Thats one of the questions I often get asked by older folk who have owned minor and the lasting impression is that the wheels fall off. My reply is usually not these days......
Bert called down this morning as he wanted me to check his points and timing and as it wasnt running as normal. He drove into the drive way and up towards the ramps, reversed back a little and as he was driving forward there was a noise and the front of the car lowered a bit, he turned the wheel a little another noise and lower again. Initial reactions was what the hell did you do there!! Heres what I found when I looked underneath.[frame][/frame][frame][/frame]
So a second nhand kingpin and lower trunnion were fitted along with a new fulcrum pin. We stripped and checked the passenger side as well just in case, though there was no damage the bottom trunion was replaced as the core plug in the bottom was damaged.
It does - if greasing is ignored. Fortunately it almost always happens at very low speed as in this case. Interestingly the larger 9" Wolseley brake backplates don't allow it to happen . the backplate traps the lower trunnion if it comes away from the leg.
sorry, could you clarify something for me, exactly which part failed here?
Reason I ask is because I'm soon to replace all the bushes on the front suspension, so would be good for me to check all the relevant bits for wear while I'm doing that, especially whatever caused this.
A guy I know had this happen to him years ago when he was a lad. Said he took out a lampost but could have been a lot worse and told me to be wary, now I can see what he's talking about
The bottom trunion has failed, they are threaded and if not greased regularly the thread wears away and it can come apart, like a nut stripping off a bolt
It might just be my small screen at the moment but that trunnion looks like it's been greased, certainly doesn't look dry yet it's given way !!! A bit of a worry when you've just bought a car as it could have just been greased before sale and look like it's been maintained correctly. I recon i'l check for wheel wobble tonight !!!!!!!!!
I agree it looks very much as if there has been lubricant around the swivel and trunnion but if the seals are no good and the water/dirt gets into the bottom trunnion it will act like grinding paste and wear the trunnion and swivel threads away and eventually they will fail.
So no matter how much you grease the trunnion poor seals will eventually kill the threads.
I find that you have to be very selective when buying trunnion seals as there are some very loose fitting ones out there. If you can get NOS BMC ones so much the better. Auto jumbles are a good place for picking up NOS trunnion seals.
The suspension on my Series MM collapsed some years ago. I had just been driving up the M1 at 60 mph followed by side roads. Just as I turned in to the hotel entrance the right front suspension collapsed. What made it worse was that I was attending an MMOC meeting and the entire committee were there to witness it. On inspection there was plenty of grease around the swivel pin but it had solidified so that fresh grease was not getting in. Now I give the grease nipples a couple of shots when I remove the wheels to adjust the brakes or other maintenance.
When I bought my Traveller the first job I did was to change the suspension as a precaution
Well I'm going to be giving the front trunnions on old Boris a good looking at over the weekend as he does have a clonk from the passenger side front when hitting a bump or when using full lock. I did check for play but couldn't find anything apart from a slight bit in thr rack. Will get a helper to wobble the wheel and I'll hold the joints. I'm in 2 minds as to say sod it and change the lot both sides so I know I'm starting with a new set up as ite not overly expensive.
Wobbling the wheel wont show up wear in the bottom trunnion as it's under tension from the torsion bar.
I think MOT testers use a long lever to raise the lower arm and look for play in the joint with the wheel off the ground.
A very dodgy process with a bottle jack, probably OK with a trolley jack but care needed.
"Once you break something you will see how it was put together"
This car has been owned by Bert for bout 16years and regularly greased. Prior to him buying it the last owners wife was driving when the passenger side went and she said she wasnt driving it again! It seems to have been replaced and the drivers wasnt, so I expect it was the original one on that side, so despite regular greasing it was probably already worn. In all the years Ive been driving minors I think Ive only seen an MOT man check the trunnions properly on maybe 2 or 3 occasions and they were both older men who had obviously worked on them back in the day.
Ill take some close up pics of the worn parts next time Im out in the garage. The best way to check it is a completed strip down which includes taking off the hubs and brake backing plates and then this lets you screw off the bottom trunnion and get a look at the threads.
Early cars were made with bronze trunnions, this was supposed to wear away before the steel on the kingpin!
The only real way to check is to strip the joint and inspect the threads - put them together without grease and 'feel' for any play in the threads. It should be easy enough to bolt a little piece of angle iron on the backplate under the trunnion to 'catch' it if it does go wrong.
That's not a bad idea BMC about the angle iron. At least if the bottom does let go the wheel wont swing out with the resultant damage and you will still feel the warning signs. Think I might do as suggested, thanks for that.
As I said earlier - the 9" W brake backplate has a 'pocket' that traps the trunnion if it drops and prevents the accident. Whether that was an intentional improvement on the W 1500 I know not. But just give it a 1/4" / 3/8" gap and you will know it has dropped - but still be able to drive the car home. And no need for a new front wing.......
So you have the torsion bar pulling the trunion off of the kingpin going against 2/3rd 'ish' of the weight of the car pulling the kingpin off of the trunnion, and the designers came up with a screw thread with a dust seal !!! The pin that goes through the trunion might help but i'd think that'd soon chew the thread away.
I think Morris Minors are great cars but blimey the kingpin/trunnion design is just asking for trouble and if not looked after (or even if) is an accident waiting to happen.
As my Boris has alloys on I did notice one has cut marks all round on the inner rim on a rear wheel and on looking the trunnion if it let go would hit the wheel, hence it has already happened to a previous owner.
It does appear to still be a bit to common a problem, so much so that if anyone asks me if the wheels still fall off i'll now say 'YES'.
I should think it mainly happens at lower speeds due to more steering movement for corners or 3 point turns helping the trunion get pulled off by the torsion bar, but it does worry me that that could move it to the point of going then go mid journey at say 50 - 60mph which would ruin far more than your front wing.
