Fabia 1.4 MPi baffling brake problem, urgent help needed!

[Rob_OctaviavRS]

Hi everyone, 

 

My dad has a mk1 fabia 02 plate 1.4 MPi.

 

He has had a garage change the wheel bearings due to a droning/vibrating noise from the front end.  During doing this, the garage has made a bit of a mess and to cut a long story short, hes now left with a bit of a problem on the car.

 

They have hammered the wheel bearing in rather than press fit it and seem to have caused a fault with the brakes which I cannot find.  

 

When I picked it up from the garage for him, the ABS light came on, and I got the red warning light also and the beeping sound, and feedback through the pedal as if the ABS was kicking in.  

 

Since then, I've personally replaced both front hubs complete with bearings and ABS kit (I'm sure they've used the wrong bearings, and to be honest I don't want the car ever going back there again) and replaced both ABS sensors with brand new ones.  I've also replaced the driveshafts and CV's as this turned out to be the droning problem in the end, the drivers CV was completely shot.

 

Now, there are no fault codes stored, and otherwise the car feels fine.  But as soon as you brake, it feels as if the ABS is kicking in and pushing the pedal back at you, which obviously isn't right.  The car braked fine before it went to the garage and I've replaced both hubs and ABS sensors, so I'm a bit baffled, the scanner shows no ABS codes at all. (I've got a decent scanner).  He hasn't used the car for around 8 weeks now due to this issue, I've lent him mine when he needs it, but surely this can't be affected by how much its used surely? I know it can cause rusty discs, but not brake feedback.  I've driven the car tonight and its quite horrible really, but no codes appear, so I'm pretty stumped really and I don't want to spend a fortune, just hoping its not the ABS pump or anything like that.

 

Has anyone got any ideas or advice, as I've ran out myself now, and I wanna get the car sorted for him ASAP!!!

 

Cheers! :clap:  :p

[Tech1e]

Need to get it on VCDS and see which wheel is slower than the rest. This will then give you an idea which corner to look at.

[sepulchrave]

Are the tyres all exactly the same size all round?

[Rob_OctaviavRS]

Hi, tyres are all the same size premium brands matched pairs front and back, All was well until the bearings were fitted.  Wondering if it could have damaged the ABS pump on the drive back from the garage due to the bad feedback it was putting out through the pedal?

[Breezy_Pete]

How did you fit the hubs/bearings that you fitted?

[Tech1e]

Hi, tyres are all the same size premium brands matched pairs front and back, All was well until the bearings were fitted.  Wondering if it could have damaged the ABS pump on the drive back from the garage due to the bad feedback it was putting out through the pedal?

I doubt it, it's just the system operating as it is designed to. The car is assuming due to a poor signal (not electrical fault) that the wheel has locked. My money is on the bearing not being pulled in fully so the air gap in between the pick up on the bearing and sensor is too large.

[sepulchrave]

Has to be an issue with the reluctor rings on the front, they may have been damaged when the hubs were changed.

[Rob_OctaviavRS]

The hubs I've used were guaranteed salvage units complete with bearings already fitted.  The ABS sensors are brand new items, and all previous codes have been erased.

 

What about the sensors themselves? Is it possible if I used the wrong ones this could be a symptom of an incorrect sensor?

[Tech1e]

Have you got left in the left and right in the right? You can mix them up, they will still fit but won't read.

[Rob_OctaviavRS]

Thats a point! I'm sure I put them in right, but its worth a look I guess! I'll have a look at that this morning and post back later today. Cheers

[Rob_OctaviavRS]

Sensors checked, all as they should be, they will only fit one way due  to the way the electrical plug connects.

 

Driven again and it feels as if the abs is kicking in all the time every time you brake.  I haven't got VCDS so I can't check the signals etc and to be honest I wouldn't know what I was looking for anyway.

 

I can't see the reluctor rings being damaged as both front hubs have been changed and the exact same fault is still there.  No abs warning light or codes still.  If I disconnect either sensor it throws the light and drives fine (obviously without the abs working) but as soon as the circuit is connected up the problem starts.

[Tech1e]

I think it is possible to get them in backwards, One of our members has had exactly the same symptoms and has found he put a left sensor backwards in the right side so that gave him the wrong air gap.

[felicia16v]

It is possible to fit the wrong sensor.. also had problems with cheap sensors not working properly. Until you can get vcds on and look at the wheel speed data you are just guessing at it..