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Vibration when braking above 50mph


adammitch69

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Morning Gents,

The past 2 weeks I've noticed a vibration coming from the front wheels when I brake above 50mph. One of the wheels has a higher build up of brake dust so took the wheel off and took the pads out to look for un-even wear. everything looks ok, both pads are same depth and no marks on discs. Everything (DS2500 and EBC Turbo) was new in Feb.

When I spun the hub and watched the disc inbetween the caliper there seemed to be a very tiny bit of eliptic movement, only a **** hair if anything.

 

Any ideas of what this could be?

The car still brakes ok but obviously having the steering wheel shake when breaking heavy cant be good.

 

cheers

Adam

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I had this braking from motorway speeds, a vibration through the wheel from 70-40mph ish.

 

I then had new tyres fitted and balanced. It went away.

 

It may be just a balancing weight has fallen off - I'd get wheels balanced before assuming the worst.

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read Steve's thread and it sounds like the same problem with the same discs!

It started after about 4000miles from new which is a bit annoying.

 

hopefully getting the discs skimmed will fix it - i'll PM Steve as we are both in West Yorkshire.

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I'm still struggling to find someone who is actually willing to skim the discs.

 

I haven't had any response from EBC as to if they can identify someone who is willing to skim them, I can't seem to locate a phone number for them either.

 

Just for information the runout on mine where the problem is coming from is 0.36mm so to the naked eye looks like nothing but is a lot in braking terms. Spec for rears is 0.07mm and front 0.05mm. The root cause is hub runout caused by a bump to the kerb during the snow.

 

Replacing all the parts isn't garaunteed to remove the problem completely because of the tolerances in the assembled parts so a skim may still be required even with a new hub carrier, hub, bearing and disks. I work in engineering and a lot of tolerance stackups are based on statistics and in some instances you will just be unlucky.

 

A skim of the disks on the vehicle is the best solution if you are suffering any disk runout provided the disks are fairly new or you have enough meat left on them so they can be skimmed and won't go close to or below the minimum thickness.

 

Obviously first check you haven't mounted the disks on a dirty hub!

 

I'll let everyone know if I find anyone who will skim them up.

 

Cheers

Steve

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There is no such thing as warping of disc in modern cars ;) Its all DTV (disc thickness variation) which is manifest as RO (run out) which the classic symptoms when braking. The tolerances between the hubs and disc/pads worsen by wear and tear, kerbing, bumps etc and with time/age and leads to RO.

 

The prevention is always is to match new disc and pads to the hub on the car by checking the RO and skimming the disc is there is any significant DTV.

 

You should check for other causes of vibration by a thorough exam of the tyres, wheels, pads, hubs on and off the car and sand off any rust or crud deposited between mating surfaces. also check for any suspension play the wheel off the ground.

 

See this post for all full or where to get it done. Since i had mine done by Procut there has been no issues since :thumbs: I was lucky they could arrange for me to meet their mobile engineer who was scheduled to provide training at a local garage in Worcester and so my zed was used for demo and therefore had a discount ;)

 

viewtopic.php?f=17&t=32481&hilit=disc+thickness+variation&start=15

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The prevention is always is to match new disc and pads to the hub on the car by checking the RO and skimming the disc is there is any significant DTV.

I agree, it wont be warped discs. 2 options are pad build up (look for pad shaped marks on the discs) or DTV. If pad build up then bedding in the brakes again should remove it. If its DTV then you need to get them skimmed. Obviously when you fit the discs you need to check the RO and skim them accordingly otherwise it will lead to DTV. You shouldnt have any DTV when the discs are new otherwise you have some really poorly made discs!

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wow, i just thought that disks got warped if over heated :shrug:.. now there's even more abreviations and acronyms to learn!

 

Note to self, don't use brakes until topic learned :lol:

 

PS apologies to the original poster, i did click on to try and help :surrender:

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Hallelula!!!!! :yahoo::yahoo::yahoo:

 

I have found someone who will skim drilled and grooved disks who is fairly local!

I've only called about twenty places....

 

Touch wood, but it doesn't look like I'll be having to take a trip to EBC in Northampton.

 

I'll post up details when done, I'm going in tomorrow afternoon.

 

Thanks

Steve

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Right all sorted now :teeth:

 

It cost me £85 for the rear discs skimming.

They quoted me £48 per hour + VAT. They thought it would only take 45 minutes but because the nearside rear was very bad they had to do a number of very small skims so took 90mins in total. One side twenty minutes the other an hour + ten minutes set up and re fit of wheels.

 

I no longer have vibration or jerky braking as I had previously.

 

I used:

 

K N M Motors Ltd

Deanfield Garage

Leeds

LS27 9QS

telephone: 0113 253 5608

If anyone is looking for their brakes skimming and struggling to find somewhere like I did, they WILL do drilled and grooved also and have a Procut machine.

 

The garage setup seems rather good, all equipment looks to be in good nick, the owner is sound and the guy who did my car was sound too.

I will definately be using them again probably for the MOT. Its also good to support the local family businesses.

 

I'll get the DTI out at the weekend and check runouts for actual values.

However I can tell its a lot lot better, brakes have more bite even with just light braking I am currently applying.

I am ensuring the discs are fully stress relieved from the machining residual stresses before getting some proper heat into them.

 

Overall well happy!

If anyone has any questions just drop me a PM.

Cheers

Steve

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