shuddering when braking

fonzooorooo · Post by **fonzooorooo** » Mon Aug 29, 2011 7:01 pm

Our 9n's started developing the tendency to shudder/wobble through the steering when braking down to junctions on fast roads... Perhaps from 50 or 60 down to 30... Not stomping on the brake pedal - just slowing down normally.

I've had a look round it, and the wheels are straight/true as are the discs (first assumed a warped disc)
There's no play evident in the suspension bushes, and I replaced the console bushes last year. (Though I used standard pattern parts, not upgrades)

There does seem to be movement in the slides of the N/S brake caliper - you can grab it and wobble it about, though the slide bolts are tight, this is either wear or slack in the bushes. At first, I wondered if this could be causing uneven braking, but I'm starting to wonder now...

Any thoughts/ideas?

Cheers.

Dub_Dan · Post by **Dub_Dan** » Mon Aug 29, 2011 7:29 pm

from experience in my dads e46 3 series the shuddering happened to him when his pads were purely shot...

just a suggestion...

fonzooorooo · Post by **fonzooorooo** » Mon Aug 29, 2011 9:21 pm

Pads and discs are fine - Getting on for 10mm left on the pads.

benmkiv · Post by **benmkiv** » Mon Aug 29, 2011 9:51 pm

Even if pads are fine I would advise to get the run out checked in the discs. Been through three sets of discs in 6 months through warping/dtv. If you change the discs you must change the pads and ensure they're run in correctly

fonzooorooo · Post by **fonzooorooo** » Tue Aug 30, 2011 6:54 am

benmkiv wrote:Even if pads are fine I would advise to get the run out checked in the discs. Been through three sets of discs in 6 months through warping/dtv. If you change the discs you must change the pads and ensure they're run in correctly

Fair enough... I'll pop the gauge on them.

I was actually wondering if it could be an ABS issue... Thoughts?

88rsr · Post by **88rsr** » Tue Aug 30, 2011 9:04 pm

ive not had the same issue but had for example the abs kicking in even at like 10 mph, youd know if it was the abs due to the terrible noise the pump makes lol,

also had a problem where one caliper had started sticking, and not straight away but after a few motorway miles once the disc had obviously started to become quite hot you could feel a vibration through the wheel as though it was wheel balance, but it was the disc which had become warped so badly, new caliper and discs and pads solved that one, but as i say it was more apparent when the disc had gotten really hot through high speed for an extended period of time,

might be one to keep an eye out for

fonzooorooo · Post by **fonzooorooo** » Wed Aug 31, 2011 7:30 am

88rsr wrote:ive not had the same issue but had for example the abs kicking in even at like 10 mph, youd know if it was the abs due to the terrible noise the pump makes lol,

Nice.In years of driving it, I've never made the ABS cut in on the car... (To the point where I've assumed it doesn't work!)

I'll clock the discs up and investigate replacing the slide bushes in the calipers.

Jollus · Post by **Jollus** » Wed Aug 31, 2011 11:23 am

I find that my ABS kicks in only when on dusty or stoney roads. If you brake suddenly on a slippery surface ABS will kick in. You can feel it in the brake pedal. With regards to the shuddering when braking I had that. It would make a whooping sound at the same time as shuddering when braking. Since ive had new discs and pads, 2 new front tyres (balanced), and tracking done the car seems smooth again!

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