Fabia VRS rear offside brake not engaging

[VRSwizz]

Hi all, I've been trying to get to the bottom of this for weeks and feel like I've exhausted all possible options so hope someone here can help me out.

My 06 Fabia VRS rear offside brake isn't working at all. When I purchased the car a month ago the brakes felt worn and the pedal extremely stiff,the pads and rotors would make a swirling noise whenever I came to a stop.

So I decided to replace the rear pads and discs. Had a particularly tough time winding back the rear calipers, especially the offside one.

Now the pedal is incredibly spongy and I have to put my foot right down to the floor to come to a stop.

After some strong braking 3 of the discs feel hot and show swept zones, but the rear offside is stone cold. I thought maybe the caliper piston was seizing but after taking it apart and winding it in and out it moves freely, and grabbed on to the disc when I had a friend turn the disc while I applied the foot pedal.

I also now have an issue where the handbrake doesn't engage whatsoever. I have to pull the lever right up to its extremity to get any braking and when I let my foot off the clutch it dips towards the nearside rear, again proving that the offside rear isn't engaging at all.

Please could someone give me some advice, I feel like I've exhausted all options!

Thanks

[AshVrs]

It does sound like your piston has seized. Have you tried manually moving the handbrake lever on the caliper to see if it springs back to its original position?

It also sounds like the brake system needs bleeding with what you've said about the spongey pedal feel. Did you remove the caliper completely? If so have you bled the system?

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[999spender]

Handbrake lever mechanism is seized not the piston.

Search on here for helper springs and you'll find loads of info.

[VRSwizz]

Handbrake lever mechanism is seized not the piston.

Search on here for helper springs and you'll find loads of info.

Excuse my ignorance, how would this be affecting the hydraulic braking system?

[VRSwizz]

It does sound like your piston has seized. Have you tried manually moving the handbrake lever on the caliper to see if it springs back to its original position?

It also sounds like the brake system needs bleeding with what you've said about the spongey pedal feel. Did you remove the caliper completely? If so have you bled the system?

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Never removed the caliper, and not quite sure how any air would have entered the system. I'm a bit confused as to how the pedal could go from feeling stiff to completely spongy when all I did was replace the pads and discs.

[AshVrs]

My knowledge is a bit limited here, but I have had a similar problem.

My caliper piston was corroded which was affecting the operation of the foot brake and the handbrake. The handbrake mechanism would move manually (by hand), but only just, and it was incredibly stiff. There didn't appear to be anything wrong with the handbrake mechanism, it just couldn't effectively operate the piston.

This didn't however cause any brake spongeyness, I just knew it was there due to the slight brake squeal I had.

If you check the handbrake adjusting mechanism under the ashtray at the rear of the handbrake lever, a good indication you have a problem with your handbrake operation is that the cables going to the rear calipers with be on the slant meaning one is operating and one is stuck (obviously depending on whether the handbrake is stuck on or stuck off on one caliper).

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[AshVrs]

Never removed the caliper, and not quite sure how any air would have entered the system. I'm a bit confused as to how the pedal could go from feeling stiff to completely spongy when all I did was replace the pads and discs.

Yes so am I as this does sound like a tell tale sign of air in the system? If I'm honest mate, I'd just be inclined to buy a second hand caliper and replace it. I got one off ebay for £20 delivered and this saved me any further messing about.

I'm far from an expert though so I'd just hang fire till some other members have a chance to post (if you can afford to wait that is).

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[Tech1e]

Put a new caliper on.

[VRSwizz]

Just disconnected the offside rear ABS sensor and now the pedal feels much firmer and the brakes seem to be biting a lot more responsively. Could this indicate a dodgy ABS sensor and possibly be explaining my spongy pedal and ineffective offside rear braking?

[coskev]

Just disconnected the offside rear ABS sensor and now the pedal feels much firmer and the brakes seem to be biting a lot more responsively. Could this indicate a dodgy ABS sensor and possibly be explaining my spongy pedal and ineffective offside rear braking?

I doubt it.

As above your handbrake mech in rear caliper is sticking,so it's not returning fully to the off position,this then stops the caliper/handbrake mech auto adjusting.

