when EP 90 is cheap and DOES actually work.

Steve

I've also used semi fluid grease on my Elan for the last 30 years, the couple of times I've had it apart for other reasons they were in fine condition and well lubricated.