Brake Judder

[nlm13]

Hi there,

I've just been out for a drive in my wife's Boxster, and noticed that whenever I braked, there was a distinct judder through the the pedal and steering wheel. It sort of feels like the ABS is kicking in even during light braking.

Has anyone else experienced this, or have any idea what could cause it?

The car is a 2005 Boxster S if that makes a difference.

[Trev450]

It will be either pad deposits or distorted/rusty discs. If it's the former, a couple of good hard stops from high speed should cure it. If the latter, then replacement discs will be required.

[Orangecurry]

Trev450 said:

It will be either pad deposits or distorted/rusty discs. If it's the former, a couple of good hard stops from high speed should cure it. If the latter, then replacement discs will be required.

Unless the discs have been fitted recently and poorly, brake judder is due to uneven pad-deposits.

Discs don't 'warp'...unless your wife has parked too close to the Sun.

As Trev suggests, you might be able to clean-off the disc surface with an Italian tune-up, or if the disc has had a 'thick' area of pad material transferred due to the driver sitting at the traffic lights on the brakes when the friction surfaces were very hot, the discs will need replacing.

Make sure whoever does the discs ensures a clean mating-surface between disc and hub, or you'll have vibrating brakes again in a month.

(or it could be failed bushing in the front suspension)

[nlm13]

I thought it might just be build up on the discs, but after a few emergency stops from about 60, it doesn't seem to have made any difference. I think the discs may be needing replaced as the braking seems to be very poor in general compared to how I remembered it (I don't drive it that much).

As the car is out of warranty, is there a recommended disc to replace the OEM ones with? I see Brembo ones are on offer at Eurocarperts just now.

[Trev450]

Brembo are fine. Textar and Serbo are other popular brands commonly fitted. Unless you wanted to upgrade, they are much of a muchness so go for the best price.

[Jonny08]

I had the same issue with my 2014 Cayman S, noticed after taking delivery of the car in October 2015. OPC said it was warped discs and replaced under warranty. There is a thread around here somewhere when I asked the same question as you.

Some people suggested that I get up to speed and brake hard a few times to clean any deposits off the discs/pads, it may be worth giving that a go?

[Fl0pp3r]

Trev450 said:

Brembo are fine. Textar and Serbo are other popular brands commonly fitted. Unless you wanted to upgrade, they are much of a muchness so go for the best price.

Can recommend Sebro for very decent OEM discs.
http://www.sebro.eu/home.html

[johnmaddox]

If your car has backing plates between the pads and calliper it's worth getting these checked. They corrode and lift causing the pad to bind in the calliper which reduces efficiency and a common cause of judder. Happened twice to my 993 over 10 years.

[johnmaddox]

If your car has backing plates between the pads and calliper it's worth getting these checked. They corrode and lift causing the pad to bind in the calliper which reduces efficiency and a common cause of judder. Happened twice to my 993 over 10 years.

[Schermerhorn]

Going to sound like a cheapskate now but try a skim and new pads?

[Orangecurry]

johnmaddox said:

If your car has backing plates between the pads and calliper it's worth getting these checked. They corrode and lift causing the pad to bind in the calliper which reduces efficiency and a common cause of judder. Happened twice to my 993 over 10 years.

The plates on the 993 don't corrode - they are stainless-steel - but due to the design you get bi-metallic corrosion in the 'join' between the alloy caliper and the steel backing plate. The corrosion forces the plate slightly out of position, and because of this the pads jam in-situ.

Does this happen on the later Boxster?

[Orangecurry]

Schermerhorn said:

Going to sound like a cheapskate now but try a skim and new pads?

This can give excellent results (if there isn't too big a lip on the discs, otherwise you may go below minimum thickness) but if any particular area of the structure of the disc has been altered too much by the overheating pad-material fusion, even after skimming this area of the disc will attract more pad material build-up than the unaltered portions of the disc, and it will soon start to form high spots of material, and you are back where you started.

[Trev450]

Orangecurry said:

Schermerhorn said:

Going to sound like a cheapskate now but try a skim and new pads?

This can give excellent results (if there isn't too big a lip on the discs, otherwise you may go below minimum thickness) but if any particular area of the structure of the disc has been altered too much by the overheating pad-material fusion, even after skimming this area of the disc will attract more pad material build-up than the unaltered portions of the disc, and it will soon start to form high spots of material, and you are back where you started.

I'm not a huge fan of having discs skimmed. Not only for the reasons Orangecurry has given, but a new set of stock discs isn't much more than the cost of having them skimmed.

[boxsey]

Orangecurry said:

The plates on the 993 don't corrode - they are stainless-steel - but due to the design you get bi-metallic corrosion in the 'join' between the alloy caliper and the steel backing plate. The corrosion forces the plate slightly out of position, and because of this the pads jam in-situ.

Does this happen on the later Boxster?

I think the plate lift problem only applies to the calipers on our 964s and 993s and the front engine porsches of the time. Not a known issue on any of the boxster generations AFAIK. Known issues for the boxster 986/987 calipers are corrosion on the pad guide pins and the caliper bolts welding themselves to the wheel carrier leading to stripped threads when trying to remove them.

[nlm13]

I did think of having the discs skimmed, but as someone has already pointed out, its just as cheap to get new ones. Currently only £60 each. I think I'll just get them replaced. Just need to wait on a nice day as my garage is too small to work in!

[Schermerhorn]

I usually only pay £10 per corner to get a skim and sometimes forget trade or mates don't apply to everyone lol.

Oh well, if new discs are only £60 per corner, its much more viable to go that route.

[P4TT]

The discs are known to corrode on the inside face.
If after changing the discs and pads, replace the fluid.
If that doesn't work then replacing the calliper seals cured mine.
The latter I bought for a fraction of the Porsche cost from biggred.

[F40GT346]

In my experience a bent wheel rim can also give this effect - harder you brake worse it will be! Worth getting a garage to check the rims and balancing.