Why is my Megane 'Shuddering' when I brake

[MrsH]

In answer to the question about engine size, it's a 1.4 54 plate.

Thanks for everyone's replies, any further thoughts?

[davelowe]

or it could well be the dephaser as mentioned. The former can be done at home, the latter costs a lot. Back to the garage perhaps?

there isn't a dephaser on 1.4 so likely to be throttle body as mentioned or one of the many engine sensors.

Apologies - I didn't read/realise it was a 1.4. Throttle body and discs/bearings are still good contenders. Obviously a code reader would help with the sensors to some extent. A log would be better still.

[colbarnett]

This must be the quote of the week from davelowe I just love it.

Oh, and don't believe anything they tell you unless you have watched them do it!

But how true is that ? as i have found that a lot of garages are compulsive liars, i will say if you find a good garage just stick with them, as it will save you money in the end.

[speedy_glz]

Hello, I have the same problem as you. Mine started one year ago when I replaced the braking pads. That time I took it not with he dealer. There is a workshop specialized in tires & brakes and because I saw one megane there, I left it. After the pads change it started.
I took the car with a steering specialist but he couldt Find anything, the only thing that he told me was: "oh Im amazed because your steering system is so complicated because its all electronic!"
And after taje it with a breaks specialist and nothing. Then I tested it with new discs on both front and rear and nothing

So, the only thing that the dealer told me was that the problem was the pads I had, that had and irregular wear or were releasing a lot of dust.

So I gave up. Hope with the new pads Im going to get, i can get rid of it

[markren2004]

if new discs and pads have been put on and still shudder, either cheap parts have been used, or before putting on the new discs the hub has not been thoroughly wire brushed to remove the existing rust and dirt, this means the new discs do not fit 100% flush and will eventually shudder.

[MrsH]

Well we took the car back to the garage on Friday and they have now put new disks and pads on the back too that's front and back they have done now and (fingers crossed) the shuddering appears to have gone - hooray!!

Also, they cleaned out something (which our local dealer reommended) and it has cured the cutting out issue.

So, fingers crossed that things stay this way and I never have to face those awful men at the car sales place again.

Thanks for all your help and advice.

[davelowe]

This must be the quote of the week from davelowe I just love it.

Oh, and don't believe anything they tell you unless you have watched them do it!

But how true is that ? as i have found that a lot of garages are compulsive liars, i will say if you find a good garage just stick with them, as it will save you money in the end.

A good garage is an experienced one man band who you live near to and know well in a good neighbourhood! I was referring to the dealers and big faceless corporations.

Glad MrsH has it sorted.

[Nige]

It might be that the discs are warped.

Could only be warped Discs...Take it back and demand they be changed with new pads!

[speedy_glz]

What do you men with "warped" discs?

Well, reading all the post of you guys, I found one saying that maybe be the braking force is uneven, and it looks like it is in my car. The front wheels always get more dirty by pads dust than the rear wheels.

And the shuddering continues!!

Lets see what happens on the next brake service

Thanks!

[direstraits]

What do you men with "warped" discs?

Well, reading all the post of you guys, I found one saying that maybe be the braking force is uneven, and it looks like it is in my car. The front wheels always get more dirty by pads dust than the rear wheels.

And the shuddering continues!!

Lets see what happens on the next brake service

Thanks!

The braking force is uneven by default, the front wheels usally getting 70% of the power. So, that's of no concern. The number one problem with fitting new discs is that the disc fitted is not balanced (especially front ventilated discs when coming from no-name companies) or that they have not been installed properly (someone commented on this before: the hub should be thoroughly brushed before fitting so the discs are fitted 100% flush). The other problem you might have is that the calipers and other moving parts have not been cleaned before fitting the new pads. When you first changed the pads you should have checked the thickness of the disc (min. 21,8 mm); I understand that you did not change the front discs first time they changed the brake pads? If they have changed the front discs later but fitted the old pads then you have the same problem: old pads will warp the disc due to their being already shaped after the warped discs. The last but not the least: forced braking in the first 500 or so miles WILL ruin the discs (overheating due to small contact area between the disc and the pad). I have the same problem with the shuddering on front axle (my discs were measured at 22 mm) and my plan for rectifying it is as follows: change the front discs and pads at the same time, clean all the moving parts on the calipers and be very gentle for the first 500-600 miles with the brakes.

I hope this helps.