Hi guys,

Looking for some advice. My brakes keep binding, i barely made it home today. The pedal goes really hard with no travel, it does ease up over night but then gets crap again. Iv stripped the master cylinder and rebuilt it. It seems really good condition. but still the same thing. All 4 wheels are locking, not just one. so this has to be the masters fault right? It also seems to only happen when its warmer outside( warm for scotland is 15 degrees lol).
Any thoughts/help would be great

Andy

Yes, if all four wheels lock, it suggests the master cylinder

One cause of locking is the pushrod adjustment. There must be at least 5mm play in the pedal to prevent lockups. See Brake Pedal Adjustment

Do you have a single master or twin master?

always to the rescue ddgonzal. its the twin master

Just seems the pressure just builds up amd doesn't dissipate.....

so new cylinder worked a treat but iv still got a light on in the instrument panel. gets brighter when handbrake is on. Im wondering if its anything to do with the brake fluid level sensor?

Hi Andy, how's the weather in Aberdeen today? Height of summer now being here and all

Glad to hear you've got the brake binding problem fixed

If I recall correctly, you have an early B122 (1982-1989). It should have these caps:



Which light on your dash is on?

haha yup scottish summer at it prime. lovely rain.
So you are correct, that is the caps i have. Its the brake like thats partly on.

So that BRAKE light comes on for two reasons:
* Hand brake on
* Brake Fluid low

To test what is causing it, unplug the leads from the caps, and unplug the wire at the Hand Brake. If it still light up it suggests a wiring problem, maybe a short in the harness somewhere







If, when you unplug this, the light goes out, then it either needs adjustment or is defective

Ah ok, I may have short actually. could changing my dash lights to leds screw anything up?
Also I just jumped in the truck and the pedal has very little travel in it all of a sudden, not locking up yet though

Changing to LEDS can prevent the old-type flasher unit from flashing correctly, since LEDs use less power (watts) than a normal lamp. You can buy special hi-load LEDs, or use an expensive load-independent flasher unit.

But other than that, LEDs should cause no problems, and using an LED lamp for the BRAKE warning light is OK

If the BRAKE lamp glows dimly all the time, it means some circuit is shorting to ground. The BRAKE lamp is HOT (+12V) all the time IGN=ON. It should only glow when the handbrake switch connects it to ground (earth) or when the master cylinder cap sensors connect it to ground. If you disconnected those, and it still glows, the short is somewhere else

The colors shown here are for B110, for the later B120/B122 the wire colors are somewhat different