Outer Limits 4x4 Board

Just had my brakes done. ( 85` Hilux )

Had front discs machined, new pads, brake lines.
Rear - new drums, brake lines, etc.

The problem --- When I drive the 4by everything works fine, but after about an hour of driving ( thats the weird bit -- why after an hour or so ? ), all I have to do is " touch " the brake pedal lightly and the "front" ( only ) locks up and I end up skidding ?

Any ideas as to why, and how to fix it ?

Thanks in advance.

Take it back and complain to the people that did it. that sounds dangerous to me.

Could be a bleeding issue. Take it back and get their opinion and ask them to bleed the system again (if they did it to start with).

RAY185 wrote:Could be a bleeding issue. Take it back and get their opinion and ask them to bleed the system again (if they did it to start with).

A mate ( mechanic ) did it -- I have spoken to him about it, and he says he will get around to have a look at it BUT -- that could take forever

Putting up my guess on this one.

Fluid would not cause brake lockup to occur.

My first guess would to be look at the brake booster. Maybe it is getting excessive vacuum somehow?

After the brakes lock up, do they just return to normal straight away afterwords?

- David.

Dirty wrote:Putting up my guess on this one.

Fluid would not cause brake lockup to occur.

My first guess would to be look at the brake booster. Maybe it is getting excessive vacuum somehow?

After the brakes lock up, do they just return to normal straight away afterwords?

- David.

No they dont ????
Cant work out why they are ok for about an hour though ????

Has a brake line been re-routed or has a heat shield been removed anywhere?
Have you jacked up the front end and spun each wheel to see if the pads are dragging?

Ssomething getting hot and reducing tolerances. Not sure what in a disk brake assembly. Had a similar issue with Morris Minor drum brakes. They need to be adjusted up as far as possible to provide any braking at all and when done it winter they were great, come summer and one day driving home the wife rang to say the brakes started dragging and eventually stopped the car, unmoveable. By the time I got to her they had cooled enough to allow it to drive again. She however did not cool down for a looonnngg time.

Are the pads sitting in correctly, non of the shims or anything like that sitting crocked that are dragging a little a getting things too hot that something is binding. If you don't find it straight away go for a drive and take a bucket of water with you and if they do it cool them (gently) and see if they start working straight away again.

want33s wrote:Has a brake line been re-routed or has a heat shield been removed anywhere?
Have you jacked up the front end and spun each wheel to see if the pads are dragging?

Brake lines went in exactly the same as they came out.
No heat shields have been removed.
Havnt jacked up the front wheels - will do it this weekend - see what happens

Fester2au : Havnt looked at pads or shims - will do this weekend.

The only thing that hasnt been done are the Calipers ( sp? ) -- could that have something to do with it ?

I would take it back to the mechanic and ask them as they have done the work you dont want to void any warranty by playing with it yourself. It could be something as simple as a piston sticking in a caliper?? but get ya mechanic to look at it

havn't left the clamp on the rear brake line. Asuming it got clamped to remove rear wheel cylinders.

Did they adjust the pedal clearance?

If they did it may cause this as the master cylinder applies the brakes to the front first, if there is not enough clearance they may be partially applied & you finish the job off once you apply the brake causing lockup.

It is critical to have clearance at the pedal.

Could it be that the callipers are now sticking, as the pistons have been pushed back in onto all the crud in the bore.

My old Hilux used to lock the brakes on after about 20min, Turned out it was a flexible line on its way out, allowing fluid to pass to the calliper but not return to the master cylinder.

Sounds like fluid being able to get to fronts but not escape back into master.. like you've got an anti bleed back valve/grommet in the front line of the master cylinder. They're common in drum rears. After the discs get warm from normal driving, then when you apply brakes, the fluid gets to the calliper, but can't release pressure because of anti bleedback. Or the rear and front lines have been put on wrongly at the master cyl... Drive round your area and put the brakes on numerous times to get some heat in them... wouldn't be surprised to see them lock way before an hour is up, as soon as they get warm/hot.