Old clonk/clunk - New trial

[Casar66]

30 minutes ago, Joestr8 said:

I’m not sure if it’s been covered already but I think the caliper retaining bolts have different shoulder sizes depending on which callipers are fitted.  If shoulder is too small it could be the caliper that has slight movement causing the clonk.

Is that so? Why not, I will check!

[Casar66]

22 minutes ago, jerrytr5 said:

Sounds like the pads are a very sloppy fit in the caliper. Your photo shows a very clean caliper. What it needs is a bit of corrosion & brake dust!

Try jamming the pads in with small bits of wood (not on the road of course) & repeat the test.

Jerry

I did not use wood I tried it with 3m pad-tape. No change. But I will do it with wood too. 

[Casar66]

6 minutes ago, Z320 said:

Did I already ask you to measure the gap between pads (Trägerplatte) and caliper  „please“?

The pins do not hold the pads, they are too week to bear radial forces.

I had the gap on my green stuff pads only 0.5 mm —-> this was already too much and I had „good“ clonks

You mean the vertical gap, right?

I will measure it but guess it is more.

But: I am still thinking that is not a normal clunk of a loose brakepad. It is a relaxation-reaction in my eyes. If it is the pad it feels like it is tiltet and becomes free. 

[Martin50]

Caesar, you are getting a lot of input and apologies for adding.

A thought. Can you get the clunk if:

a. With car jacked up at the front, and without running engine, in neutral, and no hand brake engaged

b. Rotate the front wheel in a reverse direction and then have someone apply the foot brake

c. Once the wheel is stopped, release foot brake and try to rotate the wheel in froward direction

Does this give you the clunk sound?

If it did, then you could visually inspect and listen for where the clunk maybe coming from. Especially if it is repeatable. Hoping this may work, and really hoping you get to resolve this fingers crossed. All the best.

[JohnC]

2 hours ago, Casar66 said:

Is that so? Why not, I will check!

Yes! The early and late caliper had different size holes. I *think* early had 7/16” holes (~11.1mm) and the later had 12mm. But both were fitted to the same 7/16” thread mountings. So the later needed Frankenstein bolts. Could this be the end of your search? I so hope so!

Cheers,
JC

Edited June 18, 2025 by JohnC

[Casar66]

1 hour ago, JohnC said:

Yes! The early and late caliper had different size holes. I *think* early had 7/16” holes (~11.1mm) and the later had 12mm. But both were fitted to the same 7/16” thread mountings. So the later needed Frankenstein bolts. Could this be the end of your search? I so hope so!

Cheers,
JC

I will check this afternoon. What means Frankenstein bolts, bigger head?

[Casar66]

In the drawings I found this part. But not at my brake and not at sny brake shown in YT-videos.Do I need that? 

[stuart]

1 hour ago, Casar66 said:

In the drawings I found this part. But not at my brake and not at sny brake shown in YT-videos.Do I need that? 

Thats a caliper shim, its used to centre the caliper to the disc. Often not replaced after restorations.

Stuart.

[Casar66]

2 hours ago, Martin50 said:

Caesar, you are getting a lot of input and apologies for adding.

A thought. Can you get the clunk if:

a. With car jacked up at the front, and without running engine, in neutral, and no hand brake engaged

b. Rotate the front wheel in a reverse direction and then have someone apply the foot brake

c. Once the wheel is stopped, release foot brake and try to rotate the wheel in froward direction

Does this give you the clunk sound?

If it did, then you could visually inspect and listen for where the clunk maybe coming from. Especially if it is repeatable. Hoping this may work, and really hoping you get to resolve this fingers crossed. All the best.

No to all, unfortunately

[Casar66]

Update for today:

- The caliper bolts should be the right ones.

-the outer pad has very little vertical play in the caliper, I guess around 2/10 mm. The inner pad has more, appr. 1 mm.

- the pinholes of the pads have correct size. I got a new set frome another make, it is the same.

- I got also the caliper-shim. Changed nothing, I even would say it makes it worse. Only that together with the bigger play of the inside-pad give me (a very little) hope that the clunk' source is still the caliper. As a next step  I will put a piece of wood between pad and Caliper.

I got a different kind of pad-springs too. Guess ...you are right. Clunk is still there.

 It's whether something runs up and becomes tense when reversing and braking, and then relaxes when you brake again while driving forwards. In a clunk.

 

[Casar66]

Update II

I couldn't wait to try it out, so I added the “zero-play-pad-in-the-brake-caliper-test” today.

 

Instead of wood (I didn't have anything that thin), I used plastic strips. The pads then had to be pushed into the shaft of the brake calliper with gentle force and fitted tightly and absolutely free of play in the brake calliper. Anti-noise plates and the previous spring were also fitted.

Result: as always. The clunk is in perfect health.

After the test I took a control photo, the plastic strips were still in place.

 

I am now finally convinced that the clunk has nothing to do with the brake pads and their position in the brake caliper. The brake caliper itself can also be ruled out. It must be in the periphery of the caliper. Under certain circumstances, something has play and/or tension. But what?

Just as I opened the door of the TR and the door locking spring engaged, I thought that my clunk felt similar. And sounds, only muffled.

