Catastrophic brake failure like I have never seen before

[zwitter]

There I was on the way home this afternoon went to stop and the pedal went straight to the floor. No warning just zip, zero, zilch. Handbrake and gears brought her to rest without hitting anything. That was the excitement in my 1996 Defender 130.

Had a quick look under the car and was easy to see fluid everywhere passenger front wheel. Was very close to home so crawled home very carefully.

Whipped the wheel off and could not believe my eyes. The calliper was leaking from the join between the castings. Ok, but the 4 bolts that hold the two halves together were lose. I could turn them with my fingers! What the.?

I replaced both front callipers in August last year at rego time new OEM. I remember reading the paperwork "never separate the haves of the calliper, ever"

So anyone ever seen this kind of failure?
I have replaced many callipers over the years and never ever even had a spanner or socket on those bolts before?
There should not be a need to tighten them on new callipers?
Certainly could not find a torque setting for them.

Now what do I do? Take it back? Replace it? Just tighten it up?

I will be checking the other side.

Your advice welcome

James

[Andy130]

That is highly concerning if the parts were OEM and only 7 months old. I would not be touching this myself and I'd go straight back to the parts supplier for a complete replacement. Could have been a disaster if they'd let go when you really needed to stop on a dime. Following this with interest as I would really like to know the outcome.

[weeds]

Well I guess if a human assembled the caliper than mistakes happen.....brakes is about as bad as you can get with quality control.

Maybe pull it off, clean it up and resemble??

[Roverlord off road spares]

That's highly concerning what Brand were these "O.E.M" Calipers?

[Jazzman]

Personally something like this would scare me so much I'd replace them with another brand all together, maybe even genuine.

[d2dave]

I replaced both front callipers in August last year at rego time new OEM. I remember reading the paperwork "never separate the haves of the calliper, ever"
James

I would be interested to know why the calipers can't be separated. I have overhauled hundreds of the things back in the late seventies and eighties.

The overhaul kits used to even come with the seal to go between the two halves.

[bee utey]

The joys of being a pessimist is that I check and double check every visible bolt after a brake job, including the four through bolts. BTW there's nothing difficult about splitting calipers, done it quite a few times. Just make sure you have the correct seals at hand for reassembly.

[cuppabillytea]

Although you could just bolt it all up tight, you should take it back to the supplier if only to inform them of the problem. There should be a warrantee on them, so why do and pay for the work when they should?

[JDNSW]

My question is, since it has dual circuit brakes, why did this lead to total brake failure? This is exactly the sort of fault that having two braking circuits was supposed to save from leading to total brake failure.

[d2dave]

My question is, since it has dual circuit brakes, why did this lead to total brake failure? This is exactly the sort of fault that having two braking circuits was supposed to save from leading to total brake failure.

I did wonder this myself when I read the OP.

[Roverlord off road spares]

I would be interested to know why the calipers can't be separated. I have overhauled hundreds of the things back in the late seventies and eighties.

The overhaul kits used to even come with the seal to go between the two halves.
Dave most seal kits sold now days don't come with the seal for the halves, it needs to be ordered separately.

[sierrafery]

My question is, since it has dual circuit brakes, why did this lead to total brake failure? This is exactly the sort of fault that having two braking circuits was supposed to save from leading to total brake failure.
I presume cos the tank got empty and there was nothing in the master cylinder to create pressure

[loanrangie]

I presume cos the tank got empty and there was nothing in the master cylinder to create pressure

Exactly, the caliper would have leaked fluid out of the joins so having 10 circuits wouldn't make any difference.

[goingbush]

There is SUPPOSED to be a divide in the Master Cylinder so that if one circuit leaks out, theoretically there is fluid in the other circuit. Its part of the ADR's

In practice it is not the case .

Im dealing with this right now with Iveco. One fellows brake hose from master cylinder rubbed through & he had no brakes at all.

So much for Dual Circuit brakes, I also found my brakes failed totally with a broken rear brake hose on a split circuit. That is an ADR non compliance.


simple experiment , undo a brake bleeder anywhere on your car & push the pedal, if it goes all the way to the floor you have zero brakes. Makes a mockery of Dual Circuit & ADR,s

Im replacing the entire braking system on the truck with something that works.

[loanrangie]

There is SUPPOSED to be a divide in the Master Cylinder so that if one circuit leaks out, theoretically there is fluid in the other circuit. Its part of the ADR's

In practice it is not the case .

Im dealing with this right now with Iveco. One fellows brake hose from master cylinder rubbed through & he had no brakes at all.

