Pox brakes on 90 ln111 where to start?

[johnboy]

Brakes are average in general were worse till i fitted new shoes and bitey ferodo pads now if you apply them gradually they pull up but if you stab at them ie emergency death avoidance the pedal goes rock hard and no stoppy stoppy like the booster is not there. have checked and the booster holds vac so no perforation only thing i can think of is the vac pump is rooted. took to a brake place for a second opinion the following conversation took place


after a quick description of symptoms i suggested that he
" take it for a drive"
after returning with a look of total panic on his face
"they are really bad huh"
"yeah, what do you think is causing it"
"dunno i wouldnt keep driving it"
"leave it here and we'll swap stuff around till it comes good"



after explaining that i couldnt leave it as i needed a second opinion he got all shitty and i left
iwasnt so keen on the open cheque book scheme so has anyone here come across this issue before

please i need some advice


Cheers John

[dipmaker]

If you have raised the rear of the vehicle at all the proportioning valve may need adjusting, that is the rod that goes from the chassis to the diff.

[johnboy]

that wouldnt affect pedal feel just braking force plus ive cable tied it fully open to check and no difference

[Troopy93]

Master cylinder could have a rusty piston, how long since the fluid has been changed,partially siezed calipers, could be any number of things.

[Sic Lux]

Master cylinder could have a rusty piston, how long since the fluid has been changed,partially siezed calipers, could be any number of things.

Being a toyo run ONLY DOT3 as it says o the cap could be something thats caused some of the problem i'd be looking at vacuum pump or maybe still booster if it still holds vacuum the pump will be working but get it to a bake shop and see what they think get it towed if you have to.

[v6hilux]

If your tyres are bigger than 29.5" Road Grippers, then that could also be a problem.

The bigger the tyres, the more leverage, (like a 3' bar extension on a spanner), the wheels have and less breaking effort is available!

[thehanko]

now i could be wrong but

I wouldnt think:
tyre size would effect pedal feel.
brake fluid would effect pedal feel much, and is more likely to be a soft feel than hard if there are any fluid issues.
Pads shouldnt effect pedal feel.
worn master or slave cylinders would make the pedal drop slowly but not make it hard.

I would think.

if its a hard dead pedal:
could be something seized or stiff like suggested but if thats the case, then brakes would possibly stick on a bit as well.

To me the only thing left is:
Sounds like the booster is stuffed. try removing the vacume line and see if it still feels the same. this will indicate if the booster is doing its job or not. if it feels the same then drop a second hand booster in.

Is the vacume line on these from the motor or is it a seperate pump? either way check to see if they are creating a vacume.

[johnboy]

googled it and it seems this is a common problem and no real definative answer think ill swap in a new vac pump and go from there brakes feel fine till you apply them hard so my guess is that there is vacuum just not enough when under load

[johnboy]

i have brakes again fitted rebuild kit to vac pump ($100) got good vacuum again replaced leaking rear wheel cyls ($48) new master cyl ($86) still rubbish brakes replaced booster with 80 series booster now have face prints on wind screen apparently the diaphragm inside stretches and although it still holds vac it doesnt activate assistance properly so hope this helps anyone else with similar probs
cheers John

[dipmaker]

Thanks for letting us know that John, I think just about everybody with a hilux has similar problems.

[Yumsylux]

thanks for the followup mate. What model lux was that? Mine's a ln106 and I think i must have similar prob. Did yours pull left or right when you braked? I'm guessing it'll be a caliper prob but I also have that woody braking prob too.