[jerrytr5]

Have you checked that the disc is bolted up tight, also the wheel or splined adaptor if you have wires?

Jerry

[Casar66]

Yes. Also changed to Standard steel rims without CL. Bought a new hub too

[Casar66]

Just a quickie on a very hot sunday:

How do I get 1. and 2. seperated, means not only loosening bolts and nuts?

[Casar66]

I can't rest, so it was my turn again today. And only now have I noticed that there is no gap between the frame and the body at this point. Don't ask why that late. Another suspected clunk?

 

It is in front of the fulcrum

Edited June 23, 2025 by Casar66

[JohnC]

14 hours ago, Casar66 said:

I can't rest, so it was my turn again today. And only now have I noticed that there is no gap between the frame and the body at this point. Don't ask why that late. Another suspected clunk

I had contact at that point and it was a squeak. But there should be no contact as it will cause a noise of some sort.

[Casar66]

4 hours ago, JohnC said:

I had contact at that point and it was a squeak. But there should be no contact as it will cause a noise of some sort.

I have too often hoped to have found the source of the clunk to go out on a limb now.

But the first test drive was more or less "promising".

[Casar66]

It's Groundhog Day. What can I say? After working on the body to increase the space between body and frame I was in really good mood that the source of the clunk is eliminated. But it is not. 
Then I disconnect the anti-rollbar and tried it again. No change. Then the same with the balljoint of the trackrod end (of course without steering, just few Yards for and back). No change either.
I must get rid of this curse! 

Edited June 25, 2025 by Casar66

[Casar66]

next approach:

Is ist thinkable, that the Spring-seat up or down is damaged in that way, that it gives room for the spring in just that moment when I stop from low speed and there is only the minimum tension on the spring that the clunk occurs (e.g. the wheel is rolling into a litte pothole or any of depression )?

Or can save me the removing of the spring to check that, a work which I do not like honestly?

 

[JohnC]

Hi Casar,

I'm sorry you're still suffering the clonk affliction. Two suggestions, the first serious, the second perhaps less so...

1. Apology up front. I have suggested this before so you may have eliminated it and I haven't spotted it in the saga of the clonk! Anyway, I'm honestly not convinced you've eliminated pad knock back. You have most certainly eliminated pad rattle, and any possibility of the pads moving circumferentially. But knock back is when the pistons themselves are pushed slightly into the calibers by flex in the system, most often the stub axles. It's hard to test  but you might just be able to cause it by fixing the wheels against turning side to side (e.g.., lock them pointing at full lock one way or the other) and then turn the steering wheel from side to side as hard as you can. Then inspect the pad/piston clearance (that's why you locked them pointing left or right, so that you can get at the calibers more easily). Or drive over a bumpy surface, steering left and right, without applying the brakes. Stop using the handbrake. Then pull away slowly and apply the brakes. Any clonk?

2. Buy a really powerful stereo. Turn it up. Drop the roof and enjoy the music with the wind in your hair and the sun on your face

I really hope this helps.
JC

[Mike C]

Maybe hire a rolling road and have someone stand alongside and watch while you apply the brakes?

[Casar66]

18 minutes ago, Mike C said:

Maybe hire a rolling road and have someone stand alongside and watch while you apply the brakes?

I did it so many times. I even did it with bonnet open. All I and all the other "listener" can say that it is somewhere in the area of the left wheel house. It is impossible to narrow down that area. To place a camera there did not work, I guess you need special equipment. 

[Casar66]

7 hours ago, JohnC said:

Hi Casar,

I'm sorry you're still suffering the clonk affliction. Two suggestions, the first serious, the second perhaps less so...

1. Apology up front. I have suggested this before so you may have eliminated it and I haven't spotted it in the saga of the clonk! Anyway, I'm honestly not convinced you've eliminated pad knock back. You have most certainly eliminated pad rattle, and any possibility of the pads moving circumferentially. But knock back is when the pistons themselves are pushed slightly into the calibers by flex in the system, most often the stub axles. It's hard to test  but you might just be able to cause it by fixing the wheels against turning side to side (e.g.., lock them pointing at full lock one way or the other) and then turn the steering wheel from side to side as hard as you can. Then inspect the pad/piston clearance (that's why you locked them pointing left or right, so that you can get at the calibers more easily). Or drive over a bumpy surface, steering left and right, without applying the brakes. Stop using the handbrake. Then pull away slowly and apply the brakes. Any clonk?

2. Buy a really powerful stereo. Turn it up. Drop the roof and enjoy the music with the wind in your hair and the sun on your face

I really hope this helps.
JC

Hello John,

I fully agree with your analyse. I have sort out the rattle/movement of the pads but not a knock-back due flexibility somewhere in the system.  What I can say ist, that without braking it is impossible to provoke the clunk, whatever I try.

Also I blocked the wheels and moved the steering wheel against it. 

But sometimes I heared a noise that come close to the clunk when I turn the steering wheel for the first time after some days off.

How can I find the flex?

[Z320]

Do you have insulators under the coil springs?

Are they still OK ore gone?

[Casar66]

This I have mentioned in my post last friday, if my spring-seats (or isolators) cold be damaged. At first glance I do  not see anything wrong or damaged.  

Edited June 29, 2025 by Casar66