strange noise that seems to come from rear left wheel

[Niklas777]

Hi all,

1st subject opened for me as a new owner of a Lotus Elan S3 from 1968.
I have a strange "ching ching" noise that seems to come from my rear left wheel.
Anybody already had a similar issue? This noise is easier to hear at low speeds, it comes and goes, and it can disappear temporarily right after a bump/hole in the road...
I posed a small video here: https://www.youtube.com/shorts/jkHkRkSim40

Please also check this picture i took from the rear left disc that seems to have scratches on it. Maybe it could come from there?
Or maybe from a bearing? Based on my experience, bearing are not really this kind of noise when worn but who knows...

Thanks,
Nicolas

[skyarch]

Check the castle nut on the shock insert, the one that holds the insert onto the tube. You should be able to see it when the springs are extended.

[Niklas777]

Thanks very much for your answer.
I'm basically discovering this car and want to make sure i understand.
Why would this nut grip on the disc as it seems that something is touching it?
My assumptions was to look at the disc integrity itself and/or the handbrake pads that would be partially stuck on the disc.

I've noticed that the read disc is very (very) hot when i use the car normally...

[rgh0]

The rear disc should not be hot with normal road driving. It sounds like something is rubbing on the disk, most likely a siezed rear piston or the hand brake calipers. With that chip in the disc i woulkd replace it to avoid the disk cracking and failing

cheers
Rohan

[skyarch]

I agree that you should replace the disc.
But the sound may be coming from the shock tower and have nothing to do with the disc.
If the disc was causing the sound it would be rhythmic and at every revolution of the wheel.

[Niklas777]

I agree that you should replace the disc.
But the sound may be coming from the shock tower and have nothing to do with the disc.
If the disc was causing the sound it would be rhythmic and at every revolution of the wheel.

Thanks a lot for your answer.
The noise is cyclic and does correspond (except if i am mistaken) to every single revolution of the wheel since it changes with speed +/-

[Niklas777]

The rear disc should not be hot with normal road driving. It sounds like something is rubbing on the disk, most likely a siezed rear piston or the hand brake calipers. With that chip in the disc i woulkd replace it to avoid the disk cracking and failing

cheers
Rohan

Thanks for your insight Rohan. I've been through the same issue with another old car...
I have noticed other things that could guide towards a siezed brake caliper : the brake pedal has vibrations on strong brakings.
the car tends to naturally go on the left as well. If the disc is touched by something, i guess it brakes on the left side and pushes the car to go left...
The centralizing clips on the handbrake pads got rearranged the last time i brought it to the repair shop, so theorically, it could be a siezed Brake caliper on the rear left wheel.
I have seen on the invoices that the caliper got renewed in 2017, but the car has not done a lot of miles since...
I hope to be able to discover the source of all this, and finally enjoy the ride on this fun British machine.

[alan.barker]

Brake pedal vibration is a distorted Disc.
Caused by one Cylinder ceased in the Caliper. Worn bearings can distort Disc and also the 3 pads for locating Disc not running true.
Alan

[ianthomson72]

It’s worth checking the tightness of the rotofkex coupling bolts.

[Niklas777]

Brake pedal vibration is a distorted Disc.
Caused by one Cylinder ceased in the Caliper. Worn bearings can distort Disc and also the 3 pads for locating Disc not running true.
Alan

Thanks. If it is due to a cylinder ceased in a caliper, can it come from the handbrake caliper, the « generic » rear brake caliper or both? This rear left wheel seems to be partially slowed down sometimes after waiting at a traffic light for instance.

[ncm]

I cannot offer advice with the problem however I have noticed that the caliper mounting bolts have not been lockwired as specified in the manual.

Brian.

[nmauduit]

Thanks very much for your answer.
I'm basically discovering this car and want to make sure i understand.
Why would this nut grip on the disc as it seems that something is touching it?
My assumptions was to look at the disc integrity itself and/or the handbrake pads that would be partially stuck on the disc.

I've noticed that the read disc is very (very) hot when i use the car normally...

Bonjour,

as indicated by Rohan above, the disk getting very hot should be addressed without delay: I don't suppose the car (S3) being equipped with a tandem master cylinder, so in case the overheating disk eventually gets the brake fluid boiling you'll have no braking at all (pedal to the floor), a feeling that can get one by surprise (approaching the pay line at speed on the highway etc... ).

Handbrake pads and general "emergency brake" operation adjustment can be done sliding below the car, but these pads being relatively slow I doubt that alone would be a cause to the disk getting hot (while a sticking piston would).
Servicing the brakes would be the number one thing to do when taking ownership of an elan, it's not difficult and imho essential for peace of mind and proper car enjoyment...

keep it on the road !

[Niklas777]

Thanks very much for your answer.
I'm basically discovering this car and want to make sure i understand.
Why would this nut grip on the disc as it seems that something is touching it?
My assumptions was to look at the disc integrity itself and/or the handbrake pads that would be partially stuck on the disc.

I've noticed that the read disc is very (very) hot when i use the car normally...

Bonjour,

as indicated by Rohan above, the disk getting very hot should be addressed without delay: I don't suppose the car (S3) being equipped with a tandem master cylinder, so in case the overheating disk eventually gets the brake fluid boiling you'll have no braking at all (pedal to the floor), a feeling that can get one by surprise (approaching the pay line at speed on the highway etc... ).

Handbrake pads and general "emergency brake" operation adjustment can be done sliding below the car, but these pads being relatively slow I doubt that alone would be a cause to the disk getting hot (while a sticking piston would).
Servicing the brakes would be the number one thing to do when taking ownership of an elan, it's not difficult and imho essential for peace of mind and proper car enjoyment...

keep it on the road !

Very clear, thanks for your input.
To be honest, i'll not drive the car anymore until the day when i'll drive the 3 kilometers to the repair shop to have it fixed.

[Niklas777]

FYI i've asked the repair shop if the rear caliper was seized and the answer was no.
Apparently they already checked this and the caliper was not stuck.

SO the other options would be :
-handbrake caliper touching the disc
-Bearing?

[Lotus fan]

Nicklas, I seem to have had exactly the same issue.

https://m.youtube.com/shorts/3RnUCAZfC9Q

This started happening about 300 miles after my full restoration.
It bugged the life out of me but it disappeared after roughly another 700 miles.
Brake pads anyone ??

Ian