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scary corrosion on brake cylinders
Mr Whippy - 15/6/20 at 04:48 PM

It's one of those times I'm so glad I go overboard every time I do a service/rebuild of my tintops. Here we have my 2004 Fiesta rear brake cylinders OMG look at the corrosion at the brake pipe union caused by galvanic corrosion with the steel back plate. That is a lucky find and it was like that when it passed it's last MOT





I you have a similar car I suggest a quick check may be worthwhile.

Cheers.

[Edited on 15/6/20 by Mr Whippy]

SteveWalker - 15/6/20 at 05:12 PM

I may be wrong, but looking at the colour of the metal, the lack of rust and the fine lines along the surface, they look like extruded alloy cylinders. If so that is a serious design fault by Ford, as such dissimilar metals would be bound to suffer galvanic corrosion and could be deadly in such a "hidden" location. 16 years old is not really unusual for vehicles these days and they should have allowed for much more than that.

[Edited on 15/6/20 by SteveWalker]

Mr Whippy - 15/6/20 at 05:19 PM

I think it's terrible tbh, I've worked on some very old very neglected cars and never seen anything like it, usually I'd be just replacing the seals. In a couple of years that pipe would just come off...

theconrodkid - 15/6/20 at 05:40 PM

they look like they are made from top grade Chinesium, i am sure Ford ones are iron, either way, good find.

obfripper - 15/6/20 at 06:17 PM

They are genuine factory fit ford items, they were originally clear anodised.
Most modern oe wheel cylinders are made with similar materials and processes, only the cheap patterned parts are cast iron, and they don't get a chance to externally corrode as they're generally unserviceable after a year.

What has made them corrode faster is the replacement copper pipe making a higher potential cell for galvanic corrosion.
The other thing that causes this to accelerate is dung/urea from country lanes, i have seen similar corrosion on many farmers vehicles.

Dave

gremlin1234 - 15/6/20 at 06:23 PM

youtuber 'hubnut' had something very similar on his 2cv at mot
detail at about 27 min

Mr Whippy - 15/6/20 at 06:58 PM

quote:
Originally posted by obfripper

What has made them corrode faster is the replacement copper pipe making a higher potential cell for galvanic corrosion.

Dave


Now that's a very interesting point, yes it has had the rear pipes replaced with copper. I didn't know that could cause problems. I will paint the replacement cylinders and the new pipe to prevent it happening again.

I'm not sure if they are original, some work has been done on the back before I got it but all the replacements are aluminium too.

Cheers.

[Edited on 15/6/20 by Mr Whippy]

Charlie_Zetec - 15/6/20 at 07:14 PM

quote:
Originally posted by Mr Whippy
I think it's terrible tbh, I've worked on some very old very neglected cars and never seen anything like it, usually I'd be just replacing the seals. In a couple of years that pipe would just come off...


I'm a LR fan, and own and have worked on a number of Defenders - they suffer from the dreaded Galvans corrosion between the ali panels and steel brackets - but i've never seen anything THAT bad. Just astonishing, truth be told, that such a new car can suffer so badly....

JeffHs - 15/6/20 at 07:51 PM

My wife has a much loved 04 Fiesta! I'll be crawling underneath!

Mr Whippy - 15/6/20 at 09:24 PM

quote:
Originally posted by JeffHs
My wife has a much loved 04 Fiesta! I'll be crawling underneath!


Issues I have found so far on mine which I'd say was a very typical example are -

1) Corrosion on the rear suspension, the part that holds the bush. On the web an MOT site showed one example that the bush broke free and the car crashed killing the driver.

2) Rear springs rust very badly at the base due to no rubber between the spring and the seat, results in springs snapping and doing all sort of things like ripping off the brake lines, stabbing the tyre... The Fiesta based fusion has these gaskets which I have fitted to mine called - Ford Fiesta Mk6 Fusion Rear Lower Suspension Spring Antisqueak 1206873. There are similar "antisqueak" bushes for the front too.

3) Very bad corrosion can set in one the rear chassis member due to very poor design see my post - linky, if left this will kill your car, I was lucky to catch it in time.




[Edited on 15/6/20 by Mr Whippy]

minitici - 16/6/20 at 10:17 AM

My Suzuki Ignis had a corroded rear brake cylinder, like that, and the brakes failed under an emergency stop.
The pipe blew out of the remains of the thread on the cylinder.
Luckily there was a suitable verge to swerve onto to avoid the muppet who pulled out on me.

Mr Whippy - 16/6/20 at 10:27 AM

quote:
Originally posted by minitici
My Suzuki Ignis had a corroded rear brake cylinder, like that, and the brakes failed under an emergency stop.
The pipe blew out of the remains of the thread on the cylinder.
Luckily there was a suitable verge to swerve onto to avoid the muppet who pulled out on me.


Wow you were super lucky

coyoteboy - 16/6/20 at 03:54 PM

Since that's not a service item, and clearly is a material mismatch (clear ano won't be applied in the threads, or account for damage during insertion), and hidden in a drum, I'd say that was borderline class-action worthy on a car 6 years old. On a car 16 years old it's more of an "eek that's what you get on old cars".

Personally I've never had a steel cyl corrode to the point of not working.

[Edited on 16/6/20 by coyoteboy]