Member Since: 10 Apr 2005
Location: Near Bristol, UK
Posts: 433
Uneven brake pad wear , what are the things to investigate
Just changed the brake pads and the passenger side were worn almost to the plate but the drivers side not down to the bottom of the wear indicators ( photo should be attached ) . What are the possible causes and things to investigate. The pistons did go back in but did seem harder to retract on the most worn side so i was thinking perhaps the callipers were seized but no idea how to test as the pistons went right in when i replaced the pads. So a bit confused , any advice appreciated.
24th Jan 2016 11:37 am
sputnixb51
Member Since: 23 Apr 2013
Location: Morayshire
Posts: 833
Usually the first signs of a calipers beginning to sieze and difficulty pushing back the piston rather than how far back is another clue if it hasn't gone far enough back you wouldn't get the calipers back on over the new pads, the other thing to cause such a problem is the slider pins seizing but not so common on the D3 as it used to be on the D2. I have had X 3 calipers sieze in the last three years X 2 rears X 1 front.
24th Jan 2016 12:00 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
See it a lot on the trucks, nearly always down to air trapped in the slider gaiter, sounds weird but they build the calliper up and its carrier then fit it, if the calliper slider is built up in the extended mode it traps air at atmospheric pressure so when the calliper is fitted the very low air pressure holds one pad against the disc very lightly, but enough to cause uneven wear.
We use a needle to release the pressure, the rubber gaiter being silicone seals the hole up.
I would clean and lube the sliders, not with copaslip and monitor their progress, if not happy new callipers are pretty cheap.
24th Jan 2016 12:24 pm
cmyers_uk
Member Since: 10 Apr 2005
Location: Near Bristol, UK
Posts: 433
Thank you both for the replies , ill try the sliders and lube first and as you say a new calliper is less than £100 . it was very hard to push the pistons back in on that side , so perhaps thats the simplest and easiest thing to do , through some money at it
Cheers
Chris
24th Jan 2016 1:49 pm
cmyers_uk
Member Since: 10 Apr 2005
Location: Near Bristol, UK
Posts: 433
ohh one more point if i go down the calliper route do you change both at the same time, my assumption is its fine to replace just the one thats seized but thought id check as its brakes
24th Jan 2016 1:51 pm
Dusty
Member Since: 23 Sep 2013
Location: London
Posts: 1022
You can just replace the side that's seized, but as they are not too exspensive I change both sides at the same time. My theory being if one is on the way out the other side could possibly be not far behind, and it can only promote more even braking. Although as with all components one caliper could quite easily last much longer than the other.Discovery 4 HSE
SDV6
2015
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