New discs with 300 mile old pads running in ??

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thedadio
Posts: 14
Joined: 13 Feb 2005, 00:06

New discs with 300 mile old pads running in ??

Post by thedadio » 03 Mar 2005, 04:26

Hi I need a bit of help, after somehow damaging my original well worn discs with crap pads and incorrect bedding in, i decided to buy cheapo discs and attempt to run them in with the new cheapo crap pads, again not following any sort of run in process.. MAJOR judder througout speed range. Removed discs cleaned mating sufaces completley, still judder. So changed pads for Lucas much better quality, and cheaper than the cheapest pads i could find, and i bought them from a Lucas shop!. Even more judder. These were changed in cornwall 1 hour b4 a trip back to slough. Major judder at any speeds, light braking from 90 felt like driving over multiple speed humps and the steering wheel didnt know which way i wanted to go. Minimal Run-out b4 fitting.
Replaced discs with 12.49 each ones, still have the lucas pads on, ive only done 20 miles of town driving with very soft braking.
No judder wobble at all,
Any tips on running-in this new setup? I cant afford another set of discs and pads, nor can i handle a 9 th time this week taking apart the brakes in the snow!
Cheers

jeremy
Posts: 3959
Joined: 20 Oct 2002, 16:00

Post by jeremy » 03 Mar 2005, 15:59

general advice is to brake gently for about 250 miles. Object is to avoid sudden or excessive heating of the disc so no crash stops or gentle long braking down steep hills.
jeremy

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Kowalski
Posts: 2557
Joined: 15 Oct 2003, 17:41

Post by Kowalski » 03 Mar 2005, 16:56

Did you look at your caliper slides?
Brake judder on Xantias is often a sign that the caliper slides are sticky and need some oil/grease putting on them. Brake discs ALWAYS have some run out on them its inevitable, the calipers have to be able to cope with a certain amount hence they're able to slide. Search the forum for more info, including how to sort out sticky slides.

ItDontGo
Posts: 253
Joined: 20 May 2004, 04:58

Post by ItDontGo » 03 Mar 2005, 21:47

Maybe you didn't have the first set of discs fitted very well. Maybe there was some dirt or rust behind them which made them go on at a slight angle.
I know that to bed the brakes in on a race car you want to brake very gently but get the pads absolutely fried. However if you do fry the brakes you then must keep the car rolling to cool them down before you stop or the heat transfer through the pads will warp the discs. You will know when they are hot because they will stink. Thats kind of the quick way to do it if you dont have 200+ miles to potter around without braking hard.

CommY
Posts: 119
Joined: 29 Aug 2004, 23:18

Post by CommY » 04 Mar 2005, 01:07

When puting pads from different disks on a car I always get some fine abrasive sheet on a flat surface and take the top off the pads until there is a flat clean surface to the friction material. This is also a good solution to rear pads that have worn with a camber due to corrosion build up, or pads that have been glazed by the excessive heat of over enthusiastic braking.
I then run them in as you would new pads, this has always worked OK in the past.