Page 1 of 1

Hilux brakes with prop valve

Posted: Sun Nov 29, 2009 4:21 pm
by NIK
Im trying to get my brakes sorted for the rta.
I got a brake test that checks the braking force on each wheel and the passenger rear only had about 18%.
I took the brake cylinder out and 1 side was siezed so I cleaned it up and put some brake lube on it but they still arnt any better. The piston that was seized still dosnt move unless I hold the other brake shoe still.
It dosnt look like there is any brake fluid leaking past the cylinder seals and they are properly bled.
I have a prop valve for the rear line just after the m/c then the single line splits into 2 at the t piece at the diff.
Could it be possible that the magority of the brake fliud is going to the nearest side?
Nik

Posted: Sun Nov 29, 2009 6:43 pm
by NIK
I had another good look at it.
I rebled the rear brakes (both sides) adjusted the shoes out as far as I could before putting the drums back on and it was the same.
There is a small kink in the hard line going to the passenger side but it still bleeds easily.
I jacked up the driver side for a comparison and im positve it locked hard and I couldnt turn the wheel by hand.
So we swapped the drums side to side to see if maybe the kink in the line was causing it or the drum was too worn.
Now both sides can be turned by hand with the brakes on.
Also I opened the brake prop valve completely to eliminate it but its still the same.
Nik

Posted: Mon Nov 30, 2009 12:33 am
by mr green
hey NIK, just cause no one else has replied i thought i'd have a go! :P
firstly it won't matter how long or short the pipes are. the pressure will be even through the system with your foot on the brake.
by the sounds of it your are adjusting your shoes and then fitting the drums? is there any lip on the drum? i usually take them up as much as possible before fitting the drum and then adjust it through the peep hole in the backing plate to the point that you can hear the shoes starting to touch the drum at rest.
also how is your brake pedal feel. i would think it must be fairly low if you havn't got any braking effort at all in the rear. if so it will come down to adjustment or air.
i wouldn't be worried about the shoes not moving at the same time with the drum off. it will move the easiest shoe but with brake effort they will be even.
i think if you are positive there is no air in the system and your brakes are adjusted correctly and you can still turn the wheel by hand with the brakes on, i would pull the hose off at the back and see if you can stop the fluid coming through by hand. if you can restrict the flow i would think you have a clagged master cylinder. even though i know you just fitted the suby version.
finally, when im bleeding brakes i only use about 2/3 of the pedal travel to avoid running the mc cups over crap that they don't usually come in contact with.
jason.

Posted: Mon Nov 30, 2009 4:51 am
by NIK
Thanks mate.
Yes Im adjusting the shoes as far as I can till you have to almost force the drums on and you can feel they are just grabbing.
There is no lip on the drums but I thought maybe they were too worn but the pedal is only moving bout 2-3" max before going hard so there is plenty of travel to push more fluid.
So you mean pull the line off and put my finger over it and get someone to pump?
Nik

Posted: Mon Nov 30, 2009 5:57 am
by 11_evl
i am having the same problem after fitting the suby M/c
i have an alright pedal, but practialy no braking force. if i clamp off the front and just have the rear there is pretty much nothing.
front only and it bare;y stopps. i might go back to sierra one, it worked great

Posted: Mon Nov 30, 2009 8:05 pm
by mr green
NIK wrote:Thanks mate.
So you mean pull the line off and put my finger over it and get someone to pump?
Nik
thats what i'm thinking. if you have zero braking at the rear you must have a major drop in pressure somewhere.

Posted: Tue Dec 01, 2009 4:56 am
by NIK
I turned my prop valve ALL the otherway to check it was nothing silly like it was marked wrong but it didnt change so I,l take the drums off and get them looked at today.
Nik

Posted: Wed Dec 02, 2009 6:38 pm
by NIK
All fixed guys, I adjusted the brakes with the drums and rims on now they work :oops:
Nik