So much for Dual Circuit brakes, I also found my brakes failed totally with a broken rear brake hose on a split circuit. That is an ADR non compliance.


simple experiment , undo a brake bleeder anywhere on your car & push the pedal, if it goes all the way to the floor you have zero brakes. Makes a mockery of Dual Circuit & ADR,s

Im replacing the entire braking system on the truck with something that works.

So that front and rear are isolated ?, i believe that is how it is so theoretically you should still be able to pull up with a leak in the front circuit.

[zwitter]

Update.
Well I pulled the calliper off and split the halves using nothing more than fingers.
There are rubber seal things? Not o rings or gaskets. I washed the lot with metho and reassembled. Tightened the bolts up a lot to about 100Nm
I put it back on the car and bled the brakes. Put the wheel back on and test drove. So far no leaks and the brakes work!

Now am looking up the receipt and will write all this to the supplier. Calliper was in a green box (bearmach?).

Not happy about this at all but where is the proof? Never seen a calliper ever have those bolts come lose. I would have thought they would have been loctited in and impossible to remove.
I will be asking if they should be loctited as at this stage I did not put any on them on reassembly

James
Zwitter

[goingbush]

I'd be checking to see if the bolts on the other caliper are loose .

[goingbush]

So that front and rear are isolated ?, i believe that is how it is so theoretically you should still be able to pull up with a leak in the front circuit.

Yes that is the theory, Iveco is supposed to have a 50-50 split, according to the Official Workshop manual of misinformation. One page shows Front & rear are isolated, the next shows a diagonal split , in either case its moot because there is no divider in the MC , One leak & the lot drains out !

As an asides & off topic, I'm ditching the Iveco Brake system completely & am putting HydroBoost & Master cylinder from Chev Suburban, Yes there is a divider in reservoir, 34mm MC inplace of the 29mm Iveco MC . Mercedes rotors up front already done, F250 Rotors on rear with Cadillac callipers. (will keep the Bosch ABS. )

You should not have to do this to a new car to get brakes as they should be in the 21st century. My 1973 SWB Landy with original dual circuit drums stops better & is safer ( but crack one bleeder & pedal still goes to floor)

[sierrafery]

That split chamber thing in the master cylinder is useless as only the primary piston is moved mechanically by the rod the secondary piston's movement is achieved through fluid pressure so if any chamber goes out of fluid there will be no pressure in the cylinder... an overcomplicated construction without effect... they should have built a cylinder with bolth pistons actuated mechanically by the rod

[DoubleChevron]

Have a look in the manual and see if those caliper bolts should have thread locker on them. I seem to remember my range rover classic having thread lock on the caliper bolts when I removed them to change the front 'CVs.

seeya,
Shane L.

[loanrangie]

Have a look in the manual and see if those caliper bolts should have thread locker on them. I seem to remember my range rover classic having thread lock on the caliper bolts when I removed them to change the front 'CVs.

seeya,
Shane L.


You wouldn't split the calipers to change cv's though.

[Jazzman]

That split chamber thing in the master cylinder is useless as only the primary piston is moved mechanically by the rod the secondary piston's movement is achieved through fluid pressure so if any chamber goes out of fluid there will be no pressure in the cylinder... an overcomplicated construction without effect... they should have built a cylinder with bolth pistons actuated mechanically by the rod

Exactly without pressure they still will not function. No different to electronics, the fluid will take path of least resistance.... onto the ground. If for argument sake the dual circuit was working when the leak was small, that might explain why he didn't notice earlier... he sure noticed when there was no fluid left.

Unless you had 2 master cylinders too, they are not independent dual circuits.

[d2dave]

There is SUPPOSED to be a divide in the Master Cylinder so that if one circuit leaks out, theoretically there is fluid in the other circuit. Its part of the ADR's

In practice it is not the case .

Im dealing with this right now with Iveco. One fellows brake hose from master cylinder rubbed through & he had no brakes at all.

So much for Dual Circuit brakes, I also found my brakes failed totally with a broken rear brake hose on a split circuit. That is an ADR non compliance.


simple experiment , undo a brake bleeder anywhere on your car & push the pedal, if it goes all the way to the floor you have zero brakes. Makes a mockery of Dual Circuit & ADR,s

Im replacing the entire braking system on the truck with something that works.

So a 96 Defender does not have a divider in the master cyl reservoir yet a 96 Disco does.

I find this a bit strange, considering mechanically both vehicles are very similar.