Brake problems again!

[Robho]

I've a 2006 1.6HDi Combi. I've had several problems with front brake callipers (apparently) but with the latest occurrence wonder if there is more to it. 

I have had another nsf brake sticking/seizing. Lot of heat generated and the acrid small of brake material.

The caliper was replaced 4 months ago (see history below). It is warm today (but not that warm, at 25-deg). I believe calipers are quite simple and this being the third failure over time..surely it must be something else, but what?  

Master cylinder? Servo? 

Has anyone experienced anything like this before?

I don't know that it could be related but over the last week I've noticed the wheel bearing seemed to be getting noisy (Murphy's Law, I intended to check it this weekend).

I had to abandon the vehicle, hopefully once its cooled I'll be able to get it home.

any suggestions welcome.

thanks
Rob


Prior history:

Bought the vehicle in 2020, with 80k miles. Disability conversion, appeared well looked after. A couple months into ownership had a problem where the nsf calliper stuck on. Replaced the calliper and, as good practice, replaced the osf at the same time. I don't now recall exactly the detail but there must have been a recurrence of a similar problem thereafter since I received some advice that my mechanic acted on - best he  can recall from 5 years back:

"If I remember rightly, I undid the fluid reservoir, pulled it away and slightly turned the rod to gain a little more free play. I don't recall if it was under the dash connected to the pedal, or possibly needed access both places". Whilst not very specific, you get the gist and maybe someone will recognise exactly what...

(This tip was given to me by a classic car garage which was working on on old sportscar of mine).

Anyway, it worked well, and cured the problem.

Fast forward to September 2023, ie three years later and probably 15k miles further, and a recurrence - this time the osf brake seized on. This was however in the freakish heatwave we had and it was 35-deg C at the time. A contributing factor? (it likely didn't help). 

The night before leaving for holiday, it left us marooned, and I had it attended to whilst we were away (another calliper, to the osf).

Then, a couple of weeks ago, another 9k miles; and I experienced an unusual vibration through the steering, as if a front wheel had lost a balance weight....but very oddly, 'coming and going' ...for want of a better description, at 50mph "on" for 3 seconds and "off" for 3 seconds, repeating. I was half a mile from home so decided to continue steadily down the quiet rural road. When stopped, I could smell brake material and, sure enough, the nsf this time was hot. Let it cool down, lifted the front and the brake was virtually seized. Another calliper.

So, that's two on each since over the course of c. 20k miles and five years. Vehicle is used every few days for a journey of 10-25miles, typically, by the way.

The last calliper was replaced a fortnight ago.

[jj9]

. . . .  I received some advice that my mechanic acted on - best he  can recall from 5 years back:

"If I remember rightly, I undid the fluid reservoir, pulled it away and slightly turned the rod to gain a little more free play. I don't recall if it was under the dash connected to the pedal, or possibly needed access both places". Whilst not very specific, you get the gist and maybe someone will recognise exactly what...

(This tip was given to me by a classic car garage which was working on on old sportscar of mine).

Anyway, it worked well, and cured the problem.

I think I would check the position of the Servo (Brake Booster) pushrod, (this sounds like the rod being described by your mechanic) ....  maybe it worked itself too tight again.... maybe the locknut wasn't tightened.







.

[Robho]

. . . .  I received some advice that my mechanic acted on - best he  can recall from 5 years back:

"If I remember rightly, I undid the fluid reservoir, pulled it away and slightly turned the rod to gain a little more free play. I don't recall if it was under the dash connected to the pedal, or possibly needed access both places". Whilst not very specific, you get the gist and maybe someone will recognise exactly what...

(This tip was given to me by a classic car garage which was working on on old sportscar of mine).

Anyway, it worked well, and cured the problem.

I think I would check the position of the Servo (Brake Booster) pushrod, (this sounds like the rod being described by your mechanic) ....  maybe it worked itself too tight again.... maybe the locknut wasn't tightened.







.

Hmmm, I did (at least I thought I did!) post a reply but it seems not.

That's a good video thanks, and we'll take a look at the rod in more detail next time my mechanic is here. In the meantime I've ordered a new master cylinder, to try to isolate one more thing...and I enquired about the push rod but its only available as part of the servo - which is no longer available (though aftermarket ones are). I think we'll disassemble it in the hope that seeing it 'in the open' might give some clues.

[jj9]

It would be nice if you did find that the push rod was too tight up against the master cylinder as that would solve the mystery.

Let us know what you find.

Good luck.

.

[Robho]

It would be nice if you did find that the push rod was too tight up against the master cylinder as that would solve the mystery.

Let us know what you find.

Good luck.

.

Indeed! Thanks.

[Robho]

Here's the update:

Removed the master cylinder (very tight for access). Finally had clear sight of the aforementioned servo rod. However, unlike the ones I've seen (variously) on You tube the adjustment is not straightforward. I had expected a locking nut to loosen and then wind the rod in/out to achieve the desired clearance...but there is none. There is a 'knurled' end* which possibly takes a special tool (which we did not have). We tried various tools to try to grip the rod, but to no avail, and obviously didn't want to risk damaging it. 

*It was very difficult to see clearly in situ but after many attempts I did manage to get a reasonable photo - which I can add. I tried to 'paste' it below, but no luck. Nor, the image icon which requests a URL. If someone tells me how to upload, from my folders, I'll try thanks.

Fortunately, the clearance was correct - I don't know what I'd have done otherwise, but we were able to proceed with fitting the new m/cyl (even more tight when refitting due to a slightly different casing. It was a real pain.

So, re-assembled..and now its a case of a waiting game. Hoping that there was a problem with the removed m/cyl, which has been cured by fitting a new one....but I'll only know if the problem doesn't recur.

[evdama]

An image would be interesting.
Its a bit of a faff but you can place a  picture by going to https://postimages.org/

Upload the photo and copy one of the links it gives you.
I find "Direct" is reliable.

Return to berlingo forum and paste the copied link into the URL box that appears when you click the Image icon

[Robho]

An image would be interesting.
Its a bit of a faff but you can place a  picture by going to https://postimages.org/

Upload the photo and copy one of the links it gives you.
I find "Direct" is reliable.

Return to berlingo forum and paste the copied link into the URL box that appears when you click the Image icon

Sorry for the delay. I have tried the method described but I get an error message '403' from the page. Any other suggestions?