Brake pedal goes up and down when pressed/wobble
 

Hi all.

I replaced my discs and pads a few thousand miles back. The discs were past their best and I was experiencing some wobble/pedal moving up and down and some groaning like Whales mating when braking.

Took my time changing discs and pads, cleaned and copper slipped everything. Drove really gently for a good few hundred miles. All seemed ok. Since then the groan has returned at slow speeds and now the wobble/pulsating/pedal moving up and down under my foot noticeable at M’way speeds and grabby brakes at low speeds.

I didn’t replace slider bolts or shims as they all seemed ok. The brakes are not binding, and the car doesn’t pull to either side.

Does anyone have any theories as to what I’ve done wrong or how to rectify?

Thanks in advance.

What make of discs and pads did you use ?
Did you get any rust build up off your the hub face ?
Did you check hub run out with a dial test indicator ?

Very often with new discs that re warp it’s because the hub face is not flat and square , you fit the new parts and all seems ok until a few heat cycles and the discs starts to take the shape of the warped hub .

Another one .....do you ever coming flying off a motorway and do mega braking to the end of the slip road ,then sit there at the junction or lights or whatever with your foot still on the brake pedal .....this can put massive localised heat into the area of disc where the pads are clamping it ....this can set off a warp issue .

Another one .....DTV.... disc thickness variation , on bedding in new discs and pads they normally have a bedding in surface , in some cases if not done properly the cementite in the pads can bond to the disc causing DTV ....it gives same symptoms as warped discs ...pumping of pedal

It’s said that your not supposed to use copper slip between the disc and hub face it should just be clean and grease free , if anything don’t use copper grease where you have metal and aluminium together e.g aluminium wheel , aluminium calipers and so on..... copper between diss similar metals can cause galvanic corrosion , there are non metallic greases for these purposes like Ceratec , copperslip is ok where it’s metal on metal .

Hi Lee.

Thanks for that. Discs and pads are Brembo. I wire brushed the hub surface before fitting the discs and used copper slip sparingly on the caliper where it meets the shim and brake pad metal.

Previously I’ve bed pads in slowing from 50-40 mph without stopping etc, but this time I just drove very gingerly for a good few hundred miles.

I’m not heavy on the brakes and don’t use them when stopped, preferring the EPB.

Was the Brembo stuff off Euro car parts ?

Yes mate. Why?

Waiting for Lee's educated response with bated breath.
Have Europarts dropped another clanger?
Oh dear, hope that it is a quick and easy fix John.
You know where I am if you need some assistance with the loud swear words

Me too Ray. Lee knows his onions! I don’t know why the reseller would be relevant,... But Lee clearly does.

I’m thinking new slider bolts may be needed. But I’ve no clue. I’m sure brake pads used to come with new shims and slider bolts years ago, maybe I’m imagining it.

Going to need lots of help with swear words Ray. I know you’ve got my back there.

My pad warning light came on twice yesterday whilst pottering around Warrington picking upsome bits for the model railway.
The light stayed off after a restart each time and has not come back since.
Quick visual check they look good so hoping that it is one of the normal D3 gremlins due to over monitoring everything.
Gwen must be improving, be it slowly, she shouted some strange words of a dubious nature that I've never heard before just because I did not hear her the first time she ordered a fresh cuppa :rolleyes:

sounds a bit like slider bolts. I had a similar issue on the W12 D3 Brakes fitted to my D2 and changing the sliders cured about half of the wobble then getting the discs skimmed on the car cured the rest and theyve been great ever since +++

Did you like how I guessed correctly them being from euro hehe !!

Where we can we tend to use genuine parts ....yes yes I know the genuine parts can be mega expensive on some things , we have used ecp since 1988 and back in the day the parts used to be pretty good quality , but over the last few year we use them less and less , lots of under handed going’s on .....Chinese copy parts in Bosch boxes ..... guess which batteries come back for warranty issues more than any other ...yes Bosch .....air mass meters , egrs , crank/cam sensors ,abs sensors , starters and alternators ...we have had more trouble with ecp parts than any other ...LUK clutches and dual mass flywheels going faulty after a couple of thousand miles ....it’s ok them saying take it back out and we will
give you a replacement ( which also will go faulty ) some of these clutch jobs are engines out or very labour intensive ....6 , 7 , 8 hour jobs .....yes we can claim the labour back but at THERE labour rate £30 an hour , we are on £60 an hour so we have to stand that as our loss , we have ended up fitting dealer parts to some of our come back clutch jobs and they have been fine since .
Ecps Padgid brakes have gone down hill aswell ....caused alot of friction with some customers (see what I did there ) .

We fitted some of the Brembo stuff to a few range rovers and some of the bigger cars we do , one set warped , a couple of the others customers complaining about brake fade , some of the others seemed happy enough with them .

I could go on and on with issues , at the minute we only use them for Mann filters and Lemforder suspension parts , any other track rod ends and such steer clear of em ( snigger ).

We have been using Ferodo premier brakes for the last year or so and they seem to be pretty good ,we get these through another local factors .



Architex ......there’s an engineering beauty of skimming discs on the car as the skim will allow for any imperfection on the hub aswell .



Did I tell you the one about the 40 foot shipping container pulled in at the docks full to the top with Chinese copy SKF wheel bearings , perfect copy boxes with the hologram sticker .....wonder where they was headed .........