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Discussion Starter · #1 · (Edited)
Hello everyone. A loud grinding noise started coming from my rear brakes recently. You can only hear it on slow speeds.
I had a look at the disc brakes and the problem is obvious.
Automotive tire Tire Wood Automotive lighting Rim


Both rear discs are very rusty but the van is being driven daily. So I imagine there must be a problem with calipers not functioning properly. Do you have any ideas what could have caused all this rust build up?

Thanks.
 

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Our old van did this, the brake pads were sized fast into the brake carriers. Cleaned all the rust and filed down new pads and discs and all ok.
Have also seen brake slider pins sized into the carrier so only way to tell is strip down I'm afraid!

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Do you have a disc protection housing still intact? I had a similar issue last year but not as bad as yours. My issue was the rust falling off the disc protective housing, turns out when your protection housing starts to rust it becomes completely counterproductive. From my perspective the rust flakes got caught up in the caliper bracket and the brake pads causing damage to the disc. Mine were not as bad as yours but similar defects, I put a complete new set of discs, protection housing, calipers and pads and the problem was resolved. I'd recommend you do the same as your discs are shot, if you do, make sure to change the other side as well so the brakes are even (y)
 

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Discussion Starter · #4 ·
Do you have a disc protection housing still intact? I had a similar issue last year but not as bad as yours. My issue was the rust falling off the disc protective housing, turns out when your protection housing starts to rust it becomes completely counterproductive. From my perspective the rust flakes got caught up in the caliper bracket and the brake pads causing damage to the disc. Mine were not as bad as yours but similar defects, I put a complete new set of discs, protection housing, calipers and pads and the problem was resolved. I'd recommend you do the same as your discs are shot, if you do, make sure to change the other side as well so the brakes are even (y)
It is there but I wouldn't call it intact 😂 That makes sense, will definitely need to change everything in the back. Thanks.
 

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Do you have a disc protection housing still intact? I had a similar issue last year but not as bad as yours. My issue was the rust falling off the disc protective housing, turns out when your protection housing starts to rust it becomes completely counterproductive. From my perspective the rust flakes got caught up in the caliper bracket and the brake pads causing damage to the disc. Mine were not as bad as yours but similar defects, I put a complete new set of discs, protection housing, calipers and pads and the problem was resolved. I'd recommend you do the same as your discs are shot, if you do, make sure to change the other side as well so the brakes are even (y)
Would explain the grinding noise, not the rust. Would be disproven if the caliper isnt hot. (Neysayer cause I dont want to do required brake jobs)
 

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Its not a T4 thing its a common fault on lots of different makes.

The rear brakes are not used as much as the fronts and as such this sort of problem is down to the pads rusting down the sides and wedging themselves into the calliper, this makes them work even less and as such, the discs go rusty.

When we get a car in the workshop for a general service, one of the jobs is to inspect the brakes but most garages including main dealers will have a quick visual inspection and if it has wide gaps in the alloys, even better they dont even have to take the wheels off to do this!

What we do is, up goes the car and all wheels off, the pads in whatever condition they look are removed and cleaned, the callipers are also cleaned, then a smear of grease is used on the metal to metal edges before being put back together. This does not take too long and its what we call doing the job properly as the whole proccess of servicing is to pre empt problems and see if we can find a solution to prevent the problem rather than replace parts as they fail.
 

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Discussion Starter · #8 ·
Its not a T4 thing its a common fault on lots of different makes.

The rear brakes are not used as much as the fronts and as such this sort of problem is down to the pads rusting down the sides and wedging themselves into the calliper, this makes them work even less and as such, the discs go rusty.

When we get a car in the workshop for a general service, one of the jobs is to inspect the brakes but most garages including main dealers will have a quick visual inspection and if it has wide gaps in the alloys, even better they dont even have to take the wheels off to do this!

What we do is, up goes the car and all wheels off, the pads in whatever condition they look are removed and cleaned, the callipers are also cleaned, then a smear of grease is used on the metal to metal edges before being put back together. This does not take too long and its what we call doing the job properly as the whole proccess of servicing is to pre empt problems and see if we can find a solution to prevent the problem rather than replace parts as they fail.
Thanks for the information. Do you think that would put more stress on the front brakes? Front discs were changed 5k miles ago because of warping and I had some whistling which would go away as soon as pedal is pressed slightly. Nothing was done to the rear brakes. And now I have pulsing in the brake pedal and whistling again.
 

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In itself, the rear brake problem wont make the fronts any different, but I suppose that you could! Without realising it, you will be braking longer and possibly harder to compensate for not having anything happening at the back end.

All that said above, applys to the front brakes too, a good old fashioned clean up at both ends is the rule with servicing. I have seen people tapping the brake pads into the caliper with a hammer just because they pads were a bit snug and a hammer is quicker than a file down the sides of the pads. Even with a new pad we more than often have to run a file down the metal edges to get a nice fit.

Sort the back end out with new pads and discs, clean up the front end and see if you still have a pulsing, if you do then unfortunately its new fronts again.
 

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Have you considered the bias adjuster (if fitted....not if you have ABS).
These can get rusty and stop working.
Also, if the ride height has been altered, it needs setting up correctly.
Setting requires a 4 wheel rolling road (I think).

