Trunnions

[DaveW]

As a newbie about to investigate trunnions on a recent purchase, could I ask advice please? I've read that weight needs to taken off steering before greasing, but I don't know how to recognise whether there is too much wear/trunnions need replacing. Advice appreciated; thank you.

[svenedin]

Have a look at a picture of a swivel pin leg assembly (like this picture: https://www.morrisminorspares.com/front ... -h-p830575. You can see that the swivel pin leg has a stub axle (where the wheel goes) and a thread top and bottom where the trunnions go. The risk is that the threads get worn because owners don't grease them. If the threads wear very badly the trunnions can detach and the front suspension collapses. Fortunately, this usually happens at low speed on a lot of steering lock such as when going around a roundabout.

An annual MoT test should detect any suspension problems before anything fails. Many MoT stations will do an "inspection" which isn't an actual recorded MoT but for the same price.

Greasing the top and bottom trunnions is important but unless you take the weight off the front suspension, the grease can't get into the threads properly and it is a waste of time. To grease the trunnions, park the car somewhere safe and flat. Put the handbrake on and ideally chock the rear wheels. Raise either one side or both sides of the car at the front. To do this a trolley jack is ideal. The reinforced section of the chassis rail where the front end of the tie bar attaches is usually a good solid place to jack but you must spread the load with a piece of wood if the jack doesn't have a nice big flat pad. With the car on the jack you then place a piece of wood on the chassis rail behind the jack and use an axle stand to support the car by gently letting down the jack. Now either do the same on the other side or move on to taking the load off the suspension. Now place your jack under the lower suspension arm and slowly raise the jack. All you are doing is taking the weight off the suspension (the weight of the wheel, brake drum etc). Do not go too far and start lifting the car off the axle stand, it really isn't much. Now clean the grease nipples, attach your grease gun and grease the trunnions. Never work on a car only supported by a jack. This may all sound complicated but it really isn't. You can often opportunistically grease the trunnions when, for instance you are adjusting the brakes.

A variation of the above is to take the wheels off. This makes it easier to inspect the suspension, to access the grease nipples and you can adjust the brakes at the same time. Loosen the wheel nuts before raising the car and torque the wheel nuts correctly once the wheel is on the ground.

I am going to adjust the clutch operating rod today and I may take some photos to illustrate the trunnions procedure if I have time (mine don't need grease just now).

Stephen

[DaveW]

Steven
Thank you very very much for such a detailed reply. Extremely helpful. I will go and have a look this afternoon. I bought the car in order to learn about maintenance as well as enjoy the driving. Achieving both!! I'm of an age when Moggies were "current" when I started driving and my last Classic was a Super Snipe Estate in the eighties, but at that time I got somebody else to look after it. Old dog and new tricks.......maybe!!

[svenedin]

Welcome back then and do have fun!

I have owned my Minor since I was a student. They were old cars then, even the newest ones, and somehow I knew just enough to keep the car going on an almost non-existent budget (most of which seemed to go on engine oil). Back then they gave away tools and torches etc with engine oil which was just as well!

With the help of the folks on this forum I have gradually become more adventurous in what I will tackle but there are still jobs that I have to ask a garage to do.

Just ask on here as you go along and I am certain you will get the help you need. Try the search facility (which often works better from google than within the forum search) but unfortunately a lot of the older topics are missing their photographs.

Stephen

[svenedin]

PS Get a copy of the workshop manual AKD 530. It's very good. You can either get the book or you can find an electronic copy and print out the pages you need for a particular job. Sometimes laminated copies show up at Autojumbles. The only issue with the workshop manual is that it assumes a certain level of knowledge. For instance it might say "drift out and replace the bearings" but not give give any indication of how to do that.....

Stephen

[DaveW]

Thanks again Stephen