Brake imbalance

bogart · Jul 20th, 2011, 14:51

Around a week ago my V70 failed the MOT on brake application. Appears offside is weaker of the two and registers 110 whereas the nearside registers 200. Additionally the offside builds up to 110 at a lower rate ie still attaining 110 when the nearside is already at 200. So I stripped both sides down. Calipers look fine, cleaned any rust off them and applied small amount of copperslip to where the pad holders slide in the caliper mounting bracket.
Discs also look fine nice and smooth wear and both same thickness. Both sets of pads hardly used and all wearing evenly. Bled the system, no air was present anyway.
Today failed the retest on same problem. Am a bit bemused as to the possible cause.
Possible causes are pads glazed which in truth they do look to be slightly but all 4 are the same. Did think of a warped disc but that to my mind would cause the application rate to vary not be poor. Sticking caliper to my mind would cause different rates of wear on the pads, all are even.
So any obvious thoughts?
Thanks

Brendan W · Jul 20th, 2011, 15:30

Next on my list would be a sticking piston or a hose breaking up internally.

Peter D · Jul 20th, 2011, 15:53

When you had the pads out did you check the free movement of the piston. I assume you are referring to front brake imbalance. Check the rear pads for the bold failing between the pad and the steel backing plate. If all OK then as the fronts as single pot calipers you may have a Master Cylinder problem. Regards Peter

bogart · Jul 21st, 2011, 14:05

Sorry yes is front brakes. BUt honestly cannot see how a master cylinder fault would only affect one side.

Jul 20th, 2011, 14:51	#1
bogart Master Member Last Online: Jan 31st, 2023 09:51 Join Date: Nov 2003 Location: Languedoc Roussillion	Brake imbalance Around a week ago my V70 failed the MOT on brake application. Appears offside is weaker of the two and registers 110 whereas the nearside registers 200. Additionally the offside builds up to 110 at a lower rate ie still attaining 110 when the nearside is already at 200. So I stripped both sides down. Calipers look fine, cleaned any rust off them and applied small amount of copperslip to where the pad holders slide in the caliper mounting bracket. Discs also look fine nice and smooth wear and both same thickness. Both sets of pads hardly used and all wearing evenly. Bled the system, no air was present anyway. Today failed the retest on same problem. Am a bit bemused as to the possible cause. Possible causes are pads glazed which in truth they do look to be slightly but all 4 are the same. Did think of a warped disc but that to my mind would cause the application rate to vary not be poor. Sticking caliper to my mind would cause different rates of wear on the pads, all are even. So any obvious thoughts? Thanks

Jul 20th, 2011, 15:30	#2
Brendan W Premier Member Last Online: Jun 10th, 2024 09:51 Join Date: Dec 2007 Location: Wexford	Next on my list would be a sticking piston or a hose breaking up internally.

Jul 20th, 2011, 15:53	#3
Peter D Peter D Last Online: Mar 2nd, 2015 21:03 Join Date: Dec 2002 Location: Livingston	When you had the pads out did you check the free movement of the piston. I assume you are referring to front brake imbalance. Check the rear pads for the bold failing between the pad and the steel backing plate. If all OK then as the fronts as single pot calipers you may have a Master Cylinder problem. Regards Peter

Jul 21st, 2011, 14:05	#4
bogart Master Member Last Online: Jan 31st, 2023 09:51 Join Date: Nov 2003 Location: Languedoc Roussillion	Sorry yes is front brakes. BUt honestly cannot see how a master cylinder fault would only affect one side.

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