Front end rattle

[Jim McCrae]

There are several possible sources of knocking in the front suspension. Little has been said of this stream about what you have done to check your suspension. I suggest that you examine the following:
1. Check that all nuts and bolts are tight. Don't forget the front of tie rod and the nut holding the eye bolt to the chassis.
2. Check for signs of worn or damaged bushes (Top trunnion, eye bolt, tie rod)
3. With the car supported on axle stands, place a jack under lower arm to remove tension from king pin. Check for play
in top and bottom trunnions, and in king pin itself.

I have had a troublesome knock on my traveller for some time. Recently I had a conversation with someone on the Morris Minor Community stand at the Restoration show and they offered some less obvious possible causes:
4. There is a washer between the eye bolt and the chassis to set the correct camber. This needs to be fitted with the inner bevel towards the eye bolt or it will not be possible to fully tighten the bolt to the chassis.
5. The lower trunnion swivel pin is very similar BUT NOT identical to the pin used in the torsion bar/eye bolt and the rear
leaf spring shackle. If the wrong pin is used it will not clamp the trunnion properly. The correct pin uses 3/8 UNF
nuts, the wrong pins use 3/8 BSF nuts.

Good luck

[philthehill]

Reference paragraph No: 5 above.
The lower trunnion pin is completely different to the pin used in the eye bolt.
The lower trunnion pin is 11/16" diameter whilst the eyebolt pin is 1/2" diameter.
The two pins are not interchangeable and if you do try to change them over it will soon become obvious that something is wrong.
The lower trunnion pin usually has 3/8" UNF threads whilst the eyebolt pin can have either UNF or BSF threads.
What does happen is the the cup that fits onto the rear of the eyebolt pin and which fits into the Minor thick suspension arm can become loose in the thick arm and/or come loose on the eyebolt pin and cause a rattle.
To alleviate any problems with the Minor eyebolt pin and cup I have used a Marina/Ital thick suspension arm and splined Marina eyebolt pin.
The forward end of the splined Marina eyebolt pin needs to be machined down and threaded to suit a 3/8" UNF nut.
The Minor thin suspension arm is used to the front of the Marina/Ital thick arm.
The Marina/Ital thick suspension arms have the same major dimensions so are interchangeable providing you use the modified Marina splined eyebolt pin.

[myoldjalopy]

Jim, Phil, thank you for your additional comments. I have checked the swivel, trunnions and tie bar as suggested and can find nothing amiss there. Bolts seem tight, although they all look typically rusty. I even took the car to an MOT station where it was put up on ramps and shaken violently but nothing was found except confirmation of my previous worn wheel bearing suspicion and identification of slight play in the rear damper link - but I can't see how either of those would cause the knock/rattle over bumps. I am now wondering about the eye bolt, its pin and cup, especially after what Phil mentioned. Need to take a closer look. Am going to get a second pair of eyes on this as I have failed to find the answer so far.......

[myoldjalopy]

Wheel bearing replaced and further investigation revealed that damper bolt had not stripped the thread in the captive plate but snapped in two! So friendly mechanic cut into inner wing and replaced broken bolt with new nut and bolt. Also further tightened the remaining damper bolts on both sides (don't know why they had come loose again, really, but never mind) and nasty clonk/rattle gone I'm pleased to say.

[michael4]

Excellent news.

I've been following this with interest since your description seems to match my rattle/clonking.

If the noise seemed to come from the nearside was it at its worst on left hand bends over bumps?

[philthehill]

The reason the damper bolts come loose is because the damper body is alloy and a soft alloy at that.
Tightening the bolts squashes the body of the damper so loosening the bolts.
Putting a large thick washer under the bolt heads spreads the load so reducing the tendency to squash the alloy body.
The bolt tab washer is not thick enough to spread the load.
The same squashing problem occurred with the early alloy rocker shaft pedestals. BMC came to their senses and replaced them with cast iron and later steel items.

[myoldjalopy]

Michael - noise was coming from front nearside and, in retrospect, I should have suspected the damper as it *seemed* to be in the front footwell area, but a bit higher up. But its not always easy to pinpoint exactly where these noises originate when driving and I couldn't replicate it when car stationary, except if I pushed/waggled the damper there was a faint 'tick/click' noise. Hardly enough to make me think it would allow the awful rattle/clonk I was getting, but obviously the force would be much greater when travelling over a bump/hole in the road. Didn't matter whether going round bents or straight but any bump/pothole would set it off.
Phil - presumably the washer would need to go under the tab washer, or it would make it hard to bend the tab washer over the bolt head?

[svenedin]

Agree. It's hard to determine where rattles are coming from even with a passenger on rattle location duty! I was just doing this and bouncing the stationary car around will not recreate my rattle. Nor will running the engine with the car stationary.

Stephen

[michael4]

Being deaf in one ear doesn't help either!

I think there are three potential culprits:

The damper bolts
The rack or rack damper
The torsion bar etc.

Plan of action

1 Stuff the rack full of grease. I know this is 'not correct' but if it shuts it up for a few miles the culprit has been identified.

2 Check the damper bolts with it under a light load

3 Again with everything under a light load take a crowbar to the torsion bar etc and wiggle around in search of play

Any other suggestions?

[philthehill]

You can put the thick washer under the locking tab washer. Make sure that the thick washer covers the whole of the bolt hole outer face.
Even better use a piece of steel strip and using the locking tab washer as a pattern drill two holes as per locking tab centres. The steel strip will then act as a thick washer and act as a support for the locking tab and you will have more of a pressure point on the damper body.

[myoldjalopy]

Being deaf in one ear doesn't help either!

I think there are three potential culprits:

The damper bolts
The rack or rack damper
The torsion bar etc.

Plan of action

1 Stuff the rack full of grease. I know this is 'not correct' but if it shuts it up for a few miles the culprit has been identified.

2 Check the damper bolts with it under a light load

3 Again with everything under a light load take a crowbar to the torsion bar etc and wiggle around in search of play

Any other suggestions?

I don't think 'stuffing' the rack with grease is a good idea - you might split the bellows and if the rack is not the culprit, what then?
As for the dampers, I would release the lock tabs and see if the bolts can be tightened up, then knock the tabs back over the bolt heads. They will be found to be either loose, or not.
The Haynes manual suggests ways in which to check the trunnions etc.
You could take the car to a trustworthy garage or MOT station and ask them to test the rack and suspension components for you. I did suspect the steering rack and a local garage confirmed my diagnosis of a worn rack. Later, because there was still a rattle on the near side, I booked the car in an MOT station and they tested the suspension for free and, at the same time, found the worn bearing. But it seems the damper bolts were loose as well so they had to be tightened before the rattle was eliminated.

[michael4]

You are right, having checked the damper bolts I've decided to take the car to the garage, they are happy to diagnose and quote.