You don't say what van you have.
Obviously, a 1200 with no load in the back will hardly ever use the rear brakes.
I "think" there are at least 5 different springs used on the bias adjuster...dependent upon the load rating and ride height.
Mines a 1200.....but very rarely used with that weight.
When I had the suspension lowered, I had to go to VW dealer to get the bias valve set correctly....this was due to Norwegian regs.....also needed a computer readout showing the results.
"Only" cost me around 250 quid....a "bargain" in no-ones head!!!
It did take them 2 hours though!

I've heard of vans failing the MOT in UK....rear brakes not sufficient....2 bags of sand/cement right at the back cured it!!!!
 

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Discussion Starter · #11 ·
Have you considered the bias adjuster (if fitted....not if you have ABS).
These can get rusty and stop working.
Also, if the ride height has been altered, it needs setting up correctly.
Setting requires a 4 wheel rolling road (I think).

You don't say what van you have.
Obviously, a 1200 with no load in the back will hardly ever use the rear brakes.
I "think" there are at least 5 different springs used on the bias adjuster...dependent upon the load rating and ride height.
Mines a 1200.....but very rarely used with that weight.
When I had the suspension lowered, I had to go to VW dealer to get the bias valve set correctly....this was due to Norwegian regs.....also needed a computer readout showing the results.
"Only" cost me around 250 quid....a "bargain" in no-ones head!!!
It did take them 2 hours though!

I've heard of vans failing the MOT in UK....rear brakes not sufficient....2 bags of sand/cement right at the back cured it!!!!
The van is 2002 2.5 TDI AJT. Converted to a camper. It was on a lowering springs when I bought it but now I have it raised quite a bit.

Thanks, I'm hearing about things I didn't know existed.
 

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Always worth a check on anything in the curcuit.

The brake bias sometimes called a proportioning valve or rear brake compensator is sat somewhere in between the rear wheels and its job is to allow more rear braking when you have weight in the van. It is linked to the anti roll bar and as you put weight in, the suspension sinks, twisting the anti roll bar, this in turn pull on the valve to allow more pressure through for rear brakes. When the load is taken out the anti roll bar twists back and so is the valve back to the minimum amount needed for no load.

These valves can sieze but it will usually still work just not adjust, a clean and grease of the linkage is all that it normally needed here but…….. If someone has been playing around with suspension set ups, lowering as such, they may have adjusted the rod to the anti roll bar so it is worth a check on this. Having said that most people that lower things dont touch the brake bias as they dont understand it.
 

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Sorry to p*ss on your strawberries Spike, but not many vans HAVE a rear anti-roll bar.
It's an "optional"...fitted as std to Ambulances (a big one), and a few Caravelle/Multivans.
Std vans never had one fitted.
It DOES improve the handling on corners, as I found out when I had one installed some 14 years ago!
Brickwerks used to have them, but stock seems to have dried up.

The std bias valve has links to the rear suspension arms....that "pull" on it under load, adjusting the valve bias.
It sits almost in the middle of the rear section of the van....well in front of the "axle".

The "Anti-roll" bar ONLY twists when cornering....to avoid "roll".
No matter what load you put in the back, it will NOT twist (unless cornering)....it just rotates in the mountings with the suspenders (err...typo!)
 

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No worries about my strawberries, I dont like them anyhow!
I must admit never realy looked too much at mine as it all works and is clean apart from the grease on it. i was in Citroen mode when typing, these do come from the anti roll bar as they are a height corrector that also helps with brake pressure, no need for a seperate valve on these.

The principle is still the same as it does a pull when loaded and gives more oomph to the brakes.
 

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Yeah, but Citroen have a more complex suspension system (as YOU damn well know!)
VW just "measured" the height of the rear (to compensate for load), and that is all the valve does.
Works (or NOT) for both rear brakes at the same time.

My rear brakes disks often show signs of "minor use" on them......but they must work as it passes the stringent Norwegian EU Kontrol.
 

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Very possibly Spike.....
As from my post, as the rear brakes never do much if not set correctly (and even if they are, very little actual use), there is a fair chance the whole caliper system is seized.
Not sure how the hand-brake normally works (mine's ex-disabled van), has an electric hand-brake....using something like a wiper motor I guess!.
I have (a couple of times) actually driven with it on...and hardly noticed! (As it's an auto-box, I only ever use it unless on a steep hill)
I guess it mechanically operates the calipers.
 

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Discussion Starter · #18 ·
Very possibly Spike.....
As from my post, as the rear brakes never do much if not set correctly (and even if they are, very little actual use), there is a fair chance the whole caliper system is seized.
Not sure how the hand-brake normally works (mine's ex-disabled van), has an electric hand-brake....using something like a wiper motor I guess!.
I have (a couple of times) actually driven with it on...and hardly noticed! (As it's an auto-box, I only ever use it unless on a steep hill)
I guess it mechanically operates the calipers.
Hand brake seems to work without any problem. And the sound is much worse when trying to drive with a hand brake on.
 

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Both rear discs are very rusty
Had a recent similar issue with mine, turned out on mine that the handbrake cables had rusted solid, preventing the free return movement of the brakes pads and cylinders, (at least, that's what I think was happening) not allowing the self adjustment mechanism to operate and transfering most of the braking force to the front wheels, strange as that sounds. Fitting new brake cables sorted it.
 

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Discussion Starter · #20 ·
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Just if someone's interested. I took the wheel off to inspect. Obviously will be changing everything. Back side of the disc looks nice though.
 
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