Knock the handbrake arm back to the stop on the rear calipers,then pump the brake pedal a few times,then try your handbrake.

For the price of calipers I would put a new pair on,and fit the helper springs to them

[VRSwizz]

I've found the culprit! Turns out the rear offside ABS speed sensor had snapped and become defective. The sensor cable was plugged into the socket but the plastic arm coming from the mount had snapped, exposing two of the prongs. 

This would be consistent with the brakes working effectively when the engine is switched off, as well as when I removed the ABS fuse.

There are pictures below. Do you guys think this would be causing the spongy brake pedal as well as reduced braking performance?

I figured if the speed sensor couldn't accurately measure the wheel speed, then this would cause the ABS to prevent the brakes from applying properly.

I guess I'll just buy a replacement speed sensor for the LH rear and hope that resolves all of the problems.
 

 

 

 

Edited 22 November, 2015 by VRSwizz

[coskev]

If that sensor was not working your ABS light would be lit on dash to let you know there was a fault?

Won't have anything to do with your brake issues.

[VRSwizz]

If that sensor was not working your ABS light would be lit on dash to let you know there was a fault?

Won't have anything to do with your brake issues.

The ABS light wasn't on previously but has now come on since I removed and reattached the ABS speed sensor. I'm wondering if the connection was previously intermittent and has only started being an issue since the weather has been worse.

[Toxicvrs]

Not a hope in hell of being related to your braking issues. It's the calliper and handbrake unit on calliper ffs

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[DanHarper]

Put a new caliper on.

 Listen to this man

[coskev]

The ABS light wasn't on previously but has now come on since I removed and reattached the ABS speed sensor. I'm wondering if the connection was previously intermittent and has only started being an issue since the weather has been worse.

LOL,as I thought you've broke the sensor either removing or refitting the plug

[Toxicvrs]

LOL,as I thought you've broke the sensor either removing or refitting the plug

Didn't release clip properly pulled a bit fierce and off comes the weak old plastic :P

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[coskev]

Didn't release clip properly pulled a bit fierce and off comes the weak old plastic :P

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Bingo

[VRSwizz]

LOL,as I thought you've broke the sensor either removing or refitting the plug

It has been as pictured since I bought the car. I slid it off the exposed prongs the very first time I found this issue as the plastic was already broken and it was hanging precariously on the prongs.

Edited 22 November, 2015 by VRSwizz

[Toxicvrs]

It has been as pictured since I bought the car.

Well you've disturbed something if the light has only just come on, so you need a new sensor and then need to solve the original problem which is with the calliper

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[VRSwizz]

Have ordered a replacement abs speed sensor. Going to fit this and see what effect it has. Calliper and caliper handbrake mechanism seem to be moving freely and engaging fully, and brakes were operating without any issues when engine was switched off, so i'm hopeful that for some reason the ABS is affecting the rear offside brake when engine is on.

[Toxicvrs]

The ABS will not effect it. How did you inspect they were moving freely?

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[VRSwizz]

The ABS will not effect it. How did you inspect they were moving freely?

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When i engaged the handbrake the handbrake mechanism on the back of the caliper was fully tightened, this then fully returned to the open position when the handbrake lever is down. I took the caliper in question away from the disc and pads and inserted the winding tool in an attempt to let what I then thought was a seized piston move slightly back in to try and free it up. The piston seemed to move freely when the brake pedal was applied.

I then fitted the caliper back on to the pads and discs with the wheel still off, put the wheel nuts in and used a breaker bar to turn the hub while my friend applied the the brakes. The calipers were fully engaging the pads onto the discs and stopping any rotation. 

This was all while the engine was off and seemed to indicate that there are no problems with the caliper or its piston. It's hard to determine if any braking is occurring as the disc is significantly cooler than its counterparts after extended braking. I can't work out whether it is not engaging at all, or just engaging very little.

Also, since the ABS warning light has come on - the pedal sponginess has disappeared - the brakes now seem much more responsive and with more bite. However, after the initial braking effect, the pedal continues to sink down with sponginess.

[Toxicvrs]

The ABS system will not affect it, and as such system will only be active under emergency braking situations

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[VRSwizz]

Is there a chance it's linked to the fact that the handbrake doesn't work then?