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Clonk on Braking
Posted: Sun May 25, 2025 11:19 am
by svenedin
I am getting a clonk from the front suspension right side (driver’s side) on braking first thing when the car is cold. The clonk will happen two or three times and then becomes a tut, tut, tut noise on braking rather than a clonk. Then it disappears completely and will not happen again unless the car is left for several hours. The handling is completely normal.I will ask the experts here in France on Minors on Tour but any ideas? I think it is a sticking polyurethane bush. All the bushes are poly and around 2 years old.
Stephen
Re: Clonk on Braking
Posted: Sun May 25, 2025 12:33 pm
by svenedin
Following a conversation with another MoT colleague this is due to loose tie bars. The nylock nuts I used have worked loose probably from driving on cobbled streets. Very dangerous if the tie bar(s) had detached. I am putting castle nuts and split pins back. The same thing happened to an MoT-er last year but I didn’t know this.
Stephen
Re: Clonk on Braking
Posted: Sun May 25, 2025 1:10 pm
by philthehill
If you are going to put the castellated nut back on the front of the tie bars use 'R' clips instead of split pins.
'R' clips were used instead of split pins on the tie bars of the Morris Marina/Morris Ital.
The 'R' clips are stronger than the split pin.
Re: Clonk on Braking
Posted: Sun May 25, 2025 1:52 pm
by svenedin
Thanks Phil. R-clips will have to wait until I’m back in the UK. For now I’ll put castle nuts or any other nut that fits as locknuts in addition to the nylocks already fitted. Will have to see what nuts we have between us on this trip.
Re: Clonk on Braking
Posted: Sun May 25, 2025 2:52 pm
by svenedin
Thé nylock nuts had worked loose and were on the end of the thread.I have tightened them and there is now plenty of thread showing. I no longer trust thé nylocks though. Someone in the group thinks they may have some castle nuts

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Re: Clonk on Braking
Posted: Sun May 25, 2025 3:31 pm
by Bill_qaz
Have they been used more than once? EG fitted and refitted, they are most effective on first use. Or fit two plain nuts one locked against the other until you get home.
Re: Clonk on Braking
Posted: Sun May 25, 2025 3:37 pm
by svenedin
Bill_qaz wrote: ↑Sun May 25, 2025 3:31 pm
Have they been used more than once? EG fitted and refitted, they are most effective on first use. Or fit two plain nuts one locked against the other until you get home.
No they are new and have only been fitted once. Yes, if anybody has the correct nuts
Re: Clonk on Braking
Posted: Sun May 25, 2025 5:38 pm
by Bill_qaz
Anyone got loctite or purchase locally refit nylocs and leave overnight to cure, maybe an idea for your peace of mind

Re: Clonk on Braking
Posted: Sun May 25, 2025 5:55 pm
by svenedin
Yes but unfortunately it doesn’t seem to be the tie bars after all (though the nuts were definitely loose). The clonk is still there and unchanged. I don’t understand why it goes away completely after a few minutes driving
Re: Clonk on Braking
Posted: Sun May 25, 2025 7:37 pm
by myoldjalopy
Just a guess, but could it be wear in the steering rack causing the sound, which is then quietened after the rack oil gets squeezed around by the bellows after a bit of driving? I did once have a car that had an occasional tapping noise from the RHS of the rack but it was not constant and sometimes absent for long periods.
Re: Clonk on Braking
Posted: Sun May 25, 2025 8:20 pm
by Sleeper
A quick-fix when re-using nylok nuts is a hammer blow to the crown, re-compresses the nylon.
John ;-)
Re: Clonk on Braking
Posted: Sun May 25, 2025 9:02 pm
by Bill_qaz
svenedin wrote: ↑Sun May 25, 2025 5:55 pm
Yes but unfortunately it doesn’t seem to be the tie bars after all (though the nuts were definitely loose). The clonk is still there and unchanged. I don’t understand why it goes away completely after a few minutes driving
Is it something in your new front brakes and it changes when used a couple of times.
Re: Clonk on Braking
Posted: Sun May 25, 2025 9:12 pm
by svenedin
Bill_qaz wrote: ↑Sun May 25, 2025 9:02 pm
svenedin wrote: ↑Sun May 25, 2025 5:55 pm
Yes but unfortunately it doesn’t seem to be the tie bars after all (though the nuts were definitely loose). The clonk is still there and unchanged. I don’t understand why it goes away completely after a few minutes driving
Is it something in your new front brakes and it changes when used a couple of times.
It’s possible. I don’t think so but I can’t be sure at this stage. Tomorrow morning I am going to borrow some axle stands and check everything I can. I just want to either find the fault or reassure myself that it’s not something dangerous that is going to fail at speed.
Re: Clonk on Braking
Posted: Sun May 25, 2025 9:13 pm
by svenedin
myoldjalopy wrote: ↑Sun May 25, 2025 7:37 pm
Just a guess, but could it be wear in the steering rack causing the sound, which is then quietened after the rack oil gets squeezed around by the bellows after a bit of driving? I did once have a car that had an occasional tapping noise from the RHS of the rack but it was not constant and sometimes absent for long periods.
Could be but only just started doing it.
I am puzzled. If it was something loose I would expect it to get worse at speed but it doesn’t. After 5 minutes driving it’s like nothing at all is wrong.
Re: Clonk on Braking
Posted: Sun May 25, 2025 9:34 pm
by Bill_qaz
Maybe cylinder are being pushed back, does the brake feel change? Try pumping brake a couple of times before initial drive and see if alters the noise.
Re: Clonk on Braking
Posted: Sun May 25, 2025 9:42 pm
by svenedin
Bill_qaz wrote: ↑Sun May 25, 2025 9:34 pm
Maybe cylinder are being pushed back, does the brake feel change? Try pumping brake a couple of times before initial drive and see if alters the noise.
Will do. It could be anything. I did try repeated braking from low speed to a stop earlier and it clonked every time then 5 minutes later, nothing. Brake feel felt normal the whole time. I even braked hard enough to lock the front wheels (on purpose)
Re: Clonk on Braking
Posted: Mon May 26, 2025 10:11 am
by svenedin
All completely sorted. Loose front brake back plate bolts. Thanks for your help!
Stephen
Re: Clonk on Braking
Posted: Mon May 26, 2025 10:31 am
by myoldjalopy
Well done! Peace of mind now for further adventures in France!

Re: Clonk on Braking
Posted: Mon May 26, 2025 10:49 am
by svenedin
myoldjalopy wrote: ↑Mon May 26, 2025 10:31 am
Well done! Peace of mind now for further adventures in France!
Exactly!
Re: Clonk on Braking
Posted: Mon May 26, 2025 10:54 am
by Bill_qaz
Glad you sorted it, an all round bolt check sounds in order after your rebuild, 2nd loose fitting
Maybe being a bit too gentle on assembling?