Bombsquad Posted September 4, 2010 Share Posted September 4, 2010 Working on a b2000, its been for a wof and failed on the rear brakes overpowering the fronts (eg the rears lock up easily and skid while the fronts dont seem to lock at all.) I have no fucking idea whats causing this but have been told it could be the brake proportioning valve?? Can anyone tell us how to adjust this and hopefully fix the issue?? Quote Link to comment Share on other sites More sharing options...
Simon Posted September 4, 2010 Share Posted September 4, 2010 Would be my guess too. Could have had a big load in the back, and the valve decided to put more power on the rear. Then it's stuck and kept the back brakes with more bias than necessary. Or the valve is just faulty. It will be somewhere at the rear and probably have a big spring and leaver on it. Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted September 4, 2010 Share Posted September 4, 2010 if it's slammed or sagged suspension like alot of the extra cab ones are then it'll make the proportioning valve think that there's a hooj load on it. shortening the rod to put it back to somewhere near stock position would help with this. also, if there's a much higher co-efficient of friction to the rear shoes than the front pads then this will also perhaps affect the efficiency readout. as will a small amount of fluid on the rear shoes. I'm thinking it's gon' be a slamme dute though so read the first bit? Quote Link to comment Share on other sites More sharing options...
fuel Posted September 4, 2010 Share Posted September 4, 2010 A variable proportioning valve not being setup for the lowered ute was immediately what I thought it was, but Alex assures me that it doesn't have a rod at all going from the diff to the valve, and that the valve is not variable, and that he's pulled it out and it seems sweet. Quote Link to comment Share on other sites More sharing options...
shizzl Posted September 4, 2010 Share Posted September 4, 2010 our proceed did this when the tyres were naffed in the back... was epic crapping myself in the wet sometimes when you forget that it locks up.. is all good now with good tyres and new front pads,re adjusted the rear shoes.. Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted September 4, 2010 Share Posted September 4, 2010 if it's meant to have one but it's missing, it;ll be rear bias as fuck. Quote Link to comment Share on other sites More sharing options...
Jase Posted September 4, 2010 Share Posted September 4, 2010 if you are sure its not the valve... your shoes may well be at the end of there life, if they have no radius to grip gradually onto the drum they tend to lock up instantly, quick fix-wind your adjusters in go for wof, proper fix-new shoes Quote Link to comment Share on other sites More sharing options...
Bombsquad Posted September 5, 2010 Author Share Posted September 5, 2010 Nah rear pads are still good as, will attempt to wind them in more and see where that leaves me Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 5, 2010 Share Posted September 5, 2010 Biggest reason for locking up rear brakes in vehicles with a light load over the rear wheels (vans, utes) is badly adjusted brakes or contaminated linings. Strip the drums off and check the wheel cylinders are free and not leaking then check there is no diff oil or brakefluid on the linings (replace shoes if there is or has been contamination) If they are clean of contamination then give them a decent cleanup with some brakekleen and scuff up the linings with some rough sandpaper. Reinstall the drums and adjust them up till they just start to lightly drag, stomp on the brake pedal a few times and pull the handbrake on a couple times to recentralise the shoes and readjust till they just start dragging again If they still lock up it could be a bung proportioning valve or master cylinder.. Quote Link to comment Share on other sites More sharing options...
Bombsquad Posted September 5, 2010 Author Share Posted September 5, 2010 Strip the drums off and check the wheel cylinders are free and not leaking then check there is no diff oil or brakefluid on the linings (replace shoes if there is or has been contamination) If they are clean of contamination then give them a decent cleanup with some brakekleen and scuff up the linings with some rough sandpaper. Reinstall the drums and adjust them up till they just start to lightly drag, stomp on the brake pedal a few times and pull the handbrake on a couple times to recentralise the shoes and readjust till they just start dragging again Cheers mate I will give this a go tomorrow. The rear wheel cyclinder on the left side was replaced by me not long ago, pads are in good condition and not contaminated, but the adjustments could well be out. Quote Link to comment Share on other sites More sharing options...
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