A Funny Thing Happened On The Way To Work

[bigjohnh]

This morning on my daily drive to work my brakes started behaving strangely.

The symptoms are that with initial application there is little or no effect and I have to press quite hard at which point I get strong braking. A bit disconcerting for whoever is following but I will take it easy on the way home tonight.

I will have a look at them in the morning, in the meantime any ideas?

John

[rowanmoor]

1) Air - as in they need bleeding? If that is the case then the effect is actually that when you first put your foot on the brake it does nothing and then after a while they come on, but before that you have instinctively pushed harder. However, why would it have suddenly got air in both front and rear like that and to that extent?

2) Sticky Doser valve? Am I right that there are a load of springs in there so if it has gone a bit sticky then it could well explain it.

Mine did something similar (less exaggerated by the sounds of it) a while ago for a couple of weeks and then went back to normal. I haven't thought about it since.

[rowanmoor]

Oops - double post due to our silly firewall here giving timeouts.

This post has been edited by rowanmoor on November 16, 2007 05:35 pm

[techmanagain]

If not air in the LHM system, it is likely to be a split diaphragm in a sphere discharging into the system. Probably main accumulator
The only other alternative is a sticking doseur valve operating lever - not entirely unknown on RHD models.

[bigjohnh]

It sounds like the symptoms of air in the system, delayed action brakes although it was much better on the way home. I will bleed the brakes as a start.

Looking at the haynes manual it says to get the car off the floor and bleed the brakes with all 4 wheels off. Can I do one wheel at at time using 1 jack and 1 axle stand as I think this is safer for the home mechanic?

John

[techmanagain]

CAN be done that way, but it will take for ever and a day! Start with the rear brakes and make sure you get clean, bubble-free LHM comng through before going to the next. If you do the two rears together, set the height to max so that the bumpstop rubbers are solid to the suspension arms.