Technical noise when braking!

[saljet]

Any ideas on this, punto 1.2 needed new brake pads and discs, all changed and bled twice, simple!
Now, when you press the brakes hard there is a grinding/thumping noise, very noticable when inside the car, on the passenger side.
Any ideas would be gratefully recieved

 

[Si1969]

Can you hear what sounds like a pump/motor running for a period at the same time? It could be the ABS is your ABS light coming on after 10 miles or so or before? I wonder if the ABS sensor has been damaged/moved when the pad/disc fitting took place. I have a grinding/knocking type noise when i brake too and am certain it's the ABS. Unfortunately, it's not a cheap fix. The wheel it sounds to be coming from might not be the one causing the problem too! If you google how ABS works you'll soon realise it's all to do with wheels travelling at similar speeds. If a sensor is damaged/dirty & gunked up then it appears the other wheels are travelling at a different speed (the car thinks you're skidding) and the ABS tries to compensate. I'm no car expert, but that was my understanding.
I just have my loss of power problem and ABS light to sort out yet too!!

 

[brenner19]

Any ideas on this, punto 1.2 needed new brake pads and discs, all changed and bled twice, simple!
Now, when you press the brakes hard there is a grinding/thumping noise, very noticable when inside the car, on the passenger side.
Any ideas would be gratefully recieved

Hey I could be way off but your problem sounds the same as the problem I had a few months back I changed the brake pads and discs and when i was breaking it happened but it happened when I turned aswell and u didnt mention that so maybe i'm wrong but mine turned out to be the CV Joint.

 

[Noddy]

Could also be a loose caliper, when you brake hard its snatching the caliper.
May also be a worn or damaged suspension parts.
Best advice would be to take the front wheels of and have a look around at what youve disturbed first.

 

[saljet]

Hi
Thanks for the guidance so far...
I have checked the calipers, all fine
suspension appears to be ok
The grinding/thumping sounds do appear to be at the front of the vehicle, although I am not rul;ing out the rear!
I have just looked at the abs system behind the hub (rear wheel) and it seems to have no teeth and is slightly worn on one side. This said, does it now seem logical that this could be the problem?
I am supposed to be selling the car in the morning.....I am not selling anything that is remotely dodgy, or likely to fail!
The brakes do work perfectly, but the noise is very bad.......

 

[Ralf S.]

Is it likely that the brake pads are not correctly seated in the caliper? I'd take them out and re-fit them.

New pads are sometimes noisy but it would be a fairly quiet grinding noise and disappear when you press harder on the pedal.

The "thump" could be a wishbone bush worn out, or as has been suggested a CV joint.. but it's unlikely to have happened just at the same time as the brake change. Did you (or menders) jack the car up using the wishbone mount? That might have done it.


Ralf S.

 

[Si1969]

Are you hearing a pump/motor running sort of sound when you break and get the grinding/thumping? If it's the ABS then you might notice it even at 20 mph sort of speeds when breaking. If you are then it sounds like an ABS problem like mine. If you get a knocking when going around a corner then it's usually a CV joint - round a right corner (roundabout) will be the left CV and round a left corner will be the right CV joint. The reason it works like that is that those are the turns that put the most stress on the CV at that point. Not a really expensive job - a lot cheaper than the ABS put it that way!

Si

 

[MadMan0]

Other wise check the wheel nuts were tightend in opposites. Our panda had a similar sound to what you discribed. the wheel wasn't tight.

 

[Si1969]

Still think it sounds like your ABS. I had the same symptoms and it turned out that I had to have both rear ABS rings replaced. It's all down to the last time the shoes were changed - there's a natural lip that occurs (like the lip you get on your front discs) and it needs to be taken off where fitting the shoes is concerned or else when the shoes are opened up to fit over the lip the handbrake adjustment is well on the way to it's limit. Because of this it causes wear to the rings and your ABS goes! That's the way i understood it from Fiat. The fact that you'd had your brakes done recently makes it even more suss to me.
Get the ABS checked pal. Bad news is - you're looking at about £220 - £250 for both rear rings and fitting. possibly cheaper if you get it done at a back street garage, but make sure they take that lip off or adjust the adjuster so that your handbrake doesn't have loads of travel or your ABS will be knackered again in the future.
Si